We used automated tractography to examine whole-brain and mean FA of the tracts most frequently reported in ADHD; corpus callosum forceps major and forceps minor, left and right superior-longitudinal fasciculus, and left and right corticospinal tract (CST). Associations between FA and hyperactivity severity appeared when in-scanner head motion was not accounted for as mediator. However, causal mediation analysis revealed that these effects are fully mediated through in-scanner head motion for whole-brain FA, the corpus callosum forceps minor, and left superior-longitudinal fasciculus. Direct effect of hyperactivity severity on FA was only found for the left CST. This study illustrates the crucial role of in-scanner head motion in the identification of white matter integrity alterations in ADHD and shows how neglecting irremediable motion artifacts causes spurious findings. When the mediating effect of in-scanner head motion on FA is accounted for, an association between hyperactivity severity and FA is only present for the left CST; this may play a crucial role in the manifestation of hyperactivity and impulsivity symptoms in ADHD.Attention-deficit/hyperactivity disorder (ADHD) is a common and debilitating neurodevelopmental disorder associated with various negative life impacts. The manifestation of ADHD is very heterogeneous, and previous investigations on neuroanatomical alterations in ADHD have yielded inconsistent results. We investigated the mediating effect of in-scanner head motion and ADHD hyperactivity severity on motion-corrected fractional anisotropy (FA) using diffusion tensor imaging in the currently largest sample ( Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder diagnosed in approximately 7.2% of school-age children . ADHD afHowever, past research on the white matter underpinnings of ADHD has produced discrepant results , 10, 11.Previous findings are exceptionally mixed for the corpus callosum (CC), the superior longitudinal fasciculus (SLF), and the corticospinal tract (CST) including the corona radiata (CR), internal capsule (IC), and cerebral peduncle (CP) , 12. SomPotential reasons for these discrepancies may be small sample sizes , and disAnother major issue in past research concerns the handling of in-scanner head motion during preprocessing and statistical analysis , 10, 48.Here, we investigate the causal mediation effect of in-scanner head motion and ADHD on whole-brain and tract-wise FA of six tracts previously most commonly reported in relation to ADHD; forceps minor of CC, forceps major of CC, left and right CST, and left and right SLF. Prior to the causal mediation analysis, we compared two approaches to identify which ADHD representation best explains the measured data: using an ADHD rating scale for a full-spectrum dimensional representation of hyperactivity severity  and the Participants were included from the Healthy Brain Network (1st–7th release), an ongoing open data acquisition initiative by the Child Mind Institute . All parn = 65) or an ADHD-HI diagnosis (n = 30) were excluded due to underrepresentation and overall rarity of ADHD-HI in the global population [Participants were included if they received an ADHD diagnosis or had no diagnosis of any mental disorder . Participants underwent acquisition of structural T1-weighted imaging and diffusion tensor imaging (DTI). All participants included were right-handed, defined as an Edinburgh Handedness Inventory (EHI) total score above 40 , 58, andpulation . SpecifiParticipants whose MRI data could not be preprocessed due to severe artifacts or did not pass visual inspection by a rater blind to the demographics and psychological conditions were excluded  pipeline  using FMBriefly, DTI scans were denoised  and corrPreprocessing continued with outlier detection and robust estimation of MRI parameter , tensor We used the deterministic streamline-tracking algorithm Automating fiber-tract quantification  –78 to exFirst, a T1-weighted scan, which was co-registered to the DTI scan, was used to set anatomical regions of interest as seeds for tractography. Second, whole-brain tractography was computed with the default FA threshold of 0.2, an FA mask threshold of 0.3 , and an We obtained FA tract profiles for 100 equidistant segments for each participant and tract of interest. From these profiles, we calculated for each participant (a) whole-brain mean FA based on all profiles of all identifiable tracts and (b) a tract-wise mean FA by averaging the FA tract profile for each of the following six tracts: the CC forceps minor and major, the left and right CST, and the left and right SLF see Fig. . Hence, All statistical analyses were conducted in R version 4.1.1. Formulas are described using the Wilkinson notation.First, we identified the best generalized linear mixed-effects model for explaining the data. We used both a categorical and dimensional representation of ADHD on whole-brain FA to identify the most explanatory model for both approaches. The base model contained whole-brain FA (continuous) as dependent variable, in-scanner motion (continuous) as variable of interest and age (continuous), sex , IQ (continuous), and acquisition site  as confounding factors. The acquisition site was included to account for different scanning sites . ThWe used a causal mediation analysis  to invesModel M0: FA ~ Age + Sex + IQ + Site + SWAN-HY.Model M to assess the effect of SWAN-HY on in-scanner head motion was defined asModel M: Motion ~ Age + Sex + IQ + Site + SWAN-HY.Model Y, which comprises the effect of SWAN-HY and the effect of in-scanner head motion on FA, was defined asModel Y: FA ~ Age + Sex + IQ + Site + Motion + SWAN-HY.Models M and Y were used as input for causal mediation analysis. Figure Nested model comparison using ANOVA . At tract level, a significant ACME was observed for the CC forceps minor , and the left SLF . An average direct effect (ADE) of SWAN-HY on FA was observed for the left CST  (Table p < 0.0102 using the method suggested by Nyholt (2004) [The premise for causal mediation analysis revealed that ADHD symptomatology  is associated with larger in-scanner head motion in all structures analyzed in this study Table . The caut (2004)   considered head motion as a confounding factor in their statistical analysis , and NagIn contrast, a direct effect of SWAN-HY on lower FA was observed for the left CST. This supports previous findings of lower FA , 26–29 iThe CST is a projection fiber tract originating at the corona radiata (CR) and extends into the internal capsule (IC) and further into the cerebral peduncle (CP) . The CSTA clear limitation of this study is the lack of an ADHD-HI subgroup in all analyses; this presentation was excluded due to the small sample size. Furthermore, the SWAN-HY score is not a clinical diagnostic measure. High SWAN-HY scores need not imply an underlying ADHD-C or ADHD-HI diagnosis yet are highly correlated with clinical presentations .Another limitation concerns the interpretability of FA and its reflection of white matter integrity. Lower FA is commonly interpreted as resulting from deficient myelination or poorer fiber health, which is often summarized as poorer white matter integrity , 100. Hop < 0.0102 using the method suggested by Nyholt (2004) [Furthermore, the reported effects would not have survived correction for multiple comparisons when considering a corrected significance level of t (2004) . Thus, fIn light of the disagreement on categorical vs. dimensional representations of ADHD manifestations, we compared these two approaches. We identified the SWAN-HY score as more suitable in comparison to the SWAN-IN score and the clinical DSM-5 diagnosis, and used it in line with the RDoC to identify neuroanatomical underpinnings of ADHD with causal mediation analysis. When disregarding the role of in-scanner head motion, we observed an effect of the SWAN-HY score on FA in several tracts. However, the causal mediation analysis revealed most of these associations to be mediated by in-scanner head motion. Therefore, future investigations should focus on the distorting effect of irremediable motion artifacts in DWI. When accounting for a mediating effect of in-scanner head motion, we identified the left CP of the CST tract as the only structure to be directly influenced by hyperactivity. This finding and the role of the CP in the fronto-striatal-cerebellar neurocircuitry supports its interpretation as a biological substrate of ADHD.Supplemental Material


The factors responsible for promoting or inhibiting β-H elimination are explored via density functional theory (DFT) calculations, in metathesis of ethylene or styrene (a representative 1-olefin) by Ru–CAAC and Ru–NHC catalysts. Natural bond orbital analysis of the frontier orbitals confirms the greater strength of the orbital interactions for the CAAC species, and the consequent increase in the carbene trans influence and trans effect. The higher trans effect of the CAAC ligands inhibits β-H elimination by destabilizing the transition state (TS) for decomposition, in which an agostic MCB Cβ–H bond is positioned trans to the carbene. Unproductive cycling with ethylene is also curbed, because ethylene is trans to the carbene ligand in the square pyramidal TS for ethylene metathesis. In contrast, metathesis of styrene proceeds via a ‘late’ TS with approximately trigonal bipyramidal geometry, in which carbene trans effects are reduced. Importantly, however, the positive impact of a strong trans-effect ligand in limiting β-H elimination is offset by its potent accelerating effect on bimolecular coupling, a major competing means of catalyst decomposition. These two decomposition pathways, known for decades to limit productivity in olefin metathesis, are revealed as distinct, antinomic, responses to a single underlying phenomenon. Reconciling these opposing effects emerges as a clear priority for design of robust, high-performing catalysts.Ruthenium–cyclic(amino)carbene (CAAC) catalysts, used at ppm levels, can enable dramatically higher productivities in olefin metathesis than their N-heterocyclic carbene (NHC) predecessors. A key reason is the reduced susceptibility of the metallacyclobutane (MCB) intermediate to decomposition  via β-H elimination, but increase susceptibility to bimolecular decomposition.In ruthenium catalysts for olefin metathesis, carbene ligands of high trans influence/effect suppress decomposition  Indeed, despite a handful of examples in specialty-chemicals and pharmaceutical manufacturing,26 industrial uptake of molecular olefin metathesis catalysts has been much slower than anticipated when the ruthenium catalysts were first developed in the 1990s.30Olefin metathesis is prized for its versatility in enabling the catalytic assembly of unactivated alkenes.31–33 . Now well established are the mechanisms of degradation by nucleophiles34–37 and Brønsted base.37,38 As well, in advances critical for applications in chemical biology and related contexts (including DECL technology), we are beginning to understand how these catalysts decompose in water-rich environments.5,39–41Much effort has been committed to identifying the pathways that underlie decomposition of the widely-used “second-generation” ruthenium catalystsintrinsic decomposition modes – that is, pathways inherent to the catalysts themselves – involve bimolecular coupling of the [M] PBM data was replaced with SVG by xgml2pxml:<glyph-data id="z.dbd" format="PBM" resolution="300" x-size="8" y-size="10" xml:space="preserve">00000000000000000000000000000000111111110000000011111111000000000000000000000000</glyph-data><svg xmlns="http://www.w3.org/2000/svg" version="1.0" width="13.200000pt" height="16.000000pt" viewBox="0 0 13.200000 16.000000" preserveAspectRatio="xMidYMid meet"><metadata>Created by potrace 1.16, written by Peter Selinger 2001-2019</metadata><g transform="translate scale" fill="currentColor" stroke="none"><path d="M0 440 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z M0 280 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z"/></g></svg>CH2 intermediates, and β-H elimination of the metallacyclobutane . Coordinative saturation and ligand bulk or rigidity can thus inhibit β-H elimination.47–50 Recent studies reinforce the critical role of steric and geometric factors in enabling C–H agostic binding.49,51 Aside from the requirement of an empty metal d orbital to accept electron density from the Cβ–H bond ,48,50 electronic effects are less clear-cut.47–59 Whereas a more electron-rich metal has been suggested to accelerate Cβ–H bond-breaking,54 high trans-influence60 ligands  have been reported to inhibit β-H elimination by destabilizing the required transition-state species.52,53,57–59In the broader context, the factors that promote or suppress β-H elimination for a given organometallic complex are incompletely resolved. Textbook requirementse.g., the Shell Higher Olefin Process,61 Mizoroki–Heck coupling),62,63 and its detrimental role in others  of terminal olefins). Critical in the latter two reactions is formation of an unsubstituted MCB that is particularly susceptible to β-H elimination.66 This vulnerability underlies the highly detrimental impact of ethylene on metathesis by Ru–NHC and Ru–phosphine catalysts,67 documented in process chemistry,26–29 continuous-flow metathesis,68–72 and in the renewables sector,26,73,74 where CM with ethylene (‘ethenolysis’) would otherwise offer the simplest, most powerful means of transforming fatty acid methyl esters (FAMEs) into α-olefins. Less discussed, but likewise critical, are the implications for stereoselective olefin metathesis, given the ability of isomerization-active catalyst decomposition products to erode the selectivity designed into the precatalysts.75–77Insights into the parameters that govern β-H elimination have broad relevance in catalysis, given the central, enabling role of β-H elimination in certain contexts .78 Contrasting behavior was observed for H2IMes catalysts , all of which decomposed via a combination of BMC and β-H elimination, with the exception of GIII.43 Diagnostic for β-H elimination is the observation of propene products, formed via loss of the metallacyclobutane ring. While the yield of propenes for nG-C1Ph or nG-C2Me was nearly nil, it was >50% for, e.g., the widely-used Grela catalyst nG . In assessing complete catalyst decomposition, the intensity of the NMR signals for the organic products is evidently of greater quantitative value than those for the Ru species.2IMes complexes, the unsubstituted MCB has been identified as much more susceptible to β-H elimination than its substituted analogues.66 In the present calculations, we therefore focused on the unsubstituted MCB. viaTS2′-2 are 22.8 or 30.6 kcal mol−1 for C1Ph and C2Me, respectively . Reaction with ethylene generates the active 14-electron complex 2′, in which the methylidene is anti to the CAAC NAr moiety. Reaction of 2′ with ethylene affords the square-pyramidal π-complex 3′, in which the bound ethylene and the methylidene ligand are mutually perpendicular. Cycloaddition generates the trigonal bipyramidal (TBP) MCB intermediate 4, which upon cycloreversion gives π-complex 3. The latter releases ethylene to form the most stable 14-electron methylidene complex 2, thus completing the unproductive ethylene metathesis reaction. The reverse pathway starts from 2 and ends with 2′.This has important implications for the CAAC complexes, owing to their lack of symmetry. In all three square-pyramidal precatalysts 1, the most stable geometry is that in which the alkylidene and the CAAC NAr group are via β-H elimination , propenes are a clear and unambiguous marker for decomposition via β-H elimination.42,43,78In the absence of competing reactions, this process is repeated until MCB 4 decomposes mination .83 The l−1; see Table S2via β-H elimination, and hence the reference point against which free energies are calculated . These DFT-calculated differences in free-energy barriers are sufficiently large that less β-H elimination is expected for CAAC catalysts than for nG, consistent with the much higher proportion of propene decomposition products for the latter.78Reaction of the catalyst precursors with ethylene to form the unsubstituted MCB 4 is exergonic in all cases  enables a reduction in the Ru-Cα-Cβ-Hβ dihedral angle by more than 70° on going from 4 (where it is ca. 119°) to TS4-5.It may be noted that β-H elimination for any of these MCBs is expected to be slower than for any corresponding acyclic structures, because the requirement for 2IMes catalyst will react with ethylene more readily than do its CAAC counterparts. Whereas ethylene binding to methylidene complexes 2/2′ to form π-complexes 3/3′ is endergonic for the CAAC catalysts, ethylene binding stabilizes the H2IMes catalyst; it also lowers the barrier to MCB formation viaTS4-3 or TS3′-4. We will return to the origin of this difference below. Although somewhat slower MCB formation is predicted for the CAAC catalysts, the barriers to formation of 4 from 2/2′ are negligible. More significantly, the preferred Ru methylidene rotamer 2 is 2.0–3.8 kcal mol−1 more stable (vs. the resting state 4) for the CAAC complexes than their H2IMes analogue. Higher concentrations of the 14-electron methylidene 2 will therefore be present during catalysis for the CAAC catalysts, accounting for their faster decomposition via bimolecular coupling.42,43Importantly, the calculations also predict that the H2IMes derivative. Here we evaluate the relative metathesis productivity of these catalysts, by comparing their barriers to β-H elimination (viaTS4-5) vs. those to self-metathesis of styrene to form trans-stilbene  and styrene metathesis  is seen for the H2IMes catalyst than the CAAC catalysts. Specifically, the difference is 6.3 kcal mol−1 for nG, vs. 10.4 or 8.7 kcal mol−1, respectively, for nG-C1Ph or nG-C2Me: see 2IMes catalyst thus has a lower energetic ‘buffer’ against β-H elimination from the unsubstituted MCB, consistent with its greater susceptibility to this decomposition pathway.78A smaller energy difference between the barriers to β-H elimination , which is centered on the carbene carbon atom and has σ-symmetry with respect to the metal–carbene bond. The lowest unoccupied molecular orbital (LUMO) is the corresponding unoccupied carbene frontier orbital with π-symmetry. The energies of the frontier orbitals suggest that the two CAAC ligands should have similar donor/acceptor properties, but that both should be better σ-donors and better π-acceptors than H2IMes.To probe the stereoelectronic factors responsible for the outstanding productivity and robustness of the CAAC catalysts, we examined properties of the carbene ligands and their Ru complexes. In general, CAAC ligands are known to have less stable σ-donor orbitals and more stable π-acceptor orbitals than corresponding cyclic diaminocarbenes, and therefore to be both better σ-donors and π-acceptors.he metal .93,94 Ca96 of 4 confirmed stronger σ-donation as well as π-back-donation for the CAAC complexes  than for the H2IMes complex (0.57/0.15 electrons). The stronger orbital interactions for the CAAC ligands give rise to stronger bonds to ruthenium: the calculated bond dissociation free energies are ca. 5 kcal mol−1 higher  than for H2IMes .Critical in metathesis is the impact of these differences on the frontier orbital energies in the unsubstituted MCB. Following the procedure described in ref. 60 In addition to weakening trans-positioned bonds in equilibrium geometries, the strong orbital interactions of the CAAC ligands have critical kinetic consequences. In transition state TS4-5, the rupturing Cβ–H bond approaches the ruthenium center trans to the carbene  have been found to retard oxidative addition of methane and ammonia at the site trans to X in Ir(i) complexes.97 A related, more indirect, effect on the rate of β-H elimination has been observed in olefin metathesis for d0 molybdenum and tungsten catalysts, in which higher barriers to β-H elimination have been calculated for oxo-stabilized MCBs than for their imido analogues.58 The d0 metal catalysts preferentially undergo β-H elimination after isomerizing to a square-pyramidal MCB, in which the Cβ–H bond approaches the metal cis, rather than trans, to the imido or oxo ligand. The latter ligands are trans to one of the rupturing M–C bonds of the MCB, and hence destabilize the β-H elimination transition state58 .60 A similar role of the oxo ligand in retarding β-H elimination was recently described for vanadium–oxo olefin metathesis catalysts.57 Taken together, all these examples suggest that high trans-effect ligands offer an important general strategy, valid across multiple catalytic manifolds, to suppress β-H elimination.Computational studies of alkyl cross-coupling via bimolecular coupling.42 These two decomposition pathways, long viewed as independent, can now be recognized as opposing responses to a single underlying phenomenon, which originates in strong ligand binding. This is particularly important given the transformative role played by strong carbene donicity in Ru-catalyzed olefin metathesis.30,98In ruthenium-catalyzed olefin metathesis, the capacity of the high trans-effect carbene ligand to inhibit β-H elimination can now be explicitly identified as a key contributor to the remarkable productivity of the CAAC catalysts. The high trans effect also has negative consequences, however, as we recently demonstrated: the labilizing effect of the CAAC ligand increases the concentration of the four-coordinate methylidene species 2/2′, and thus promotes decomposition CH2 bond,99–101 and the double bond is nearly intact, with very little interaction with the methylidene, as suggested by a Wiberg bond index 102 of >1.5 for the ethylene Cα–Cβ bond, and <0.15 for its Cβ–Cα bond to the methylidene . The barrier to metathesis of ethylene hence increases by ca. 5 kcal mol−1 for the CAAC complexes, compared to the H2IMes analogue.In addition to retarding β-H elimination, the high trans influence of the CAAC ligands destabilizes the ethylene π-complexes 3/3′, in which ethylene  binds trans to the carbene. “Early” transition states are seen en route to the MCB 4 (TS3′-4 and TS4-3). That is, the TS geometries closely resemble those of the square-pyramidal π-complexes : the ethvia a “late” transition state  or is well on the way to forming the fourth σ-bond (TS8-9 and TS9-10′). The Ru–Cβ Wiberg bond indices of these late transition states ; see Styrene metathesis is thus little affected by the carbene trans effect, in contrast to β-H elimination and ethylene self-metathesis. Indeed, the barriers to styrene metathesis are within 1.3 kcal molPh, vs.nG-C2Me  is presumed to reinforce the positive effects of the quaternary phenyl substituent on metathesis productivity.79,103These differences in barrier heights imply that the CAAC catalysts are less susceptible to non-productive cycling with ethylene. The superior productivity of the CAAC catalysts thus arises not merely from their resistance to β-H elimination, but from their improved selectivity for 1-alkenes, relative to ethylene. The slightly reduced preference for ethylene self-metathesis calculated for nG-C1Again, the favorable properties of the CAAC ligands originate in the high trans effect exerted by these carbenes in the transition states for β-H elimination and ethylene self-metathesis.104 calculated for 4  and the natural steric exchange repulsion energy105 calculated between the carbene, the methylidene, and the chloride ligands in the methylidene complexes 2/2′ . From both methods, C1Ph appears only slightly bulkier than H2IMes and C2Me. In short, neither the differences in overall bulk, nor those in spatial steric distribution  is more stable than rotamer 2′ by 3.7 kcal mol (see −1) calculated for the latter. The explanation lies in overriding electronic effects  and corresponding transition state (TS3′-4) leading to 4. Consistent with these contrasting predicted rotamer stabilities, NOESY-NMR analysis revealed interactions between the [Ru]CHAr proton and the quaternary phenyl group for the Piers-class catalyst P-C1Ph , the ruthenium–CAAC metathesis catalysts studied are essentially immune to decomposition via β-H elimination from the metallacyclobutane. Calculations predict a higher barrier to β-H elimination in the CAAC systems, consistent with the distinctions in behavior observed experimentally. Also predicted is higher selectivity for metathesis of styrene, vs. unproductive ethylene self-metathesis, relative to the Ru–NHC catalysts. The poorer selectivity of the latter , in conjunction with the greater vulnerability to β-H elimination of the unsubstituted MCB thus formed, represent a lethal combination of effects that explains the lower metathesis productivity of the popular NHC catalysts relative to the emerging CAAC systems.Unlike their NHC predecessors  and transition states (trans effect) involving competing orbital interactions trans to the carbene, notably TS4-5 (β-H elimination) and TS3′-4/TS4-3 (ethylene self-metathesis). Thus, both the greater resistance to β-H elimination and the improved selectivity for productive 1-alkene metathesis of the CAAC catalysts are due to the higher trans effect of this carbene class.52,53,57,58 underlining the generality and the scope of this ligand effect in catalysis. Crucially, for ruthenium, the impact is manifested in lower rates of reaction (both β-H elimination and ethylene cycloaddition) taking place directly trans to the ligand.The findings above add ruthenium olefin metathesis catalysts to the systems for which high trans-influence ligands have been found to retard β-H elimination,42 The positive impact of a strong trans-effect ligand in limiting β-H elimination is thus offset by its potent accelerating effect on bimolecular decomposition. These two decomposition pathways have long been known to limit productivity in olefin metathesis. They are here revealed as distinct, antinomic, responses to a single underlying phenomenon. Reconciling these opposing effects is a clear priority for catalyst design. More robust and productive olefin metathesis catalysts will aid in expanding applications in demanding contexts. One specific, compelling goal is the development of stereoselective catalysts resistant to β-H elimination, including as-yet-undiscovered stereoselective CAAC catalysts.The high trans influence and trans effect are clearly critical to the breakthrough success of the CAAC ligand family. However, these properties also have a profound negative consequence, greatly enhancing the susceptibility to bimolecular coupling of 4-coordinate methylidene species 2/2′.110viahttps://doi.org/10.19061/iochem-bd-6-113.The complete computational data is available from the ioChem-BD repository,DEF and VRJ designed and supervised the project. GO performed the DFT calculations, with initial contributions from MF. MF handled, organized, and stored the computational data (see Data availability). DLN performed the experiments. All authors analyzed the computational and experimental results. GO wrote the initial draft. DEF and VRJ wrote the final manuscript, with contributions from GO, MF, and DLN. All authors have approved the final manuscript.There are no conflicts to declare.SC-013-D2SC00855F-s001SC-013-D2SC00855F-s002


Intimate partner violence (IPV) has a very high prevalence (25%) in society and has serious consequences for its victims. As former studies showed minimal effectiveness of therapeutic interventions addressing IPV, the Dutch guideline for Familial/Domestic Violence  recommends to focus more on systemic factors and on individual risk factors of IPV. ADHD is one of these individual risk factors. This presentation focuses on the association between ADHD and IPV, presenting data and clinical examples. ADHD was missed in 56% of a sample of forensic outpatients. Reasons for this issue of underdiagnosis of ADHD in case of aggression and IPV are discussed. Also, data of the ITAP (impact of treatment of ADHD on IPV) study are presented, showing that ADHD in offenders of IPV with ADHD scored higher on minor physical aggression, minor and severe psychological aggression and clinician-rated IPV than offenders without ADHD. Further, after a one year treatment of ADHD and IPV, decrease in IPV was mainly associated with decrease in ADHD symptoms. The importance of screening and treatment of ADHD symptoms in all IPV offenders is discussed to make treatment of IPV more effective.No significant relationships.


Background and Objectives: ADHD is a neurodevelopmental disorder characterized by inattention and hyperactivity/impulsivity and can persist in adulthood. The aim of this study is to deepen knowledge about adult ADHD follow-up. Materials and Methods: This observational study consists of one retrospective part aimed at collecting records of children and adolescents treated for ADHD in the Children and Adolescent Mental Health Service (CAMHS) from 1995 to 2015 and, successively, at identifying their adult follow-up in Adult Mental Health Service (AMHS); the second part consists of ADHD scale administration, Diagnostic Interview for ADHD in Adults (DIVA 2-0) and Adult Self Rating Scale (ASRSv1.1), for the subjects currently being treated at AMHS who agreed to participate in the study. Results: We observed that among the 55 patients treated at CAMHS between 1995 and 2015 for ADHD and subsequently at the AMHS, none presented a diagnosis of ADHD; instead, they were treated for Intellectual Dysfunction (33%), Borderline Personality Disorder (15%) and Anxiety Disorders (9%), and two individuals were also diagnosed with comorbid substance/alcohol abuse (4%). Of the 55 patients, only 25 (45%) were treated at AMHS during the study period. Though we asked for their informed consent to administer the questionnaires, we were able to test only seven patients. The ASRS-V1.1 score showed that 43% of patients reported symptoms of ADHD persistence in adulthood. For DIVA 2.0, 57% of individuals reported scores indicating the persistence of the ADHD inattention component, and 43% the persistence of both ADHD dimensions. Conclusions: ADHD cannot be considered a disorder confined to childhood/adolescence but instead is a chronic and complex condition that can persist into adulthood. The very small size of our final sample may account for both the high ADHD dropout rate over the long follow-up period and the difficult transition from child to adult health care in ADHD treatment. Our investigation suggests the need for specific training in the diagnosis and treatment of adult ADHD and the implementation of transition protocols between minor and adult services to improve long-term treatments. Attention-deficit/hyperactive disorder (ADHD) is one of the most common neurodevelopmental disorders. It normally presents two symptom dimensions: inattention and impulsivity/hyperactivity ,2. The dAlthough the first scientific description of ADHD was given by a pediatrician, George Frederic Still, in 1902 . FollowiThe pathogenesis of ADHD is multifactorial and conditioned by genetic vulnerability ,17,18, eIn adulthood, prevailing symptoms are inattention, restlessness and disorganization in daily activity but not hyperactivity, while impulsiveness can persist ,15,25,26For completing the diagnostic investigation, the Diagnostic Interview for Adult ADHD, which is available in the 5th version (DIVA-5) as semi-structured questionnaire, is a valid and reliable tool ,32. To dThe clinical manifestation of associated disorders as well as ADHD sub-threshold symptoms can lead to misdiagnosis, even if more recent research shows a trend of increasing numbers of diagnoses in adulthood, suggesting changes in clinical practice . TherefoADHD is often associated with one or more comorbid psychiatric disorders, leading to worse prognosis and more complex treatments . More coSymptoms of ADHD are linked to abnormalities in dopamine and norepinephrine signal pathways, which constitute the main therapeutic target of psychopharmacological drugs . In factThe aim of this study is to deepen knowledge about ADHD follow-up in adulthood in order to improve its clinical management from childhood to adulthood. After having conducted a scoping review on the persistence of ADHD in adulthood and its complications , we inveThis observational naturalistic study presents both a retrospective and prospective design. It consists of two parts: the first retrospective one was aimed at collecting records of children and adolescents treated for ADHD in the CAMHS in Modena from 1995 to 2015 and, successively, at identifying their adult follow-up in AMHS, collecting demographic and clinical information about individuals treated from services databases; the second part consists of ADHD scale administration to the subjects currently being treated at AMHS who agreed to participate in the study, giving us their informed consent.This study received the approval of the Ethics Committee of the Area Vasta Emilia Nord (Prot. No. AOU0007877/19 of 19/03/2019 and subsequent amendment Prot. No. AOU0024912/20 of 09/15/2020) and was authorized by the Modena Local Health Authority (Decision No. 658 of 26/03/2019).The primary objective of the study was to determine how many patients were still being treated in AMHS among those treated for ADHD as minors from 1995 to 2015 in CAMHS, evaluating the demographic and clinical factors that could have influenced the evolution of ADHD in patients treated in CAMHS from 1995 to 2015: single parenting, adoption, age of treatment start at CAMHS, schooling, intellectual disability, the presence of comorbidities and types of treatments.The secondary objective was the evaluation of ADHD persistence in adulthood by means of scale administration, and the presence or absence of psychiatric and substance use comorbidities.All patients with a diagnosis of ADHD (ICD-10: F.90.0 and F.90.1) , who werThe variables were selected to describe the demographic and clinical characteristics of our sample both in childhood and in adulthood among those available in the information system of outpatient services. Data collected from the CAMHS information system were the following: single parenting, adoption, age at the time of treatment start in CAMHS, referral to CAMHS, possible coexistence of intellectual disability or other comorbidities and types of treatments .We retrospectively collected the following variables from the AMHS information system: psychiatric diagnosis and substance use, period of treatment, schooling, employment, housing, hospitalizations, treatments, social service support and legal problems. More information was sought from the referral psychiatrist of the adult individuals treated at AMHS.The prospective part was aimed at the evaluation of ADHD persistence in adulthood. It consisted of the administration of two questionnaires validated in Italian, the Adult Self-Report Scale (ASRS-v1.1) and Diagnostic Interview for ADHD in Adults (DIVA-2.0), after having received patients’ written consent.The Adult Self Rating Scale (ASRS-V1.1)  investigthe criteria for Attention Deficit (A1);the criteria for hyperactivity / impulsivity (A2);the age of onset and the dysfunction caused by the symptoms of ADHD.The Diagnostic Interview for ADHD in Adults (DIVA) is based on the criteria of the DSM-IV and is the first Dutch structured interview for ADHD in adults, developed by Kooij and Francken . The intEach of the 18 criteria described by DSM-IV is investigated one at a time, first assessing the presence in adulthood and then the possible presence in childhood.In order to make it easier to verify the presence or absence of the 18 symptomatic criteria of ADHD, both in childhood and adulthood, the interview provides a list of concrete and realistic examples, referring to both current (adult) and child behavior. These examples are taken from the most frequent descriptions given by adult patients in clinical practice and concern the difficulties typically associated with symptoms in five areas of daily life: work and education, love and family relationships, social relationships, leisure and hobbies, self-esteem and self-image. If possible, DIVA 2.0 should be administered to adults in the presence of the partner and/or a family member, to obtain more information. DIVA 2.0 administration takes about one hour/one hour and a half. DIVA 2.0 only investigates the key symptoms of ADHD required to diagnose ADHD according to the DSM-IV and does not investigate any symptoms, syndromes or psychiatric disorders present in comorbidities.t-test was applied for unpaired data and the chi-squared test was used to compare percentages.Data were statistically analyzed and included mean ± Standard Deviation (SD) and percentage for descriptive analysis. For the comparison between means, Student’s We retrospectively collected 303 patients diagnosed with ADHD, in accordance with ICD-10, from the CAMHS database . Of thesWe excluded from the study the total number of individuals who were not treated at local CAMHS (n = 237) and those who were exclusively treated at Substance Use Services (SUS) (n = 11) .From the sample of children/adolescents treated at CAMHS (n = 303), 55 were treated in adulthood at AMHS (18%) and 11 (4%) at Substance Misuse Service; 7 (2%) individuals among them were taken in care by both services .Most of our sample was composed of males (71%) and Italians (84%). Regarding the demographic characteristics, 44% of the sample had obtained a secondary school diploma, 35% a lower secondary school diploma and only 6% a university degree. Currently, 38% of individuals were employed in a protected job, 16% were engaged in studies, 15% were employed in a regular job, 13% were unemployed and a further 13% received a disability pension. Most individuals lived with their family of origin, composed of both biological parents in 56% of cases, a single parent in 9% of cases, adoptive parents in 6% of cases and foster parents in 2% of cases; 13% lived in a protected apartment or in a community, 4% with their acquired family and 2% alone.60% of the individuals were taken into care before the age of 5;in 42% of cases, the referral to CAMHS was made by school;most of the minors were treated at CAMHS for a long period of time, ranging between 10 and 15 years in 49% of cases;53% of individuals were treated with only rehabilitative intervention and 47% with multimodal  treatment;29% of individuals were also in care at Social Service for Minors;89% were discharged from CAMHS at an age ranging between 18 and 21 years;49% of individuals were taken into care by Adult Mental Health Service at the age of majority;58% of the patients treated in CAMHS for ADHD had a psychiatric comorbidity, whereas 27% a neurological comorbidity and 9% a congenital/hereditary type.Analyzing the childhood clinical variables of subjects treated at CAMHS for ADHD and subsequently at AMHS in adulthood (n = 55), we highlight the following results:The psychiatric diagnosis most frequently associated with ADHD in childhood was found to be intellectual disability (44% of cases), which was mild in 54% of individuals, moderate in 38% and severe in 8%. The diagnosis of ADHD was associated with specific developmental disorders of school skills (50% of cases), conduct and emotional disorder (29%), oppositional-defiant disorder (18%), anxiety-depressive disorders (13%), Asperger Syndrome (7%), unspecified manic episodes (4%) and obsessive-compulsive disorder (4%). In a percentage of 2% for each, we found a concomitant diagnosis of Schizotypal Personality Disorder, Post-Traumatic Stress Disorder, Cyclothymia, Gilles de la Tourette Syndrome and Autism.45% of individuals were still being treated at AMHS (n = 25);the majority  of adult individuals appeared to have had their first access to AMHS at an age ranging between 18 and 20 years, 24% of patients between 21 and 24 years, and 6% under 18 years;in 49% of cases, the referral to AMHS was CAMHS, in 27% a general practitioner, in 9% spontaneous access, 7% though Social Services, and 6% other sources ;15% of patients were hospitalized, with a single case (2%) being compulsory hospitalization;15% of patients were sent to a community treatment;7 individuals (13%) had also been treated by SUS and successively discharged;70% of individuals were also in care at Social Services (n = 38);62% of the sample was treated with drug therapy and socio-rehabilitation interventions (n = 34);15% of the sample was treated with a psychotherapy (n = 8);7% of individuals were found to have had legal problems (n = 4);3 individuals were legally supported by a so-called legal administrator.As regards the analysis of the adulthood clinical variables of our sample treated at AMHS (n = 55), we found the following:no patient was diagnosed with ADHD;the diagnosis of intellectual disability represented the most frequent diagnosis (24% of the sample);other diagnoses were represented by borderline personality disorders (15%), bipolar disorders (12%), anxiety disorders (9%), schizophrenia spectrum disorders (8%), maladjustment disorders (7%), autism (4%), alcohol/other substance addiction (4%), obsessive-compulsive disorder (2%) and unspecified non-psychotic mental disorders following organic brain damage (2%);7 patients (13%) were evaluated at AMHS, but no psychiatric diagnosis was found during consultation;only 12 individuals (22%) presented non-psychiatric medical comorbidities, in particular epilepsy (11%) and obesity (4%).As regards the diagnoses of adult patients in our sample, we found the following:Of the 55 patients treated in adulthood at AMHS, 25 were currently in care during the study period in 2021 .We contacted all patients still in care at AMHS (n = 25) to evaluate the persistence of ADHD by means the administration of DIVA 2.0 and the ASRS-V1.1. As shown in they were not traceable (n = 5);they did not provide informed consent (n = 3);they were not evaluable due to moderate/severe intellectual dysfunction (n = 10).The remaining seven patients accepted the administration of the scales .The ASRS-V1.1 self-assessment scale scores showed that three of seven patients (43%) reported symptoms of persistent ADHD in adulthood.4 subjects (57%) did not obtain a positive score for adult ADHD;3 subjects (43%) reported symptoms of both ADHD components (inattention and impulsivity/hyperactivity);1 subject (14%) reported symptoms of inattention but not of impulsivity/hyperactivity.From the administration of DIVA 2.0, we report the following:All but one of the patients who had a DIVA 2.0 positive score in at least one of the two ADHD dimensions had a similarly positive score in ASRS-v1.1, indicating that most had a subjective awareness of this disorder.2 = 3.73; p = 0.05) compared with those with a negative score, whereas individuals with a negative score for both dimensions of DIVA 2.0 (n = 3) were older than those with positive DIVA 2.0 scores   . Moreove t-test) .This study aimed to evaluate the ADHD follow-up from childhood to adulthood in a real-world setting in order to highlight the percentage of adult ADHD persistence and association with psychiatric and substance use comorbidities as well as social problems. In the literature, studies on ADHD in childhood have allowed us to develop shared and comprehensive guidelines, whereas, up to now, the available epidemiological studies on adult ADHD have reported discordant results ,67.The retrospective part of this study included 55 individuals followed in childhood at the CAMHS for ADHD and subsequently treated at AMHS in the same Northern Italian town. Of these, 71% were males, data in line with the literature, which highlights a prevalence in males with a 2:1 ratio . The 15-Our analysis highlights that only 18% of minors treated for ADHD were subsequently treated by the Adult Mental Health Service on direct indication from CAMHS, 78.9% were discharged or had stopped treatment and 14.3% were self-discharged from CAMHS. This figure is in line with the high dropout rate of subjects with ADHD in the post-adolescent period and testifies to the difficulties relating to the transition from child to adult care . In accoOur study did not retrospectively report any diagnosis of ADHD in our adult sample, although test scores highlighted that more than half of our patients presented ADHD symptoms in adulthood, further suggesting the difficulties in diagnosing adult ADHD. In this regard, many authors ,69 put iThe prospective part of our study, which analyzed the prevalence of ADHD diagnosis in adulthood through the administration of ASRS-v1.1 and DIVA.2 scales, found the persistence of inattention symptoms in 57% of individuals, whereas both components of this disorder (inattention and impulsivity-hyperactivity) were maintained in 43% of individuals. These results are in line with what is reported in the literature: about 57% of adults with a clinical history of ADHD in childhood meet the diagnostic criteria of the disorder in adulthood, whereas 66% have more than one ADHD symptom causing discomfort and impaired functioning ; in adulFurthermore, we observed that all our patients, except one, obtained comparable scores for the ASRS-v1.1 to those reported for DIVA 2-0, indicating that most had subjective awareness of this disorder.The administration of DIVA 2.0 found that two of seven individuals did not obtain a suggestive score for childhood ADHD in either dimension, despite having been followed up for this disorder at CAMHS. This discrepancy could be due to a difficulty in remembering some of the information requested in the diagnostic interview. In fact, to overcome this problem, the presence of a family member is required, where possible, in order to integrate the lack of retrospective information.It should also be noted that no patient treated due to ADHD at a minor age had maintained this diagnosis in adult mental health services, even in the cases that presented scores suggesting symptoms of ADHD inattention and/or impulsivity on the questionnaires administered. This data could indicate the difficulty in diagnosing a clinical course not yet well defined in adulthood by the current classification systems or also indicate different types of this disorder as hypothesized by some authors .The retrospective study revealed that no individual in the sample continued treatment with methylphenidate or atomoxetine in adulthood. A multicenter study conducted in a sample of adolescents with ADHD documented a 62% reduction in the use of drugs in the age group between 17 and 21 years . The NatIn our sample, the psychiatric comorbidity more frequently associated with ADHD was Intellectual Disability, both in childhood (44%) and in adulthood (33%). The literature shows heterogeneous data in this regard, since the disorder itself involves a deficit of executive functions. Patients with ADHD show, in fact, deficits in numerous cognitive domains, particularly in the attentional and decision-making processes. Similar cognitive difficulties have also been observed in adults ,74. In pOther disorders frequently associated with ADHD in childhood were Conduct Disorders (29% of cases), specific developmental disorders of school skills (25%) and Oppositional-Provocative Disorder (18%). Similar data emerged from the scoping review , in whicCriminal activities and judicial problems were found in 7% of our sample. The scoping review highlighted an association between ADHD arising in childhood and crime in adulthood in 32% of cases [Our study observed that most individuals in our sample were currently engaged in a protected job supported by AMHS (38%), while few individuals (15%) had independently achieved work stability. Among the individuals with rating scale scores positive for adult ADHD, the data are even more evident: 50% worked in a protected environment, and none were employed in regular work. These data, which are in accordance with other study results , furtherThe very small size of our final sample can represent the difficult transition between child and adult care for complex disorders previously considered uniquely confined to minors, such as ADHD, which survive into adulthood. In particular, for a person with ADHD, it can be difficult to maintain continuity of care due to hyperactivity/impulsivity and inattention that can predispose one to both therapy dropout and social-relational maladjustment. The adolescents with ADHD “lost in transition” can undergo negative outcomes in adulthood, as highlighted by many authors ,84.Transition care is a “multidimensional and multidisciplinary process” , which sThis research has several limitations, the main one being the very small size of the final sample due to many factors: the long follow-up period, the high dropout rate in ADHD treatment as reported by literature , the difHowever, the follow-up design of this study and its implementation in a real-world health setting allowed us to report a realistic course of ADHD from childhood to adulthood in a group of individuals treated in both CAMHS and AMHS and to highlight the difficulties in diagnosing and treating ADHD in the transition between minor and adult services. The careful diagnostic process for ADHD in adults, including both a screening instrument (ASRS v1.1) and a dedicated diagnostic interview (DIVA-2), can be mentioned as a relevant point of strength of the present work.This study highlighted that 18% of individuals treated for ADHD in childhood successively needed to be treated by Adult Mental Health Services, in particular due to Intellectual Dysfunction, Borderline Personality Disorder and Anxiety Disorders. Among individuals currently treated in AMHS who agreed to be screened for adult ADHD, we highlight a persistence of at least one of two ADHD dimensions in more than half of cases, although none of these individuals were ADHD diagnosed at AMHS, confirming the difficulty in diagnosing this disorder in adulthood.ADHD in our adult patients was associated with intellectual disability and social maladjustment. In particular, adult patients who obtained scores indicating ADHD on questionnaires required more social support and clinical care from multiple services than others, suggesting the greater clinical severity related to this disorder. Our investigation also revealed the poor adherence to treatment, with the frequent drop-out of patients with ADHD, which likely conditioned the small size of our final sample, suggesting, at the same time, the difficulty of healthcare services in maintaining continuity in the minor-to-adult age transition.An enlargement of the sample could have provided more detailed data regarding the chronicity of ADHD or its clinical course in adulthood; however, the very small size of our final sample can represent the difficulty in collecting information and clinical evidence in a real-world health setting regarding the ADHD follow-up. Moreover, further research is needed to highlight the role of drug and/or rehabilitative treatments in preventing the persistence of this disorder and the onset of other clinical problems in adulthood.Based on our results, we can conclude, in line with the most recent literature, that ADHD should not be considered a disorder confined to childhood/adolescence but rather a potentially persisting condition that associated with other psychiatric disorders and can greatly reduce functioning skills in adulthood. Our study suggests the need for specific training in the adult diagnosis and treatment of this disorder and the implementation of transition protocols from child to adult health services in order to ensure the continuity of care.


GRIK1 gene, in brain regions responsible for learning and memory, we hypothesized that GRIK1 might have a role in ADHD. GRIK1 variants rs363504 and rs363538, affecting the receptor function, were analyzed by case–control and family-based methods to identify the association with ADHD. The impact of these variants on ADHD-associated traits and pharmacological intervention were also analyzed. GRIK1 expression was quantified in the peripheral blood. The probands and their fathers had a higher frequency of rs363504 ‘CC’ and rs363538 ‘CA’ genotypes. Family-based investigation revealed maternal over transmission of rs363504 ‘C’ and rs363538 ‘A’ alleles to the probands. Quantitative trait analysis exhibited an association of rs363504 ‘TT’ and rs363538 ‘AA’ genotypes with higher hyperactivity scores of the probands. In the presence of rs363504 ‘TT’ and rs363538 ‘CC’ genotypes, MPH treatment improved hyperactivity and inattention, respectively. GRIK1 expression was significantly downregulated in the probands. We infer that GRIK1 affects ADHD etiology, warranting further in-depth investigation involving a larger cohort and more functional variants.Executive dysfunctions caused by structural and functional abnormalities of the prefrontal cortex were reported in patients with Attention deficit hyperactivity disorder (ADHD). Owing to a higher expression of the glutamate ionotropic receptor kainate type subunit 1 (GluK1), encoded by the  The disorder is characterized by cardinal symptoms of age-inappropriate inattention (IA), hyperactivity (HA), and impulsivity (Imp)1. High heritability, genetic association studies, and case–control linkage analyses indicate a significant role of genetics in the etiology4. In addition, environmental factors like low birth weight, prenatal exposure to nicotine, alcohol, drugs, and adverse life experiences have also shown significant contributions to ADHD4.One of the most prevalent neurobehavioral disorders worldwide is Attention deficit hyperactivity disorder (ADHD)5. Functional abnormalities of the prefrontal cortex (PFC), a brain region regulating executive functions including working memory, sustained attention, decision making, and emotional control, were documented in subjects with ADHD6. The glutamatergic pyramidal neurons are the PFC's major cellular constituents; hence, a primary role of glutamatergic neurotransmission in PFC-dependent executive functions was speculated8. The influence of glutamate in ADHD was also evident from the hyperfunctional glutamatergic system in the PFC of spontaneously hypertensive rats9. Methylphenidate (MPH), a psychostimulant used for treating subjects with ADHD10, was reported to target the glutamate receptors in the PFC neurons13.Although molecular genetic studies were primarily focused on catecholaminergic dysregulation, the glutamatergic system was also reported to influence ADHD aetiology14. The GluR, responsible for post-synaptic excitation of neural cells, are subdivided into metabotropic (mGluR) and ionotropic (iGluR) receptors based on their pharmacological properties15. The mGluR, capable of increasing or decreasing the excitability of the post-synaptic cells, is a class C family of G-protein coupled receptors including eight members, mGluR1/GRM1-mGluR8/GRM8) and induces a slow response through a signal transduction cascade16. On the other hand, the ionotropic receptors (iGluR) mediate fast excitatory neurotransmission through three ligand-gated ion channels, N-methyl-D-aspartate (NMDA), α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA), and kainate receptors (KARs)18.The action of glutamate, the most abundant excitatory neurotransmitter, is mediated through the glutamate receptors (GluRs) located chiefly on the membranes of the neuronal and glial cellsGRIK1–GRIK5 genes, form functional ion channels by combinations of five different subunits, i.e., GluK1–GluK519. KARs modulate both glutamate and GABA release23. Hippocampal KARs containing GluK1 subunits are primarily expressed in interneurons, where the reduction of GABA release results in the increased excitability of glutamatergic principal neurons23. In the pyramidal cells of the hippocampus, KARs activation leads to G-protein activation and phospholipase C and protein kinase C signaling, which decreases GABA release20. On the other hand, in the hippocampal mossy fiber-CA3 synapses, medial geniculate nucleus at the thalamus, and lateral amygdala synapses, metabotropic action of KARs leads to a reduction in glutamate release resulting in long-term depression22. Glutamate release in the Schaffer collateral-CA2 synapses of the hippocampus24 and cerebellum synapses25 is also affected by KARs, which involve G-protein and protein kinase A activation. The metabotropic action of KARs also takes place in a biphasic manner. At the same time, the G-protein independent, Ca2+ dependent intracellular signaling cascade facilitates glutamate release, G-protein and Ca2+ dependent signaling cascade decrease the glutamate release27. Further, the pre-synaptic KARs activation through Ca2+—calmodulin complex was also reported to stimulate glutamate release in the hippocampal mossy fiber-CA3 synapses, thalamocortical synapses, and cerebrocortical synaptosomes, thereby inducing the long-term potentiation29.The kainate receptors (KAR), encoded by 32. Irregular KARs activity in the temporal lobe was reported to induce epileptogenic neuronal activity at the hippocampal synapses33. The GluK2 subunit was found to have a role in seizure35, and a bi-allelic loss of function mutation in the KARS-encoding gene, GRIK2, was detected in patients with neurodevelopmental disorders36. Abnormalities in the kainate receptors were also reported in patients with bipolar disorder, autism, and intellectual disability37. Genome-wide association studies identified a GRIK1 intronic variant as a candidate for ADHD38. However, no exploration was performed on the association between GRIK1 exonic variants and ADHD traits. We, for the first time, investigated two GRIK1 exonic variants, rs363504 [c.2705T > C (p.Leu902Ser)] and rs363538 [c.522A/C (p.Thr)], in a group of ethnically matched subjects by case–control as well as family-based methods to identify their association with ADHD, different traits, post-therapeutic changes in the trait scores of the ADHD probands and GRIK1 expression in the peripheral blood.Several investigations were carried out to determine the role of KARs in disorders such as epilepsy, pain, ischemic brain injury, stress and anxiety, ASD, schizophrenia, alcohol abuse disorder, bipolar disorder, and depressionGRIK1 genetic variants were analyzed in a group of ethnically matched families with ADHD probands and controls. Genotyping success rates were 99% and 98% for rs363504 and rs363538, respectively. Genotypic frequencies followed the Hardy–Weinberg equilibrium (P > 0.05) in all the case and control groups.The P = 0.04, OR = 9.74, CI = 1.00–95.45; Power 40%). The probands also showed a higher frequency of the rs363538 ‘CA’ genotype .Population-based comparative analysis revealed an absence of the rs363504 ‘CC’ genotype in the control group Table , while tP > 0.09; Supplementary Table The gender-based stratified analysis on allele/genotype frequencies failed to show significant differences between the probands and the controls , rs363538 ‘C’ allele  and ‘CA’ genotype . The mother showed a higher frequency of rs363538 ‘CA’ genotype  than the gender-matched controls.The father of the probands showed a higher occurrence of the rs363504 ‘CC’ genotype  to the probands, chiefly to the male probands   from both the parents as well as the mother  (Table The transmission disequilibrium test (TDT) revealed biased maternal transmission of the rs363504 ‘C’ allele  and ‘TT’ genotype  on the hyperactivity (HA) score measured using the Conners Parent and Teacher Rating Scale-Revised (CPRS-R). No significant association was detected for other traits assessed by the CPRS-R (Supplementary Table P = 0.005) and Parental Account of Children’s Symptoms  scores. Probands with genotypes having the “T” alleles  and PACS .Genotype–phenotype association analysis Table  revealedP = 0.04, Add Value = 0.05) and ‘AA’ genotype , while the traits scores  were reduced in the presence of the ‘CA’ genotype  and ‘CA’  genotypes showed higher IQ scores (Table P = 0.03), whereas the ‘C-A’ haplotype had a negative impact on ODD (P = 0.005) and PACS (P = 0.01) scores  were higher in the presence of the rs363538 ‘A’ allele  or non-stimulant (atomoxetine/ATX) medications based on the age at presentation, presenting symptoms, and availability of the medicine, and the treatment efficacy was tested in the probands having different Statistically significant lower expression  of GRIK1 mRNA was detected in the peripheral blood of the ADHD probands as compared to the age-matched control   in exon 17 and results in a non-synonymous change (Leu902Ser) that affects the intracellular C-terminal domain of the receptor subunit. In the European and African populations, the rs363504 ‘TT’ genotype showed an association with opioid and cocaine dependency174 and affecting the extracellular ligand-binding loop47. Population-based analysis revealed a higher frequency of the rs363538 ‘CA’ genotype in the probands with a concomitantly lower frequency of the “AA” genotype. Familial transmission analysis showed higher parental transmission of the rs363538 'A' allele to the female probands, chiefly due to higher maternal transmission. QTA revealed a higher IA score in the presence of rs363538 ‘A’/’AA’, whereas the probands harboring the ‘CA’ genotype showed lower IA scores predominantly due to the ‘C’ allele. The IQ score was higher in the presence of the ‘C’ allele. The probands carrying the ‘CC’ genotype on MPH treatment showed improved IA scores. Based on these data, we conclude that the probands with rs363538 ‘C’ allele may have a better function of the GRIK1, and those with the “A” allele, especially the female probands, require more intensive intervention due to low IQ and higher IA.rs363538 (C522A) is localized in the exon 3, causing a silent transversion coding for ThrP = 0.53) and rs363538 ‘AA’  genotypes had lower GRIK1 expression . However, the same genotypes, i.e., rs363504 ‘TT’ and rs363538 ‘AA’, were found to increase the trait scores. In experimental rodents, a behavioral abnormality was induced by altered GABAergic transmission due to loss of modulation of GRIK1 in the amygdala neurons48. Similar downregulation in the GRIK1 expression in the peripheral blood of the ADHD probands may indicate an alteration in GABAergic transmission. Based on this information, it can be concluded that GRIK1 may be a potential candidate for ADHD, which requires further in-depth investigation.GRIK1 mRNA expression was 2.70-fold downregulated in the ADHD probands. Analysis of correlation using mean values of normalized mRNA levels revealed that the ADHD probands having the rs363504 ‘TT  ADHD-associated traits and (2) MPH-induced changes in the trait scores of the ADHD probands. In addition, we have detected significant downregulation in GRIK1 mRNA expression in the probands. The primary limitations of the present study are (a) the analysis of GRIK1 mRNA expression in only a limited number of samples and (b) marginally significant associations between the studied genetic variants and ADHD, as is evident from the close to significance p-values, low relative risk, and power of the association tests. However, based on the significant associations of the studied genetic variants with ADHD traits, improvement in the trait scores after MPH treatment, and down-regulation in GRIK1 expression, a possible role of GRIK1 can be predicted in the etiology of ADHD, which warrants further validation in a large cohort of subjects belonging to different ethnicities.For the first time, this study showed significant associations between 53. Behavioral problems (BPr), inattention/cognitive problems (IA), hyperactivity (HA), and ADHD index (AI) were assessed using the Conner’s Parents Rating Scale-Revised (CPRS-R)54. Parental Account of Children’s Symptoms (PACS) was used to evaluate the severity of BPr55. Scores for the co-morbid oppositional defiant disorder (ODD) were assessed based on the DSM criteria. Intelligence Quotient (IQ) was determined using the Wechsler’s Intelligence Scale for Children-III56. Ethnically matched control subjects  were also recruited following the DSM criteria. Written informed consent was obtained from the participants/ parents/caregivers during recruitment. All methods were performed per the relevant guidelines and regulations. The study protocol (No. PR-003-17) was approved by the Manovikas Ethics Committee on Human Subjects, having Scientists, Psychiatrists, Psychologists, Advocates, and Social workers as members.Nuclear families with ADHD probands  were recruited following the DSM57. Genotyping of rs363504 and rs363538 was performed by polymerase chain reaction (PCR) amplification in the Applied Biosystems ProFlex™ PCR system, followed by Restriction fragment length polymorphism analysis using Ase I and Btg I enzymes, respectively.At the time of recruitment, peripheral blood was collected from treatment naïve ADHD probands, their parents, and controls. Genomic DNA was isolated by the phenol/chloroform methodMethylphenidate at a dose of 0.3 mg/kg body weight/day was prescribed for two months to ADHD probands with age-inappropriate HA, residing in urban areas and < 10 years of age, followed by 0.6 mg/kg body weight/day for another four months. ADHD probands with significant IA, > 10 years of age, and residing in rural areas where availability of stimulant medication is limited, were prescribed ATX at a dose of 0.8 mg/kg body weight/ day for two months, followed by 1.2 mg/kg body weight/day for another four months. Probands available for follow-up after six months of treatment (N = 74) were re-assessed by the CPRS-R.−ΔΔCt.RNA was isolated from the blood by the TRIzol method , and following DNAase treatment, the concentration of isolated RNA was measured by a Qubit 4 Fluorometer. The total RNA (700 ng) was reverse transcribed into complementary DNA (cDNA) using the reverse transcriptase enzyme (High-capacity cDNA reverse transcription kit of Thermo Fischer Scientific). GRIK1 mRNA expressions were examined in the ADHD probands (n = 17) and age-matched control subjects (n = 19). Amplification was carried out in QuantStudio 3 (Applied Biosystems by Thermo Fisher Scientific) using PowerUp SYBR Green Master Mix (Thermo Fisher Scientific). The cycle threshold value  for each sample was obtained. The data was normalized against Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) expression, serving as an internal control, and expressed as ΔCt. Normalized gene expression or fold change is defined as 2http://www.oege.org/software/hwe-mr-calc.shtml/) to determine the genotypic frequencies of the studied variants were constant or not. Population-based comparative analysis and family-based transmission analyses were performed using the UNPHASED version 3.1.758, after 1000 permutations, which takes care of the multiple corrections. Quantitative trait (QT) analysis to identify the association between the genetic variants and ADHD-associated trait scores was also performed using the UNPHASED version 3.1.758. Odds ratio (OR) and confidence intervals (CI) were calculated using the Odds Ratio calculator (http://www.hutchon.net/ConfidORnulhypo.htm). Relative Risk (RR) of the studied variants was calculated using a relative risk calculator, and the Power of the significant observations was calculated using piface software59. Relative GRIK1 mRNA expression in the peripheral blood of controls and ADHD probands were analyzed by the Unpaired t-test using Prism 9.0 . Improvement in the trait scores after pharmaceutical interventions were calculated by 1-Tn/To  as detailed in a previous article60 and are presented as the improvement index. Association between GRIK1 variants and treatment-induced changes in the trait scores, measured based on the improvement index, was analyzed by the Unpaired t-test using the Prism 9.0 software, and data from the unpaired t-test are presented as Mean ± Standard error of the mean (SEM).Hardy Weinberg Equilibrium (HWE) was calculated using online software (Supplementary Information 1.Supplementary Information 2.


KTN1) has recently been reported to significantly regulate GMVs and ADHD risk. In this study, we aimed to identify sex-specific, replicable risk KTN1 alleles for ADHD and to explore their regulatory effects on mRNA expression and cortical and subcortical GMVs. We examined a total of 1020 KTN1 SNPs in one discovery sample  and three independent replication European samples  to identify replicable associations within each sex. We examined the regulatory effects of ADHD-risk alleles on the KTN1 mRNA expression in two European brain cohorts (n = 348), total intracranial volume (TIV) in 46 European cohorts  and the ABCD cohort, as well as the GMVs of seven subcortical structures in 50 European cohorts  and of 118 cortical and subcortical regions in the ABCD cohort. We found that four KTN1 variants significantly regulated the risk of ADHD with the same direction of effect in males across discovery and replication samples (0.003 ≤ p ≤ 0.041), but none in females. All four ADHD-risk alleles significantly decreased KTN1 mRNA expression in all brain regions examined (1.2 × 10–5 ≤ p ≤ 0.039). The ADHD-risk alleles significantly increased basal ganglia (2.8 × 10–22 ≤ p ≤ 0.040) and hippocampus (p = 0.010) GMVs but reduced amygdala GMV (p = 0.030) and TIV (0.010 < p ≤ 0.013). The ADHD-risk alleles also significantly reduced some cortical  and cerebellar but increased other cortical (0.007 ≤ p ≤ 0.050) GMVs. To conclude, we identified a set of replicable and functional risk KTN1 alleles for ADHD, specifically in males. KTN1 may play a critical role in the pathogenesis of ADHD, and the reduction of specific cortical and subcortical, including amygdalar but not basal ganglia or hippocampal, GMVs may serve as a neural marker of the genetic effects.Attention deficit hyperactivity disorder (ADHD) is associated with reduction of cortical and subcortical gray matter volumes (GMVs). The kinectin 1 gene ( Attention Deficit Hyperactivity Disorder (ADHD) is characterized as a behavioral syndrome with core symptoms of inattention and/or hyperactivity and impulsivity. Numerous imaging studies have focused on identifying structural brain markers of ADHD. Overall, the total intracranial volume (TIV) –6, cortiThe BG-cortical and -subcortical circuits play an important role in motivation, emotion, motor and cognitive processing , 49. ForKTN1, DCC, BCL2L1 and DLG2) and caudate nucleus (FAT3)  to determine the zygosity. A pair of subjects with P(IBD) equal to 1.0 (0.95–1.0) were identified as monozygotic twins, P(IBD) = 0.5 (0.4–0.65) as dizygotic twins or siblings, and P(IBD) < 0.4 as unrelated pairs. In self-reported data, a pair of subjects with the same birthday (± 1 day), sex and race in the same family were reported as monozygotic twins (with possible bias); a pair with the same birthday (± 1 day) but different sex or race in the same family was reported as dizygotic twins; a pair within the same family but with different birthday was reported as siblings; and others were reported as unrelated. Self-reports may not be accurate . Thus, only those unrelated subjects confirmed both by genetic inference and self-report were included in this study.The ABCD subjects included unrelated subjects, siblings, and dizygotic and monozygotic twins or triplets. We inferred the genetic relationship (zygosity) between any pair of two subjects using the whole genome data. To determine the zygosity between subjects, we calculated the probability of identity-by-descent [P(IBD)] using the program PLINK . First, –8); (c) were not associated with any known mental disorder; (d) were in Hardy–Weinberg Equilibrium (p > 0.05), and (e) were completely independent (r2 = 0) of each other.To quantify the degree of admixture in these subjects, we estimated the ancestry proportions for each individual with the program STRUCTURE . We examhttp://dbm.neuro.uni-jena.de/vbm/), following published routines [http://www.brain-development.org/), to drive the DARTEL normalization. Skull-stripping and final clean up (to remove remaining meninges and correct for volume effects in some regions) was performed with default parameters. Normalized GM maps were modulated to obtain the absolute volume of GM tissue corrected for individual brain sizes. Finally, the GM maps were smoothed by convolving with an isotropic Gaussian kernel (FWHM = 8 mm). We evaluated the GMVs separately for the right and left hemispheric brain regions.We implemented voxel-based morphometry (VBM) to quantify the gray matter volumes (GMVs) of 52 cortical regions and six subcortical structures identified from high resolution T1-weighted images with the CAT12 toolbox  that corresponded to the race of White, Black, Hispanic and Asian. A family-based association test was conducted in the replication Samples #1 and #2 using the “—dfam” as implemented in PLINK; and the allele frequencies were compared between cases and controls in the replication Sample #3 using the Fisher’s Exact Test as implemented in PLINK. A SNP-ADHD association within the same sex with p < 0.05 across the discovery sample and at least one replication sample with the same association direction was taken as a replicable association. We applied a replication design, instead of the overly-conservative Bonferroni correction for multiple testing, to reduce false positives.KTN1 mRNA expression in human postmortem brains in a UK European cohort  [cis-eQTL analysis. These subjects were free of neurodegenerative and neuropsychiatric disorders. In the UK European cohort, a total of eight cortical and subcortical brain regions were analyzed, including the prefrontal cortex, occipital cortex, temporal cortex, limbic system , BG (putamen and substantia nigra) and cerebellar cortex. In the European-American cohort, a total of 11 brain regions were analyzed, including the prefrontal cortex (Brodmann Area or BA9), anterior cingulate cortex (BA24), amygdala, hippocampus, hypothalamus, BG , and cerebellum. Normalized mRNA expression levels were compared between different alleles of each variant using t-test.We examined the potential regulatory effects of ADHD-risk variants on the dataset)  and a Eudataset)  using ciThe total intracranial volume (TIV) and the GMVs of BG  and limbic system  of ABCD subjects were analyzed in relation to ADHD-risk SNPs with multiple linear regression. The covariates included four dimensions of ancestry proportions and ADHD T-scores, as well as the TIV . We performed the analyses for left and right hemispheric areas and for males and females separately.The TIV of 18,713 European subjects (17 CHAGE + 29 ENIGMA2 cohorts)  and the We examined the potential regulatory effects of ADHD-risk variants on the TIV and regional GMVs using multiple linear regression, controlling for age, sex, 4 MDS components, TIV (for non-TIV phenotypes) and diagnosis . Males and females were not analyzed separately in this existing cohort, but sex was controlled for as a covariate.The potential regulatory effects of ADHD-risk variants on a total of 104 GMVs of 52 cortical regions (right and left hemispheres separately) were analyzed using a multiple linear regression, in which the GMV of each region served as dependent variable, the SNPs served as independent variables, and the covariates included TIV, four dimensions of ancestry proportions, and ADHD T-scores. Males and females were analyzed separately.In the discovery sample, among the 1020 cleaned, imputed SNPs, 137 and 40 SNPs were nominally (p < 0.05) associated with ADHD T-scores in males and females, respectively.2 < 0.05), including rs10132888 (50 kb flanking 5’ of KTN1) and rs10150277 (36 kb flanking 3’ of KTN1), rs8004764 (58 kb flanking 3’ of KTN1) and rs17090738 (245 kb flanking 3’ of KTN1). The former three were common variants with minor allele frequencies (MAF) > 0.05 and the latter one was a rare variant with MAF < 0.05. The major allele A (f > 0.5) of rs10132888 increased both the ADHD T-score in the discovery sample  and risk for ADHD in the replication sample “PUWMa”  (Table f > 0.5) of rs10150277 and the major allele T (f > 0.5) of rs8004764 increased both ADHD T-score in the discovery sample  and risk for ADHD in the replication sample “IMAGE”  (Tables f < 0.5) of rs17090738 increased the ADHD T-score in the discovery sample  and risk for ADHD in the replication samples, including “PUWMa”  and “META_PGC_DBS_males”  , BG (nucleus accumbens and substantia nigra) and cerebellum  the The ADHD-risk alleles of rs10132888  consistently across multiple independent samples , temporal , parietal , and occipital lobes , as well as the limbic system (posterior cingulate cortex), and cerebellum (hemisphere and vermis). Specifically, the ADHD-risk allele of rs10132888 increased (β > 0) the GMVs of the right posterior cingulate cortex p = 0.040) and left lingual gyrus (p = 0.045), but decreased (β < 0) the GMVs of the right hemisphere (p = 0.041) and vermis (p = 0.011) of the cerebellum , most prominently in the BG. The ADHD-risk alleles significantly increased the GMVs (in both ENIGMA2 and ABCD) of the BG and hippocampus (in ENIGMA2), but reduced the GMV of the amygdala (in ABCD) and the TIV (in ENIGMA2), and increased or decreased the cortical GMVs (in ABCD) as well.Four KTN1 mRNA expression, TIV, and subcortical and cortical GMVs, supporting the roles of the KTN1 variants in the development of ADHD in males. These findings also suggested potential sex difference in the genetic bases of ADHD.We identified four replicable, independent risk variants for ADHD specifically in males, each located at the 5′ (rs10132888) or 3′  flanking region. Variants rs10132888 and rs10150277 have also been reported earlier in association with ADHD risk . All fouKTN1 alleles regulated the mRNA expression, and/or GMVs widely across brain regions, including both cortical and subcortical structures and the cerebellum. The affected cortical structures included those in the frontal, temporal, parietal and occipital lobes as well as the limbic system, including the posterior cingulate cortex. The affected subcortical structures included primarily the BG—caudate, putamen, nucleus accumbens and pallidum. In the BG, the GMV of the putamen was most significantly and reliably affected by this set of KTN1 ADHD-risk alleles, consistent with the report that KTN1 was the most significant gene regulating the GMV of putamen [KTN1 and ADHD [Globally, the ADHD-risk alleles decreased the TIV, consistent with numerous previous findings –6. Regio putamen , and theand ADHD .KTN1 alleles. However, we also demonstrated that this set of ADHD-risk alleles significantly decreased other cortical  and subcortical  GMVs  , alteredKTN1 alleles. Therefore, the exact mechanisms underlying the effects of these ADHD-risk alleles on BG GMVs remain to be clarified. We provided two potential hypotheses. Firstly, the cortical volume reduction, as observed here for some brain regions, may decrease the neurotransmission in the “cortico-BG-thalamo-cortical” loop. As a compensatory response to the reduction of excitatory glutamatergic cortical projections to the BG, the volume of BG may expand to maintain the neurotransmission within the loop, leading to the observed association between the ADHD-risk alleles and higher BG GMVs. The expanded BG volume did not mediate the risk effects of this set of KTN1 alleles on ADHD, but rather reflected the consequences of the compensation response to expression of ADHD-risk alleles in the cortical structures. Broadly in support of this hypothesis are findings that boys relative to girls [KTN1 alleles, might be stimulated to express phenotypes that included the BG volume reduction and ADHD symptoms. The compensated BG volume reduction caused by the ADHD-risk KTN1 alleles usually does not completely restore the expanded BG volume and neurotransmission induced by other dominant genetic and environmental factors. This hypothesis well interpreted the associations between the ADHD-risk alleles and the expanded BG volume (Table KTN1 alleles on the ADHD risk, but might an inducer of the expression of ADHD. Besides these two hypotheses, other mechanisms to interpret our findings cannot be excluded.Notably, the most significant and consistent regulatory effects of this set of ADHD-risk alleles on regional GMVs were observed for the BG. However, as discussed above, BG GMVs did not mediate the ADHD risk effects of this set of to girls  and ADHDto girls  showed hme Table . Again, KTN1 mRNA expression but increased BG and some cortical GMVs, indicating that lower KTN1 mRNA expression was not necessarily associated with lower GMVs. This may reflect incongruence between mRNA and protein expression levels in these structures. Furthermore, the ADHD-risk allele of rs8004764 decreased the GMVs of the right hemisphere and vermis of cerebellum, but the risk allele of rs10150277 increased the GMVs of the cerebellum, suggesting that cerebral GMVs represent a multi-genic phenotype.Finally, the ADHD-risk alleles decreased the KTN1 alleles for ADHD. These alleles increased the risk for ADHD, decreased the KTN1 mRNA expression in the brain, and reduced cerebellar, some cortical, and amygdalar GMVs. Studies are warranted to further investigate the roles of these KTN1 risk alleles in the pathogenesis of ADHD.In summary, we identified a set of significant, functional, and robust risk


Genome-wide association studies (GWASs) have identified numerous genetic variants associated with attention-deficit/hyperactivity disorder (ADHD), which is considered highly genetically heritable. However, because most of the variants located in the non-coding region of the human genome, the onset of ADHD requires further exploration.The risk genes involved in ADHD were identified by integrating GWAS summary data and expression quantitative trait locus (eQTL) data using summary-data-based Mendelian randomization (SMR) method. We then used a stratified linkage disequilibrium score regression (LDSR) method to estimate the contribution of ADHD-relevant tissues to its heritability to screen out disease-relevant tissues. To determine the ADHD-relevant cell types, we used an R package for expression-weighted cell type enrichment (EWCE) analysis.By integrating the brain eQTL data and ADHD GWAS data using SMR, we identified 247 genes associated with ADHD. The LDSR applied to specifically expressed genes results showed that the ADHD risk genes were mainly enriched in brain tissue, especially in the mesencephalon, visual cortex, and frontal lobe regions. Further cell-type-specific analysis suggested that ADHD risk genes were highly expressed in excitatory neurons.The study showed that the etiology of ADHD is associated with excitatory neurons in the midbrain, visual cortex, and frontal lobe regions. Attention-deficit/hyperactivity disorder (ADHD) is a commonly diagnosed neurodevelopmental disorder which is usually characterized by inattention, impulsivity, and hyperactivity. It has been reported that approximately 5% of children and 2.5% of adults in worldwide population were affected by ADHD . MoreoveCurrently, ADHD is diagnosed in clinics using the DSM-5 or ICD10. Furthermore, clinical therapeutics for ADHD usually require long-term care, and the recurrence of symptoms is common . The GWAS summary statistics data are available for download from the Psychiatric Genomics Consortium website (https://www.med.unc.edu/pgc/results-and-downloads).Attention-deficit/hyperactivity disorder genome-wide association study data were obtained from the meta-analysis by Demontis et al. , which ihttps://yanglab.westlake.edu.cn/software/smr/#DataResource), which contained cis-eQTL information using RNA-seq expression and genotype data of 2,865 brain cortex samples from 2,443 unrelated European individuals. Qi et al.  to filter out results with PHEIDI < 0.01.We applied SMR to integrate ADHD GWAS data and eQTL data to identify the ADHD risk genes. In the SMR analysis, ADHD-relevant SNPs were used as instrumental variables (IVs) to test the causal effect of the exposure (gene expression) on the outcome (ADHD) . Detailei et al.  meta-anai et al. , CMC  (All risk genes were uploaded to the Synapse Gene Ontology (SynGO) website   for furtt-statistics was first calculated for the specific expression in the target tissue during the LDSC-SEG analysis. The genes were then arranged in descending order according to the t-statistics, and those within the top 10% were defined as the tissue-specific gene set. As an additional step, a 100 kb window was added to both sides of the transcription region of the genes in the tissue-specific gene set to construct tissue-specific genome annotations. The LDSC-SEG analysis was then applied to the different annotated groups to estimate the contribution of various tissues or cells to the target phenotypic heritability. Detailed information about the theoretical principle, model hypothesis, and algorithm implementation of the LDSC-SEG analysis is provided in the original publication   method was used to identify disease-relevant tissues using gene expression data from different tissues and GWAS summary statistics . For eaclication . We downdscores) , 21. Allhttps://github.com/NathanSkene/EWCE/. PEWCE < 0.05 was considered as significant.Single-cell transcriptome expression data are used to generate a probability distribution genes list containing the average expression in a cell of interest. The gene expression level is then estimated using the target gene set to check whether it is higher than that of randomly chosen genes in the cell of interest . We usedCAMK1D, a member of the calcium/calmodulin-dependent protein kinase 1 family that is responsible for the growth of hippocampal neurons dendrites; KCTD16, a subunit of the gamma-aminobutyric acid-B receptor, which is involved in the excitability of dendrites; and CTNNB1 alongside the transcription factor LEF1/TCF, which promote the expression of genes responsible for developmental processes, such as neurogenesis and synaptic plasticity , visual cortex (P = 0.02), and frontal lobe (P = 0.02)  . This rePEWCE = 1.6 × 10−3) and excitatory neurons in deep layer 2    22). Th. ThPEWCE = 0.04)  23). Ta. TaPEWCEAttention-deficit/hyperactivity disorder is a polygenic and complex heritable disorder, whose heritability is consisted of many common variants with small effects and relatively small number of rare variants with large effects. Most common variants identified by GWAS were located in non-coding regions , 6, withIn this study, we collected ADHD GWAS data, brain eQTL data, tissue expression profile, and cortical single-cell sequencing data to identify the ADHD-associated risk genes, relevant tissues, and cell types. We screened out 336 ADHD-associated risk genes, including multiple neurodevelopment-related genes and some of these genes, like KIZ and CTNNB1, were also indicated to be related to ADHD in previous studies , 29. TheThe LDSC-SEG results for the integrated tissue expression profile and ADHD GWAS data revealed that multiple brain regions were involved in the onset ADHD. Although the results were not adjusted by multiple correction, the most significant tissues were located in the brain. Therefore, we consider our results reliable. However, because of the high similarity in expression profiles among various brain tissues, we were unable to identify specific ADHD-associated brain tissues using the current methods.Although hundreds of risk genes for ADHD have been identified using SMR analysis, identifying the specific brain regions in which these risk genes exert its function requires further exploration because of cellular heterogeneity. Previous studies have shown that, in contrast to neurological disorders, GWAS data of psychiatric disorders map primarily onto neurons, rather than glial cells , 30. Thivia the regulation of the “core genes.” According to this notion, the majority of genes identified in our study likely belong to the “core genes.” In addition, we screened out multiple ADHD-associated risk genes that were also involved in neurodevelopment, which demonstrated that ADHD is a neurodevelopmental disorder  can be found in the article/W-QW and HS designed the study and drafted the manuscript. Y-JC, X-WL, and RZ analyzed the data. YL and X-WL revised the manuscript and provided expert consultation on the design of the study. All authors critically reviewed the manuscript and approved of it in its final form.This research was supported by Wuhan Municipal Health Research Fund (WG17M01 to YL).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.