Catenin alpha 1 (CTNNA1), encoding α-catenin, is involved in several physiological activities, such as adherens junction synthesis and signal transduction. Recent studies have suggested additional functions for CTNNA1 malignancies. This review systematically summarizes the varying functions of CTNNA1 in different tumors and briefly describes the diverse pathways and mechanisms involved in different types of tumors. CTNNA1 is abnormally expressed in leukemia and solid tumor such as cancers of digestive system, genitourinary system and breast, and it's related to the occurrence, development, and prognosis of tumors. In addition, the possible physiological processes involving CTNNA1, such as methylation, miRNA interference, or regulatory axes, similar to those of CDH1, SETD2, and hsa-miR-30d-5p/GJA1 are also summarized here. The precise mechanism of CTNNA1 in most cancers remains uncertain; hence, additional pre-clinical studies of CTNNA1 are warranted for potential early tumor diagnosis, prognosis, and treatment. Cancer is one of the most life-threatening diseases CTNNA1 is widely expressed in normal human tissues Immunohistochemistry assays reveal that CTNNA1 expression is decreased in colorectal cancer (32/82) compared with that in normal colorectal mucosa and colorectal adenoma 8/10). Meanwhile, CTNNA1 expression decreases or is very low in lymph node metastases (6/10). This suggests that low CTNNA1 expression correlates with lymphatic metastasis, poor differentiation, and poor prognosis of colorectal cancer . MeanwhiAlmost all intestinal adenomas from familial adenomatous polyposis (FAP) mouse lines that carry a truncation mutation at codon 580 in adenomatous polyposis coli (Apc580D) have both CTNNA1 and adenomatous polyposis coli (APC) gene deletions. Furthermore, loss of heterozygosity (LOH) of CTNNA1 is obtained in the cis configuration of mutant APC, a mutant construct of APC in intestinal adenoma, except for one cell line with almost normal α-catenin expression. Somatic recombination alters the cis configuration of mutant APC and CTNNA1, resulting in wild-type CTNNA1 retaining the trans configuration with APC; this configuration may result in somatic recombination between APC and CTNNA1 sites in a cell line, possibly before APC LOH. This retains CTNNA1 expression and prevents the decrease of α-catenin, despite LOH. Under these conditions, it is believed that CTNNA1 retention supports the early initiation of intestinal adenoma in the absence of APC, while inhibition of intestinal adenoma only occurs when CTNNA1 is in the cis configuration with APC , while patients with colorectal cancer (CRC) with CTNNA1 mutations have considerably increased lymph node metastasis K-Ras expression slightly increases in DLD-1, while CTNNA1, β-catenin, and E-cadherin show a significant decrease compared with those in control Coca-2  Therefore, CTNNA1 may maintain the polarization state of cells in colorectal cancer, which in turn maintains the epithelioid morphology of cancer cells via regulating K-Ras phosphorylation , lobular carcinoma in situ with concurrent invasive lobular carcinoma (ILC), and LCIS with concurrent infiltrating ductal carcinoma (IDC)/ductal carcinoma in situ (DCIS)  Fig. B 26. Meain situ, which deteriorates to the more aggressive, ductal carcinoma, suggesting that breast cancer α-catenin levels may influence the degree of progression. A CTNNA1 deletion in tumor tissues and subsequent metastatic lesions is consistent with this. Parallel DNA sequencing of four tumor samples reveals two overlapping deletions on chromosome 5 in all three tumor samples, including CTNNA1, suggesting that CTNNA1 deletion may be involved in metastasis α-catenin reduction coincides with lobular carcinoma progression in vitro, indicating that CTNNA1 deletion serves an important role therein The expression of CTNNA1 and CDH1 is related to the estrogen-positive phenotype in grade III breast ductal carcinoma CTNNA1 forms a stable structure with IκBα and inhibits its ubiquitination and binding with protease. It prevents localization of Re1A and p50 to the nucleus, which reduces the expression of TNF-α, Re1B, and IL-8. In this way, CTNNA1 inhibits the NF-κB pathway. CTNNA1 expression significantly decreases in basal-like breast cancer with negative CDH1, which shows a negative correlation with the level of TNF-β and Re1B. This demonstrates that the NF-κB pathway is activated in basal-like breast cancer with negative CDH1 due to the loss of CTNNA1 Fig. F 34.CRISPR/Cas9 knockdown of CTNNA1 and CDH1 reverses the inhibitory effect of Beclin-1 on breast cancer cell proliferation. Enhanced Beclin-1 expression increases cell surface localization of E-cadherin complexes  Induced loss of LSD1 in luminal cells significantly increases lung metastasis in a luminal breast cancer mouse model. However, loss of LSD1 reduces the expression of cell adhesion molecules (including CDH1 and CTNNA1); furthermore, TRIM37, encoding histone H2A ubiquitin ligase, is upregulated in either LSD1 or GATA3 knockdown cell lines, leading to the aforementioned inhibition A very small number of breast cancer cases have somatic mutations or homozygous deletions of CTNNA1 (14/1101), accompanied by homologous recombination pair deletions with high similarity to BRCA1/2, according to The Cancer Genome Atlas (TCGA) data from 1101 breast cancer cases The loss of CTNNA1 releases the suppression of the NF-κB pathway in breast cancer, while a CTNNA1 deletion attenuates the tumor suppressive effect of Beclin-1. Loss of LSD1 reduces the level of CTNNA1 and other cell adhesion molecules, suggesting that CTNNA1 also plays a role in the cancer suppressive function of LSD1. Notably, interference of CDH1, also an inhibitor of cancer, may be involved in the cancer inhibitory effect of CTNNA1. Future studies should consider excluding the interference of CDH1 and demonstrating the interaction between CTNNA1 and CDH1.in situ hybridization techniques and array comparative genomic hybridization were used to detect partial chromosomal deletions and genomic deletions in acute myeloid leukemia (AML) cells, including those of CTNNA1 Analysis of all 297 patients identified 30 differentially expressed genes, including CTNNA1 An analysis of copy number aberrations and copy-neutral loss of heterozygosity in a case of MDS with normal karyotypes detected a minimal 5q deletion, including CTNNA1 PTEN regulates CTNNA1 expression by modifying the ratio of P42 CCAAT/enhancer binding protein (C/EBP) to P30 C/EBP, thereby affecting the progression of bone marrow dysplasia and AML. Retention of CTNNA1 proximal promoter binding to P30 CEBP (low P42/P30 ratio) inhibits CTNNA1 expression by inhibiting H3K27me3 to recruit more polycomb complex 2 (PRC2). On the contrary, binding to P42 CEBP (high P42/P30 ratio) relieves the inhibition and promotes CTNNA1 expression. Knockdown of PTEN in wild zebrafish and mice causes a decrease in the expression of wild-type PTEN product (P42) and α-catenin, inducing bone marrow dysplasia The reduced expression of CTNNA1 in AML is associated with its methylation during cell apoptosis. Combined with the existing literature, we speculate that this may be related to the methylation of H3K27me3 at the promoter of this gene; PTEN has been demonstrated to promote the expression of CTNNA1 and thus inhibit myeloproliferation. The role of other pathways, such as JMJD3 and HOX CDH1 is a suppressor gene of gastric cancer, Although the variation in CTNNA1 was not initially noticed since it did not induce carcinogenesis Immunohistochemical and PCR analyses showed that CTNNA1 mRNA was decreased or absent in 13/19 gastric mucosa from gastric cancer cases and their first-degree relatives (including 7 cases with CTNNA1 loss and 6 with decreased expression), which were significantly different from that of normal gastric mucosa. Additionally, decreased CTNNA1 expression was discovered in the gastric and antrum mucosa of first-degree relatives . The decrease or downregulation of CTNNA1 mRNA in the gastric mucosa was associated with Helicobacter pylori infection (P < 0.05) At present, pathogenic mutations in CTNNA1 explain < 2% of the HDGC family, while previous studies have detected at least 25 mutations in CTNNA1 in gastric cancer Positive expression of CDH1, CTNNA1, and CTNNB were associated with good prognosis for endometrial cancer Five hypermethylated genes  and three hypomethylated genes  are significantly associated with poor recurrence-free survival of ovarian cancer tissues from TCGA (n = 391) using multivariate Cox regression analysis. After adjustment for age and stage, patients with at least two hypermethylated sites in CTNNA1, DLC1, or MFAP4 were significantly correlated with a worse progression-free survival Decreased expression of CTNNA1 and PTEN correlated with a high pathological stage of bladder cancer through immunohistochemical analysis of 133 cases of bladder cancer (P = 0.01) A group of pancreatic cancer cells with high metastasis had over 40 differentially expressed genes (including CTNNA1) with liver metastasis tissues of pancreatic cancer; this was three times more than untreated cells The inhibitory effect of CTNNA1 in bladder cancer was implicated in enhancing CDH1 expression and inhibiting EMT. In pancreatic cancer, ablation of SETD2 caused the deletion of CTNNA1, thereby mediating the enhancement of EMT, which strongly suggests that CTNNA1 plays a role in suppressing EMT.+ cells of hepatitis C virus-associated HCC compared with normal controls, including CTNNA1, which may be responsible for the development and/or progression of the disease Targeted next-generation sequencing of 14 hepatocellular carcinomas (HCC) patients revealed molecular abnormalities that activate multiple pathways, including the Wnt pathway (CTNNA1 and CTNNB mutations) and the PI3K/AKT/mTOR pathway  in vitro. Microarray analysis showed that pycnogenol induced changes in the expression of various pathway genes in cancer cells, including the downregulation of CTNNA1, which is associated with increased survival of synovial sarcoma cells Downregulation or inhibition of CTNNA1 expression has been reported in osteosarcoma induced by the bone-seeking alpha emitter, 238Pu  Current reviews on the role of CTNNA1 in malignancies are limited mainly to HDGC in situ breast carcinoma to invasive carcinoma.In many malignancies, CTNNA1 inhibits adhesion, invasion, and induces apoptosis of tumor cells by promoting or collaborating with CDH1 or inhibiting Wnt pathway. Current studies have identified reduced CTNNA1 expression in many types of tumors, including colorectal, breast and endometrial cancers. The reduced expression of CTRNNA1 is often accompanied by reduced expression of related proteins of cell adhesion complex E-cadherin-catenin, such as CDH1 and CTNNB1. For example, decreased expression CTNNA1 and CTNNB1 corresponds to the progression of Mechanistically, CTNNA1 deletion has been shown to lead to an abnormal localization of E-cadherin and apoptosis resistance, resulting in cancer cells with invasive and anti-apoptotic properties. Knockdown of CDH1 leads to the reduced expression of CTNNA1 and CTNNB1 in endometrial epithelial cells, causing them to acquire invasive characteristics. CTNNA1 inhibited the transcription of genes related to tumor cell invasion by disrupting the binding of β-catenin-Tcf complex to DNA and suppressing the invasion of tumor cells. In collaboration with APC, CTNNA1 can promote the ubiquitination of β-catenin and inhibited the Wnt pathway. In addition, CTNNA1 can promote the metabolism of β-catenin by stabilizing APC, thereby inhibiting the Wnt pathway and suppressing cancer development. Future studies on CTNNA1 in malignancies should determine how CTNNA1 specifically affects the Wnt pathway and the E-cadherin-catenin complex, as well as its upstream targets, such as LSD1, PTEN and miRNAs.CTNNA1 inhibits the metastasis of cancer by inhibiting EMT. Current findings have indicated that EMT contributes to tumor metastasis Hypermethylation of CTNNA1 is associated with shorter relapse-free survival in some malignancies. Current studies have observed that DNA methylation is widespread in aging cells and in various cancer At present, CTNNA1 mainly plays an essential role of inhibiting cell proliferation, promoting apoptosis, repressing invasion, and metastasis in malignancies. In some cancers, such as colorectal, bladder, breast cancers, the anti-cancer mechanism of CTNNA1 is well understood, which has been translated into clinical practice, such as screening CTNNA1 to guide the management of HDGC; however, in other cancers, such as endometrial, ovarian, and pancreatic cancers, the mechanism and related signaling pathway of CTNNA1 remain to be fully understood. Further studies will provide novel insights into the etiology and pathogenesis of more carcinomas, thereby improving treatment outcome.


Attention Deficit Hyperactivity Disorder (ADHD) is a Neurodevelopmental Disorder characterized by persistent pattern of inattention and hyperactivity / impulsivity. There is considerable difficulty in diagnosing ADHD, mainly to discriminate what could be symptoms arising from ADHD or typical age behaviors. The decision tree model is a statistical algorithm, a predictive model built with comparisons of values for a given objective that can be compared with other constant values, placing these variables in a database at hierarchical levels.This study aims to apply the decision tree model in directing the screening of ADHD complaints to analyze which cognitive and behavioral parameters would be better associations with ADHD accurate diagnosisWe used a database of research protocol with 202 children assessed with complaints of ADHD and a control group with 185 participants. Decision tree analyzed parameters selected from the cognitive instruments, such voluntary attention, Continuous Performance Test indexes, WCST indexes, Wechsler Intelligence indexes and behavioral scales from CBCL/6-1 and TRF/6-18.The highlighted results points to WCST index like: “Perseverative answers” and “Perseverative errors” and “learning to learn” joint to “CPT omissions” and behavioral scales as “CBCL ADHD”, and “CBCL Problems of Attention” produces accuracy of diagnosis discrimination from 84.7% to 60% in the precision of the decision tree.The decision tree and machine learning approaches can be effective in directing the screening of typical ADHD complaints.No significant relationships.


Uncovering the neural mechanisms that underlie symptoms of attention deficit hyperactivity disorder (ADHD) requires studying brain development prior to the emergence of behavioural difficulties. One new approach to this is prospective studies of infants with an elevated likelihood of developing ADHD.We used a prospective design to examine an oscillatory electroencephalography profile that has been widely studied in both children and adults with ADHD – the balance between lower and higher frequencies operationalised as the theta–beta ratio (TBR). In the present study, we examined TBR in 136 10‐month‐old infants  with/without an elevated likelihood of developing ADHD and/or a comparison disorder .lower TBR than infants without a first‐degree relative with ADHD. Further, lower TBR at 10 months was positively associated with temperament dimensions conceptually related to ADHD at 2 years. TBR was not altered in infants with a family history of ASD.Infants with a first‐degree relative with ADHD demonstrated This is the first demonstration that alterations in TBR are present prior to behavioural symptoms of ADHD. However, these alterations manifest differently than those sometimes observed in older children with an ADHD diagnosis. Importantly, altered TBR was not seen in infants at elevated likelihood of developing ASD, suggesting a degree of specificity to ADHD. Taken together, these findings demonstrate that there are brain changes associated with a family history of ADHD observable in the first year of life. Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental condition, with an estimated worldwide prevalence of 3%–5%  is a strong candidate method for investigating early neurocognitive markers of ADHD, given its high temporal resolution and suitability for infants and young children. Indeed, previous research suggests that EEG can be used to detect neural phenotypes (including increased absolute and relative theta power) that may be related to ADHD liability in infants . Research on TBR in relation to the core features of ASD is sparse. A recent study conducted by Isaev et al.  found a We selected this age range because previous studies have indicated that behavioural differences in infants at elevated likelihood of ADHD may begin to emerge from 12 months of age , a first degree relative with community clinical diagnosis or probable ADHD , or no first‐degree relatives with either diagnosis  128‐electrode Hydrocel Sensor Net, online referenced to Cz at 500Hz. Infants were seated on their parents/caregiver’s lap, 60cm from a screen displaying naturalistic Social (women singing) or Nonsocial (toys moving) dynamic videos , and 1‐second segmented. Data were manually artefact rejected in NetStation 4.5; segments with excessive artefact (e.g. gross motor movement and eye blinks), where infants were not looking at the video or with >25 noisy channels were manually excluded. Infants with fewer than 10 artefact‐free trials in either condition were excluded  with compound symmetry and maximum likelihood estimates. The relevant EEG metric was the dependent variable and models included fixed factors of Sex , Condition , Likelihood  and Region . Models were repeated with age in days, highest level of maternal education and number of artefact‐free segments as covariates Appendix , accountF = 4.21, p =.042, ηp2 = .03; Figure F = .93, p = .335, ηp2 = .007] or an interaction of ASD*ADHD elevated likelihood ; Figure Infants with an elevated likelihood of ADHD showed a lower TBR than those with a lower likelihood of ADHD , indicating that those with an elevated likelihood of ADHD showed lower TBR across the scalp. Male infants demonstrated higher TBR . In an additional GEE model, the interaction of Sex and ADHD‐L did not have any significant influence .As expected  = 5.25, p = .023, ηp2 = .04] across all areas of the brain , and lower for the Nonsocial versus Social video . There was no effect of an elevated likelihood of ASD , nor an interaction of ASD*ADHD‐L . There was no effect of Sex .Theta power was lower in infants with an elevated likelihood of ADHD F = 4.32, p = .04, ηp2 = .03] over all brain regions . Beta power was higher in the Nonsocial condition  and higher in females than males . There was no effect of an elevated likelihood of ASD  or interaction effect . A broadly similar pattern was also found with a higher frequency band definition of beta  over the Whole Head collapsed across experimental condition ; see Appendix r(25) = −.43, p = .03] at 24 months, but not Effortful Control  or Negative Affect . Exploring associations between TBR‐Low and Surgency components, we found lower levels of TBR‐Low were associated with greater Impulsivity  and greater Sociability Appendix S1. Relative power figure.Appendix S2. Methods.Appendix S3. Results.Appendix S4. Motion.Appendix S5. Medical and Psychiatric History interview.Click here for additional data file.


Bartonella spp. and found a low frequency (7.9%) of positive animals. This study showed that European bison may be infected by at least two Bartonella species, namely B. bovis and B. schoenbuchensis. Our results demonstrated that further research is needed to determine the distribution of Bartonella species in wild and domestic ruminants, and it is important to identify the transmission route.The European bison is the largest ruminant in Europe. The population of European bison in Lithuania is increasing and several free-ranging herds exist. Owing to their protected status, studies of vector-borne pathogens in European bison are still lacking. By analyzing European bison and ticks collected from them in Lithuania, we checked for the presence of Bartonella bacteria infect the erythrocytes and endothelial cells of mammalians. The spread of the Bartonella infection occurs mainly via bloodsucking arthropod vectors. Studies on Bartonella infection in European bison, the largest wild ruminant in Europe, are lacking. They are needed to clarify their role in the maintenance and transmission of Bartonella spp. The aim of this study was to investigate the presence of the Bartonella pathogen in European bison and their ticks in Lithuania. A total of 38 spleen samples from bison and 258 ticks belonging to the Ixodes ricinus and Dermacentor reticulatus species were examined. The bison and tick samples were subjected to ssrA, 16S–23S rRNA ITS, gltA, and rpoB partial gene fragment amplification using various variants of PCR. Bartonella DNA was detected in 7.9% of the tissue samples of European bison. All tick samples were negative for Bartonella spp. The phylogenetic analysis of 16S–23S rRNA ITS, gltA, and rpoB partial gene fragment revealed that European bison were infected by B. bovis (2.6%) and B. schoenbuchensis (5.3%). This is the first report addressing the occurrence of B. bovis and B. schoenbuchensis in European bison in Europe. Bartonella species are Gram-negative bacteria that infect mammalian erythrocytes and endothelial cells. They are transmitted via direct contact  and by bloodsucking arthropod vectors such as fleas, lice, ticks, sand flies, and deer keds [Bartonella bovis, Bartonella capreoli, Bartonella chomelii, Bartonella schoenbuchensis, and Bartonella melophagi [Bartonella henselae and ‘Candidatus Bartonella davousti’ have been detected in domestic cattle [Bartonella species detected in ruminants are rarely implicated in animal diseases. To date, only B. bovis has been associated with bovine endocarditis [eer keds ,2. Domeselophagi ,4,5,6. Ic cattle ,8. Bartocarditis .Bartonella have been detected in domestic and wild animals and their ectoparasites. Bartonella grahamii, B. tailorii, B. rochalimae, B. tribocorum, B. coopersplainsensis, B. doshiae, and B. washoensis have been identified in several species of small rodents and in the fleas, ticks or mites collected from them [B. henselae, B. clarridgeiae and the Bartonella sp., closely related to B. schoenbuchensis have been detected in domestic cats and their fleas [Bartonella pathogens in domestic or wild ruminants in Lithuania.In Lithuania, various species of rom them ,11,12,13ir fleas . HoweverBison bonasus), the largest ruminant in Europe, is known for its status as an animal under species protection. Recent studies have demonstrated that bison may play a role as a natural reservoir of Anaplasma phagocytophilum, Babesia divergens, and Babesia venatorum [Bartonella infection in European bison in Europe. In the present study, we aimed to investigate the presence of the Bartonella pathogen in European bison and their ticks (Ixodes ricinus and Dermacentor reticulatus) in Lithuania using real-time PCR targeting the ssrA gene, and to characterize Bartonella strains by the PCR and sequence analysis of the 16S–23S rRNA ITS (the 16S–23S rRNA intergenic species region), gltA (citrate synthase gene) and rpoB (RNA polymerase β-subunit) genes.The European bison . Due to the status of animals under species protection, the tissue samples of European bison were taken from animals found dead in the field (n = 6), accidentally killed on roads (n = 10), and eliminated from nature under a protection plan due to diseases or genetic disorders (n = 22). The bison sampling was conducted with permission from the Environmental Protection Department under the Ministry of Environment . A total of 258 ticks were collected from 6 animals that had died due to unknown causes. Ticks were placed in 1.5 mL tubes with 70% ethanol and kept at 4 °C until investigation. Tick species were identified based on morphological criteria [Ixodes ricinus  and Dermacentor reticulatus . A total of 116 ticks were engorged (85 I. ricinus and 31 D. reticulatus) and 143 non-engorged (45 I. ricinus and 98 D. reticulatus).A total of 38 spleen samples of European bison  were collected in the period 2019 to 2022 in Central and Northern Lithuania (Kėdainiai and Panevėžys regions). Bison samples were collected in all seasons  according to the manufacturer’s recommendations. DNA from non-engorged ticks was extracted using 2.5% ammonium hydroxide .Bartonella DNA (124 bp product of ssrA gene) was conducted by using TaqMan real-time PCR with ssrA-F1 and ssrA-R1 primers and a ssrA-P1 probe, as previously described [Bartonella-positive samples in real-time PCR were further analyzed using nested PCR assays that amplify partial sequences of the 16S–23S rRNA ITS region  and conventional PCR assays of gltA (primers BhCS.781p and BhCS.1137n) and rpoB (primers 1400 F and 2300 R) genes [Bartonella-infected rodents, confirmed by sequencing) and negative  controls were included in each PCR run. PCR products were identified by electrophoresis on 1.5 % agarose gel.Screening for the presence of escribed . BartoneR) genes ,20,21,22Bartonella-positive samples were extracted from agarose gel and purified using the GeneJET™ Gel Extraction Kit . The obtained partial 16S–23S rRNA ITS region, gltA, and rpoB gene sequences were analyzed using the MegaX software package [PCR products of all gltA, and rpoB gene sequences for representative samples obtained in this study were submitted to the GenBank database under accession numbers OP888096 for the ITS region, OP894362–OP894364 for the gltA gene, and OP894359–OP894361 for the rpoB gene.Partial 16S–23S rRNA ITS region, Bartonella DNA was detected in three out of the thirty-eight (7.9%) tissue samples of European bison. Positive results were obtained in each animal when applying all three PCR techniques . The Bartonella infection was detected in samples collected during winter. All ticks (n = 258) collected from the six European bison specimens not infected with Bartonella were negative for Bartonella spp. All positive samples were subjected to sequence analysis. B. bovis sequences isolated from domestic cattle from France, Guatemala, and Israel   was 100% identical to M371094) .gltA partial gene fragments were obtained from three European bison samples. The sequence analysis revealed that the Bartonella strain (GenBank: OP894362) derived from one individual European bison clustered with B. bovis isolated from cattle from various countries  with an identity score 100%. The other two sequences  demonstrated a 100% similarity with B. schoenbuchensis isolated from roe deer , deer ked from Germany (GenBank: AJ564632), and a human sample from France (GenBank: HG977196)  .rpoB gene sequence (GenBank: OP894361) clustered with other B. bovis sequences. The highest similarity (99.9%) was shared with B. bovis, previously isolated from cattle from France (GenBank: KF218217). Meanwhile, two sequences derived from two bison specimens  were 99.1% similar to the B. schoenbuchensis sequences isolated from roe deer from Germany (GenBank: CP019789) and human (GenBank: HG977196), differing at six nucleotide positions (B. capreoli isolated from red deer from USA (GenBank: HM167505), differing at fifteen nucleotide positions.The ositions . AdditioB. bovis and B. schoenbuchensis in European bison in Europe. Furthermore, we tested I. ricinus and D. reticulatus ticks collected from bison and did not detect the presence of Bartonella species. The role of ticks in the transmission of Bartonella is not fully understood [Bartonella spp. in ruminants [This study reports the first molecular detection of derstood ,6. Otheruminants .Bartonella bovis is mainly detected in cattle. Infection with B. bovis is usually asymptomatic, but it is known that it can be associated with bovine endocarditis [B. bovis in domestic cattle ranges from 7% to 36% in Europe and from 5% to 90% in other continents [B. bovis infections also have been reported in wild ruminants such as moose, red deer, and roe deer [B. bovis DNA has been identified in 3.2% of ticks collected from cattle [Bartonella infection in ticks has not been detected. This study presents a low frequency of B. bovis (2.6%) in European bison in Lithuania. A previous study conducted in Poland has shown that 6.8% of cattle (Bos taurus), a closely related species to European bison, had asymptomatic B. bovis infection [Bartonella in Lithuanian ruminants, an epidemiological study with a larger sample size is needed.carditis ,9. The pntinents ,26,27. Froe deer ,29. A reB. schoenbuchensis. This result is not unexpected because previous studies reported cases of B. schoenbuchensis in domestic and wild ruminants from Georgia, Poland, France, and Norway [Bartonella spp. highly similar to B. capreoli, B. chomelii, and B. schoenbuchensis had been identified in deer ked distribution areas [Bartonella species. Furthermore, outside the deer ked distribution area, other vectors such as ticks or culicoides biting midges could also be involved in Bartonella transmission [The present study revealed that two individuals of European bison (5.3%) were infected with d Norway ,28,30,31d Norway . Accordion areas ,31,33. Tsmission ,34. Eurosmission .Bartonella species, namely B. bovis and B. schoenbuchensis. Further research is needed to determine the vectors of transmission of Bartonella species among bison and other ruminant species.The results of this study suggest that European bison may be infected by at least two


ADHD is associated with multiple adverse outcomes and early identification is important. The present study sets out to identify early markers and developmental characteristics during the first 30 months of life that are associated with ADHD 6 years later.9201 participants from the prospective Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort were included. Outcome measures were parent‐rated ADHD symptom scores  and ADHD diagnosis  at age 7. Seventeen putative markers were identified from previous literature and included: pre‐ and peri‐natal risk factors, genetic liability , early development, temperament scores and regulatory problems. Associations were examined using regression analysis.B = 0.107, CI = 0.083–0.132), vocabulary delay , fine motor delay  and ADHD PRS  were associated with future symptoms (R2 = 10.7%). In a multivariable logistic regression model, ADHD PRS  and temperament activity scores  showed association with ADHD diagnosis.Univariable regression analysis showed that multiple early life factors were associated with future ADHD outcomes, even after controlling for sex and socio‐economic status. In a multivariable linear regression model; temperament activity scores (As well as male sex and lower socio‐economic status, high temperament activity levels and motor and speech delays in the first 30 months of life, are associated with childhood ADHD. Intriguingly, given that genetic risk scores are known to explain little of the variance of ADHD outcomes, we found that ADHD PRS added useful predictive information. Future research needs to test whether predictive models incorporating aspects of early development and genetic risk scores are useful for predicting ADHD in clinical practice. Identifying early antecedents and markers of ADHD is important to support early detection and intervention.In a large comprehensive study of children from a population cohort, we identified that ADHD PRS, fine motor delays at 18 months, speech delays and higher temperament activity both at 24 months, showed independent association with ADHD traits at age 7. ADHD PRS and temperament activity were also associated with age 7 ADHD diagnosis.This study is the first to suggest that ADHD PRS, when combined with clinical and developmental variables, is associated with later ADHD symptoms and diagnosis.This study potentially helps inform practitioners which children may need more intensive surveillance or prevention strategies to support their later ADHD.Future research could investigate the specificity and potential causality of the identified markers and antecedents.Attention‐deficit/hyperactivity disorder (ADHD) is a highly heritable neurodevelopmental disorder that typically onsets early in life , a prospective longitudinal population‐based birth cohort of a representative sample of parents and children . Child psychiatrists then reviewed the data for each participant, to determine a final definitive DSM‐IV diagnosis of ADHD.The DAWBA structured assessment was sent as a paper questionnaire to carers and teachers when the children were 7 years old and provided information for ADHD diagnoses. The ADHD section assesses inattention, hyperactivity, impulsivity, age of onset and impairment. In accordance with the DAWBA protocol, initially the DAWBA computer algorithm ascertained the probability of having ADHD for each participant , preterm birth and APGAR score at 5 min were obtained from obstetric clinical records. Head circumference (HC) at birth was assessed by trained ALSPAC staff.Preterm birth was defined as those born at <37 weeks of gestation based on best clinical estimate of expected date of delivery. APGAR score is a measure of vitality of a new‐born infant, routinely calculated by the attending clinician after every birth , sleeping and crying (at 30 months) habits and these questions were utilised to assess regulatory problems, following a previously used scoring system. The presence of seven sleeping problems and six feeding problems were assessed on a 4‐point scale used to identify the presence of a problem (1–3 vs. 0) and summed to create total scores. A total crying problem score was derived by summing the answers to five items and binary clinically relevant crying, sleeping and feeding variables were defined as >1 SD above the sample mean, in‐line with previous work  were included as covariates because ADHD is more common in males and in more socially disadvantaged groups  in Model 3, prior to conducting multivariate regression analysis, to correct for multiple testing. Sensitivity analyses, were conducted separately for females and males to evaluate if predictors varied by sex  and diagnosis (assessed using the DAWBA), respectively. First, a univariable model analysed each predictor separately (Model 1), then adjusted for sex (Model 2) and SES (Model 3). Variables showing an association in the univariable adjusted model (Model 3), were subsequently included in a fully adjusted multivariable model. We used Bonferroni correction . Descriptive statistics for all study variables can be found in Table There was no evidence of multicollinearity between early markers (see Table S1), therefore all were included in regression models . There was also weaker evidence of associations with younger mothers at birth, IUGR and microcephaly at birth.Seven early markers showed association with ADHD scores in univariable analysis when controlling for sex and SES Table , Model 3In multivariable adjusted analysis (Model 4), four markers remained associated with ADHD scores: ADHD PRS, fine motor delay, vocabulary delay and higher temperament activity . There was also weaker evidence of association with gross motor delay. In the multivariable model (Model 4), ADHD PRS and temperamental activity showed strong evidence of association (see Table N = 27), stratified analysis was carried out only for males which were generally consistent with those in the whole sample (Table When controlling for sex and SES, ADHD diagnosis was associated with five early markers Table , Model 3le Table .In this prospective cohort, we observed that ADHD PRS, fine motor delays at 18 months, speech delays and higher temperament activity at 24 months showed independent association with ADHD traits at age seven. ADHD PRS and temperament activity were also associated with subsequent ADHD diagnosis.The aspects of temperament and regulation analysed here are related to the core features of ADHD and could represent the starting point of a developmental trajectory of dysregulation (Baumann et al., The developmental antecedents found here are in line with those observed in other cohorts such as the national birth cohort in Denmark (Lemcke et al., The results of our study also suggest that genetic liability indexed as ADHD PRS were associated with subsequent ADHD diagnosis. Many studies have shown that participants with higher ADHD PRS have an increased chance of meeting ADHD diagnostic criteria, higher ADHD symptom levels and ADHD persistence (Riglin et al., This study is the first to our knowledge to suggest that ADHD PRS, when combined with clinical and developmental variables, is associated with later ADHD symptoms and diagnosis. Our results may therefore have important practical implications because identifying precursors and antecedents of ADHD, even when not causal, could be important in risk assessments of ADHD, for example, determining follow‐up options for individuals who are at clinical risk of future illness. However, the clinical utility of these results needs evaluation especially as the variance explained by this group of early markers was limited.As we learn more about the early manifestations of clinical psychopathology, we will also be able to suggest and evaluate preventive intervention approaches targeting some of the early predictors. Moreover, this area of research is particularly relevant for ADHD because, in contrast to Autism spectrum disorder, clinicians lack effective screening tools that help them to distinguish ADHD precursors (Carter et al., This study has several strengths, such as a large representative sample and prospectively collected information using well‐validated instruments. Although some variables are based on objective measures or obstetric data, most of the variables were collected through parental report, which may have introduced a measurement error. However, our variables represent data available in the real world and in general, evidence suggests that parent report and directly assessed measures of language and motor skills are significantly correlated (Miller et al., The study also has some limitations. The ALSPAC cohort shows attrition (Taylor et al., Also, ADHD shows a high level of co‐occurrence with other neurodevelopmental disorders (Thapar & Cooper, Future research may focus on interaction between predictors, non‐linear interactions and the specificity of early markers. It is also of interest to analyse the persistence of predictors in ADHD diagnosis at an older age or studying if early features represent markers or predictors at the individual level. Future research may also look at the use of the identified early markers and precursors to develop a prediction model for later ADHD. However, the use of prediction models within child and adolescent psychiatry has been shown to have limited utility, in part due to methodological issues such as sample size and replicability, which would have been seen in this study had we developed such a model (Larsson, 2021; Senior et al., The results of this study suggest that genetic liability indexed by ADHD PRS, aspects of temperament, and early developmental delays act as antecedents and represent early precursors of later ADHD.This area of research has important clinical implications because it may inform practitioners about which children need more intense surveillance or preventive strategies. The combination of PRS with clinical and developmental variables has potential to contribute to risk assessment and aid clinical decision‐making.Esther Tobarra‐Sanchez: Conceptualization, Data Curation, Formal Analysis, Funding Acquisition, Methodology, Investigation, Visualization, Writing – Original Draft. Lucy Riglin: Resources, Writing Review and Editing. Sharifah S. Agha: Writing Review and Editing, Supervision. Evie Stergiakouli: Conceptualization, Funding Acquisition, Methodology, Supervision, Writing Review and Editing. Kate Langley: Conceptualization, Funding Acquisition, Formal Analysis, Investigation, Methodology, Project Administration, Supervision, Writing Review and Editing. Anita Thapar: Conceptualization, Funding Acquisition, Investigation, Methodology, Project Administration, Supervision, Writing Review and Editing.The authors declares that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.Approval obtained from the ALSPAC Ethics and Law Committee.Supporting information S1Click here for additional data file.


ADHD is classically seen as a childhood disease, although it persists in one out of two cases in adults. The diagnosis is based on a long and multidisciplinary process, involving different health professionals, leading to an under-diagnosis of adult ADHD individuals. We therefore present a psychometric screening scale for the identification of adult ADHD which could be used both in clinical and experimental settings.n = 110 control individuals and n = 110 ADHD individuals. The number of items was reduced using multiple regression procedures. We then performed factorial analyses and a machine learning assessment of the predictive power of the scale in comparison with other clinical scales measuring common ADHD comorbidities.We designed the scale from the DSM-5 and administered it to Internal consistency coefficients were calculated satisfactorily for TRAQ10, with Cronbach’s alpha measured at .9. The 2-factor model tested was confirmed, a high correlation between the items and their belonging factor. Finally, a machine-learning analysis showed that classification algorithms could identify subjects’ group membership with high accuracy, statistically superior to the performances obtained using comorbidity scales.The scale showed sufficient performance for its use in clinical and experimental settings for hypothesis testing or screening purpose, although its generalizability is limited by the age and gender biases present in the data analyzed.The online version contains supplementary material available at 10.1186/s12888-022-04048-1. ADHD is a multifactorial disorder presenting a heterogeneous psychopathological profile with heterogeneous neurocognitive deficits, but with core symptoms implicating function of the frontal-subcortical-cerebellar pathways that control attention, saliency, inhibitory control and response to reward . This coActually, the recognition of the importance of diagnosing and treating ADHD is growing, as it was recently shown that there is a higher prevalence of ADHD in some clinical populations such as addictive, forensic, and personality disorder patients . In factHowever, ADHD is usually diagnosed through a time-consuming multidisciplinary evaluation process, including at least the visit to behavioral specialists such as psychologists and to mental functioning specialists such as neurologists or psychiatrists, increasing the diagnostic process duration which can extend over long periods of time. With the increasing need for screening, this led to the creation of psychometric auto-administered scales, such as the well-known Adult ADHD Self-Report Scale , which wIn order to meet the demands of the French ecosystems in terms of screening, we have developed an adult ADHD screening scale in 6 points built around the personal pronoun “I” and theoretically articulated around the DSM-5. Moreover, as machine-learning approaches have enabled considerable progress on a large variety of numerical problems in a wide variety of fields such as physics , 14, cheWe thus generated 43 preliminary items based on the DSM-5 criteria (pTRAQ: Preliminary Trognon & Richard ADHD Questionnaire), and administered this scale to 110 ADHD subjects and 110 controls. We then statistically selected the most discriminating items in regard to the presence or absence of the subject’s clinical condition in order to generate the final Trognon & Richard ADHD Questionnaire French 10-items (TRAQ10). We then analyzed its psychometric properties, in terms of internal consistency, as well as factor structure, under the prism of a 2-factor model accounting for the behavioral expression of cognitive symptomatology . Finally, we examined the predictive power of the scale using a machine-learning approach, relying on operational metrics such as sensitivity and specificity, in comparison to other scales measuring ADHD comorbidities. We then selected three scales: the TRAQ, the target questionnaire, which was designed to evaluate behavioral traits of ADHD, as the scale we are assessing. We then selected two other scales as controls: first, the Depression Anxiety Stress Scales 21-items –24; thenThe initial questionnaire in 43-items was adapted from the DSM-5 and every item was matched to one cognitive domain affected accordingly to the behavioral expression of the symptomatology of ADHD on two domains: attention, and inhibition/impulsivity  from the general French population participated in this study through an online voluntary aleatory sampling. All questions were completed by all participants, thus, all measures were available for all subjects. The entire dataset is available in .Items were developed from the widely-used Diagnostic and Statistical Manual - Fifth Edition . For eaci) in order to elucidate the factors by which the dependent variable was about to be influenced and for selecting discriminating items to highlight the diagnosis of ADHD.We then conducted a reiterative stepwise top-down regression multiple linear regression  and Tucker-Lewis Index (TLI) for fit relative to a null model , 29; theTo evaluate the scale’s ability to capture the ADHD diagnosis, we chose to base our analysis on a machine-learning model. Machine-learning approach consists in training an algorithm on a subset of the whole dataset and testing the algorithm on an independent subset. Here, we used a XGBoost classification algorithm to assess the predictive power of the TRAQ10 participant’s responses in order to diagnose and exclude ADHD diagnosis in comparison to the other scales used in this research. XGBoost is a scalable end-to-end tree boosting system which is aware about sparsity and weight quantile sketch for approximate tree learning . In thisn = 154) and test set (n = 66) using Sci-Kit Learn Libraries with a 70/30 ratio. For each scale , a XGBoost algorithm classifier was constructed based on training set data. A grid search was performed in order to optimize each classifier. We optimized the following hyperparameters: the eta (from 0.1 to 1 by step of .05); the gamma (from 0.1 to 1 by step of .005); the max depth (from 1 to 10 by step of 1); the min child weight (from 0 to 1 by step of .25), the subsample (from 0.1 to 1 by step of .01), the sampling method (two levels: uniform or gradient based), the alpha (from 0 to 1 by step of .25), the lambda (from 0 to 1 by step of .25), the refresh leaf (two level: 0 or 1), and the colsample by tree, level, and node (each from 0.1 to 1 by step of .0025). The scoring method was set for accuracy optimization. Hyperparameters settings are shown in Additional File After data collection, the whole dataset was split randomly to constitute an independent training set n = 15 and testDescriptive statistics of the study sample are shown in Table i) revealed that ADHD makes significatively vary scores on pTRAQ3 , pTRAQ11 , pTRAQ41 , pTRAQ4 , pTRAQ1 , pTRAQ28 , pTRAQ26 , pTRAQ24 , pTRAQ14 , and pTRAQ7 . Measures obtained on the 10 remaining items out of the 43 was .Multiple linear regression analysis (stepwise elimination procedure) using diagnosis as the dependent variable and patients’ scores on pTRAQ (project questionnaire) as independent variables . All measures were above the minimum acceptable rate of .70 and was close from the maximum expected value of .9.The Cronbach’s alpha was measured at .9 .Confirmatory factor analysis suggested a good model fit with the TRAQ10 questionnaire. Significant items selected by the multiple regression were regrouped in two factors for the two behavioral modules described in the DSM-5. Items TRAQ1;2;4;8;10 was combined in the “Attention” factor, and items TRAQ3;5;6;7;9 were combined in the “Inhibition/Impulsivity” factor. Confirmatory factor analysis suggested that the 2-factors model has an acceptable fit with the TRAQ10 questionnaire, with metrics that remains slightly below the pre-defined cut-off . These results differ from whose obtained in other conditions: first, for DASS21 predictions, the classifier was able to identify correctly the group appurtenance of remaining participants with an accuracy of .74, identifying correctly 27 of the 36 ADHD participants and 22 of the 30 controls . Finally, for AVDI predictions (negative control), the classifier was able to identify the group appurtenance of the remaining participants with an accuracy of .59, identifying correctly 23 of the 36 ADHD participants and 16 of the 30 controls .2,27]=29.81,p < .001], and further Tukey’s post-hoc analysis revealed significant differences between predictions from TRAQ10 and DASS21 [p < .001] and from TRAQ10 and AVDI [p < .001], but not between predictions from DASS21 and AVDI [p = .39].Further two-ways ANOVA on 10-fold cross validation accuracy measures (accuracies~source) revealed a significant effect for source [F [These results suggest that participant’s responses to TRAQ10 questionnaire are sufficient to predict ADHD diagnosis with high accuracy. In fact, even if other questionnaires (i.e. DASS21 and AVDI) are able to perform beyond chance, both showed similar lower and statistically different accuracies when compared to the TRAQ10 performances.The present study verified the reliability and the construct validity of the Trognon & Richard ADHD Questionnaire 10-items French version for Adults (TRAQ10) and allowed the production of a tool that can be used both in clinical routine and in experimental settings.Cronbach’s alpha values suggested that the TRAQ10 was internally reliable, with measured alpha remaining in the .70 ≤ ɑ ≤ .90 intervals recommended by  , 27, excFurther confirmatory factor analysis supported our two-factors structure for the TRAQ10 questionnaire, with items TRAQ1;2;4;8;10 grouped in the “Attention” factor, and TRAQ3;5;6;7;9 grouped in the “Inhibition/Impulsivity” factor. Analysis showed that this model has an acceptable fit according to the standards defined by  . FurtherIn our analysis, we used machine-learning procedures to analyze the pattern of participant’s responses to the TRAQ10 questionnaire among ADHD and neurotypical population, and compared these results with two others scales to validate formally its predictive power. The XGBoost machine-learning classifier trained on the data of the TRAQ10 questionnaire performed with high accuracy and very few rates of false positive. This model showed better  performances from those based on the two others scales (i.e anxiety and democracy adhesion) scales, demonstrating its predicting power in order to label ADHD attribute in comparison with other scales which carry (i.e. DASS21) or not (i.e. AVDI) direct or indirect link with ADHD construct; thus outlining the manner in which this type of classifier could facilitate the professional’s diagnostic process of ADHD, given its automated design, allowing it to be used during a consultation without the need to manually calculate results or use statistical tables, which is a significant gain of time, less susceptible to human error, and directly implementable. In addition, its automated design would pave the way for its use in a dynamic, mobile, fast, and flexible manner, particularly in the research ecosystems which could use this type of computational screener to automatically assign the clinical label according to a pre-trained model, making it possible to carry out large-scale psychometric studies, without prior knowledge of the population to be sampled. However, future work on this classifier is still needed, in particular on its differential performance when applied to datasets carrying several and/or confounding clinical conditions (such as bipolar disorder or Asperger’s syndrome).More generally, we believe that these computational screening strategies will have an important role to play in the current context of Evidence-Based Practices, especially in the context of treatment, which is one of the major themes discussed about ADHD in these fields of expertise . Indeed,Nevertheless, the present study suffers from several limitations that reduce its generalizability. First, a strong age bias  was measured simultaneously with a weak socio-cultural level bias  which may have biased the training of the algorithms. We were also unable to obtain the same number of individuals for each sex, despite having obtained the same number of individuals of each sex for each group, leading us to consider an established validity for women, while remaining partial for men. We did not measure ethnicity as well. Furthermore, we did not perform a positive control or convergent validity experiment by measuring the performance of tools already available in French or English that could have been translated and we were not able to check for corrupted data, given the computerized aspect of the administration of the questionnaires, thus not allowing us to check for the presence of artifactual or erroneous data. Finally, we did not cross-reference the typical symptoms mentioned by the DSM-5 with other classifications, such as those proposed by Barkley or Fedele and their respective collaborators , 36, andWe concluded from these analyses that the TRAQ10 can be used to attribute ADHD attribute in a French survey sample. From a clinical point of view, we believe that this scale could be used during a first consultation or at the end of the consultation to support the health professional’s clinical expertise and serve as a decision aid in deciding whether to pursue a multidisciplinary diagnostic process. In contrast, from an experimental point of view, we believe that this tool could be used to automatically label the attribute ADHD in a given sample, and thus allow to perform psychometric without a priori knowledge of the sampled population, but whose generalizability will be limited by the biases present in the study sample.Additional file 1.Additional file 2.Additional file 3.Additional file 4.Additional file 5.Additional file 6.


ADHD is associated with impairments in different inhibitory functions, including suppression of an already initiated response and inhibition of distracting information. This work used a protocol that combines the Stroop-matched and stop-signal tasks to examine the association between the frequency of ADHD symptoms and different inhibitory abilities in a young adult.To investigate how the symptoms of inattention and hyperactivity / impulsivity are associated with three forms of inhibition evaluated by the Stroop-matched / stop-signal task: inhibiting an automatic response, controlling interference and canceling a response.38 participants  completed Adult ADHD Self-Report Scale (ASRS) assessing ADHD symptoms before performing the task. Reaction times, accuracy and stop-signal reaction time  were calculated for each task condition.There was a significant correlation of ADHD symptoms and SSRT in the condition with the higher perceptual load . This correlation was negative , which indicates that participants with higher ADHD symptoms frequency had more efficient inhibitory processes in this condition.(1) the perceptual load of the task influences the cancellation of responses; (2) individuals with higher frequency of ADHD symptoms may have a better inhibitory capacity when the perceptual load is high, possibly reflecting a lower availability of attentional resources to process distracting information.No significant relationships.


Bartonella are intracellular bacteria that are transmitted via animal scratches, bites and hematophagous arthropods. Rodents and their associated fleas play a key role in the maintenance of Bartonella worldwide, with > 22 species identified in rodent hosts. No studies have addressed the occurrence and diversity of Bartonella species and vectors for small mammals in Arctic and Subarctic ecosystems, which are increasingly impacted by invasive species and climate change.Bartonella species in rodents and shrews (n = 505) from northern Canada using conventional PCR targeting the ITS (intergenic transcribed spacer) region and gltA (citrate synthase) gene. Metagenomic sequencing of a portion of the gltA gene was completed on a subset of 42 rodents and four rodent flea pools.In this study, we characterized the diversity of rodent fleas using conventional PCR targeting the mitochondrial cytochrome c oxidase II gene (COII) and Bartonella positivity. Occurrence based on the ITS region was more than double that of the gltA gene and was 34% (n = 349) in northern red-backed voles, 35% (n = 20) in meadow voles, 37% (n = 68) in deer mice and 31% (n = 59) in shrews. Six species of Bartonella were identified with the ITS region, including B. grahamii, B. elizabethae, B. washoensis, Candidatus B. rudakovii, B. doshiae, B. vinsonii subsp. berkhoffii and subsp. arupensis. In addition, 47% (n = 49/105) of ITS amplicons had < 97% identity to sequences in GenBank, possibly due to a limited reference library or previously unreported species. An additional Bartonella species (B. heixiaziensis) was detected during metagenomic sequencing of the gltA gene in 6/11 rodents that had ITS sequences with < 97% identity in GenBank, highlighting that a limited reference library for the ITS marker likely accounted for low sequence similarity in our specimens. In addition, one flea pool from a northern red-backed vole contained multiple species (B. grahamii and B. heixiaziensis).Year, total summer precipitation the year prior to sampling, average minimum spring temperature and small mammal species were significant factors in predicting Bartonella communities in hosts and vectors.Our study calls attention to the usefulness of a combined approach to determine the occurrence and diversity of  Bartonella consists of a diverse group of emerging zoonotic bacteria that infect a range of hosts, including mammals, reptiles and birds  for average maximum and minimum temperature (°C) and total precipitation (mm). Data were collected from Yellowknife A Weather Station  and obtained from the Government of Canada (climate.weather.gc.ca), as climate data from all locations in the study were not available. Models for three outcome variables were tested, including Bartonella positivity with (i) ITS region, (ii) gltA gene and (iii) positive result with both target sequences. Analyses were conducted in SPSS .Occurrence and 95% confidence intervals (CI) were calculated using EpiTools epidemiological calculators . Possibln = 45), 2018 (n = 273) and 2019 (n = 187). Northern collared lemmings were collected from Cambridge Bay, NU (n = 9). Fleas were collected from the carcasses of 69 rodents from the NT , including 59 northern red-backed voles (17%), 4 meadow voles (20%) and 6 deer mice (9%). Fleas from four Ungava collared lemmings were collected in Salluit (Quebec).A total of 446 rodents and 59 shrews was collected, including 349 northern red-backed voles, 20 meadow voles, 68 deer mice and 9 northern collared lemmings. Most of the small mammals originated from the NT, including 82 from Yellowknife, 113 from Fort Smith, 99 from Fort Liard, 115 from Fort Resolution, 13 from Fort Simpson and 72 from Inuvik  in small mammals from the NT was 34% . Occurrence based on gltA PCR (positives) was 16% , and only 12% of small mammals were positive on both PCRs . Results for Bartonella genetic markers for each rodent species are compared in Table gltA gene did not produce any positives for deer mice or meadow voles. Occurrence in animals (ITS positives) was 22% in 2017 ; 26% in 2018  and 47% in 2019 .The occurrence of Bartonella sequences in GenBank, Fig. Bartonella identified in both northern red-backed and meadow voles was B. grahamii  in small mammals for each location sampled in the NT was 48% for Fort Liard , 21% for Fort Resolution , 62% for Fort Simpson , 31% for Fort Smith , 40% for Inuvik  and 32% for Yellowknife  , only 56 (53%) provided a species identification  was significantly associated with Bartonella positivity in small mammals across all three models, with the highest exposure in 2019. No additional biological factors were associated with small mammal exposure in the model that defined Bartonella positivity as a PCR positive result via the ITS region . Rodent species  became statistically significant alongside year  in the model that defined Bartonella positivity with the gltA gene . Similarly, when Bartonella positivity was defined as a positive result on PCR assays for both the ITS and gltA markers, rodent species  and year  were statistically significant . Across all three models, total summer precipitation for the year prior to sampling and average minimum spring temperature during the year of sampling were statistically significant , with colder minimum spring temperatures and higher precipitation during the year prior to sampling linked to more PCR-positive small mammals.Year  and all flea samples successfully amplified on the modified gltA PCR. Our two no-template controls yielded 0 and 67 reads. An average of 12,272 raw reads per sample were obtained . Following quality filtering, two northern red-backed voles were removed from further analysis because of extremely low sequence read counts (< 50 reads) leaving 46 samples . Twenty-two unique amplicon sequence variant (ASV) sequences were identified. Four ASV sequences were removed from further analysis since they were determined not to be gltA sequences based on alignment to reference data. The average total ASV count per sample was 5662 .gltA ASV sequences and selected reference sequences. Four of the ASVs clustered with B. grahamii, nine with B. heixiaziensis, one with Candidatus B. rudakovii and three with B. vinsonii, all with good bootstrap support  . There was no agreement between sequences obtained via ITS and modified gltA PCRs for these rodents, likely because of the absence of ITS sequences for B. heixiaziensis in GenBank. There was no agreement between ASVs that resembled B. vinsonii and Candidatus B. rudakovii, despite the availability of ITS sequences in GenBank. Multiple species were not detected in rodents, and only one flea pool contained more than one species (B. grahamii and B. heixiaziensis). Of the 46 samples that underwent deep sequencing, 24 (52%) contained multiple ASVs.Seventeen unique ASVs were detected that accounted for at least 1% of the counts in at least one sample. A phylogenetic analysis was performed based on a 309-bp alignment of the Sequence data have been deposited to the NCBI Sequence Read Archive and are associated with BioProject PRJNA813524.Bartonella present in northern Canada, demonstrating the utility of conventional and metagenomic approaches. Ten distinct flea species from rodents were identified morphologically. Molecular identification with the COII gene verified the genus of most flea species (n = 9/10) and highlights the need for a larger reference library for northern vectors  that underwent deep sequencing contained Bartonella DNA, though this does not provide definitive proof of vector competence. As seen with B. henselae and cat scratch disease, a source of flea-borne transmission involves the indirect inoculation of infected flea feces, which can remain viable for up to 72 h, into cuts or abrasions on the skin [Bartonella spp. identified in small mammals and fleas during this study, similar passive mechanisms of transmission may be involved. Bartonella bacteria are dominant members of bacterial communities in several rodent fleas and mixed infections occur in the rat flea, Nosopsyllus fasciatus [Bartonella transmission is driven by interspecies interactions and exchange of fleas with low host specificity [Bartonella, revealing that conventional molecular methods underestimate Bartonella diversity in pooled vector samples.This study supports the diversity of fleas on northern small mammals and identifies a complex community of rodent-associated es n = 9/0 and hignditions , 31, 40.the skin –44. Giveasciatus , 20. Thicificity . Though Bartonella in rodents and shrews from the NT  have also been identified in Arctic foxes from the neighboring territory of Nunavut, Canada [Conventional PCR targeting the ITS region identified six species of NT Table . Rodentsudakovii . In addishoensis , 46. Cas, Canada , 47. To Bartonella (ITS PCR positives) in small mammals from northern Canada was 34% , which may not accurately represent other sampling sites. Regardless, climate change is likely to impact the survival of both ectothermic insects and small mammals [Bartonella has previously been found to be density dependent [Bartonella positivity in our study [Bartonella positivity in small mammals during 2019. Rainfall at critical times could cause flooding of rodent habitats and burrows, increasing interactions due to limited habitat as rodents search for higher ground [Bartonella. Lower spring temperatures may also lead to high rodent density as delayed snowmelt may provide longer protection in subnivean spaces and promote rodent survival [Average minimum temperature during spring (°C) and total summer precipitation during the year prior to rodent sampling (mm) were associated with  mammals , 52. Rodependent , and cliur study . There wr ground , 56. Norr ground . In turnr ground , 59. Consurvival , 59.Bartonella positive small mammals during the summer of 2019. The presence of fleas on rodent carcasses was not significantly associated with PCR positive animals across all three models . However, snap-trapped rodents are often collected up to 24 h after death, providing a window of time for ectoparasites to abandon the host, which likely caused the prevalence and abundance of fleas in our study to be underestimated.Fleas are ectothermic and sensitive to changes in temperature and precipitation ; howeverBartonella positivity as a positive ITS result. However, it was significant in the two models that defined Bartonella positivity as a positive gltA result or a positive result on both conventional PCRs. Interpreting associations between rodent species and Bartonella positivity is complicated in this case as primers targeting some genetic markers may amplify host DNA and sensitivity of the conventional gltA PCR may be lower than that of the ITS PCR  of the 170 positive small mammal samples identified on the ITS PCR were successfully sequenced and 47% (n = 49/105) of these sequences had < 97% identity with previously reported sequences in GenBank. While it is possible that the low sequence identities were due to known challenges with ITS sequence alignment or the identification of uncharacterized species, we hypothesized that these were likely due to the limited reference library available for ITS sequences [Bartonella species [gltA PCR and metagenomic sequencing. There was high agreement between the ITS and gltA targets for most rodents that were infected with B. grahamii (Table B. heixiaziensis) was detected with the metagenomic approach  on Heixiazi Island (on the border of China and Russia) [B. heixiaziensis in North America. Bartonella heixiaziensis was the second most common species detected with deep sequencing, and there were no ITS sequences available in GenBank. Thus, we suggest that the absence of reference sequence data for the ITS region accounts for many of the specimens with low sequence similarity following conventional PCR (Table B. heixiaziensis DNA via deep sequencing of the gltA gene. These sequences are available in GenBank (accession numbers ON226744 and ON226745).Only 62%  [Bartonella positivity and addressed previously reported strengths and weaknesses of conventional PCR with genetic loci (gltA and ITS) commonly used for detection and identification of Bartonella spp. A metagenomic approach was used to detect one additional species of Bartonella (B. heixiaziensis) in northern red-backed voles that was previously unreported in North America and demonstrated that northern flea pools can contain multiple bacterial species. Future studies that aim to describe the composition of Bartonella communities in hosts and vectors accurately should use multiple loci to identify species and implement a metagenomic approach to detect the diversity of Bartonella within samples.We found a diversity of previously undescribed rodent-associated r hosts) . In addi


Qualitative data was collected based on feedback from participants to gain insight into how the gSST was received by participants. A positive correlation was observed between impulsive/hyperactivity and gSST performance, however there was insufficient evidence to suggest that impulsivity predicted performance. With regards to accuracy, results suggested that impulsivity level significantly predicted the rate of go-omission errors. No relationships were observed between intrinsic motivation inventory (IMI) subscales and performance or IMI and impulsivity. Nevertheless, mean IMI scores were overarchingly high for each of the IMI subscales, suggesting that regardless of performance and/or level of impulsive behaviour, the child sample obtained in this study demonstrated high levels of intrinsic motivation, which was supported by the predominantly positive subjective feedback provided by the child participants. The present study provides some evidence based on quantitative and qualitative results for the efficacy of gSST for use with children. Future research with a larger sample of children is warranted to examine how performance on the SST and gSST compare/differ.This proof-of-concept study provides an appraisal of a remotely administered gamified Stop-Signal Task (gSST) for future use in studies using child sample. Performance on the standard Stop-Signal (SST) task has been shown previously to differentiate attention-deficit-hyperactivity-disorder groups from controls. As is the case with the SST, it was envisaged that those with greater impulsivity would perform worse than those with lower levels of impulsivity in the gSST. The potential advantage of the gSST is that it could be perceived as less monotonous than the original SST and has the potential to provide higher data quality in child samples, however future research will need to be conducted to determine this. The gSST was administered remotely  Impulsivity is a multifaceted behaviour which encompasses, for example, poor response inhibition and reduced ability to delay reward . Higher via motor responses such as in the Stop-Signal Task . SST stimuli are typically presented in black and white on a screen without interfering distractions . While tGamification is the application of game design elements to improve participant motivation . GamificGamification may help to improve engagement and reduce dropout rates, which is imperative when carrying out research on hard-to-reach samples . HoweverMore recently, This validation study has shown promising results, whereby the gSST was rated as more enjoyable than the SST without compromising on the task’s internal validity, which provides support for the gSST as an accurate measure of response inhibition. Results demonstrated that using a more visually complex and immersive task environment is useful in enhancing the ecological validity of the task, which is necessary to alter participants’ affective states, rather than merely changing the aesthetics of the stimuli .The aim of the present proof-of-concept study was to administer the gSST on a community sample of children aged 8–12 for the first time in order to ascertain whether future research with the gSST in child samples would be viable. As the gSST has not been previously administered with children before, level of burden to participants was kept to a minimum so as not cause unwanted fatigue. In doing so, only the gSST was administered, meaning there was no control measure (comparison results on gSST with SST). Nonetheless, the impact of ADHD behaviours and intrinsic motivation on gSST task performance were examined. As such, it was investigated whether impulsivity level was related to the degree of intrinsic motivation when engaged with the gSST. In addition, any feedback provided by participants throughout gSST administration was collected to gain insight into the experience of playing the gSST from the perspective of children.via video chat using a laptop or computer. Firstly, the parent/guardian would provide brief demographic details followed by completion of the Barkley ADHD symptom scale on behalf of their child  and one of their parents. Four parents indicated that their child had a diagnosis of ADHD, the remaining had no ADHD diagnosis. Type of ADHD diagnosis, where applicable, was not recorded in the sample. Participants were recruited via posters and information sheets circulated by teachers/principals in five primary schools around Ireland to parents of children within this age range. Child participants did not require an ADHD diagnosis in order to take part. Children with ADHD were, however, eligible to take part so as to capture the variability of impulsivity within a community sample and four of the children (out of 30) had a diagnosis of ADHD.Data were obtained from 30 children aged between 8 and 12 , in which participants were presented with an avatar running down a path towards a series of crossroads. Participants were instructed to use their keyboard arrow keys to follow the directions given by a magical fairy who would point her arrow in either the left or right direction in order to guide the avatar out of the haunted forest. The narrative describes an evil witch who masqueraded as the fairy, who can be identified The gSST consisted of four blocks of trials, each containing 50 trials, 75% of which were go-trials and 25% were stop-trials. Between separate blocks, a pause of 15 s was given to allow the participant to get ready for the next block. The go-stimulus was presented for a maximum of 1,500 msec or until a response was produced. The stop-signal sounded over the laptop/computer speakers. Retaining the integrative method of the Horse Race Model see , on succa = 0.961) is based on an 18-item DSM-5 ADHD symptoms checklist. Parents were asked to rate whether their child experienced each symptom on a scale of 0 (never) to 3 . Nine items related to inattention and nine items related to impulsive/hyperactivity. Of the impulsive/hyperactivity items, three related to impulsivity alone. This scale does not have a cut-off for ADHD diagnosis, so it was not possible to classify children as ADHD or non-ADHD  consisting of 4 subscales: Enjoyment/interest (a = 0.864), perceived competence (a = 0.807), effort/importance (a = 0.588) and pressure/tension  was used to extract the gSST data and exported to IBM SPSS statistics (Version 27). The gSST data was matched with the survey data obtained t (24) = −0.104, p = 0.918] or age . There were no observable difference in SSRT scores between those with and without an ADHD diagnosis . See There were no significant differences in performance with regards to gender  than stop-trials as expected for the gSST results to be validated on the present sample. See In order to validate the stop-signal data obtained, a paired samples t-test was used to confirm that there was a significant difference between the mean go-trial reaction time and the mean stop-trial reaction time (failed response inhibition) as recommended by r (24) = 0.357, p = 0.037 as was expected based on previous findings, see r (24) = 0.323, p = 0.054 and inattentive subscale r (24) = 0.179, p = 0.191, there were no significant correlations observed which does not support previous findings which suggest that impulsivity predicts performance on the gSST. As expected, there was no association between inattentiveness and gSST performance. Given that only one of the three subscales demonstrated a significant relationship with gSST performance, a simple linear regression model was produced to investigate the effect impulsive/hyperactivity behaviours had on SSRT scores. However, there was not enough evidence to suggest that level of impulsive/hyperactivity predicted gSST performance  = 3.503, p = 0.073).The primary research question sought to explore the effect of impulsivity on gSST performance (SSRT). See R2 = 0.318; F  = 3.426; p = 0.035]. According to the model, it can be said that approximately 32% of the variance in go-omission error rate can be attributed to ADHD symptoms. Looking at the coefficients, it was found that the impulsivity subscale alone significantly predicted variation in go-omission error rate  while impulsive/hyperactivity  and inattentiveness  did not. Taking the adjusted 2R into consideration, the model was strengthened by the removal of the inattentive subscale as a predictor from the model. . See All three ADHD symptom subscales were analysed as predictors of go-omission error and go-commission error rate. For go-omission errors, the multiple linear regression model was statistically significant  were observed to significantly predict rate of go-commission errors made by respondents in this sample. It must be noted that there was a very low count overall of go-commission errors obtained within the present sample. See The multiple linear regression model was repeated to examine whether ADHD symptoms predicted go-commission error rate. In this case, none of the three ADHD subscales of impulsivity, impulsive/hyperactivity or inattention , perceived competence , effort/importance  and pressure/tension .There was no relationship observed between intrinsic motivation and gSST performance for any of the four subscales: Interest/enjoyment , perceived competence , effort/importance  and pressure/tension . See There was no significant relationship observed between impulsivity with regards to intrinsic motivation: Interest/enjoyment  look like me?” and other elements of game appearance “I do not like fairies, can I change the fairy to a monster.” While there is risk that introducing an overarching sense of urgency to the game may drive feelings of extrinsic motivation rather than intrinsic motivation, there is some scope to introduce some of the suggested elements in order to retain motivation in the latter stages of the task to combat fatigue , it is something worth assessing in future studies with larger samples. That being said, previous studies have struggled to find differences in SST performance in samples of children who demonstrate impulsive/hyperactive behaviours compared with controls . Future With regards to errors on the gSST, impulsivity alone predicted almost 32% of the variance in go-omission errors which bolsters previous response inhibition research on ADHD vs. non-ADHD samples . TherefoImpulsivity did not predict level of go-commission errors. However, prevalence of this type of error remained low in the sample. Future gSST studies should investigate differences in error rates when child participants are subjected to both the original SST and the gSST. While The relationship between intrinsic motivation and gSST performance as well as the effect of impulsivity on intrinsic motivation were analysed, with no relationship observed for either construct. Despite this, overall high mean IMI scores were observed. Therefore, regardless of performance and/or level of impulsive behaviour reported, the present sample demonstrated high levels of intrinsic motivation during the gSST. Making loose inferences between the present IMI scores and those obtained in the validation study, intrinsic motivation was higher within this child sample, indicating that the gSST may be more aptly suited to child cohorts than adult cohorts . HoweverFeedback and recommendations from participants were collected about the gSST. Many useful insights were expressed, providing valuable perspectives and suggestions for task improvement. For example, providing some level of performance feedback to participants either during or upon completion of the gSST could contribute to improving feelings of competency. Such simple adaptions could be beneficial over others which may create an extrinsically motivated pull that could distract from what is essentially being measured.Remote administration of the gSST proved possible. Children took part in the game remotely from the comfort of their own home. Level of task understanding was satisfactory, with data from only 2 of 30 participants excluded from final analyses due to lack of understanding of task requirements. However, it is unknown whether remote administration had any effect on gSST performance, and it could be argued that the casual setting may have contributed to the rate of go-omission errors due to participant distraction. It is possible that the benefits may outweigh disadvantages, especially for those who tend to perform less well in pressured situations, and allow researchers to collect data from a wider, more representative sampling pool . HoweverIn this community sample, type of ADHD was not accounted for, whether that be impulsive/hyperactive type, inattentive type, or combined type . As a reFurthermore, it should be noted that the overall internal reliability of the IMI scale was suboptimal within the present sample. IMI subscales have previously been adapted for administration in child/adolescent samples to suit the context and age of the cohorts . Some adFurthermore, there was no data recorded as to whether the participants in the sample were interested in/engage in online games, which may have biased the enjoyment of and performance on the gSST if the games they play test response inhibition. Future research using the gSST should take this into consideration.Future research is needed to validate the gSST in a child sample. The gSST has the potential for further optimisation in order to render the task more applicable for everyday scenarios. The qualitative feedback obtained from participants in the present study has provided insightful suggestions for improvement of game characteristics. For example, a follow-up study by However, it must be noted that while positive feedback was provided, it is not possible to ascertain whether the gSST was better received by the children than the original SST as they were not subjected to both tasks.Further, future studies may aim to validate the gSST in a larger child sample, as well as administer the basic task version for comparative purposes. However, future researchers need to consider that children, in particular, are prone to experimental fatigue and must plan the study accordingly .This proof-of-concept study has provided some evidence for the efficacy of the gSST for use with children through feedback provided from participants as well as high levels of intrinsic motivation observed.The original contributions presented in the study are publicly available. This data can be found here: osf.io/p4b5y [DOI 10.17605/OSF.IO/GF3VX].The studies involving human participants were reviewed and approved by University College Dublin Ethics Committee. Written informed consent to participate in this study was provided by the participants' legal guardian/next of kin.All authors listed have made a substantial, direct, and intellectual contribution to the work, and approved it for publication.MF was supported by the German Research Foundation  and the Max-Planck Society.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Diagnosis and pharmacological treatment of ADHD are more common among the youngest children in a classroom, born in the months immediately preceding the school entry cutoff date. The mechanisms behind this phenomenon, called the relative age effect (RAE), are not yet well understood. Nearly all hypotheses involve the school system, various teachers’ actions, and concern children’s immaturity. However, most previous studies have been based on reports of health professionals’ diagnoses and prescriptions found in official databases rather than on reports of teachers’ behavior identification or suspicion of ADHD, despite their being at the first stages of the medicalization process. Our study overcomes this limitation by using reports of parents’ and teachers’ behavior identification or suspicion of ADHD within a three-level multilevel survey design, comprising 1294 children, 130 teachers, and 17 elementary public schools. The goal of our study was to investigate whether RAE stems (1) from adults’ judgement of the child’s expression of immaturity or (2) from the consequences associated with the child’s double burden of being immature and exhibiting ADHD behaviors. Our multilevel analyses put forward the first hypothesis only, supporting the medicalization of immaturity. RAE in ADHD seems mostly initiated by teachers’ pre-diagnostic actions toward younger children. Attention Deficit/Hyperactivity Disorder (ADHD) is a psychiatric diagnosis characterized by abnormal levels of hyperactivity, impulsivity, and inattention expressed in at least two settings . With aNevertheless, the absence of a clear-cut test indicating the presence or absence of ADHD in children and the fact that ADHD symptoms are common children’s behaviors open the door to identification and labeling errors, in addition to questions concerning the validity of the diagnosis ,5,6. FroAmong the reasons for the misdiagnosis and overdiagnosis assumptions is the unequal distribution of ADHD-related symptoms, diagnosis, and medication, according to children’s specific social characteristics. Many studies have shown, for example, that youth from low socioeconomic backgrounds and boys have increased probabilities of being diagnosed with ADHD and prescribed medication to manage their symptoms ,12,13. ITo determine when a child should enter school, his/her birthdate is compared with the school entry cutoff date. Up to a year can separate the youngest and oldest children in a classroom, which makes a world of difference at such a young age. Compared with their older classmates, younger students have been found to be more at risk of being diagnosed with and taking medication for ADHD. This phenomenon has been observed in various regions worldwide, including North and South America .Parents’ and teachers’ accounts of behaviors have been considered in only a handful of studies on the RAE in ADHD ,21,22,23At least six hypotheses have been proposed to explain the RAE in ADHD ,17,32. TThe remaining four hypotheses share common elements but propose different mechanisms of actions. They all occur within the school system, involve various teachers’ action, and concern children’s immaturity. The first one suggests that school policies regarding the timing of school entry may explain the relationship between RAE and ADHD diagnosis. Some countries, such as Denmark, have more flexible school entry policies, which encourage some children to wait an extra year before entering school . This prA second hypothesis suggests that “entering school at a young age triggers ADHD” due to the younger-in-class students generally struggling to meet the demands of the classroom ,34. In tA third hypothesis suggests that adults, mainly teachers, may mistake children’s immaturity for ADHD-related behaviors ,20. ImmaA fourth hypothesis proposes rather that the RAE in ADHD stems from a functional impairment in children created by a double burden. Whereas younger students in a class are not expected to show higher levels of ADHD behaviors than their older peers do, they are expected to have more difficulties dealing with the social and academic demands of the classroom ,33. ThusHypothesis 1 (H1).School policies regarding the timing of school entry may explain the relationship between RAE and ADHD diagnosis.Hypothesis 2 (H2).Entering school at a young age triggers ADHD.Hypothesis 3 (H3).Adults’ confusion between ADHD symptoms and immaturity.Hypothesis 4 (H4).The RAE in ADHD stems from a functional impairment in children created by a double burden (immaturity and ADHD behaviors).H3) by looking for the RAE in ADHD at various stages of the medicalization process: (a) identification of ADHD-related behaviors, (b) informal medical labeling of ADHD through suspicion, and (c) official medical labeling and its associated treatment  of 1.11  1.06–1.16). Specifically, being born in September is associated with an OR of 3.03 (CI 1.81–5.07) of being suspected of ADHD by teachers.Teachers suspected ADHD in 20.9% of the children, which was significantly greater than the parents’ suspicion rate  and the outcome teacher’s having mentioned ADHD to parents .Similarly, the student’s relative age variable was statistically significant for the outcome medication intake would be more beneficial . However, the RAE phenomenon was not statistically significant for taking ADHD medication , despite an important difference between children born in September (29.1%) and those born in October (15.8%). Thus, younger children had a greater risk of being diagnosed with ADHD but not of being prescribed medication.ADHD diagnosis was reported in 16.5% of children born in October, a proportion that has almost doubled for children born in the months preceding the cutoff date: August (27.3%) and September (30.9%). The student’s relative age variable was statistically significant for this outcome  were significantly associated with struggling in school but RAE was not . The second step involved testing for a double interaction between relative age and ADHD behaviors in the probability of struggling in school. The results of the multivariate multilevel logistic regression analyses showed a statistically significant double interaction between ADHD-related behaviors and RAE . Therefore, the effect of a student’s relative age on struggling in school differs with hyperactivity and inattention behaviors. The decomposition of the interaction term showed a steady decline in the strength of the association between ADHD-related behaviors and struggling in school for each month between October  and September . The results then show that the effect of age on struggling becomes less strong when ADHD-related behaviors are higher. The third step of the analysis consisted of testing for a three-way interaction between relative age, ADHD behaviors, and struggling in school in the probability of teachers suspecting ADHD. Results of the multivariate multilevel logistic regression analyses showed that the triple interaction was not statistically significant .The results of the fixed effects of the multilevel regression models for each model testing Hypothesis 4 did not support this assumption. The analysis of the main effects showed that ADHD behaviors  [H3).In sum, whereas our study design cannot totally rule out the possibility of the involvement of other mechanisms, such as children’s ADHD being triggered once they enter the school system (H2) , our resH4), which suggested that teachers were more likely to identify children having the double burden of being young in class and exhibiting ADHD behaviors because of their greater struggle in school. This hypothesis emphasized the importance of functional impairment as the main reason to seek medical care [We tested another hypothesis  the inclusion of various adults’ viewpoints on the child and (b) an examination of various stages of the medicalization process. To our knowledge, our study is the first in which the authors checked for the presence of the RAE in parents’ and teachers’ suspicions of ADHD. This may provide insight into the mechanism underlying the RAE in official medical diagnoses, given that teachers and parents are the first to suggest ADHD in children ,28. ThisNevertheless, a limitation of our study is the fact that we could not compare the perception of the various adults on every ADHD-related outcome. Most outcomes were reported by either the teachers or the parents; only suspicion of ADHD was reported by both. Future studies would benefit from a comparison of answers to common questions, which would help in understanding the role of various adults in the ADHD labeling and medicalization process. The identification of teachers’ characteristics that may be more or less associated with the medicalization process of younger-in-class students could help in building more effective preventive actions targeting teachers and other school actors . AdditioThe greater risks of ADHD-related outcomes among younger-in-class students are explained mostly by the medicalization of immature behaviors, which gives strength to the fears about ADHD overdiagnosis ,10. Rese