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.

Annual Research Review: A meta-analysis of the worldwide prevalence of mental disorders in children and adolescents

Purpose of reviewPrevalence 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 pre

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

Although ADHD comorbidity has been widely studied, some issues remain unsolved. This multicenter observational study aims to examine comorbid psychiatric disorders in a clinical sample of newly diagnosed, treatment naive children and adolescents with and without ADHD and, to compare treatment efficacy based on the type of comorbidity. We performed an analysis of the medical records of patients identified from the Regional ADHD Registry database, enrolled in 18 ADHD centers in the 2011-2016 period. 1919 of 2861 subjects evaluated (67%) met the diagnostic criteria for ADHD: 650 (34%) had only ADHD, while 1269 (66%) had at least one comorbid psychiatric disorder (learning disorders, 56%; sleep disorders, 23%; oppositional defiant disorder, 20%; anxiety disorders, 12%). Patients with ADHD of combined type and with severe impairment (CGI-S ≥5) were more likely to present comorbidity. 382 of 724 (53%) followed up patients improved after 1 year of treatment. ADHD with comorbidity showed greater improvement when treated with combined interventions or methylphenidate alone. Specifically, combined treatment showed significant superiority for ADHD with learning disorders (ES 0.66) and ODD (ES 0.98), lower for ADHD with sleep or anxiety disorders. Training intervention alone showed only medium efficacy (ES 0.50) for ADHD and learning disorders. This study was the first describing comorbidity patterns of ADHD in Italy, confirming, in a multicenter clinical setting, that ADHD is more often a complex disorder. Findings highlight important diagnostic, therapeutic, and service organization aspects that should be broadly extended to ensure an appropriate and homogenous ADHD management.

Comorbidity prevalence and treatment outcome in children and adolescents with ADHD

While in the last 5 years several studies have been conducted in Italy on the prevalence of mental disorders in adults, to date no epidemiological study has been targeted on mental disorders in adolescents. A two-phase study was conducted on 3,418 participants using the child behavior checklist/6–18 (CBCL) and the development and well-being assessment (DAWBA), a structured interview with verbatim reports reviewed by clinicians. The prevalence of CBCL caseness and DSM-IV disorders was 9.8% (CI 8.8–10.8%) and 8.2% (CI 4.2–12.3%), respectively. DSM-IV Emotional disorders were more frequently observed (6.5% CI 2.2–10.8%) than externalizing disorders (1.2% CI 0.2–2.3%). In girls, prevalence estimates increased significantly with age; furthermore, living with a single parent, low level of maternal education, and low family income were associated with a higher likelihood of suffering from emotional or behavioral problems. Approximately one in ten adolescents has psychological problems. Teachers and clinicians should focus on boys and girls living with a single parent and/or in disadvantaged socioeconomic conditions.

/pdf/prevalence-and-correlates-of-mental-disorders-among-182utxftng.pdf

Prevalence and correlates of mental disorders among adolescents in Italy: the PrISMA study

This is a nationwide epidemiological study using DSM-5 criteria to assess the prevalence of mental disorders in a large sample of Austrian adolescents between 10 and 18 years including hard-to-reach samples A sample of 3615 adolescents from four cohorts (school grades 5, 7, 9, 11; age range 10-18 years) was recruited from 261 schools, samples of unemployed adolescents (n = 39) and adolescents from mental health institutions (n = 137) were added The Youth Self-Report and SCOFF were used to screen for mental health problems In a second phase, the Childrens' Diagnostic Interview for Mental Disorders was used to make point and lifetime psychiatric diagnoses Mental health service use was also assessed Point prevalence and lifetime prevalence rates for at least one psychiatric disorder were 239% and 358% The highest lifetime prevalence rates were found for anxiety disorders (156%), neurodevelopmental disorders (93%; ADHD 52%) and depressive disorders (62%) Forty-seven percent of adolescents with a lifetime psychiatric disorder had a second diagnosis Internalising disorders were more prevalent in girls, while neurodevelopmental disorders and disruptive, impulse control and conduct disorders were more prevalent in boys Of those with a lifetime psychiatric disorder, 475% had contacted mental health services Of the residual 525% who had not contacted mental health services, 181% expressed an interest in treatment DSM-5 mental health disorders are highly prevalent among Austrian adolescents Over 50% had or were interested in accessing treatment Early access to effective interventions for these problems is needed to reduce burden due to mental health disorders

/pdf/mental-health-problems-in-austrian-adolescents-a-nationwide-3tkar1o6b4.pdf

Mental health problems in Austrian adolescents: a nationwide, two-stage epidemiological study applying DSM-5 criteria

The Italian preadolescent mental health project (PrISMA--Progetto Italiano Salute Mentale Adolescenti) is the first Italian study designed to estimate the prevalence of mental disorders in preadolescents (10-14 years old) living in urban areas, and to analyse the demographic and biological correlates of emotional and behavioural problems. This paper describes the rationale, methods and the analysis plan of the project. The design of the study used a two-stage sampling procedure, one screening stage of emotional and behavioural problems in a large sample of subjects attending public and private schools and a second stage of diagnostic assessment in a sample including all high scorers and a proportion of low scorers. In the screening stage, parents of preadolescents were asked to fill in the Child Behavior Checklist (CBCL), whereas in the second stage preadolescents and their parents were administered the Development and Well Being Assessment for the assessment of mental disorders together with the Strengths and Difficulties Questionnaire and two scales (C-GAS and HoNOSCA) designed to evaluate the functioning of the preadolescent in different areas. Genetic samples were collected during the screening stage, after parents gave their informed written consent. The findings of this study are expected to allow an adequate planning of interventions for the prevention and the treatment of mental disorders in preadolescence as well as efficient health services.

/pdf/the-italian-preadolescent-mental-health-project-prisma-3unl019n8w.pdf

The Italian preadolescent mental health project (PrISMA): rationale and methods.

The present study examined the extent to which individual differences in personality that have been previously associated with aggression in non-clinical subjects (Caprara et al., European Journal of Personality, 27(3), 290–303, 2013, Caprara et al., Developmental Psychology, 50(1), 71–85, 2014) account for aggression among adolescents referred to psychiatric services with diagnosis within the externalizing spectrum (i.e., conduct disorder, oppositional defiant disorder, and attention deficit hyperactivity disorder). In particular a conceptual model was examined in which individual differences in basic traits (i.e., emotional instability and agreeableness), lower order traits (i.e., irritability and hostile rumination), and social cognitive mechanisms (i.e., moral disengagement) account for aggressive behavior. One hundred and nine adolescents (81 males, 74.3%), ranging in age from 11 to 18 (M = 13.83, SD = 1.70) and referred to psychiatric services for the above diagnoses, participated at the study. Adolescents filled in questionnaires measuring the Big Five traits, as well as irritability, hostile rumination, and moral disengagement; their parents filled in the Child Behavior Checklist to assess children’s aggressive behavior. Findings corroborated the posited pattern of relations previously found in non-clinical samples. In accordance with those findings, moral disengagement largely mediated the association between traits and aggressive behavior. The model explained a significant portion of variance in aggressive behavior. As a novelty, findings showed a direct association between emotional instability and aggressive behavior, pointing to the major relevance of emotional disregulation in adolescents referred for externalizing problem behaviors in comparison to non-clinical adolescents.

Mauro Walder

Papers

Prevalence and correlates of mental disorders among adolescents in Italy: the PrISMA study

The Italian preadolescent mental health project (PrISMA): rationale and methods.

Individual Differences in Personality Associated with Aggressive Behavior among Adolescents Referred for Externalizing Behavior Problems