Aim: The aim of this study was to determine the prevalence of childhood psychopathologies in Turkey. Method: A nation-wide, randomly selected, representative population of 5830 children (6–13 years-old) enrolled as a 2nd,3rd or 4th grade student in 30 cities were evaluated for presence of a psychiatric or mental disorder by a Sociodemographic Form, Kiddie Schedule for Affective Disorders and Schizophrenia for School Age Children-Present and Lifetime Version (K-SADS-PL), and DSM-IV-Based Screening Scale for Disruptive Behavior Disorders in Children and Adolescents scales. Impairment criterion was assessed via a 3 point-Likert scale by the parent and the teacher independently. Results: Overall prevalence of any psychopathology was 37.6% without impairment criterion, and 17.1% with impairment criterion. Attention-deficit hyperactivity disorder was the most frequent diagnosis, followed by anxiety (19.5% and 16.7% without impairment, 12.4% and 5.3% with impairment, respectively). Lower education level and presence of a physical or psychiatric problem of the parents were independent predictors of any psychopathology of the offspring. Conclusion: This is the largest and most comprehensive epidemiological study to determine the prevalence of psychopathologies in children and adolescents in Turkey. Our results partly higher than, and partly comparable to previous national and international studies. It also contributes to the literature by determining the independent predictors of psychopathologies in this age group.

Objective: Suicide is the second leading cause of death in adolescence. Genetic studies implicate the genetic component of suicide independent from associated psychiatric disorder. Although genetics is an important factor that might be associated with suicide, limited progress is achieved to identify the candidate genes in adolescents. Methods: The study included 97 patients and 106 controls. Five leptin receptor single nucleotide polymorphism (SNP) region examined. Depressive scores were measured with Children Depression Inventory and suicidal behaviour was measured by Suicide Probability Scale. Logistic and linear regression analysis used for determining to predictors. Results: In linear regression analysis (R²: 0.786) both previous suicide attempt (B:5.553, t:2.613 p: .035) and having a mutant allele in rs1171276 SNP region (B:4.346 t:2.220 p: .048) have been associated with suicidal behaviour. In logistic regression analysis, family history of depression (p < .0001, OR: 4.2 [1.7–9.6]) and number of stressful life events (p: .001, OR: 1.7 [1.3–2.1]) predicted depression significantly. Conclusion: Leptin receptor polymorphism could result in an increase in impulsive behaviour and suicide scores with leptin resistance. Our research is the first study to investigate the relationship between depression, suicidal behaviour and leptin receptor polymorphism in adolescent sample. Similar studies could be carried out on a community basis.