P < 0.001) and CHIP-CE (P < 0.05) domains (indicating reduced HRQoL) for the ADHD group compared with the T1DM and control groups. Parent/carer and child ratings were significantly correlated for both measures of HRQoL , but only with low-to-moderate strength. Correlation between ADHD severity and HRQoL was significant with both PedsQL and CHIP-CE for all parent/carer (P < 0.01) and most child (P < 0.05) ratings; more ADHD symptoms were associated with poorer HRQoL. These data demonstrate that ADHD has a significant impact on HRQoL (as observed in both parent/carer and child ratings), which seems to be greater than that for children with T1DM.The impact of attention-deficit/hyperactivity disorder (ADHD) on health-related quality of life (HRQoL) is reported to be similar to that of other mental health and physical disorders. In this cross-sectional study, we hypothesized that children with ADHD and children with type 1 diabetes mellitus (T1DM) would have significantly worse HRQoL compared with healthy children, and that better clinical status in ADHD and T1DM would be associated with better HRQoL. Children were recruited from three outpatient services in Scotland. Responses to two frequently used validated HRQoL instruments, the Paediatric Quality of Life Inventory (PedsQL) and Child Health and Illness Profile-child edition (CHIP-CE), were obtained from parents/carers and children (6–16 years) with/without ADHD or T1DM. Child and parent/carer-completed HRQoL measurements were evaluated for 213 children with ADHD, 58 children with T1DM and 117 healthy children (control group). Significantly lower self and parent/carer ratings were observed across most PedsQL ( Health-related quality of life (HRQoL) is a complex, multifaceted construct that describes an individual’s perception of the impact of their health status on their physical, psychological and social functioning. HRQoL can be measured using a wide range of instruments –3. Most Clinicians, academics and regulators are becoming increasingly interested in the potential for HRQoL measures to be used as an index of clinical change and the effectiveness of therapeutic interventions , 9. For Attention-deficit/hyperactivity disorder is the most common behavioural childhood disorder and has a global prevalence in children of approximately 3.4–7.1 % –15. It iTo help address these issues, we conducted a cross-sectional investigation into the HRQoL of children with ADHD, a symptomatic (psychiatric) disorder, compared with that of children with type 1 diabetes mellitus (T1DM) and healthy controls. The ADHD and diabetic clinics from which patients were recruited for this study were responsible for all cases of these disorders within the local population and, therefore, had a broad range of presentations and clinical status, representative of local clinical practice. Both ADHD and T1DM are chronic disorders for which daily treatment is often required. Daily requirements for T1DM, such as the regular monitoring of blood sugar, balancing of insulin doses and managing of injections, are often difficult for parents/carers and children alike.Findings on HRQoL in T1DM vary. While several studies have reported reduced HRQoL and particular disease-specific HRQoL issues, others have not –28. SincHere, we report responses from children (6–16 years) with ADHD, T1DM or healthy controls, and their parents/carers, using two very different but commonly used validated generic paediatric HRQoL instruments: the PedsQL and the CHIP-CE questionnaires –32. Our Boys and girls aged 6–16 years were recruited from three outpatient services in Dundee, Scotland . The dental clinics provide general dental services to the same local population as the ADHD and diabetic clinics; those invited to participate in this study were attending for a general check-up rather than specific treatments or emergency care. Postal invitations with an explanation and outline of study purpose were sent to all parents/carers of children attending the clinics via their respective clinical service or dentist (control group) prior to booked clinic appointments. If both the parent/carer and child could not participate, recruitment of either the parent/carer or child was acceptable.The ADHD group consisted of children diagnosed with ADHD by an experienced child and adolescent psychiatrist trained in research methods, following a structured clinical assessment and using Diagnostic and Statistical Manual of Mental Disorders-IV criteria. Children were consecutive attendees at an ADHD continuing care clinic within the Tayside child and adolescent mental health service (CAMHS) at the Centre for Child Health, Dundee between September 2008 and January 2011. All children were receiving routine clinical care from the CAMHS service, which could include psychosocial and/or pharmacological treatment, or no treatment, for ADHD at the time of the study. The T1DM group consisted of children with T1DM  who were attending a diabetic clinic at Ninewells Hospital, Dundee between September 2010 and July 2011 as part of their routine clinical care. The community control group consisted of children/adolescents attending the Lochee Dental Practice, Kings Cross Hospital or Dundee Dental Hospital between January 2012 and January 2013.In the ADHD group, children were excluded if they had a history or current clinical diagnosis of other mental health disorders , or who had moderate or severe intellectual disability (IQ < 50), or T1DM or any chronic medical condition requiring specialist treatment or requiring hospital admission for >24 h within the past year that may impact on HRQoL. Children with comorbid psychiatric disorders such as oppositional defiant disorder and conduct disorder were included in the study to increase the representativeness of the sample; however, these conditions must have been judged by the clinical team to be secondary to ADHD and not currently requiring treatment. In the T1DM group, children with a history or current diagnosis of mental health disorders (as above) or ADHD were excluded. In the control group, exclusion criteria were the same as for the ADHD and T1DM groups. Respondents who were considered unable to understand or complete questionnaires were also excluded from all study groups. No compensation was received for participating in the study.Sample size for the primary outcome was calculated using data from previous HRQoL studies in ADHD , 33, 34.The assessment procedure was the same for all groups, with questionnaire instructions provided in a standardized format and according to questionnaire-specific recommendations. The parent/carer and child completed questionnaires independently. A research assistant was available to ensure that the content and study procedures were understood and to check for completeness/missing data.Two generic measures of HRQoL were used: 1) the child-self report and parent-proxy report versions of the PedsQL, which comprises four domains  and a total score; and 2) the longer child-report and parent-report versions of the CHIP-CE, which comprises five domains  but no total score. Both scales have been shown to be reliable and valid –32. For C)  were conducted for demographics and clinical variables. The scores for each HRQoL measurement completed by parents/carers and children with ADHD were compared with the responses from those with T1DM and healthy controls. All HRQoL and age data met assumptions of normality and homogeneity of variance group differences, and were analysed using multivariate analysis of covariance and thereafter by determination of simple effects through planned contrasts . CorrelaOverall, 484 invitations were distributed . In total, 388 children and parents/carers agreed to participate (80 %). All children and/or their parents/carers completed HRQoL measurements: 213 in the ADHD group, 58 in the T1DM group and 117 in the control group. There were significant differences between the groups with respect to age, sex and SES  for the ADHD group compared with both control and T1DM groups for all parent/carer-rated domains and for child ratings on the comfort, risk avoidance and achievement domains  across all domains for both self and parent/carer ratings . Domains demonstrating significant correlations largely remained significant when data were analysed separately by study group and by age for children aged 6 to <11 years and adolescents aged ≥11 years  and HRQoL were for child-rated school functioning on the PedsQL scale , and child-rated satisfaction , resilience  and risk avoidance  on the CHIP-CE scale  and HRQoL were significantly correlated for all parent/carer ratings and for most child ratings  on both HRQoL scales Table . In all le Table . Where tThis study provides child- and parent/carer-rated HRQoL data from two validated instruments for children with ADHD receiving routine clinical care, children with T1DM and healthy controls. Despite being on treatment, the reported HRQoL of children with ADHD was lower than those of the T1DM or control groups for all parent/carer ratings with both instruments, all child ratings with PedsQL and most child ratings with CHIP-CE. Results for PedsQL-measured HRQoL are consistent with previous findings from Limbers et al. in children with ADHD and comorbid psychiatric disorders compared with children with T1DM . LimbersThe PedsQL and CHIP-CE are both modular, multi-domain, validated, generic HRQoL measures with child and proxy ratings. The findings were generally consistent for the two different instruments; further analyses are required to identify whether both instruments are measuring similar aspects of HRQoL or whether they are indexing similar levels of disruption across different aspects.The effect sizes for parent/carer and child ratings were similar for both instruments, although the strength of effect was somewhat less for several of the child-completed CHIP-CE domains than was seen for the other measures. Parent and child ratings were significantly correlated with each other on both scales. However, the strength of both effect and correlation varied by domain, and child–parent/carer correlations did not reach significance for the social functioning and school functioning domains of the PedsQL. Our findings of a strong child-rated effect on the PedsQL and several of the CHIP-CE domains contrast with previous studies that reported reductions in parent but not child-rated HRQoL in ADHD , 43–45. In contrast to the limited correlations between disease severity and HRQoL for T1DM, the correlations between disease severity and ADHD were significant on both scales for all parent/carer and most child ratings . However, these correlations were only low to moderate in strength, suggesting that, although there is overlap between the two, they are assessing different aspects of functioning. Both disease severity and quality of care impact HRQoL and, in the present study, fewer symptoms were associated with better HRQoL. These findings clearly carry a significant message to those delivering clinical care to patients with ADHD: that optimizing symptomatic control will have a positive impact on HRQoL. This is important as most studies investigating quality of routine clinical care suggest that treatment outcomes are often not optimized  and thatThe HRQoL of participants with T1DM in this study was not impaired compared with the control group. Although these findings were not expected at the outset of the study, they are in keeping with the results of a more recent systematic review . AlthougThe limitations of this cross-sectional HRQoL study include non-response to study invitations, which can result in bias, and as data on non-responders were unavailable, differences in the demographic and disease characteristics between responders and non-responders could not be evaluated. In addition, group sizes were not equally matched and there were age, sex and SES differences between groups. The bias towards males observed in the ADHD group is typical of clinical samples; however, sex did not appear to affect HRQoL, and age and SES were adjusted for in the analyses. While patients attending the ADHD and T1DM clinics were initially referred for treatment and, therefore, not an epidemiological sample, attendees were recruited sequentially from the whole clinic populations. Although patients in the ADHD group were receiving clinical care for ADHD, medication status was not collected and could not be included in the analyses. As parents/carers and children both contributed information to the clinician-scored ratings of ADHD symptoms (ADHD-RS-IV) and HRQoL, these ratings were not entirely independent of each other. This may have inflated the correlations between the two. However, while correlations between these measures were significant, they were not highly correlated, supporting the value of measuring HRQoL in addition to symptoms.These data demonstrate that ADHD has a significant impact on generic HRQoL, and that this appears to be greater than seen for T1DM. This impact also appears to be related to ADHD severity and, importantly, is observed in both parent/carer and child ratings. We consider that these findings should be generalizable, at least for a referred population of patients. Furthermore, the degree of impairment of HRQoL reported here is similar to that seen in other studies, and agreement was observed between the parents/carers and children, and between the two measures. However, the findings are preliminary and it may be prudent to obtain ratings from both instruments for an accurate scientific perspective of HRQoL. We believe that further studies are necessary to obtain a consensus opinion of the validity and value of HRQoL measures.


Background. Over the last few decades, an increasing number of studies have suggested a connection between neurodevelopmental problems (NDPs) and body mass index (BMI). Attention deficit/hyperactivity disorder (ADHD) and autism spectrum disorders (ASD) both seem to carry an increased risk for developing extreme BMI. However, the results are inconsistent, and there have been only a few studies of the general population of children.Aims. We had three aims with the present study: (1) to define the prevalence of extreme (low or high) BMI in the group of children with ADHD and/or ASDs compared to the group of children without these NDPs; (2) to analyze whether extreme BMI is associated with the subdomains within the diagnostic categories of ADHD or ASD; and (3) to investigate the contribution of genetic and environmental factors to BMI in boys and girls at ages 9 and 12.Method. Parents of 9- or 12-year-old twins  were interviewed using the Autism—Tics, ADHD and other Comorbidities (A-TAC) inventory as part of the Child and Adolescent Twin Study in Sweden (CATSS). Univariate and multivariate generalized estimated equation models were used to analyze associations between extremes in BMI and NDPs.Results. ADHD screen-positive cases followed BMI distributions similar to those of children without ADHD or ASD. Significant association was found between ADHD and BMI only among 12-year-old girls, where the inattention subdomain of ADHD was significantly associated with the high extreme BMI. ASD scores were associated with both the low and the high extremes of BMI. Compared to children without ADHD or ASD, the prevalence of ASD screen-positive cases was three times greater in the high extreme BMI group and double as much in the low extreme BMI group. Stereotyped and repetitive behaviors were significantly associated with high extreme BMIs.Conclusion. Children with ASD, with or without coexisting ADHD, are more prone to have low or high extreme BMIs than children without ADHD or ASD. A recent report estimated that 43 million children worldwide are either overweight or obese, and another 92 million are at risk of becoming overweight . The samEqually important is the recognition of underweight in children; moderate to severe low BMI carries the risk of medical instability and long-term medical consequences . The incMany studies of twins and families have quantified the contributions of genetic and environmental factors to inter-individual differences in BMI. They were summarized in two reviews , which rBesides BMI, in the present study we aim to focus on mental health, as measured by the diagnoses of attention deficit/hyperactivity disorder (ADHD) and the broadly defined autism spectrum disorders (ASD) . ADHD isOf the few studies that have attempted to analyze the association between BMI and NDPs, most have been conducted in mainly adult populations. While it is not possible to draw a general conclusion from these studies, they have found a tendency for an overlap between overweight and ADHD or ASD . A recenIn the present report, we aimed to pursue this finding by analyzing the association between extreme (low or high) BMI and the presence of ADHD and or ASD using the data collected in one of today’s largest child twin studies. Because we used cross-sectional data, we did not attempt to disentangle causality between these factors.The specific aims of the present study were to investigate:(1)the prevalence of extreme BMI in the group of children with ADHD and/or ASD;(2)whether extreme BMI is associated with the subdomains within the diagnostic categories of ADHD or ASD; and(3)the contribution of genetic and environmental factors to BMI in boys and girls at ages 9 and 12.n = 12,496) who participated in the CATSS-9/12. We excluded 407 children with congenital or early brain damage, known chromosomal syndromes, diabetes, cancer, celiac disease, or other defined medical conditions with potential weight effect, and another 734 (6% of those who participated in the study) because of missing data. The final study population thus consisted of 11,355 children, with close to equal distribution between boys and girls  and 9- and 12-year-olds . Distribution of zygosities in the study was 27% monozygotic (MZ) twins, 35% dizygotic (DZ)–same sex (ss), and 33% DZ–different sex; 5% of the children could not be typed by zygosity. Only twin pairs with complete data on weight, height, and symptoms of NPDs were included in calculating heritability estimates; 1518 MZ and 1900 DZss twin pairs were eligible for inclusion.The study population was recruited from the ongoing Child and Adolescent Twin Study in Sweden (CATSS), a longitudinal, nationwide study focusing on mental health problems during childhood and adolescence . CATSS i2. For children, the use of BMI as a tool for assessing body fat is more complex than for adults. BMI references for children are age- and gender-specific, and the cutoffs for underweight, overweight, and obesity are population-specific. Many countries have their own population references in addition to the well-known international references of the World Health Organization  and 12-year-old  children from the Karlberg study  we had a much larger database than those used in the WHO and the Karlberg studies, (2) our sample represented twins, not singletons, and (3) our data include newer generations of children. BMI scores were transformed with the help of Box–Cox transformations to ensure normal distribution  inventory was developed for CATSS as a screening instrument to identify most major child and adolescent psychiatric conditions by evaluating parental information about children, collected during a telephone interview. The 96 A-TAC items reflect diagnostic criteria listed in the  4th ed.  and wellalidated  and founalidated .In the present study, children scoring ≥6.0 in the ADHD domain will be referred to as the ADHD group, children scoring ≥4.5 in the ASD domain as the ASD group, and those fulfilling criteria for both ADHD and ASD as the ADHD + ASD group. The children not fulfilling criteria for ADHD or ASD constitute the comparison group .Gender and age were close to equally distributed in the four groups. However, since NDPs were twice as frequent in boys as in girls, there were slightly more girls in the comparison group.n = 95) received medication with potential influence on weight, and over half of these (n = 48) did not screen positive for ADHD or ASD. Only one of the 81 children who screened positive for ASD, 20 of the 832 who screened positive for ADHD, and 26 of the 262 children who screened positive for ADHD and ASD combined had medication. Of the 95 children who were on potentially weight-modulating medication, 93% had a normal BMI, 3% had an extremely high BMI, and 4% had an extremely low BMI.Overall, parents reported 17 different prescription drugs used by children either daily or during the month prior to the interview; only three of these  had known effects on weight. In the total study population less than 1%  models were used to estimate the association between the dependent variable, the BMI categories  and the independent variables, ADHD and ASD scores as covariates, and age and gender as cofactors. First, univariable models were applied to study the separate effects of ADHD and ASD on BMI; then multivariable models were used to investigate the effects of coexisting ADHD and ASD on BMI. These GEE models take the statistical dependence within twin pairs into consideration. When a significant effect of ADHD or ASD scores was measured, new GEE models were fitted to investigate the detailed contribution of subdomains within the domain. In these models, the scores on activity/impulsiveness and attention (ADHD dyad) and social interaction, flexibility, and language (ASD triad) could be used as independent covariates.Twin modeling can help to disentangle genetic from environmental effects based on the difference in genetic relatedness between MZ and DZ twins. MZ twins are genetically identical while DZ twins share, on average, half of their segregated alleles. Comparisons between MZ and DZ twin pairs can indicate whether the examined traits are affected by genetic factors. In this study intra-class correlations were calculated separately for MZ and DZ twins and univariate structural equation modeling was performed using Mx model-fitting software. In the ACE model, genetic factors contributing to a trait are typically denoted as “A” (additive genetics) components, while environmental factors can be classified either as “C”  or “E” .The CATSS study complies with the Helsinki Declaration and has been granted ethical approval by the Karolinska Institutet Ethical Review Board (Dnr 03-672 and 2010/507-31/1). All subjects participated under an informed consent procedure. All data analyses were performed on anonymized data.X2  = 39.941, P < 0.00).There was a normal distribution of BMI in the comparison group, with 69% of the children having a normal BMI and close to equal distribution of the lower and higher ends of the scale . The BMIBoth ADHD and ASD modules were weakly but significantly associated with high and high extreme BMI in the univariable models. In the multivariable model (including both ADHD and ASD as covariates) only the ASD module kept its significant positive association with these dependent variables .When measuring the association of the subdomains in univariable models, problems with attention from the ADHD domain and problems with social interaction and flexibility from the ASD domain increased the risk for high BMI. Only the social interaction subdomain kept its significant positive association with high BMI in a multivariable model. All three ASD subdomains were significantly associated with high extreme BMI in univariable models, while in the multivariable model only the subdomain measuring problems with flexibility retained a significant relation . Among tNeither ADHD nor ASD were associated with low BMI, but ASD, in a univariable model, had a weak positive association with low extreme BMI. The flexibility and language subdomains were associated with this risk, but only the flexibility subdomain retained its significant effect in a multivariable model.Intra-class correlations were measured in gender- and age-specific groups. They were stronger in MZ than in DZ twins  in all gUsing the newly constructed Swedish BMI reference (specific to 9- and 12-year-old twins) for this study , there wMajor findings of the present study were:1.In the group of children with ASD (with or without ADHD), there was an increased prevalence of both high extreme and low extreme BMI.2.High extreme BMI was associated with high scores on the inattention subdomain of ADHD, while both high and low extreme BMIs were associated with high scores on the subdomain of ASD measuring inflexibility.3.The genetic effect on BMI was higher and the effect of shared environment was lower in 12-year-olds compared to 9-year-olds.4.BMI of twins seems to be representative of the general population.In the present study, children who scored above the diagnostic cutoff for ASD were overrepresented on both extreme ends of BMI. Three times as many children with ASD as children with no ASD or ADHD had high extreme BMIs, and twice as many had low extreme BMIs. BMI in the group of children with ADHD followed a close to normal distribution, and the coexistence of ADHD with ASD seemed less often associated with extreme BMIs than ASD on its own. Extremes in BMI have previously been observed in children with ASD identified as overweight  and undeThe results of the present study show that the presence of ADHD is associated with a high extreme BMI, while ASD is associated with both the high and the low extremes of BMI.While there are findings showing that impulsiveness in healthy adult females and males is associated with overeating , an earlAs previously shown, the variance in children’s BMI is largely influenced by genetic factors . HoweverBecause ASD was overrepresented on both ends of the BMI categories, it was not possible to conduct bivariate analyses of NPDs and BMI. The interpretation of such a model would be difficult and potentially misleading since ASD in the high end of BMI might be a different construct than ASD in the low end. Even with the relatively large number of subjects included in this study, tetrachoric correlations between ASD/ADHD and high and low BMIs could not be performed because too few individuals fulfilled each category to allow any conclusion to be drawn. Therefore, the present study did not analyze the importance of common genetic and environmental factors in the expression of NDPs and extreme BMI.Because twins are generally smaller than singletons at birth, special twin BMI references are recommended for following them during their first years of life . The infOur study confirmed that in pre-pubertal children, the BMI of twin samples could be considered to be representative of the general population of children. However, we found discrepancies between the twins’ and national and international BMI standards for extremes in under- and overweight. This could be explained by the large sample size, which could increase the visibility of those more rare extremes. Another explanation could be that this is an expression of time trends in the BMI development of children. A third explanation would be that although mean BMIs in twins seem to be similar to those of singletons, twins may be overrepresented at the extreme ends of the BMI curve. These findings emphasize the need for a more updated and relevant BMI reference when assessing BMI deviations among twins in research and clinical practice.Children with ASD, with or without coexisting ADHD, are more prone to have low or high extreme BMIs than children without ADHD or ASD. The present study suggests that the inflexibility of children with ASD might affect their eating habits and contribute to high or low extremes in BMI, while the inattention problems of children with ADHD are associated solely with high extreme BMI.To our knowledge, we are among the first to analyze the distribution of ADHD and ASD in children at the extremes of BMI in a nationwide study population. We have seen that most of the children with ADHD or ASD have normal BMIs, but that the prevalence of children at the extreme ends of the BMI curves was significantly higher among those with NDPs than in children without NDPs; that is, NDPs seem to carry increased risks for extreme BMIs. One obvious limitation is that the children were not clinically assessed and all data pertaining to NDPs and BMI were parent-reported. The accuracy of parentally reported weights and heights was assessed through comparisons with national and international standards of BMI (Result 1 and Based on our results we suggest that BMI references constructed for singletons may also be used in the clinic to recognize extremes of BMI in pre-pubertal twins.Severe overweight and severe underweight should always be recognized in the assessment of children because of its impact on current and future health. Similarly, in children with ADHD, and even more so in those with ASD, the increased risk for both overweight and underweight should be considered.10.7717/peerj.1024/supp-1Appendix S1Click here for additional data file.


Anxiety disorders and attention deficit/hyperactivity disorder (ADHD) develop before school age, but little is known about early developmental pathways. Here we test two hypotheses: first, that early signs of anxiety and ADHD at 18 months predict symptoms of anxiety and ADHD at age 3½ years; second, that emotional dysregulation at 18 months predicts the outcome of co-occurring anxiety and ADHD at age 3½ years. The study was part of the prospective Norwegian Mother and Child Cohort Study (MoBa) at the Norwegian Institute of Public Health. The 628 participants were clinically assessed at 3½ years. Questionnaire data collected at 18 months were categorized into early behavioural scales of anxiety, ADHD, and emotional dysregulation. We investigated continuity in features of anxiety and ADHD from 18 months to 3½ years of age through logistic regression analyses. Anxiety symptoms at 3½ years were predicted by early signs of anxiety (Odds ratio (OR) = 1.41, CI = 1.15–1.73) and emotional dysregulation . ADHD symptoms at 3½ years were predicted by early signs of ADHD  and emotional dysregulation . Co-occurring anxiety and ADHD symptoms at 3½ years were predicted by early signs of anxiety , ADHD , and emotional dysregulation . We conclude that there were modest continuities in features of anxiety and ADHD through early preschool years, while emotional dysregulation at age 18 months was associated with symptoms of anxiety, ADHD, and co-occurring anxiety and ADHD at age 3½ years. Anxiety disorders and attention deficit/hyperactivity disorder (ADHD) tend to have an onset at a young age and result in chronicity and impairment , 2, but That high occurrence and co-occurrence rates are detectable in preschoolers implies a need to investigate the predictive validity of anxiety and ADHD during the first years of life. Early intervention has been recommended for both anxiety and ADHD , 11. HowLongitudinal studies in schoolchildren have found symptom continuity for both anxiety disorders and ADHD, although with varied subtypes at different ages –14. At pResearch has been particularly scarce on the early course of co-occurring anxiety and ADHD . StudiesOne factor that has been proposed as a possible link explaining the development of anxiety in children with ADHD is emotional dysregulation, which is conceptually similar to emotional lability  as well Emotional dysregulation has been implicated in the development of co-occurring disorders in ADHD –36. As bIn this prospective, longitudinal study of preschool children we set out to test two hypotheses: the first that early signs of anxiety and ADHD at 18 months would predict the outcome of anxiety and ADHD symptoms at 3½ years of age, both when occurring alone and together; the second, that emotional dysregulation at 18 months of age would predict co-occurring anxiety and ADHD symptoms at 3½ years of age.www.fhi.no/morogbarn). In brief, about 89 % of the participating mothers were ethnic Norwegian, recruited from all over Norway from 1999 to 2008, and were predominantly white Caucasians [www.fhi.no/morogbarn). The mean household income was about 40,000 Euro, which is equal to the population mean.A total of 628 preschool children participated in the present study. They were recruited from the Norwegian Mother and Child Cohort Study (MoBa) at the Norwegian Institute of Public Health. The MoBa is an ongoing longitudinal study from which the mothers receive questionnaires about child behaviour at several time points, including at child age 18 and 36 months. The MoBa sample has been described previously , 38, anducasians . The cohThe questionnaire at 36 months included a total of 11 questions about hyperactivity, impulsivity and attention problems; six items from the child behaviour checklist (CBCL/1.5–5) , and fivThe Regional Committee of Ethics in Medical Research, the Data Inspectorate, the Norwegian Institute of Public Health and Oslo University Hospital approved the study. Informed written consent was obtained from the parents of the children in the study.Diagnostic assessment of the child was based on the preschool age psychiatric assessment (PAPA) interview with caregiver . The intn = 175) was defined by the presence of one or more DSM-IV criterion of selected anxiety disorders. The four anxiety disorder subtypes known to be most frequent in preschoolers were included: specific phobia, social anxiety, separation anxiety disorder, and generalized anxiety disorder [Anxiety symptom group (ANX)  included all preschoolers reported to meet all, or nearly all, of the DSM-IV criteria for an ADHD subtype. When there were fewer symptoms than required to fulfil the DSM-IV diagnoses , impairment had to be present in order for the child to be included. Impairment was considered present if the parent reported that the child showed at least some impairment in one or more areas.ADHD symptom group (n = 123) included preschoolers with symptoms as defined in both (1 and 2).Co-occurring ANX and ADHD symptom group (n = 20) or anxiety symptoms (n = 45) were excluded leaving a total of 82 children in the control group.Controls: a total of 147 children were originally selected as controls from the MoBa population. In the present study, children with ADHD symptoms above threshold  score was 9.3 with a standard deviation (SD) of 2.0 (range from 3 to 21). Cronbach’s alpha was 0.60.An anxiety scale was constructed based on the child behaviour check list (CBCL/1.5–5)  and inclM = 14.7, SD = 2.1, range from 4 to 18). Cronbach’s alpha was 0.68.An ADHD scale was constructed from the emotionality activity sociability (EAS) temperament measurement scale  and one M = 9.3, SD = 2.2, range from 3 to 15). Cronbach’s alpha was 0.62.An emotional dysregulation scale was constructed by the three items: “cries easily”, “gets upset or sad easily”, and “reacts intensely when upset” on a five-point response scale from very typical to not typical. These items were taken from the emotionality subscale of the EAS temperament questionnaire , 45. Higχ2 = 1,212.4, p < 0.0001. An initial analysis was run to obtain eigenvalues for each component in the data. Four components had eigenvalues over Kaiser’s criterion of 1 and in combination explained 52 % of the variance. The scree plot showed inflexions that would justify retaining both three and four components with the eigenvalue of the fourth component of only 1.1 (explaining 7 % of the variance). For the purposes of the analyses presented here, the three-factor solution was used which resulted in only one item, “clings to adult or is too dependent”, loading to both the anxiety and the emotional dysregulation factors. Omitting this item from the further analyses did not alter the main findings  measure verified the sampling adequacy for the analysis, KMO = 0.70. Bartlett’s test of sphericity, n = 82) in our study: the anxiety scale : mean = 8.4, SD = 2.1 . The ADHD scale : mean = 13.3, SD = 2.1 . The emotional dysregulation scale , mean = 8.2, SD = 2.3 .The distributions of the three scales were analysed in the entire MoBa sample of more than 66,000 participants at 18 months of age. Mean scores and SDs were close to the selected control group .A disruptive behaviour scale at age 18 months was constructed based on four CBCL items  “hits otIntellectual ability (IQ) at age 3½ years was estimated from a combined score of the “Object Matrices” , and the “Vocabulary Task”  from the short version of the Stanford-Binet Scales .Statistical analyses were performed using the Statistical Package for the Social Science .p < 0.05 level, and all statistical tests were two-tailed.A principal component analysis on the 14 predictor items of the EAS and CBCL supported a three-factor structure and is described above. Analysis of variance (ANOVA) with Bonferroni corrections was performed to compare groups at 3½ years of age on background data, and reported mean behaviour scale scores at 18 months of age. The three outcome categories at 3½ years of age: ANX, ADHD, and co-occurring ANX and ADHD  were investigated separately in bivariate logistic regression analyses contrasted to the control group (coded 0). In the process of fitting the model, IQ and gender were entered in the respective models, but as these covariates did not contribute significantly to any of the models, they were excluded from further analyses. In the final multivariate models early signs of anxiety, ADHD, and emotional dysregulation were entered as independent variables. In addition, we adjusted for early signs of disruptive behaviour to see if the findings of the final models were confounded by disruptive behaviour. Statistical significance was defined at the Table n = 123), ADHD (n = 248), ANX (n = 175), and controls (n = 82). There were statistically significant higher mean scores of anxiety at 18 months in the ANX group and in the co-occurring ANX and ADHD group compared to the ADHD group and the controls. Similarly, there was a significantly higher ADHD mean scores in both the ADHD group and the co-occurring ANX and ADHD group compared to the ANX group and the controls at 3½ years. All the three symptom groups at 3½ years had significantly higher mean scores of emotional dysregulation at 18 months compared to controls, with no significant differences in emotional dysregulation scores between the three symptom groups.Table χ2 = 47.79, p < 0.0001; Hosmer–Lemeshow χ2 = 10.10, p = 0.26. ANX only: χ2 = 43.32, p < 0.0001; Hosmer–Lemeshow χ2 = 3.59, p = 0.89. ADHD only: χ2 = 53.00, p < 0.0001; Hosmer–Lemeshow χ2 = 4.51, p = 0.81). Table In the multivariate logistic regression models early signs of anxiety, ADHD, and emotional dysregulation were entered as independent variables. All three models showed good model fit  may be assumed to tap directly into ODD. Within the DSM-V, the other three items appear more closely related to conduct disorder (CD), and two more specifically from the CD specifier for “limited prosocial emotions” .Good predictive validity of symptoms in preschoolers could aid clinicians in identifying children in need of intervention at a young age. Our findings suggest that caution should be exercised in predicting future psychopathology when early features of anxiety, ADHD, and/or emotional dysregulation are reported at the age of 18 months. The increase in risk was low, though statistically significant. This implies that identifying children at risk at 18 months is clinically challenging. There is a risk of over-identification and giving treatment to preschool-aged children who will not develop ADHD or anxiety disorders over time. The reason for the low increase in risk through the early preschool years might be that there are vast developmental changes in cognition, language, and emotional regulation during this period , 56. ThiThe strength of the present study is that a large group of preschoolers from a population-based cohort was clinically assessed and their parents interviewed about psychiatric symptomatology. The study design, with a sampling procedure for ADHD symptoms, increased the number of children with symptoms. Clinical studies usually have selection biases of increased comorbidity, symptom severity, and impairment, particularly for preschool children as they are seldom referred to specialist clinics .Our results should be viewed in light of several limitations. The MoBa had a participation rate of about 40 % with an under-representation of risk groups such as young mothers, mothers living alone, and mothers with previous birth complications . One wouBoth interview data and questionnaire data were based on parent report, mostly from mothers, with the possibility of report bias that has been shown to affect other studies on co-occurrence of psychiatric symptoms , 61.We based our analyses on reports of psychiatric symptoms from parents only. It is likely that the diagnostic symptom groups would have been different if information from preschool teachers were included in the assessments. However, most other studies on preschool psychopathology and diagnostic entities have used parental reports only , 8.Our defined symptom group included children who fulfilled, or nearly fulfilled, DSM-IV criteria for anxiety and/or ADHD. We reported symptoms that had lasted for 3 months or longer without excluding any particular items such as specific phobic symptoms. This gives a risk of having included normative behaviour, and thus elevated symptom rates. We used the duration criteria of 3 months in accordance with other preschool studies , 15, 57,The MoBa measures at 18 months had only a limited number of items selected from the subscales from the CBCL , and theChildren in our control group were included only when they did not have significant symptoms of ADHD and anxiety. This may have resulted in larger differences between controls and symptom groups in our study. However, the analyses of our 18-month predictors for the entire MoBa sample of over 66,000 participants did not support an under- or overestimation of problems within our control group. This, in turn, strengthens the findings of our logistic regression models.In conclusion, this study indicates that there is a modest continuity of anxiety and ADHD through early preschool life. Future studies should investigate these trajectories further, preferably utilizing diagnostic interviews.


Working memory, inhibition, and expressive language are often impaired in ADHD and many children with ADHD have lower IQ-scores than typically developing children. The aim of this study was to test whether IQ-score influences associations between ADHD symptoms and verbal and nonverbal working memory, inhibition, and expressive language, respectively, in a nonclinical sample of preschool children.In all, 1181 children recruited from the Norwegian Mother and Child Cohort Study were clinically assessed at the age of 36 to 46 months. IQ-score and working memory were assessed with subtasks from the Stanford Binet test battery, expressive language was reported by preschool teachers (Child Development Inventory), response inhibition was assessed with a subtask from the NEPSY test, and ADHD symptoms were assessed by parent interview (Preschool Age Psychiatric Assessment).The results showed an interaction between ADHD symptoms and IQ-score on teacher-reported expressive language. In children with below median IQ-score, a larger number of ADHD symptoms were more likely to be accompanied by reports of lower expressive language skills, while the level of ADHD symptoms exerted a smaller effect on reported language skills in children with above median IQ-score. The associations between ADHD symptoms and working memory and response inhibition, respectively, were not influenced by IQ-score.Level of IQ-score affected the relation between ADHD symptoms and teacher-reported expressive language, whereas associations between ADHD symptoms and working memory and response inhibition, respectively, were significant and of similar sizes regardless of IQ-score. Thus, in preschoolers, working memory and response inhibition should be considered during an ADHD assessment regardless of IQ-score, while language skills of young children are especially important to consider when IQ-scores are average or low. Attention Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder with a typical onset in preschool years. This period is important for cognitive development. For instance, elementary forms of Executive Functions (EF) components, such as working memory (WM) and inhibition, are already emerging before the age of three and develop rapidly in preschool years . LanguagChildren with ADHD have been shown to have lower IQ-scores . The terA number of studies have reported inconsistent findings regarding deficits in WM and inhibition in preschoolers with ADHD . For exaIn older children, a strengthening of associations between inattention, verbal WM, and verbal memory has been shown to occur through the school years ,22. Contmental age/IQ-score. Hence, IQ-score could moderate the association between ADHD symptoms and nonverbal WM. Put differently, an interaction between IQ-score and ADHD symptoms on verbal WM might be expected: the higher the IQ-score, the stronger the association between ADHD symptoms and verbal WM. On the other hand, according to Sowerby and colleagues [Combined, findings from most preschool- and school aged samples raise the question if associations between ADHD symptoms and WM are strengthened with age. Cognitive functions must have reached a certain level of maturity before delays or deficits are visible and executive aspects of WM are just emerging at the age of three ,25. Baselleagues , weaker lleagues ,27, whiclleagues . Howeverlleagues . In the An interaction between ADHD symptoms and IQ-score on response inhibition is not likely, as impaired inhibition is closely related to ADHD symptoms ,5, and cWe would expect weaker associations between ADHD symptoms and preschool teacher-reported language skills with higher IQ-score, for the same reason as expecting weaker associations between ADHD symptoms and verbal WM with increasing IQ-score. As teacher-reported expressive language skills are closely related to intellectual ability , high IQIn sum, a higher IQ-score may either make cognitive problems related to ADHD symptoms more visible or it may act as a protector from the impact of such cognitive deficits, or there may be no effect of a high IQ-score on the association between ADHD symptoms and cognitive functions in preschoolers. In order to investigate these possible interactions, nonclinical samples should be used, minimizing the risk of studying samples with disproportionally few children with well-developed cognitive functioning and/or higher IQ-scores. The use of nonclinical samples may be particularly important when studying preschoolers, as the classification of ADHD in young children is challenging. Yet to our knowledge, there are no studies with nonclinical samples of preschoolers to date specifically investigating the impact of IQ-score on the association between ADHD symptoms and cognitive functions.The main aim of this study was to test whether IQ-score influences associations between ADHD symptoms and WM, response inhibition, and reported expressive language, respectively, using a nonclinical sample of preschoolers. In order to address the main aim, we first investigated if there were significant associations between ADHD symptoms and the selected cognitive functions and in what direction they went and then went on to test whether there were significant interactions between ADHD symptoms and IQ on the cognitive functions mentioned above. A significant interaction would mean that the association between ADHD symptoms and the cognitive function under study depended on the level of IQ-score. To increase the clinical value of the results, follow-up analyses investigated whether negative associations between ADHD symptoms and selected cognitive functions differed in children with below median IQ-score compared with children with above median IQ-score.The present study is a sub study of a longitudinal study of ADHD in preschool children. The longitudinal study recruited its participants from the Norwegian Mother and Child Cohort Study (MoBa) , a populThe present study used a nonclinical sample of young preschool children recruited from the MoBa. A flowchart of the recruitment of the sample is presented in Figure th percentile on these questions. Children were also invited to participate when hyperactivity was reported as a health problem. Children with severe medical conditions compromising their ability to conduct the clinical assessment and/or high levels of autistic symptoms were excluded from the study before invitations were sent (n = 149). A total of 2798 children were invited from the MoBa cohort during the period from August 2007 to January 2011on the basis of these criteria. Of these, 1048 children (37.5%) participated in the clinical assessments. An additional 654 randomly drawn children from the MoBa cohort were invited, of whom 147 (22.5%) participated. The total sample of children who were clinically assessed at the mean age of 42 months was therefore 1195. Of these, the present study included the 1181 children who had valid IQ-scores (618 boys and 563 girls), all aged between 37 to 46 months. Additional information was provided by parents and preschool teachers (see below).In the MoBa, all parents received a questionnaire when their child was 36 months old. The questionnaire included 11 questions regarding hyperactivity, impulsivity and attention problems from the Child Behavior Checklist (six questions)  and diagPrior to clinical investigation, a questionnaire about expressive language (see below) was sent to the preschool teachers of all the participating children. The one-day assessment included neuropsychological tests and a semi-structured interview with a parent. The neuropsychological assessment lasted for approximately 1.5 hours including breaks, and small incentives  were at random time points given to the child to improve motivation during the neuropsychological assessment. Each child was individually evaluated by a psychologist while one parent was present. The interviews were conducted by psychologists, psychiatrists, or by trained psychology students. The examiners did not know if the child had been selected due to high levels of ADHD symptoms or if the child had been randomly drawn from the MoBa cohort. None of the children in the sample received psychopharmacological treatment at the time of the assessment.The present study included measures covering selected cognitive functions associated with ADHD symptoms.For assessment of symptoms of DSM-IV disorders, including ADHD, we used the Preschool Age Psychiatric Assessment (PAPA) . The PAPThe PAPA is the only comprehensive psychiatric interview to our knowledge with demonstrated test-retest reliability and validity for assessing psychiatric symptoms and disorders in toddlers and preschool children. We assessed interrater reliability of the number of DSM-IV symptoms and impairment scores by rescoring tapes of 79 randomly chosen PAPA interviews by raters blind to knowledge about the child. The average intraclass correlations (ICC) were .99 for number of inattention symptoms, .97 for hyperactivity symptoms, .96 for impulsivity symptoms, and .94 for total impairment score.th revision (SB-5) [The Stanford-Binet 5n (SB-5)  is a stan (SB-5)  that is th revision; the “vocabulary” task was used to assess verbal intellectual ability and the “object matrices” task was used to measure nonverbal intellectual ability. Together, these two measures provide an estimate of abbreviated IQ.IQ-score was estimated from a short version of the Stanford-Binet 5th revision was included as a measure of verbal WM. In this task, the child is asked to repeat sentences of increasing length.The tasks used for measuring WM in the present study were selected based on the assumption that these tests require preschoolers to rehearse or manipulate information while either listening to the rest of the information presented in the test item or while waiting to respond. The subtask “memory for sentences” from the Stanford-Binet 5Nonverbal WM was measured with the subtasks “delayed response” and “block span”. The first subtask consists of three cups under one of which a toy is hidden. The cups are either concealed for a few seconds before the child points to the correct cup (delayed response paradigm) or the cups switch places after the toy has been hidden. The “block span” subtask is a visual span task where the child has to tap blocks in the same order as demonstrated by the test administrator. Scaled scores from both WM tasks were used.The “Statue” task from the Developmental Neuropsychological Assessment (NEPSY) , which ia.The NEPSY was chosen for this study because it is a well-known neuropsychological test battery for preschoolers with subtests of short duration. The tasks are appealing for young children, which is important when assessing cognitive functions of 3-year olds. The NEPSY is also one of few test batteries for preschoolers that have been translated to Norwegian. Regarding psychometric properties of the “Statue task”, only test-retest reliability from the American manual are reported, which is limited (.50) a.The Child Development Inventory (CDI) , whose sDespite their young age, the majority of children completed all the tests. Participants were only included in the study if they had less than six missing items (less than 10% missing) on the CDI questionnaire from teachers. SPSS version 20 was used to analyse the data. Number of ODD symptoms and parental education in years were considered as potential confounders and are therefore presented in Table Before investigating the main aim of the study, we checked that each association between ADHD symptoms and verbal and nonverbal WM, expressive language, and response inhibition was significant when gender and IQ-score were controlled for Table . This waIn the main analyses, multiple regression analyses were used to study possible interactions between IQ-score and ADHD symptoms on verbal WM, nonverbal WM, response inhibition, and expressive language while controlling for gender Table . The indIn addition to running the interaction analyses with multiple regression, we chose to split the sample in two at the median IQ-score (103) to provide an illustration of the differences in the associations, or lack thereof, at different levels of intellectual ability. The median was chosen as it is close to the average IQ-score and as it created two groups of similar sizes. The sample consisted of 562 children  with below median IQ-score and 619 children  with median or above median IQ-score. Multiple regression analyses were used to study associations between ADHD symptoms and the four separate cognitive measures in the “median and above median group” and in the “below median group” while controlling for gender.Demographic characteristics and descriptive data are presented in Table The sample was very homogeneous regarding age and the children were mostly from families with highly educated parents. We estimated the annual income of the MoBa, from which the sample was drawn, to equal the mean income in Norway. The sample of the present study had more ADHD symptoms and ODD symptoms than one would expect to find in the normal population. The means and standard deviations of the cognitive measures of the whole sample were approximately as one would expect to find in the normal population.Table Both IQ-score and ADHD symptoms were significantly associated with WM, response inhibition, and reported language skills. Girls outperformed boys on the measures of NVWM, response inhibition and on reported expressive language, while there were no gender differences on the VWM measure.Table There was a significant interaction effect between ADHD symptoms and IQ-score on teacher-reported expressive language skills, not on WM or response inhibition.Figure 2 = .1; median or above median IQ group (n = 600): B = -0.10, SE B = 0.03, β = -.14, t = -3.48, p = .001, R2 = .2; nonverbal WM: below median IQ group (n = 558): B = -0.13, SE B = 0.03, β = -.18, t = -4.43, p < .001, R2 = .5; median or above median IQ group (n = 616): B = -0.09, SE B = 0.03, β = -.13, t = -3.15, p = .002, R2 = .2). Associations between ADHD symptoms and response inhibition were also of similar sizes in both groups: below median IQ group (n = 482): B = -0.36, SE B = 0.10, β = -.17, t = -3.80, p < .001, R2 = .07; median or above median IQ group (n = 549): B = -0.37, SE B = 0.10, β = -.16, t = -3.85, p < .001, R2 = .05. However, associations between ADHD symptoms and reported expressive language skills were not similar in size in the two groups (below median IQ group (n = 507): B = -0.42, SE B = 0.09, β = -.21, t = -4.95, p < .001, R2 = .07; median or above median IQ group (n = 560): B = -0.14, SE B = 0.07, β = -.08, t = -2.00, p = .046 R2 = .01).Furthermore, follow-up analyses were performed to test if the findings of no interaction between ADHD symptoms and IQ-score on either VWM, NVWM, or response inhibition were due to limited statistical power. These regression analyses controlled for gender showed that associations between ADHD symptoms and verbal WM and nonverbal WM, respectively, were of similar sizes in both IQ-divided groups : B = -0.07, SE B = 0.03, β = -.09, t = -2.09, p = .037, RIQ-score and ADHD symptoms were significantly associated with WM, response inhibition, and teacher-reported language skills in our sample of children. Girls outperformed boys on most measures. ADHD symptoms had a differential effect on teacher-reported expressive language depending on IQ-score: in children with below median IQ-score, a larger number of ADHD symptoms were more likely to be accompanied by poorer teacher scores of expressive language skills, while the level of ADHD symptoms exerted a smaller effect on reported language skills in children with above median IQ-score. As for the other cognitive measures, no such interactions were found, as associations between ADHD symptoms and WM and response inhibition, respectively, were significant and of similar sizes regardless of IQ-score. Thus, our hypotheses regarding teacher reports of expressive language and response inhibition were supported.We found no interaction between IQ-score and ADHD symptoms on either verbal WM or nonverbal WM. This could mean that the association between ADHD symptoms and WM is strengthened with increasing IQ-score in some children, while the association is weakened with increasing IQ-score in others. This interpretation would partially support previous studies -23, if tSome aspects of the design of the present study must be discussed as IQ-score is interrelated with ADHD symptoms and with other cognitive functions. However, previous studies have shown that unique aspects of cognitive functions contribute to IQ-score , and thaStrengths of the present study include a large sample with a nearly even distribution of boys and girls, an assessment with a well-validated interview for preschoolers (PAPA) to assess psychiatric symptoms, dimensional characterization of ADHD symptoms, and the use of performance-based measures of the key executive functions WM and response inhibition that are developmentally appropriate for 3-year olds. Moreover, the present sample is drawn from a nonclinical cohort, increasing the likelihood of having a sample with normally distributed IQ-scores. In contrast, clinical samples usually include more severe cases of ADHD, favouring children with low IQ-scores. On the other hand, there is the risk of underrepresentation of these children in the present study, which could constitute a limitation. The initial participation rate of the MoBa was 38.7%  and addiIQ-score was found to influence the association between preschool teacher-reported expressive language skills and ADHD symptoms. In young preschool children with higher IQ-scores, ADHD symptoms were more weakly associated with delayed expressive language than in children with lower IQ-scores. IQ-score did not influence associations between ADHD symptoms and WM and response inhibition, respectively.Findings of the present study show that language skills of children should be considered when an ADHD assessment is undertaken, especially when intellectual ability is average or low. This is not routinely done, even though language delay can have considerable negative consequences at school age . FurtherFuture studies are encouraged to consider the intellectual ability of their sample before generalizing findings about ADHD symptoms and teacher-reported language skills. The results of the present study suggest that associations between ADHD symptoms and teacher-reported language skills are more likely to occur in samples with lower IQ-scores than in samples with well-developed intellectual ability.aCorrections issued from the Publisher of the NEPSY test (Psykologiförlaget AB), 2002, were used.WM: Working memory.None of the authors have competing interests.NR-B contributed to the clinical assessment of the participants, study design, literature searches, statistical analyses, interpretation of results, and writing of the manuscript. PZ and HA are scientifically and financially responsible for the design of the Norwegian Longitudinal ADHD Study (from which the data of the present study were drawn), including selection of measures and recruitment of participants for the present study, they contributed to the interpretation of results and to revising the manuscript critically for intellectual content. JE contributed to the design of the study, the interpretation of results and to revising the manuscript critically for intellectual content. KG contributed to the design of the study, statistical analyses, interpretation of results, and to revising the manuscript critically for intellectual content. AHS contributed to the clinical assessment of the participants, took part in the discussion of neuropsychological concepts under study and contributed to revising the manuscript critically for intellectual content. TR-K contributed to the design of the Norwegian Longitudinal ADHD study and the present study, interpretation of results and to revising the manuscript critically for intellectual content. All authors read and approved the final manuscript.


Ensete ventricosum (Welw.) Cheesman is a major food security crop in Southern Ethiopia, where it was originally domesticated and during millennia became pivotal crop around which an entire farming system has developed. Although its cultivation is highly localized, the enset-based farming system provides sustenance to more than 20 million people. Precise ethnobotanical information of intra-specific enset diversity and local knowledge on how communities maintain, manage and benefit from enset genetic resources is imperative for the promotion, conservation and improvement of this crop and its farming system.Kebeles (villages) representing three agro-ecological ranges. By establishing Participatory Rural Appraisal (PRA) based interactions and applying ethnobotanical interviewing methods of free-listing and open-ended questionnaires, information on the use and management of enset diversity, and its associated folk-biosystematics, food traditions and material culture was collected and analyzed.This study was conducted in Southern Ethiopia among the Wolaita 'enset culture' community. The research sample consisted of 270 households from 12 While enset agriculture is seen as cultural heritage and identity for the Wolaita, enset intra-specific diversity holds scenic, prestige and symbolic values for the household. In the present study we recorded 67 enset landraces under cultivation, and through a comprehensive literature review we identified 28 landraces reported from other areas of Wolaita, but not encountered in our survey. Landraces, identified using 11 descriptors primarily related to agro-morphological traits, are named after perceived places of origin, agro-morphological characteristics and cooking quality attributes. Folk classification of enset is based on its domestication status, 'gender', agro-ecological adaptability and landrace suitability for different food and other uses . Enset as a food crop is used to prepare 10 different dishes in Wolaita, 8 of which are exclusively prepared using enset, and their consumption ranges from daily staple to specialty food in festive occasions and ceremonies. On-farm landrace diversity and richness is guided by household needs; its dynamics is managed through regular propagation, harvesting restrain, control of landrace composition and arrangement in the enset homegardens.in situ and ex situ conservation strategies to foster conservation of enset genetic resources and associated indigenous knowledge system.This study reported on the knowledge system, socio-cultural process and community practices that drive the maintenance of intra-specific on-farm enset diversity in Wolaita, Southern Ethiopia. The information is crucial for developing community based complementary  Ensete ventricosum (Welw.) Cheesman, commonly known as enset, is a monocarpic perennial herb of the Musaceae family originated in Ethiopia [E. ventricosum is arguably the most important crop contributing to food security and rural livelihoods for about 1/4 (20 million people) of the Country's population. Enset domestication dates back to Neolithic time or even earlier [Many crop plants that have been under cultivation for millennia and are contributing to the livelihoods of local communities are scarcely known, if not completely unknown, outside the regions of their cultivations and use. Crops with such localized uses are primarily grown in subsistence farming systems in many Developing Countries, including Ethiopia, and they substantially contribute to food and nutrition security of small-scale farming households ,2. EnsetEthiopia . GeograpEthiopia ,5, ensetEthiopia . In fact earlier ,7, and i earlier ,9. Curre earlier .The enset farming system (EFS), where enset is cultivated as perennial plantation in homestead ring in association with other companion crop species growing in main agricultural land, is rich in both inter-specific and intra-specific diversity . The divStudies indicate that social attributes of human communities, such as local knowledge, experiences and cultural values, play a substantial role in the sustainable management, conservation and utilization of genetic resources and restoration of agro-ecosystems -17. WithIndigenous knowledge system (IKS), or otherwise called local knowledge system, is a wide comprehensive concept which includes, but it is not limited to, the botanical knowledge, traditional food knowledge, surrounding environmental and ecological knowledge that enable farming communities to lead stable livelihoods in their environments ,21. IKS Wolaitato Donaa (the language of the Wolaita) as uutta. The Wolaita is regarded as 'the enset people' or 'the people of enset culture' for the strong interlink that exist between enset cultivation and the local food and material culture of the people [Our study focuses on one of the indigenous 'enset culture' communities of Southern Ethiopia, the Wolaita. The Wolaita are among the ethno-linguistic groups whose agriculture is based on enset, locally known in e people . Howevere people . Earliere people ,24. EquaThe present study was undertaken with the objective of (i) exploring the status and extent of enset cultivation and diversity; (ii) investigating folk-biosystematics of enset landraces; (iii) documenting socio-cultural, dietary, ethno-medicinal and other related uses of enset; and (iv) investigating community practices relevant to maintenance of on-farm landrace diversity in Wolaita.Woredas. Within Woredas, Kebeles are the smallest administrative units. Geographically, Wolaita Zone is located between 7° 00' North latitude and 37° 45' East longitude at the edge of the East African Great Rift Valley. Inhabitants of the Wolaita Zone are primarily the Wolaita ethno-linguistic communities speaking the Omotic Wolaita language, Wolaitato Donaa. The Wolaita are predominantly agriculturalists, practicing mixed crop-livestock production and living in permanent settlements. Within their landholdings, community members maintain fruit orchards, nurseries, medicinal plants, vegetables, root and tuber crops, ornamentals, spices, as well as open areas for raising domestic animals [Kebeles belonging to 6 administrative Woredas in the Wolaita Zone  variation; and the sampled territory covered main enset growing agro-ecological zones  of Wolaita.With an area of approximately 438,370 hectares, and an estimated population of 1,750,830, the Wolaita administrative Zone is part of the Southern Nations, Nationalities and Peoples' Region (SNNPR) of Ethiopia; SNNPR is one the 9 Regions and 3 Chartered Cities in which the Federal Democratic Republic of Ethiopia is composed . The Reg animals ,26. EnseKebeles from highland, 4 Kebeles from midland and 3 Kebeles from lowland were randomly selected. In the process of Kebele selection, key informants comprising agricultural officers and Development Agents (DAs) were consulted. The number of consulted key informants in all Woredas was 10; but 9 key informants in Damot Woyide and Soddo Zuria Woredas as well as 8 key informants in Duguna Fango Woreda were participated. From the 12 selected Kebeles, a total of 270 households randomly drown from resident booklets were considered as over all sample size for the study. In 9 of the Kebeles, 25 households from each Kebele were selected for individual interviews and from each of the remaining 3 Kebeles  15 households were chosen and interviewed. Table Kebeles from 3 agro-ecologies and 6 different Woredas. Respective area (km2), population size, elevation range and number of households sampled in each of the Kebeles are also indicated.A stratified random sampling procedure was followed to define the sampling unit. Based on the three traditional agro-ecological zones of Ethiopia, lowland <1,500 m, midland 1,500-2,500 m and highland >2,500 m above sea level , the ensData were collected by combination of methodologies for the acquisition of local knowledge, including literature review, Participatory Rural Appraisal (PRA) tools, focus group discussions (FGD), in-depth individual interviews, expert elicitations and observations of cultivation techniques ,30.Literature review provided the necessary background context of enset farming systems and cultural links to the farming communities of Wolaita. Present status of enset agriculture and diversity in Wolaita was reviewed from several published and unpublished sources and reports.Kebeles involving members from local administration, community elders, key informant farmer groups and other members of participating communities, and a full consent of collaboration based on the principle of Free Prior Informed Consent was granted [Kebeles. Open questions and free-listing approaches were followed to gather information on enset landraces, in particular to assess farmers' perception of landrace diversity, vernacular naming, meaning of names, folk-biosystematics and description of use-values. Food traditions, such as names and preparation of dishes from enset, occasions of consumption and indigenous folklores, such as sayings, poems and songs associated to enset agriculture expressing the cultural tie of the society to the crop, were also documented. Interviews were conducted during drinks and coffee times in homes or homegardens, where the selected household and other interested people were gathered together. Because women of rural Wolaita are particularly responsible from the propagation, protection, harvesting, processing and storage to the final preparation of enset foods [Focus Group Discussions were held in each of the selected  granted . Individet foods , they weCollected data were carefully cross-checked for completeness and reliability. Expert elicitations, key informant comments and informal discussion with farmer groups were conducted to verify inconsistencies, enrich and validate information gathered from individual interviews. Descriptive statistical summaries such as frequencies, percentages and averages were calculated using Microsoft Excel 2007 and venn diagrams were made using the online platform VENNY .darkuwa) ring in poly-varietal perennial plantations without any crop-rotations and land-fallowing. Sometimes, farmers maintain enset landraces intercropped with perennial tree crops, such as coffee (Coffea arabica L.), avocado (Persea americana Mill.), guava (Psidium guajava L.), and annual and biennial crops, such as maize (Zea mays L.), Ethiopian kale (Brassica carinata A. Braun) and yam (Dioscorea spp.) , 7 and 13 respectively , 24 were also identified in the present study. In relation to the agro-ecological distribution of landraces recorded in this study, a total of 21 landraces from highland, 19 from midland and 13 from lowland were also found in the AARC collection, and 11 of those were shared in the three agro-ecologies and AARC  the folk biosystematics used for intra-specific enset diversity, (ii) the complex and overlapping uses derived from enset landraces, and (iii) the dynamic on-farm management practices followed to maintain landrace diversity. All the respondents believe that they have inherited this IKS from their forefathers and the custom sustained since time immemorial..The local farmers of Wolaita we approached perceive each enset landrace they grow as distinct, with clearly distinguishable peculiar characteristics. The farmers use three folk processes of indigenous biosystematics for their landrace under cultivation: they identify the landraces and then name and classify themSuitia, which means 'the bleeding', referring to the red sap color of Suitia as compared to the watery and milky sap color of most of the other landraces. Sap color and corm characteristics, mentioned by 57% and 40% of the respondents, were less frequently quoted descriptors for the identification of enset landraces in the study area.For identification, local farmers used 11 descriptors Table . Those dWoredas to the landrace names . The naming may include the indication of physical entities , cultivated plants ; domestic animals  and of wild animals . In other instances, farmers literally used words in Wolaitato Donaa to describe the specific morphological, agronomic, and cooking quality attributes of specific landraces . Table Bota-arkiya, Dawro-arkiya and Kucha-arkiya are derived from 'primary' landrace name Arkiya and the additional modifiers describe color and origin of the Arkiya landrace. It should be considered however that, the majority of enset landrace names had their implied meanings unknown to the community members.Nomenclature is the second folk process the Wolaita employ for their enset landraces after identification. Local farmers in the investigated study area give separate vernacular name for each landrace they grow. The names are often descriptive and reflect variations of landraces in places of origin, morphology, as well as agronomic and cooking characteristics. Often farmers attach names of places in neighboring Zones and The Wolaita use folk classification systems for their enset landraces, in which different categories of classification overlap. Four criteria are used in classifying enset landrace: (i) domestication status (ii) gender (iii) use-value and (iv) eco-geographic adaptability Table .Geziya). The Wolaita give the same name for all wild enset, i.e. talahe uutta, which means 'the enset of the devil'. Communities of the investigated Kebeles believe that there are farmers adding 'talahe uutta' to cultivation, but there was no farmer encountered in our interview practicing addition of wild enset into cultivation. In the focus group discussion and expert elicitation sessions, participants indicated that it is very unlikely to find wild enset in Wolaita at present.Farmers distinguish two enset types on the basis of their domestication status, wild or cultivated. Wild enset landraces in Wolaita occur naturally in river banks, swaps, gullies and near streams in highlands (darkuwa) as a homegarden crop  and 'male' enset (attuma uutta). The distinction as 'male' and 'female' is not related to the biological reproduction of the landraces. Farmers consider early maturing landraces with high edible corm quality (less fibrous and tender corm), with thin and weak pseudostems, as macca uutta, and late maturing fibrous landraces, with corms of poor cooking qualities, as attuma uutta. Of the total 67 landraces identified, 24 (36%) were classified as 'female', 28 (42%) as 'male' and the remaining 15 landrace had ambiguous sex designation, some farmers claiming them 'male' and others claiming them 'female'. Based on indigenous use-value, farmers classified enset landraces in two comprehensive use groups: food use and non-food uses . Although all enset landraces can be used both for food and non-food uses, there are preferences for specific landrace among communities for particular purposes. In the study area the majority of landraces were primarily planted for food uses and others for non-food use, such as complementing livestock feed, and animal and human medicinal requirements. Very few, such as Tuffa and Lalukiya, were grown for fiber production and water fetching from their pseudostems respectively. The other classification criterion farmers used was eco-geographical adaptability of landraces. The Wolaita farmers describe major enset ecosystems by elevation regimes: Gara  and Geziya ; they assign a set of enset landraces to specific elevation niches, i.e. as Gara uutta and Geziya uutta. Although landraces adapted to highlands can be cultivated in lowlands and vice versa, the growers claim that some landraces (e.g. Maziya) are specifically adapted to Geziya ecosystems.Cultivated enset are located in human settlements near dwellings . According to the information we obtained from the growers, enset is an old crop that has been under cultivation since time immemorial. The cultivation of enset is seen as family heirloom that the antiquity of enset agriculture in their area is what they have heard from their forefathers. The majority (87%) of the farming households surveyed started farming and growing enset crop on the plot of land with a set of landraces inherited from their fathers at adulthood. Locals believe that offering a plot of land with a mixture landraces to an adult son is an old tradition transferred from one generation to next in Wolaita.The enset plant and its cultivation has special cultural meaning and value for the Wolaita. The cultivation of enset also bears a cultural symbol for the communities and it is an expression of their identity. There is a common refrain in the area: 'Allawa) owing a large number of vigorously growing enset plants (Alla) in his homegarden. The Wolaita indicate the cultural uses of enset, its status symbol role and the strong tie the crop has with their life from birth to death using their traditional folklores. Those folklores , English translation: well dressed kids give prestige to their parents, well managed enset homegardens give prestige to household and hamlet.Every farming household in Wolaita grows some enset and maintains two or more landraces in its homegarden. Enset being highly valued as a status symbol, people appreciate a hamlet by enset around it and give special respect and name for a man  primary enset products , whereas 'male' landraces are preferred for processing. Landraces producing whiter Itima after processing are preferred for visually attractive and specialty dishes, such as Muchuwa, Baccira and Shendera.Enset foods are served both as staple daily diet as well as in occasions of cultural festivals, hence enset foods have both nutritional and cultural values for the society. In this study, we identified 10 recipes of dishes derived from 3 , a processed product from enset with extended storability, and mourn together with the family of the deceased. The traditional festival of New Year in Wolaita called Gifaata , is celebrated eating the special foods Baccira and Muchuwa on the eve and throughout the celebration weeks.The community indicate that enset foods are traditionally incorporated into cultural events, such as births, deaths, weddings and festivals. During births, a postnatal mother eats yecha, is used as traditional plate to serve food, or as wrapping material for different products and baking breads, but it can be used also as an umbrella during the rainy seasons. Dried leaves and other pseudostem parts are also collected for making traditional seats (shill'a) and mattress (konashia hitta). The outer-most dried leaf-sheaths of the pseudostem (goba), often harvested while the tree is still growing, is used as a seal (gossa) of traditional milk processing pot and for handling butter. Any dried part of the enset plant, mostly the dried lamina (gombila) and petiole, is used as a firewood. Susa, the dried and semi-dried long lamina, is used for fastening harvests of grasses, crops, and firewood. For construction of fences and traditional houses (Wolaita ketta) only dried, water-soaked and relatively strong lamina is used. The fiber of enset, gola, produced as side-product during food processing (Uncca), is a very strong and high quality fiber. It is used for making ropes, strings, baskets, sacks, house floor carpets, filters, utensils' cleansers and many traditional house decors. Also, the fiber is used for fencing and construction of houses. During our survey, all the interviewed households mentioned one or more of the aforementioned material culture values of enset.The Wolaita do not waste any part of the enset plant. Every part of enset plant has some sort of use in material culture of the Wolaita. The green enset leaf, Itima from Agino and Gefetanuwa landraces, for strengthening women after delivery, and healing bone fractures in humans respectively; (ii) very highly fermented Uncca from Maziya and Halla landraces, for curing stomach cramps; and (iii) boiled corm of Lochingia, for birth control and abortion in humans, and to feed cows to facilitate placental expulsion.The enset plant and its parts contribute to indigenous ethno-medicinal values of the Wolaita. Although all the respondents in the study area know and believe that enset is medicinally important, only a few people use it for medicinal purpose. Traditional healers in the area confidentially keep ethno- medicinal knowledge of enset landraces and many other medicinal plant and animal species. Mostly administered in the form of food products, traditional enset medicines include (i) porridge made of As described to us by the community, enset agriculture fulfils an ecological role, because it is an organic farming systems using only farmyard manures, with no external chemical fertilizers, herbicides and insecticides. In the study area, animal husbandry is commonly practiced and it benefits from enset agriculture through a year-round supply of nutritious feed; in this regard enset is considered a safety-shield cattle feed because it is available during the drought prevalent seasons of the year, when most other feed sources dry out. The enset plantation in homegardens serves also as a wind break for enset and other crop nurseries. Enset farming also fulfills an aesthetic requirement for the homegarden through colorful ornamental landraces. Both in focus group discussion and interviews, the respondents indicated that surplus production and planting materials are sold in local markets and generate income for the household.Indigenous management and maintenance of on-farm enset landrace diversity can be deciphered by means of the three broad but overlapping indigenous approaches that farmers follow: (i) regular propagation and harvesting restrain; (ii) organized assemblage and arrangement of landraces in the homegarden; and (iii) landrace composition regulation in the homegarden. All the approaches the locals follow sustain on-farm landrace diversity.Garduwa, Haata, Bashashiya, and Wosa, which distinguish propagation and harvesting cycle loops  kept underground for 1 year, are separated from the mother corm and replanted in well manured nurseries. Replanted Haata grow in the nursery for another year after which they are named Bashashiya. A successive transplanting produces a new Garduwa (three years old plants). In addition of being used as mother corm for propagation, plants at Garduwa stage may be harvested for consumption, especially in food shortage seasons, or are transplanted as the definitive establishment, where they stay until harvested for processing (Wosa stage). Propagation is a cultural practice carried out every year, from late December to early February, using a mixture of landraces: on average, the farming households we studied propagate 5–15 plants per year before the on-set of the rainy season. Farmers select a mixture of landraces for propagation. Multipurpose landraces of high food and non-food uses such as Ala-genna, Gefetanuwa, Halla, Maziya, Mochiya, Shalakumiya, and Tuzuma are the most frequently propagated landraces every year. Other landraces are propagated alternatively year after year for maintenance and their limited number of use-values. However, some old and unproductive landraces are intentionally not propagated and are purged out from the homegarden or replaced with other landraces. Propagation as a practice is, therefore, not only a way for multiplying landrace of interest in homegarden but also part of the strategy for maintaining a dynamics of landrace diversity in the enset homegardens.Regularly propagating mixture of landraces and a balanced harvest restrain are practices farmers in the study area employ to regulate enset cycle and to maintain on-farm landrace diversity. The enset cycle managed by each of the household under study, from propagation to harvesting, involves maintaining 4 different successions of age-classes of plants in homegarden viz: s Figure . Accordicegena (on-and off-set season of the moon), which is a fear factor that forces farmers not to harvest during this season, in the belief that enset plantation and processed product will be diseased and destroyed. Such convictions made farmers to distinguish and maintain landraces harvested early  and late  before and after the on/off-set of cegena in their homegarden. The tradition of multi-enset food recipes and many other material culture needs, guide harvesting of landraces in mixture and reduce harvesting pressure of any particular landrace.Harvesting for consumption and other uses is the second loop that completes the enset cycle Figure . HarvestHaata, Bashashiya, Garduwa and Wosa), sex  and multiple usage. Farmers regulate and improve landrace composition of their homegardens to meet agronomic (e.g. early and late maturing landraces), cooking qualities and taste attributes , aesthetic requirements (e.g. colorful landraces) and many other cultural values and needs. Farmer-to-farmer informal networks of 'seed sucker' transfers ensure the regulation of landrace composition in homegardens. Local farmers' informal pathways of planting materials include procurements from local markets (mainly in urban areas), gifts from neighbors and kinship groups, exchange for other landraces and bringing as living mementos from travels to add to their homegardens. Farmers' experimentation to regulate and improve homegarden landrace composition through networks of planting material systems maintains on-farm enset diversity in a dynamic way, both over time and space.Multiple landraces, at least 2, are maintained and managed in the enset homegardens of Wolaita. The landraces maintained vary according to age , recurrent drought, demographic (e.g. increasing population size) changes and associated land shortages are threatening enset agriculture. This agrees with recent reports on the vulnerability of agricultural systems and agro-biodiversity in Southern Ethiopia [According to our results, enset is cultivated by every farming household in Wolaita and it is the crop of choice for the community. In the agricultural system of the studied area, enset is the major perennial-stand permanent crop and most important food security source. Ages-old customary cultivation of enset in the area, which does not involve the use of chemical inputs ,26, portEthiopia ,13,24.Kebele (Areka) involving 105 households in the Boloso Sore Woreda of Wolaita Zone [Kebeles involving 156 respondents in Ofa Woreda of Wolaita Zone [ex situ AARC collection, where 37 enset landraces from Wolaita and many others from different enset growing ethno-linguistic communities of Southern Ethiopia are maintained  and type of enset landraces in this study is comparable with other previous reports from different parts of Wolaita ,24,34. Fita Zone . In anotita Zone , 17 landde facto conservation for their livelihood needs; during our focus group discussions and individual interviews farmers strongly expressed the desire and willingness to maintain more diversity in their homegarden. Amongst other reasons, farmers in our study area maintain a wide range of enset diversity and invest resources to sustain its cultivation with limited external supports and interventions as an insurance mechanisms against unexpected crop failures due to biotic and abiotic causes. The dynamic management followed by farmers we described here and methodological differences among the studies we reviewed, imply and call for continuous documentation and monitoring of landraces by applying a uniform and comparable procedures both over time and geographical scale for characterization and conservation of enset.A dynamic on-farm management of enset landraces, similar to what we documented here, was reported for Sidama, Gurage and Ari ethno-linguistic community in Southern Ethiopia -38. FarmSorghum bicolor (L.) Moench) in Eastern Ethiopia [ex situ collection expeditions in Southern Ethiopia, including Wolaita [Folk biosystematics, i.e. identification, naming and classification of enset landraces, is an integral part of farmers decision of maintenance, management and exchange of landraces in the study area. A similar trend of using folk biosystematics was reported for enset in Sidama  and for Ethiopia . In view Wolaita ,36,40,41 Wolaita ,38,42. L Wolaita  and rice Wolaita  were rep Wolaita ,40, we dex situ collections that were reported for enset [For a crop such as enset that lacks a well established descriptor list and a formal taxonomic system ,45, farmor enset .Shendera, Eretta) can be prepared from other crops like barley and maize with difference in texture and quality. The deep-rooted culture of using enset in daily lives from birth to death ceremonies and festive is an important bio-cultural heritage of the Wolaita as in other enset growing areas of Southern Ethiopia [Since time immemorial, the Wolaita have been using enset to meet their livelihood needs . The comEthiopia ,23. HoweEthiopia -13, farmStrengthening local institutions and farmers leadership were demonstrated to support community efforts in conservation of agrobiodiversity in many indigenous communities ,47. Simiin situ and ex situ conservation approaches, but also for the promotion of a community based on-farm management of enset diversity in the area. The results presented here strongly reaffirm the potential of community based conservation efforts such as undertaken by the Wolaita in Southern Ethiopia for conservation of agrobiodiversity and imply the need to record and uncover the wealth of IKS of farming communities for sustainable conservation of biocultural diversity.This study provided a holistic view of the Wolaita enset culture. A great wealth of indigenous knowledge on the management and utilization of enset agro-biodiversity held by local communities in the Wolaita area was documented. Utilitarian and cultural reasons are the underlying drivers for on-farm maintenance and conservation of diverse enset landraces by the farmers. Complex and overlapping folk biosystematics and management practices underpin the enset cultivation. The documented information is crucial for developing complementary Wolaitato Donaa (the Wolaita Language).Landrace names and local terms were written in CBD: The Convention on Biological Diversity; CSA: Central Statistical Agency, Ethiopia; FAO: Food and Agricultural Organization of the United Nations; FDU: Farmers’ diversity unit; IKS: Indigenous knowledge system; SNNPR: Southern People's, Nations and Nationalities Region.The authors declare that they have no competing interests.TMO carried out the field work and drafted the manuscript. BT conceived the study, followed up the field work and drafted the manuscript. MC participated in designing of the study and proof reading of the manuscript. MEP conceived the study, followed up the field work and coordinated the project. All authors read and approved the final manuscript.