Luis Augusto Rohde

Child and adolescent mental health worldwide: evidence for action

Mental health problems affect 10-20% of children and adolescents worldwide. Despite their relevance as a leading cause of health-related disability in this age group and their longlasting effects throughout life, the mental health needs of children and adolescents are neglected, especially in low-income and middle-income countries. In this report we review the evidence and the gaps in the published work in terms of prevalence, risk and protective factors, and interventions to prevent and treat childhood and adolescent mental health problems. We also discuss barriers to, and approaches for, the implementation of such strategies in low-resource settings. Action is imperative to reduce the burden of mental health problems in future generations and to allow for the full development of vulnerable children and adolescents worldwide.

Annual research review: A meta-analysis of the worldwide prevalence of mental disorders in children and adolescents.

BACKGROUND The literature on the prevalence of mental disorders affecting children and adolescents has expanded significantly over the last three decades around the world. Despite the field having matured significantly, there has been no meta-analysis to calculate a worldwide-pooled prevalence and to empirically assess the sources of heterogeneity of estimates. METHODS We conducted a systematic review of the literature searching in PubMed, PsycINFO, and EMBASE for prevalence studies of mental disorders investigating probabilistic community samples of children and adolescents with standardized assessments methods that derive diagnoses according to the DSM or ICD. Meta-analytical techniques were used to estimate the prevalence rates of any mental disorder and individual diagnostic groups. A meta-regression analysis was performed to estimate the effect of population and sample characteristics, study methods, assessment procedures, and case definition in determining the heterogeneity of estimates. RESULTS We included 41 studies conducted in 27 countries from every world region. The worldwide-pooled prevalence of mental disorders was 13.4% (CI 95% 11.3-15.9). The worldwide prevalence of any anxiety disorder was 6.5% (CI 95% 4.7-9.1), any depressive disorder was 2.6% (CI 95% 1.7-3.9), attention-deficit hyperactivity disorder was 3.4% (CI 95% 2.6-4.5), and any disruptive disorder was 5.7% (CI 95% 4.0-8.1). Significant heterogeneity was detected for all pooled estimates. The multivariate metaregression analyses indicated that sample representativeness, sample frame, and diagnostic interview were significant moderators of prevalence estimates. Estimates did not vary as a function of geographic location of studies and year of data collection. The multivariate model explained 88.89% of prevalence heterogeneity, but residual heterogeneity was still significant. Additional meta-analysis detected significant pooled difference in prevalence rates according to requirement of funcional impairment for the diagnosis of mental disorders. CONCLUSIONS Our findings suggest that mental disorders affect a significant number of children and adolescents worldwide. The pooled prevalence estimates and the identification of sources of heterogeneity have important implications to service, training, and research planning around the world.

Validity of DSM-IV attention deficit/hyperactivity disorder symptom dimensions and subtypes.

Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) criteria for attention deficit/hyperactivity disorder (ADHD) specify two dimensions of inattention and hyperactivity-impulsivity symptoms that are used to define three nominal subtypes: predominantly hyperactive-impulsive type (ADHD-H), predominantly inattentive type (ADHD-I), and combined type (ADHD-C). To aid decision making for DSM-5 and other future diagnostic systems, a comprehensive literature review and meta-analysis of 546 studies was completed to evaluate the validity of the DSM-IV model of ADHD. Results indicated that DSM-IV criteria identify individuals with significant and persistent impairment in social, academic, occupational, and adaptive functioning when intelligence, demographic factors, and concurrent psychopathology are controlled. Available data overwhelmingly support the concurrent, predictive, and discriminant validity of the distinction between inattention and hyperactivity-impulsivity symptoms, and indicate that nearly all differences among the nominal subtypes are consistent with the relative levels of inattention and hyperactivity-impulsivity symptoms that define the subtypes. In contrast, the DSM-IV subtype model is compromised by weak evidence for the validity of ADHD-H after first grade, minimal support for the distinction between ADHD-I and ADHD-C in studies of etiological influences, academic and cognitive functioning, and treatment response, and the marked longitudinal instability of all three subtypes. Overall, we conclude that the DSM-IV ADHD subtypes provide a convenient clinical shorthand to describe the functional and behavioral correlates of current levels of inattention and hyperactivity-impulsivity symptoms, but do not identify discrete subgroups with sufficient long-term stability to justify the classification of distinct forms of the disorder. Empirical support is stronger for an alternative model that would replace the subtypes with dimensional modifiers that reflect the number of inattention and hyperactivity-impulsivity symptoms at the time of assessment. (PsycINFO Database Record (c) 2012 APA, all rights reserved).

ADHD prevalence estimates across three decades: an updated systematic review and meta-regression analysis

BACKGROUND Previous studies have identified significant variability in attention-deficit / hyperactivity disorder (ADHD) prevalence estimates worldwide, largely explained by methodological procedures. However, increasing rates of ADHD diagnosis and treatment throughout the past few decades have fuelled concerns about whether the true prevalence of the disorder has increased over time. METHODS We updated the two most comprehensive systematic reviews on ADHD prevalence available in the literature. Meta-regression analyses were conducted to test the effect of year of study in the context of both methodological variables that determined variability in ADHD prevalence (diagnostic criteria, impairment criterion and source of information), and the geographical location of studies. RESULTS We identified 154 original studies and included 135 in the multivariate analysis. Methodological procedures investigated were significantly associated with heterogeneity of studies. Geographical location and year of study were not associated with variability in ADHD prevalence estimates. CONCLUSIONS Confirming previous findings, variability in ADHD prevalence estimates is mostly explained by methodological characteristics of the studies. In the past three decades, there has been no evidence to suggest an increase in the number of children in the community who meet criteria for ADHD when standardized diagnostic procedures are followed.

Epidemiology of attention-deficit/hyperactivity disorder across the lifespan.

Purpose of review Prevalence estimates of the attention-deficit hyperactivity disorder (ADHD) and the rate of persistence of symptoms across the lifespan are heterogeneous, raising questions about the validity of the diagnosis. This review aims to discuss potential reasons for variability in ADHD prevalence estimates and rates of symptom persistence, as well as to present ADHD prevalence rates during the lifespan. Recent findings The best available estimates of ADHD prevalence are around 5.29% for children and adolescents and 4.4% in adulthood. Estimates of ADHD prevalence and rate of symptom persistence over time seem to be highly affected by methodological characteristics of the studies. Summary The review of ADHD epidemiology highlights the need for standardizing study methodologies to make findings comparable. Even so, epidemiological cross-national data seem to support the validity of ADHD.

ADHD in a school sample of Brazilian adolescents : A study of prevalence, comorbid conditions, and impairments

OBJECTIVE To evaluate the prevalence, comorbid conditions, and impairments of attention-deficit/hyperactivity disorder (ADHD) among young adolescents in Porto Alegre, Brazil. METHOD 1,013 students aged 12 to 14 years were evaluated at 64 state schools, using a screening instrument based on the 18 DSM-IV ADHD symptoms. All positive screened students (n = 99) and a random subset of negative screened subjects (n = 92) had a psychiatric evaluation carried out within a hospital setting or at home. RESULTS The prevalence of ADHD was estimated to be 5.8% (95% confidence interval = 3.2-10.6), and the comorbidity with other disruptive behavior disorders was high (47.8%). Youths with ADHD (n = 23) had significantly higher rates of school repetitions, suspensions, and expulsions (p < .01) than controls (n = 168). No association was identified between ADHD and alcohol, marijuana, and inhalant use. CONCLUSION The results extend to adolescents well-documented findings in children, indicating that ADHD is quite prevalent in early adolescence and affected youths are at high risk for impairment and dysfunction in multiple domains.

Joint Analysis of the DRD5 Marker Concludes Association with Attention-Deficit/Hyperactivity Disorder Confined to the Predominantly Inattentive and Combined Subtypes

Attention-deficit/hyperactivity disorder (ADHD) is a highly heritable, heterogeneous disorder of early onset, consisting of a triad of symptoms: inattention, hyperactivity, and impulsivity. The disorder has a significant genetic component, and theories of etiology include abnormalities in the dopaminergic system, with DRD4, DAT1, SNAP25, and DRD5 being implicated as major susceptibility genes. An initial report of association between ADHD and the common 148-bp allele of a microsatellite marker located 18.5 kb from the DRD5 gene has been followed by several studies showing nonsignificant trends toward association with the same allele. To establish the postulated association of the (CA)(n) repeat with ADHD, we collected genotypic information from 14 independent samples of probands and their parents, analyzed them individually and, in the absence of heterogeneity, analyzed them as a joint sample. The joint analysis showed association with the DRD5 locus (P=.00005; odds ratio 1.24; 95% confidence interval 1.12-1.38). This association appears to be confined to the predominantly inattentive and combined clinical subtypes.

Is Adult ADHD a Childhood-Onset Neurodevelopmental Disorder? Evidence From a Four-Decade Longitudinal Cohort Study

OBJECTIVE Despite a prevailing assumption that adult ADHD is a childhood-onset neurodevelopmental disorder, no prospective longitudinal study has described the childhoods of the adult ADHD population. The authors report follow-back analyses of ADHD cases diagnosed in adulthood, alongside follow-forward analyses of ADHD cases diagnosed in childhood, in one cohort. METHOD Participants belonged to a representative birth cohort of 1,037 individuals born in Dunedin, New Zealand, in 1972 and 1973 and followed to age 38, with 95% retention. Symptoms of ADHD, associated clinical features, comorbid disorders, neuropsychological deficits, genome-wide association study-derived polygenic risk, and life impairment indicators were assessed. Data sources were participants, parents, teachers, informants, neuropsychological test results, and administrative records. Adult ADHD diagnoses used DSM-5 criteria, apart from onset age and cross-setting corroboration, which were study outcome measures. RESULTS As expected, childhood ADHD had a prevalence of 6% (predominantly male) and was associated with childhood comorbid disorders, neurocognitive deficits, polygenic risk, and residual adult life impairment. Also as expected, adult ADHD had a prevalence of 3% (gender balanced) and was associated with adult substance dependence, adult life impairment, and treatment contact. Unexpectedly, the childhood ADHD and adult ADHD groups comprised virtually nonoverlapping sets; 90% of adult ADHD cases lacked a history of childhood ADHD. Also unexpectedly, the adult ADHD group did not show tested neuropsychological deficits in childhood or adulthood, nor did they show polygenic risk for childhood ADHD. CONCLUSIONS The findings raise the possibility that adults presenting with the ADHD symptom picture may not have a childhood-onset neurodevelopmental disorder. If this finding is replicated, then the disorders place in the classification system must be reconsidered, and research must investigate the etiology of adult ADHD.

Dopamine transporter gene and response to methylphenidate in attention-deficit/hyperactivity disorder.

This study aims to evaluate whether a previously reported association between homozygosity for the 10-repeat allele of the dopamine transporter gene (10/10) and poor response to methylphenidate (MPH) would be replicated in a sample of Brazilian attention deficit/hyperactivity disorder (ADHD) boys. In a blind naturalistic study, 50 male ADHD youths were treated with MPH. Efficacy of the medication was measured by means of the 10-item Conners Abbreviated Rating Scale (ABRS), and the Childrens Global Assessment Scale (CGAS). While 75% (15/20) of the youths without 10/10 genotype demonstrated an improvement higher than 50% in the ABRS scores with MPH, only 47% (14/30) of the subjects with 10/10 genotype achieved the same level of improvement with medication (one-tailed P = 0.04). In addition, the group without this genotype had significantly higher increase in the CGAS scores than the other group (one-tailed P < 0.01). Our findings support an association between homozygosity for the 10-repeat allele at dopamine transporter gene locus and poor response to MPH.

Attention-Deficit/Hyperactivity Disorder in a Diverse Culture: Do Research and Clinical Findings Support the Notion of a Cultural Construct for the Disorder?

There is still some debate in the literature whether Attention-Deficit Disorder/Hyperactivity (ADHD) is best conceptualized as a biological disorder or if it is best understood as a cultural construct. This review aims to contribute to disentangle this issue assessing clinical and research data on ADHD in a complete diverse culture from a developing country. We performed a systematic computerized review of the literature on ADHD in Brazil. All investigations were included if dealing with ADHD prevalence, etiology, symptomatological construct, or treatment. Findings were compared to those from studies in developed countries. The prevalence rates of ADHD (5.8% using DSM-IV criteria, 1.5% using ICD-10), the bi-dimensional factor construct extracted from factor analyses (inattention and hyperactivity/impulsivity), the pattern of ADHD comorbidity in clinical samples, the family genetic data suggesting a 39% family transmission in clinical samples and the role of some potential candidate genes in dopaminergic and noradrenergic systems, as well as data on the efficacy of methylphenidate in the disorder are all very similar to findings from developed countries. Taken together, these findings suggest that ADHD is not a cultural construct, reinforcing the importance of applying similar research methodology in different cultures to make findings comparable.