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Questionnaire measures offer a time and cost-effective alternative to full diagnostic assessments for identifying and differentiating between potential anxiety disorders and are commonly used in clinical practice. Little is known, however, about the capacity of questionnaire measures to detect specific anxiety disorders in clinically anxious preadolescent children. This study aimed to establish the ability of the Spence Children's Anxiety Scale (SCAS) subscales to identify children with specific anxiety disorders in a large clinic-referred sample (N = 1,438) of children aged 7 to 12 years. We examined the capacity of the Separation Anxiety, Social Phobia, Generalized Anxiety, and Physical Injury Fears (phobias) subscales to discriminate between children with and without the target disorder. We also identified optimal cutoff scores on subscales for accurate identification of children with the corresponding disorder, and examined the contribution of child, mother, and father reports. The Separation Anxiety subscale was able to accurately identify children with separation anxiety disorder, and this was replicated across all 3 reporters. Mother- and father-reported Social Phobia subscales also accurately identified children with social anxiety disorder, although child report was only able to accurately detect social anxiety disorder in girls. Using 2 or more reporters improved the sensitivity of the Separation Anxiety and Social Phobia subscales but reduced specificity. The Generalized Anxiety and Physical Injury Fears subscales failed to accurately identify children with the corresponding disorders. These findings have implications for the potential use of mother-, father-, and child-report SCAS subscales to detect specific disorders in preadolescent children in clinical settings. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Cognitive behavioral therapy (CBT) has proven long-term effects in youth with anxiety disorders. However, only a few studies have examined predictors of long-term outcomes of CBT treatment. The present study investigated possible predictors of long-term treatment outcomes in youth with mixed anxiety disorders treated in community mental health clinics. A total of 139 youth (mean age at assessment 15.5 years, range 11-21 years) with a principal diagnosis of separation anxiety disorder, social anxiety disorder, and/or generalized anxiety disorder were evaluated a mean of 3.9 years post-treatment (range 2.2-5.9 years). Outcomes were loss of all inclusion anxiety diagnoses, loss of the principal inclusion anxiety diagnosis, and changes in youth- and parent-rated youth anxiety symptoms. Predictors encompassed youth, parent and demographic factors, and post-treatment recovery. The most consistent finding was that low family social class predicted poorer outcomes. Higher treatment motivation was associated with better outcome whereas a diagnosis of social anxiety was associated with poorer outcome. Identified predictors extend on previous findings from efficacy trials, and the results indicate a need for more specific treatment protocols.

Objective The aim was to investigate whether clinical experience, formal cognitive behavioural therapy (CBT) training, adherence, and competence predict outcome in CBT for anxiety disorders in youth. Method Videotapes (N = 181) from the sessions in a randomized controlled effectiveness trial (Wergeland et al., 2014, Behaviour Research and Therapy, 57, 1-12) comprising youth (N = 182, M age = 11.5 years) with mixed anxiety disorders were assessed for treatment adherence and competence using the Competence and Adherence Scale for CBT for anxiety disorders in youth (Bjaastad et al., 2016, Psychological Assessment, 28, 908-916). Therapists' (N = 17) clinical experience and educational background were assessed. Participants completed a diagnostic interview (Anxiety Disorders Interview Schedule, child and parent versions) and an anxiety symptom measure (Spence Children's Anxiety Scale, child and parent versions) at pretreatment, posttreatment, and 1-year follow-up. Results Higher therapist adherence was related to better treatment outcomes, whereas number of years of clinical experience and competence was related to worse outcomes. However, these findings were not consistent across informants and the time points for the assessments. Interaction effects suggested that competence among therapists with formal CBT training was related to better patient outcomes. Conclusions Therapist adherence, competence, and clinical experience are associated with outcomes of manualized CBT for youth anxiety disorders, but mixed findings indicate the need for more research in this area.

Background The ‘FRIENDS for life’ program (FRIENDS) is a 10-session cognitive behavioral therapy (CBT) program used for prevention and treatment of youth anxiety. There is discussion about whether FRIENDS is best applied as prevention or as treatment. Methods We compared FRIENDS delivered in schools as targeted prevention to a previous specialist mental health clinic trial. The targeted prevention sample (N = 82; Mage = 11.6 years, SD = 2.1; 75.0% girls) was identified and recruited by school nurses in collaboration with a community psychologist. The clinical sample (N = 88, Mage = 11.7 years, SD = 2.1; 54.5% girls) was recruited for a randomized controlled trial from community child- and adolescent psychiatric outpatient clinics and was diagnosed with anxiety disorders. Results Both samples showed significantly reduced anxiety symptoms from baseline to postintervention, with medium mean effect sizes across raters (youths and parents) and timepoints (post; 12-months follow-up). Baseline youth-reported anxiety symptom levels were similar between the samples, whereas parent-reported youth anxiety was higher in the clinical sample. Conclusions The study suggests that self-reported anxiety levels may not differ between youth recruited in schools and in clinic settings. The results indicate promising results of the FRIENDS program when delivered in schools by less specialized health personnel from the school health services, as well as when delivered in clinics by trained mental health professionals. publishedVersion

Major depressive disorder and the anxiety disorders are highly prevalent, disabling and moderately heritable. Depression and anxiety are also highly comorbid and have a strong genetic correlation (rg ≈ 1). Cognitive behavioural therapy is a leading evidence-based treatment but has variable outcomes. Currently, there are no strong predictors of outcome. Therapygenetics research aims to identify genetic predictors of prognosis following therapy. We performed genome-wide association meta-analyses of symptoms following cognitive behavioural therapy in adults with anxiety disorders (n = 972), adults with major depressive disorder (n = 832) and children with anxiety disorders (n = 920; meta-analysis n = 2724). We estimated the variance in therapy outcomes that could be explained by common genetic variants (h2SNP) and polygenic scoring was used to examine genetic associations between therapy outcomes and psychopathology, personality and learning. No single nucleotide polymorphisms were strongly associated with treatment outcomes. No significant estimate of h2SNP could be obtained, suggesting the heritability of therapy outcome is smaller than our analysis was powered to detect. Polygenic scoring failed to detect genetic overlap between therapy outcome and psychopathology, personality or learning. This study is the largest therapygenetics study to date. Results are consistent with previous, similarly powered genome-wide association studies of complex traits.

Youth mental health problems is the leading cause of disability worldwide and a major public health concern. Prevalence rates are needed for planning preventive interventions and health care services. We here report Norwegian prevalence estimates for youth mental disorders based on findings from the Bergen Child Study cohort. A web-based psychiatric interview; the Development and Well-Being Assessment, was completed by parents and teachers of 2,043 10-14-year-olds from the city of Bergen, Norway. Post-stratification weights were used to account for selective participation related to parental educational in the estimation of prevalence rates. Prevalence rates are presented for the whole sample and stratified by gender and age. The overall population weighted estimate suggests that 6.93% (95% CI 5.06–9.41) of the children met DSM-IV diagnostic criteria for one or more psychiatric disorders. There were no robust indications of age- or gender-related differences in the prevalence. 11.4% of the children fulfilled criteria for more than one diagnosis. The most common comorbid conditions were ADHD and disruptive disorders. The prevalence of psychiatric disorders was relatively low among Norwegian 10-14-year-olds, compared to published worldwide prevalence estimates. This is in line with estimates from prior studies from the Nordic countries. These findings raise important questions about the origins of different prevalence rates for psychiatric disorders between societies. The findings also illustrate the importance of locally driven epidemiological studies for planning preventative efforts and appropriately scaling mental health services to meet the need of the population. publishedVersion

The aim of the present study was to evaluate the psychometric properties of the Competence and Adherence Scale for Cognitive Behavioral Therapy (CAS-CBT). The CAS-CBT is an 11-item scale developed to measure adherence and competence in cognitive-behavioral therapy (CBT) for anxiety disorders in youth. A total of 181 videotapes from the treatment sessions in a randomized controlled effectiveness trial (Wergeland et al., 2014) comprising youth (N = 182, M age = 11.5 years, SD = 2.1, range 8-15 years, 53% girls, 90.7% Caucasian) with mixed anxiety disorders were assessed with the CAS-CBT to investigate interitem correlations, internal consistency, and factor structure. Internal consistency was good (Cronbach's alpha = .87). Factor analysis suggested a 2-factor solution with Factor 1 representing CBT structure and session goals (explaining 46.9% of the variance) and Factor 2 representing process and relational skills (explaining 19.7% of the variance). The sum-score for adherence and competence was strongly intercorrelated, r = .79, p.001. Novice raters (graduate psychology students) obtained satisfactory accuracy (ICC.40, n = 10 videotapes) and also good to excellent interrater reliability when compared to expert raters (ICC = .83 for adherence and .64 for competence, n = 26 videotapes). High rater stability was also found (n = 15 videotapes). The findings suggest that the CAS-CBT is a reliable measure of adherence and competence in manualized CBT for anxiety disorders in youth. Further research is needed to investigate the validity of the scale and psychometric properties when used with other treatment programs, disorders and treatment formats. (PsycINFO Database Record

Purpose of review To present an updated review of recent studies into the effect of cognitive behavior therapy (CBT) for anxiety disorders in children and adolescents, ways to increase access to therapy, and predictors and moderators of therapy effect. Recent findings The evidence base of CBT for anxiety disorders in children and adolescents continues to grow, demonstrating short and long-term efficacy and effectiveness. However, compared with active control conditions its effect appear to be modest; and a substantial percentage of youth do not show stable long-term remission. Standard CBT is often costly, with high noncompletion rates. New strategies to increase access to effective therapy for the large number of youth with anxiety disorders is therefore of priority. Additionally, there is a need for developing new ways to treat nonresponders, and to identify predictors and moderators of the effects of CBT. Summary Although there is evidence for the efficacy and effectiveness of CBT for youth with anxiety disorders, there is doubt regarding its superiority over active control comparisons. Long-term outcome is uncertain, as a substantial percentage of youth remains impaired at follow-up. It is essential to develop more cost-efficient strategies to reach youth with anxiety disorders with effective treatments, and to identify early indicators for youth needing additional therapy.

Background From the public health perspective, epidemiological data of child mental health and psychosocial correlates were necessary and very lacking in Lithuanian society that has been undergoing rapid socio-economic change since the past decades. Together with determining the prevalence rates of disorders and assessing the needs for the services, this study has also shifted attention from the highly selective samples of children attending children and adolescent mental health services towards less severe cases of psychopathology as well as different attitudes of parents and teachers. The aim of the first epidemiological study in Lithuania was to identify the prevalence of psychiatric disorders in the community sample of children. Methods Child psychiatric disorders were investigated in a representative sample of 3309 children aged 7–16 years (1162 7–10-year-olds and 2147 11–16-year-olds), using a two-phase design with the Lithuanian version of the Strengths and Difficulties Questionnaire (SDQ) in the first screening phase, and the Development and Well-Being Assessment (DAWBA) in the second diagnostic phase. Results The estimated point prevalence of ICD-10 psychiatric disorders was 13.1% for the total sample (14.0% for the child sample and 12.1% for adolescent sample). The most common groups of disorders were Conduct disorders 6.6% (7.1% for child sample and 6.0% for adolescent sample), Anxiety disorders 5.0% (5.9% for child sample and 6.0% for adolescent sample), with Hyperkinesis being less common 2.0% (2.7% for child sample and 1.2% for adolescent sample). Potential risk factors were related to individual characteristics of the child (gender, poor general health, and stressful life experiences), and the family (single parenthood, foster care, unfavourable family climate, disciplining difficulties, worries related to TV or computer use). Conclusions The overall prevalence of youth psychiatric disorders was relatively high in this representative Lithuanian sample compared to Western European countries. The SDQ and DAWBA measures appear useful for the further research and clinical practice in this society.

BackgroundWe previously reported an association between 5HTTLPR genotype and outcome following cognitive–behavioural therapy (CBT) in child anxiety (Cohort 1). Children homozygous for the low-expression short-allele showed more positive outcomes. Other similar studies have produced mixed results, with most reporting no association between genotype and CBT outcome.AimsTo replicate the association between 5HTTLPR and CBT outcome in child anxiety from the Genes for Treatment study (GxT Cohort 2, n = 829).MethodLogistic and linear mixed effects models were used to examine the relationship between 5HTTLPR and CBT outcomes. Mega-analyses using both cohorts were performed.ResultsThere was no significant effect of 5HTTLPR on CBT outcomes in Cohort 2. Mega-analyses identified a significant association between 5HTTLPR and remission from all anxiety disorders at follow-up (odds ratio 0.45, P = 0.014), but not primary anxiety disorder outcomes.ConclusionsThe association between 5HTTLPR genotype and CBT outcome did not replicate. Short-allele homozygotes showed more positive treatment outcomes, but with small, non-significant effects. Future studies would benefit from utilising whole genome approaches and large, homogenous samples.

A substantial number of children with anxiety disorders do not improve following cognitive behavioral therapy (CBT). Recent effectiveness studies have found poorer outcome for CBT programs than what is typically found in efficacy studies. The present study examined predictors of treatment outcome among 181 children (aged 8-15 years), with separation anxiety, social phobia, or generalized anxiety disorder, who participated in a randomized, controlled effectiveness trial of a 10-session CBT program in community clinics. Potential predictors included baseline demographic, child, and parent factors. Outcomes were as follows: a) remission from all inclusion anxiety disorders; b) remission from the primary anxiety disorder; and c) child- and parent-rated reduction of anxiety symptoms at post-treatment and at 1-year follow-up. The most consistent findings across outcome measures and informants were that child-rated anxiety symptoms, functional impairment, a primary diagnosis of social phobia or separation anxiety disorder, and parent internalizing symptoms predicted poorer outcome at post-treatment. Child-rated anxiety symptoms, lower family social class, lower pretreatment child motivation, and parent internalizing symptoms predicted poorer outcome at 1-year follow-up. These results suggest that anxious children with more severe problems, and children of parents with elevated internalizing symptom levels, may be in need of modified, additional, or alternative interventions to achieve a positive treatment outcome.

This study aimed to investigate the factor structure and external correlates of the constructs Reactive Attachment Disorder (RAD) and Disinhibited Social Engagement Disorder (DSED) from the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). The following were addressed: First, do our data support the DSM-5 conceptualization of RAD/DSED as two separate constructs? Second, are RAD and DSED distinct from other well-established dimensions of child psychopathology? Third, what are the external correlates of RAD/DSED in this sample? The study sample included 122 foster children aged 6–10 years. Foster parents completed the Strengths and Difficulties Questionnaire (SDQ), and the RAD/DSED-scale from the Developmental and Well-Being Assessment. Child protection caseworkers completed a questionnaire regarding exposure to maltreatment and placement history. Confirmatory factor analysis (CFA) of the RAD/DSED items identified a good fit for a model with a two-factor structure, which is congruent with the DSM-5 definition of RAD and DSED. A new CFA model, which included the RAD and DSED factors together with the four problem factors of the SDQ (emotional, conduct, hyperactivity-inattention, and peer problems), also demonstrated a good fit with our data. RAD and DSED were associated with the SDQ Impact scale and help seeking behavior. This was partly explained by the SDQ externalizing and peer problem subscales. Our findings lend support for the DSM-5 conceptualization of RAD and DSED as separate dimensions of child psychopathology. Thus, the assessment of RAD and DSED provides information beyond other mental health problems. publishedVersion

The aim was to investigate predictors of treatment dropout among 182 children (aged 8-15 years) participating in an effectiveness trial of manual-based 10-session individual and group cognitive behavior therapy (CBT) for anxiety disorders in community clinics. The dropout rate was 14.4%, with no significant difference between the two treatment conditions. We examined predictors for overall dropout (n=26), early (≤session 4, n=15), and late dropout (≥session 5, n=11). Overall dropout was predicted by low child and parent rated treatment credibility, and high parent self-rated internalizing symptoms. Low child rated treatment credibility predicted both early and late dropout. High parent self-rated internalizing symptoms predicted early dropout, whereas low parent rated treatment credibility predicted late dropout. These results highlight the importance of addressing treatment credibility, and to offer support for parents with internalizing symptoms, to help children and families remain in treatment.

Cognitive behavioral therapy (CBT) has demonstrated favorable long-term outcomes in youth with anxiety disorders in efficacy trials. However, long-term outcomes of CBT delivered in a community setting are uncertain. This study examined the long-term outcomes of individual (ICBT) and group CBT (GCBT) in youth with anxiety disorders treated in community mental health clinics. A total of 139 youth (mean age at assessment 15.5 years, range 11–21 years) with a principal diagnosis of separation anxiety disorder (SAD), social anxiety disorder (SOP), and/or generalized anxiety disorder (GAD) were evaluated, on average, 3.9 years post-treatment (range 2.2–5.9 years). Outcomes included loss of all inclusion anxiety diagnoses, loss of the principal anxiety diagnosis and changes in youth- and parent-rated youth anxiety symptoms. At long-term follow-up, there was loss of all inclusion anxiety diagnoses in 53%, loss of the principal anxiety diagnosis in 63% of participants as well as significant reductions in all anxiety symptom measures. No statistical significant differences in outcome were obtained between ICBT and GCBT. Participants with a principal diagnosis of SOP had lower odds for recovery, compared to those with a principal diagnosis of SAD or GAD. In conclusion, outcomes of CBT for youth anxiety disorders delivered in community mental health clinics were improved at nearly 4 years post-treatment, and recovery rates at long-term follow-up were similar to efficacy trials. publishedVersion

Few empirical studies have examined subtypes of social anxiety disorder (SAD) in youth, and limited consensus resides on the nature of potential subtypes. Identifying subtypes, based on both fear and avoidance patterns, can help improve assessment and treatment of SAD. Subtypes of fear and avoidance were examined in a sample comprising 131 youth (age 8–15 years) diagnosed with SAD using the Anxiety Disorders Interview Schedule for children and parents (ADIS-C/P). Exploratory factor analysis of fear responses revealed three factors, defining fear subtypes linked to: (1) performance, (2) observation, and (3) interaction situations, respectively. Exploratory factor analysis of avoidance responses showed these were best represented by one avoidance factor. Few youth qualified exclusively for either of the fear subtypes, thus calling into question the clinical utility of these subtypes. Nevertheless, the findings indicate distinct contributions of fear and avoidance in SAD presentation. This finding might help clinicians target and improve treatment of the disorder. publishedVersion

Background Depressive disorders are disabling conditions striking at all ages. In adults, subthreshold depression (SD) is viewed as being on a continuum with major depressive disorder (MDD). Whether this holds for children and adolescents, is still unclear. We performed the first systematic review of SD in subjects below 18 years, in order to explore if childhood SD and MDD share causal pathways, phenomenology and outcomes, supporting a dimensional view. Methods A critical systematic review in accordance with preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement. A review protocol was developed a priori, and all reports were assessed by two reviewers. Results The literature search generated 941 eligible references and 24 studies were included. Although diagnostic criteria for SD showed great variability, similarities for SD and MDD were striking. Both were common conditions with similar risk factor patterns. Clinical characteristics in both groups were depressed mood, suicidal ideation and high comorbidity. Outcomes were almost equally poor, with increased psychiatric morbidity and health service use. SD intervention studies showed promising results. Limitations Reports with data on SD not reported in keywords or abstract may have been missed by the search strategy. Conclusion A dimensional view of depressive disorders is also supported in children and adolescents, suggesting SD to be a precursor to MDD. Although SD is a somewhat milder condition than MDD, it has severe outcomes with psychopathology and impairment. There is a need of identifying cost-efficient and longlasting interventions in order to prevent development of early SD into MDD

Background: The differential susceptibly hypothesis suggests that certain genetic variants moderate the effects of both negative and positive environments on mental health and may therefore be important predictors of response to psychological treatments. Nevertheless, the identification of such variants has so far been limited to preselected candidate genes. In this study we extended the differential susceptibility hypothesis from a candidate gene to a genome-wide approach to test whether a polygenic score of environmental sensitivity predicted response to cognitive behavioural therapy (CBT) in children with anxiety disorders. Methods: We identified variants associated with environmental sensitivity using a novel method in which within-pair variability in emotional problems in 1,026 monozygotic twin pairs was examined as a function of the pairs' genotype. We created a polygenic score of environmental sensitivity based on the whole-genome findings and tested the score as a moderator of parenting on emotional problems in 1,406 children and response to individual, group and brief parent-led CBT in 973 children with anxiety disorders. Results: The polygenic score significantly moderated the effects of parenting on emotional problems and the effects of treatment. Individuals with a high score responded significantly better to individual CBT than group CBT or brief parent-led CBT (remission rates: 70.9, 55.5 and 41.6%, respectively). Conclusions: Pending successful replication, our results should be considered exploratory. Nevertheless, if replicated, they suggest that individuals with the greatest environmental sensitivity may be more likely to develop emotional problems in adverse environments but also benefit more from the most intensive types of treatment.

The aim of this study was to examine the factor structure and psychometric properties of an observer-rated youth alliance measure, the Therapy Process Observational Coding System for Child Psychotherapy-Alliance scale (TPOCS-A). The sample was 52 youth diagnosed with anxiety disorders (M age = 12.43, SD = 2.23, range = 8-15; 56% boys; 98% Caucasian) drawn from a randomized controlled trial. Participants received a manualized individual cognitive behavioral treatment, the FRIENDS for life program, in public community clinics in Norway. Diagnostic status, treatment motivation, and perceived treatment credibility were assessed at pretreatment. Using the TPOCS-A, independent observers rated child-therapist alliance from the third therapy session. Child- and therapist-reported alliance measures were collected from the same session. An exploratory factor analysis supported a one-factor solution, which is consistent with previous studies of self- and observer-rated youth alliance scales. Psychometric analyses supported the interrater reliability, internal consistency, and convergent/divergent validity of the TPOCS-A. Accumulating psychometric evidence indicate that the TPOCS-A has the potential to fill a measurement gap in the youth psychotherapy field. In youth psychotherapy, alliance may be unidimensional, so establishing a strong bond and engaging the child in therapeutic activities may both be instrumental to establishing good alliance early in treatment. However, it is important to be cautious when interpreting the factor analytic findings, because the sample size may have been too small to identify additional factors. Future research can build upon these findings by examining the factor structure of youth alliance measures with larger, more diverse samples.

This study examined independent contributions of executive functioning (EF), state regulation (SR), and social risk factors to symptom dimensions of attention deficit hyperactivity disorder (ADHD) in two cohorts, which included 221 Norwegian children and 294 Finnish adolescents. Independent contributions of EF and SR were shown in the Norwegian cohort and EF contributed independently in the Finnish cohort. When controlling for each symptom dimension, cognitive functioning and social risk factors were differentially associated with inattention and hyperactivity/impulsivity symptoms. The results show the need to include both social risk factors and cognitive functioning to obtain a better understanding of ADHD symptoms.

Background Subthreshold Depression (SD) is an impairing condition that might convert into Major Depressive Disorder (MDD). Still, the characteristics of childhood SD are largely unknown. Purpose We aim to examine how SD in children differs from MDD regarding symptom profile, comorbidity, functional impairment and associated life stressors. We will examine the frequency of childhood SD and MDD and compare previous mental health between groups. Basic procedures This is a two-phase nested case–control study within the Danish National Birth Cohort (DNBC) (N = 4500). Mothers completed the online Development and Well-Being Assessment (DAWBA) regarding their child aged 8–10 years. Main findings A total of 3421 children participated (response rate 76%); 35 children were diagnosed with MDD and 55 with SD. Anhedonia, irritability and worthlessness/guilt were more frequent in MDD than SD, and anhedonia was rare in non-depressed children (1.2%). Comorbid anxiety and conduct disorders were equally common in the groups. Children with MDD had higher functional impairment caused by the depressive condition than children with SD, but overall functional impairment was the same. Life stressors, including maternal depressive symptoms, were equally frequent for children with MDD and SD. Emotional problems and functional impairment at age 7 years predicted later SD and MDD. SD was twice as common as MDD in the DNBC (point prevalence 1.0% vs. 0.5%). Principal conclusions Children with SD and MDD display striking similarities. They differ mainly by the number of depressive symptoms and depression-related functional impairment. Both SD and MDD at age 8–10 years were preceded by emotional symptoms and functional impairment at age seven years. This indicates a continuity of childhood depressive conditions but also a window of opportunity for prevention of MDD.

Background In individual cognitive behavioral therapy (ICBT) for youth anxiety disorders, it is unclear whether, and from whose perspective, the alliance predicts outcome. We examined whether youth- and therapist-rated alliance, including level of youth-therapist alliance agreement, predicted outcome in a randomized controlled trial. Methods Youth (N = 91, M age = 11.4 years (SD = 2.1), 49.5% boys, 86.8% Caucasian) diagnosed with separation anxiety disorder, social phobia, or generalized anxiety disorder drawn from the ICBT condition of an effectiveness trial were treated with an ICBT program. Youth- and therapist-rated alliance ratings, assessed with the Therapeutic Alliance Scale for Children (TASC-C/T), were collected following session 3 (early) and 7 (late). Early alliance, change in alliance from early to late, and level of youth-therapist agreement on early alliance and alliance change were examined, in relation to outcomes collected at posttreatment and 1-year follow-up. Outcome was defined as primary diagnosis loss and reduction in clinicians' severity ratings (CSR; Anxiety Disorders Interview Schedule; ADIS-C/P) based on youth- and parent-report at posttreatment and follow-up, and youth treatment satisfaction collected at posttreatment (Client Satisfaction Scale; CSS). Results Early TASC-C scores positively predicted treatment satisfaction at posttreatment. Higher levels of agreement on change in TASC-C and TASC-T scores early to late in treatment predicted diagnosis loss and CSR reduction at follow-up. Conclusions Only the level of agreement in alliance change predicted follow-up outcomes in ICBT for youth anxiety disorders. The findings support further examination of the role that youth-therapist alliance discrepancies may play in promoting positive outcomes in ICBT for youth anxiety disorders. Clinical trial number NCT00586586, clinicaltrials.gov.

Previous meta-analyses of paediatric obsessive-compulsive disorder (OCD) have shown much higher effect size for standard individual cognitive behaviour therapy (SI-CBT) compared with control conditions than for serotonin reuptake inhibitors (SRIs) compared with placebo. Other factors, such as systematic differences in the provided care or exposure to factors other than the interventions of interest (performance bias) may be stronger confounders in psychotherapy research than in pharmacological research.These facts led us to review SI-CBT studies of paediatric OCD with the aim to compare the effect estimates across different comparisons, including active treatments.We included only randomized controlled trials (RCTs) or cluster RCTs with treatment periods of 12-16 weeks. Outcome was post-test score on the Children's Yale-Brown Obsessive Compulsive Scale (CYBOCS).Thirteen papers reporting from 13 RCTs with 17 comparison conditions were included. SI-CBT was superior to wait-list and placebo therapy but not active treatments. Effect estimates for SI-CBT in wait-list comparison studies were significantly larger than in placebo-therapy comparison studies. In addition, the SI-CBT effect estimate was not significantly different when compared with SRIs alone or combined SRIs and CBT.Performance bias may have inflated previous effect estimates for SI-CBT when comparison contingencies included wait-list. However, the calculated SI-CBT effect estimate was lower but significant when compared with placebo therapy. The effects of SI-CBT and active treatments were not significantly different. In conclusion, our data support the current clinical guidelines, although better comparisons between SI-CBT and SRIs are needed.

The association between behaviour problems and dyslexia was assessed in a population sample of 10- to 12-year-old children. Twenty-five dyslexic children and a matched control group were recruited through a screening in primary schools in the city of Bergen, Norway. For the assessment of behaviour problems the Child Behavior Checklist (CBCL), Teacher Self Report (TRF), and Youth Self Report (YSR) were filled out by parents, teachers, and children, respectively. Information on health and developmental factors were obtained from parents on a separate questionnaire designed for the study. The dyslexic group had significantly more behaviour problems than the control group according to both the CBCL and the TRF. On the YSR there was no significant difference between the groups. Dyslexic children had higher CBCL and TRF scores on the Total Behaviour Problem scale, the Internalizing and Externalizing subdomains, and the Attention problem subscale. The groups differed in social background, prenatal risk factors, birth weight, preschool language problems, and IQ, but these variables showed no relationship to the level of behaviour problems in the present sample. We conclude that pre-adolescent dyslexic children show a wide range of behaviour problems that cannot be attributed to social or developmental background variables.

A reduction or reversal of the normal leftward asymmetry of the planum temporale (PT) has been claimed to be typical of dyslexia, although some recent studies have challenged this view. In a population-based study of 20 right-handed dyslexic boys and 20 matched controls, we have measured the PT and the adjacent planum parietale (PP) region in sagittal magnetic resonance images. For the PT, mean left and right areas and asymmetry coefficients were compared. Since a PP area often could not be identified in one or both hemispheres, a qualitative comparison was used for this region. The total planar area (sum of PT and PP) was also compared between the two groups. A dichotic listening (DL) test with consonant-vowel syllables was administered to assess functional asymmetry of language. The results showed a mean leftward PT asymmetry in both the dyslexic and the control group, with no significant difference for the degree of PT asymmetry. Planned comparisons revealed however, a trend towards smaller left PT in the dyslexic group. In control children, but not in the dyslexic children, a significant correlation between PT asymmetry and reading was observed. A mean leftward asymmetry was also found for the total planar area, with no difference between the groups for the degree of asymmetry. Significantly fewer dyslexic children than control children showed a rightward asymmetry for the PP region. Both groups showed a normal right ear advantage on the DL task, with no significant difference for DL asymmetry. No significant correlation was observed between PT asymmetry and DL asymmetry. The present population-based study adds to recent reports of normal PT asymmetry in dyslexia, but indicates that subtle morphological abnormalities in the left planar area may be present in this condition.

The strengths and difficulties questionnaire (SDQ) is a broad-band child mental health instrument, which has been reported to be a good screener for the ADHD phenotype. Questionnaires containing the SDQ and the 18 SNAP-IV items corresponding to the DSM-IV ADHD symptoms were completed by parents and teachers for 66% (N = 6,233) of all 7- to 9-year-olds in the city of Bergen, Norway, 2002. Screening properties of the five-item SDQ hyperactivity-inattention subscale for the DSM-IV ADHD phenotype were examined. Using the DSM-IV ADHD phenotype based on both informants as the gold standard (5.2% of the sample), the receiver operating characteristics (ROC) analyses demonstrated an area under the curve of 0.91 (95% CI: 0.90-0.92) for parent and 0.95 (95% CI: 0.94-0.95) for teacher SDQ hyperactivity-inattention subscale ratings. The SDQ hyperactivity-inattention predictive algorithm identified 74% of those with the ADHD combined subtype as possible or probable cases, but only 22% of those with the inattentive subtype. The 5-item long SDQ hyperactivity-inattention subscale is a shorter substitute for the 18-item ADHD symptom list. The SDQ predictive algorithm had an acceptable sensitivity for the ADHD combined subtype, but low sensitivity for the ADHD inattentive and the ADHD hyperactive subtypes.

Purpose To examine whether the widely used Strengths and Difficulties Questionnaire (SDQ) can validly be used to compare the prevalence of child mental health problems cross nationally. Methods We used data on 29,225 5- to 16-year olds in eight population-based studies from seven countries: Bangladesh, Brazil, Britain, India, Norway, Russia and Yemen. Parents completed the SDQ in all eight studies, teachers in seven studies and youth in five studies. We used these SDQ data to calculate three different sorts of “caseness indicators” based on (1) SDQ symptoms, (2) SDQ symptoms plus impact and (3) an overall respondent judgement of ‘definite’ or ‘severe’ difficulties. Respondents also completed structured diagnostic interviews including extensive open-ended questions (the Development and Well-Being Assessment, DAWBA). Diagnostic ratings were all carried out or supervised by the DAWBA’s creator, working in conjunction with experienced local professionals. Results As judged by the DAWBA, the prevalence of any mental disorder ranged from 2.2% in India to 17.1% in Russia. The nine SDQ caseness indicators (three indicators times three informants) explained 8–56% of the cross-national variation in disorder prevalence. This was insufficient to make meaningful prevalence estimates since populations with a similar measured prevalence of disorder on the DAWBA showed large variations across the various SDQ caseness indicators. Conclusions The relationship between SDQ caseness indicators and disorder rates varies substantially between populations: cross-national differences in SDQ indicators do not necessarily reflect comparable differences in disorder rates. More generally, considerable caution is required when interpreting cross-cultural comparisons of mental health, particularly when these rely on brief questionnaires. Electronic supplementary material The online version of this article (doi:10.1007/s00127-011-0440-2) contains supplementary material, which is available to authorized users.

PURPOSE: To describe and validate the 'DAWBA bands'. These are novel ordered-categorical measures of child mental health, based on the structured sections of the Development and Well-Being Assessment (DAWBA). METHODS: We developed computer algorithms to generate parent, teacher, child and multi-informant DAWBA bands for individual disorders and for groups of disorder (e.g. 'any emotional disorder'). The top two (out of 6) levels of the DAWBA bands were used as computer-generated DAWBA diagnoses. We validated these DAWBA bands in 7,912 British children (7-19 years) and 1,364 Norwegian children (11-13 years), using clinician-rated DAWBA diagnoses as a gold standard. RESULTS: In general, the prevalence of clinician-rated diagnosis increased monotonically across all levels of the DAWBA bands, and also showed a dose-response association with service use and risk factors. The prevalence estimates of the computer-generated DAWBA diagnoses were of roughly comparable magnitude to the prevalence estimates from the clinician-generated diagnoses, but the estimates were not always very close. In contrast, the estimated effect sizes, significance levels and substantive conclusions regarding risk factor associations were very similar or identical. The multi-informant and parent DAWBA bands performed especially well in these regards. CONCLUSION: Computer-generated DAWBA bands avoid the cost and delay occasioned by clinical rating. They may, therefore, sometimes provide a useful alternative to clinician-rated diagnoses, when studying associations with risk factors, generating rough prevalence estimates or implementing routine mental health screening.

Objective: To test Goodman's theoretical 5-factor model of the Strengths and Difficulties Questionnaire (SDQ) in an analysis of the Norwegian parent (P) and teacher (T) versions of the questionnaire. Method: The T-SDQ was analyzed for 8,999 (95.4% of all) children in primary school grades 2-4 in Bergen, Norway, whereas the P-SDQ was examined for 6,430 children (68.2%). Main analyses were exploratory and confirmatory factor analyses. Results: The analyses supported a modestly modified version of Goodman's 5-factor model for both the P-SDQ and the T-SDQ. The correlations between latent factors were high, particularly when the conduct problem factor was involved, reflecting a high level of overlap between the problem areas. Cross-informant correlation between parents and teachers was moderate to high for the problem subscales and considerably higher than the corresponding correlation between subscales that has been found in earlier studies. Conclusions: None of the alternative models derived from the exploratory factor analysis fitted the data better than a slightly modified version of Goodman's 5-factor model, which showed acceptable goodness of fit.

Web-based surveys may have advantages related to the speed and cost of data collection as well as data quality. However, they may be biased by low and selective participation. We predicted that such biases would distort point-estimates such as average symptom level or prevalence but not patterns of associations with putative risk-factors. A structured psychiatric interview was administered to parents in two successive surveys of child mental health. In 2003, parents were interviewed face-to-face, whereas in 2006 they completed the interview online. In both surveys, interviews were preceded by paper questionnaires covering child and family characteristics. The rate of parents logging onto the web site was comparable to the response rate for face-to-face interviews, but the rate of full response (completing all sections of the interview) was much lower for web-based interviews. Full response was less frequent for non-traditional families, immigrant parents, and less educated parents. Participation bias affected point estimates of psychopathology but had little effect on associations with putative risk factors. The time and cost of full web-based interviews was only a quarter of that for face-to-face interviews. Web-based surveys may be performed faster and at lower cost than more traditional approaches with personal interviews. Selective participation seems a particular threat to point estimates of psychopathology, while patterns of associations are more robust.

This study reviews 19 randomized controlled trials examining the association between three relationship factors — participation, treatment involvement, and therapeutic relationship — and outcome of cognitive-behavioral anxiety treatments for children and adolescents. In 12 studies, parent participation was considered as an independent variable compared to child-only participation. In three studies, parental involvement was measured. Child involvement was measured in one study. The child's perception of the therapeutic relationship was considered in three studies. Six studies found a significant positive effect of parent participation on diagnostic status, symptom level, or global functioning outcome measures. One study found a significant effect of parental involvement on global outcome measures. Another study found a significant positive association between child involvement and symptom measures and global functioning measures. No association was found between the quality of the child's perception of the therapeutic relationship and treatment outcome. Clinical implications are discussed.

Around the world, cultural blending and conflict pose challenges for assessment and understanding of psychopathology. Economical, evidence-based, culturally robust assessment is needed for research, for answering public health questions, and for evaluating immigrant, refugee, and minority children. This article applies multicultural perspectives to behavioral, emotional, and social problems assessed on dimensions describing children's functioning, as rated by parents, teachers, children, and others. The development of Achenbach System of Empirically Based Assessment (ASEBA) and Strengths and Difficulties Questionnaire (SDQ) forms and their applications to multicultural research are presented. A primary aim of both questionnaires is to identify children at high risk of psychiatric disorders and who therefore warrant further assessment. The forms are self-administered or administered by lay interviewers. ASEBA problem items are scored on 6 DSM-oriented scales and 3 broader band scales, plus 8 syndromes derived statistically as taxonomic constructs and supported by uniform confirmatory factor analyses of samples from many populations. Comparisons of ASEBA scale scores, psychometrics, and correlates are available for diverse populations. SDQ forms are scored on one broad-band scale and 5 a priori behavioral dimensions supported by data from various populations. For both instruments, factor analyses, psychometrics, and correlates are available for diverse populations. The willingness and ability of hundreds of thousands of respondents from diverse groups to complete ASEBA and SDQ forms support this approach to multicultural assessment. Although particular items and scales may have differential relevance among groups and additional assessment procedures are needed, comparable results are found in many populations. Scale scores vary more within than between populations, and distributions of scores overlap greatly among different populations. Ratings of children's problems thus indicate more heterogeneity within populations than distinctiveness between populations. Norms from multiple populations can be used to compare children's scores with relevant peer groups. Multicultural dimensional research can advance knowledge by diversifying normative data; by comparing immigrant children with nonimmigrant compatriots and with host country children; by identifying outlier findings for elucidation by emic research; and by fostering efforts to dimensionalize DSM-V diagnostic criteria.

Background: The use of similar standardised measures of psychopathology for population surveys permits cross-cultural comparisons. However, interpretation of findings can be challenging because rating thresholds may differ across cultures. By combining questionnaire and interview data, we explore whether lower questionnaire scores in Norway as compared to Britain reflect genuine differences in child mental health, or simply different reporting thresholds. Methods: Information from the Strengths and Difficulties Questionnaire (SDQ) and the Development and Well-Being Assessment (DAWBA) interview were compared across recent population surveys in Norway and Britain. The Norwegian study (2002-03) had questionnaire data for 6,658 and interview data for 1,024 8-10-year-old children. The British dataset included questionnaire and interview data for 4,898 children of the same age range from two independent surveys (1999 and 2004). Results: Norwegian children had lower SDQ scores on all problem scales (emotional, behavioural, hyperactive and peer relationship) according to parents as well as teachers. DAWBA information showed that the Norwegian prevalence of externalising disorders (behavioural and hyperactivity) was about half that found in Britain, whereas rates of emotional disorders were similar. Norwegian and British children with non-emotional disorders had similar questionnaire scores and rates of problem-recognition by parents and teachers. By contrast, questionnaire scores and problem-recognition were all lower in Norwegian children with emotional disorders. Conclusions: Lower Norwegian questionnaire scores for externalising problems appear to reflect real and substantial differences between the two countries. By contrast, lower questionnaire scores for emotional problems seem to reflect under-reporting/under-recognition by Norwegian adults, and not a genuinely lower prevalence of emotional disorders. This illustrates that cross-cultural differences in psychopathology based only on questionnaire data may be misleading. Nevertheless, careful use of questionnaire and interview data can focus mental health research on cross-cultural variations likely to reflect genuine health differences.

The impact of nonresponse on estimates of mental health problems was examined in a prospective teacher screen in a community survey of 9,155 7–9 year olds. For 6,611 of the children, parents consented to participation in the actual study (Responders), while for 2,544 children parental consent was not obtained (Nonresponders). The teacher screen involved assessment of a broad set of symptoms of mental health problems and functional impairment. Calculations of non-response coefficients, a function of effect sizes and non-response proportion, revealed only ignorable nonresponse bias for both mean scores and correlations. However, the results from binary logistic regressions revealed that children ascribed signs of mental health problems by their teachers were less likely to participate. This was most frequent among children with only moderate symptoms. However, it also involved children with high symptom scores related to inattention, hyperactivity, emotions and peer relationship problems. These findings suggest that measures based on effect size can underestimate the magnitude of non-response bias and that a logistic regression approach may be more appropriate for studies geared at estimating prevalence of mental health problems in children. The original publication is available at www.springerlink.com:Kjell Morten Stormark, Einar Heiervang, Mikael Heimann, Astri Lundervold and Christopher Gillberg, Predicting Nonresponse Bias from Teacher Ratings of Mental Health Problems in Primary School Children, 2008, Journal of Abnormal Child Psychology, (36), 3, 411-419.http://dx.doi.org/10.1007/s10802-007-9187-3Copyright: Springer Science Business Mediahttp://www.springerlink.com/

Reading involves the correct and rapid identification of visual stimuli with letters and words. The processing of visual stimuli depends not only on the integrity of the peripheral and central visual system but also on the attentional systems involved. In the present study, a cue—target visual attention task was administered to a population-based sample of 25 children with dyslexia from 10 to 12 years of age. A control group matched for group size, age, and gender was obtained from the same general population. A two-stage screening process involved a spelling task of regular words followed by a battery of five single-word reading tasks. The cue—target task involved both a computer-controlled stimulus presentation and a computer-controlled measurement of reaction time. The data were analyzed by visual field, cue condition (valid, invalid, and no cue), and cue—target interval (CTI). The results showed a general pattern of slower responses in the dyslexia group compared to the control group. The dyslexia group also had longer reaction times in the short CTI condition (covert shift of attention) and in the long CTI condition (overt shift of attention). The findings may reflect a general attentional deficit to visual stimuli in dyslexia, possibly related to problems with the recruitment of necessary cognitive resources for the performance of complex reaction time tasks and for fluent reading.

BACKGROUND: The Strengths and Difficulties Questionnaire (SDQ) has been translated into the different Nordic languages between 1996 and 2003. During the past few years, SDQs have been completed for nearly 100,000 children and adolescents in population-based studies as well as in clinical samples. The largest studies have been performed in Norway and Denmark, and in these countries the diagnostic interview DAWBA has also been used in conjunction with the SDQ. AIMS: In addition to a brief overview of past and ongoing SDQ work in Sweden, Finland, Norway, Denmark, and Iceland, we present scale means and standard deviations from selected community studies with comparable age groups, including parental reports for 7, 9 and 11 year-old children and self-reports of 13 and 15 year-olds. CONCLUSIONS: The descriptive statistics suggest that the distributions of SDQ scores are very similar across the Nordic countries. Further collaborative efforts in establishing norms and evaluating the validity of the SDQ as a screening instrument are encouraged. Udgivelsesdato: 2004-null BACKGROUND:The Strengths and Difficulties Questionnaire (SDQ) has been translated into the different Nordic languages between 1996 and 2003. During the past few years, SDQs have been completed for nearly 100,000 children and adolescents in population-based studies as well as in clinical samples. The largest studies have been performed in Norway and Denmark, and in these countries the diagnostic interview DAWBA has also been used in conjunction with the SDQ.AIMS:In addition to a brief overview of past and ongoing SDQ work in Sweden, Finland, Norway, Denmark, and Iceland, we present scale means and standard deviations from selected community studies with comparable age groups, including parental reports for 7, 9 and 11 year-old children and self-reports of 13 and 15 year-olds.CONCLUSIONS:The descriptive statistics suggest that the distributions of SDQ scores are very similar across the Nordic countries. Further collaborative efforts in establishing norms and evaluating the validity of the SDQ as a screening instrument are encouraged.

In the present study, we investigated differences between dyslexic and normal reading children in asymmetry of the planum temporale area in the upper posterior part of the temporal lobe and dichotic listening performance to consonant-vowel syllables. The current study was an extension of previous studies in our laboratory on the same participants, now including also girls and left-handers. There were 20 boys and 3 girls in the dyslexic group and 19 boys and 4 girls in the normal reading group. The age of the participants was 10-12 years for both groups. The participants were screened from a population of 950 students in the fourth school grade in the greater Bergen district. The planum temporale area was measured in sagittal magnetic resonance (MR) images. Mean left and right area and asymmetry index were compared between the groups. Dichotic presentations of consonant-vowel syllables made it possible to separately probe left and right hemisphere phonological function, and to correlate this with planum temporale area. The results showed a significantly larger left than right planum temporale area for both groups. However, while the right planum temporale area was similar for the dyslexic and control groups, the left planum temporale was significantly (one-tailed t-test) smaller in the dyslexic group. Both groups also showed a significant right ear advantage to the consonant-vowel syllables in the dichotic listening test. The relation between planum temporale and dichotic listening asymmetry showed a significant correlation for the dyslexic group only, indicating a positive relation between brain structure and function in dyslexic children. The results are discussed in terms of important subject characteristics with regard to brain markers of dyslexia.

Background: it has been claimed that children with dyslexia show a general impairment in the processing of rapid auditory stimuli. However, most previous studies in this field have focused on children with language impairment or children who do not meet accepted criteria for dyslexia. Methods: in the present study, the processing of rapid non-verbal auditory stimuli (complex tones) was examined in a population-based sample of 24 children with dyslexia, 10 to 12 years of age, and a matched control group. Results: the dyslexia group showed reduced tone processing relative to the control group, with significant main effects of tone duration, inter-stimulus interval and task complexity. The deficit was not specific for temporal order errors, and could not be explained by differences in short-term memory or verbal IQ. However, correlations between tone processing and reading ability were generally low or absent. Conclusion: although a general processing deficit for rapid auditory stimuli in dyslexia was confirmed, its relevance for reading problems and hence for treatment programmes for dyslexia is questioned.

Background: Based on previous studies and due to the characteristics of dyslexia as an auditory phonological decoding disorder, we predicted that the shape of the posterior corpus callosum (CC) would differ between dyslexic and control subjects. Method: Twenty right-handed boys with developmental dyslexia were selected from a carefully screened general population sample (mean age 11 years) and compared to a matched control group. The CC contour was manually traced on the aligned midsagittal MR slice and total callosal area and its subregions were compared between the groups. A statistical shape analysis and subsequent CC classification was performed using a recently developed shape model method. Results: The shape analysis revealed shorter CC shape in the dyslexic group, localised in the posterior midbody/isthmus region. This region contains interhemispheric fibers from primary and secondary auditory cortices. A shape length difference larger than a fixed threshold in the posterior midbody region could correctly discriminate between control and dyslexic subject in 78% of the cases, where a dyslexic CC was shorter in this region than a control CC. However, there were no significant group differences with respect to overall CC area or subregions. Conclusion: A clear shape difference in the posterior midbody of the CC was found between dyslexic and control subjects. This fits with recent other studies that have reported a strong growth factor in this CC region during the late childhood years, coinciding with literacy acquisition. Our results show that the dyslexic group has not undergone the same growth pattern as the normal reading group.

We review data from our laboratory related to a view of dyslexia as a biological disorder, or deficit, caused by both structural and functional brain abnormalities. The review is focused on central auditory processing in dyslexia, and the possibility that impairments in the auditory or acoustic features of the phonological code may be at the heart of the impairments seen in dyslexia. Three methodological approaches by which to investigate central auditory processing deficits are outlined: dichotic listening (DL) to consonant-vowel syllables; magnetic resonance imaging (MRI), and the use of event-related potentials (ERPs). Consonant-vowel syllable DL is a technique for probing the functional status of phonological processing areas in the superior temporal gyrus, particularly in the left hemisphere. MRI is a corresponding structural, or morphological, measure of anatomical abnormalities in the same brain region, particularly covering the planum temporale area. The ERP technique, and particularly the mismatch negativity (MMN) component, reveals cortical dysfunctions in sensory processing and memory related to basic acoustic events. For all three approaches, the dyslexic children were seen to differ from their control counterparts, including absence of modulation of the right ear advantage (REA), in DL through shifting of attention, smaller left-sided planum temporale asymmetry, and prolonged latency in the MMN ERP complex, particularly in the time-deviant stimulus condition.

PURPOSE: To estimate the prevalence of the ADHD phenotype based on parent and teacher reports in a general population sample of 7- to 9-year-old Norwegian children and evaluate the effect of parent attrition, gender and informant on the prevalence estimate. METHODS: The population consisted of all children (N = 9,430) attending 2nd-4th grade in the City of Bergen, Norway. The 18 symptoms of ADHD corresponding to the SNAP-IV and DSM-IV were included in the Bergen Child Study questionnaire to teachers and parents. Teacher information was available for 9,137 children (97%) and information from both informants was available for the 6,237 children (66%) whose parents agreed to participate in the study. RESULTS: The prevalence of the ADHD phenotype based on the combination of parent and teacher reports was 5.2% among participants. Teacher ratings of non-participants had a doubled rate of ADHD high scorers with an OR of 2.1 (95% CI, 1.9-2.4). The non-participant ADHD high scorers had more inattentive and fewer hyperactive/impulsive symptoms as compared to participating ADHD high scorers. Teachers reported high scores of hyperactivity/impulsivity and the combined symptom constellation much more frequently in boys than girls, while the difference between genders was less marked according to parent reports. CONCLUSIONS: The ADHD phenotype was twice as prevalent among non-participants as among participants. Reported prevalences in population studies are therefore likely to be underestimates, if such attrition bias is not accounted for. Choice of informant, criteria for symptom count, definitions of subtypes and gender differences influence the prevalence estimates of the ADHD phenotype.