BackgroundTo describe the prevalence of DSM-IV disorders and comorbidity in a large school-based sample of 6–17 year old children and adolescents in northeast China.MethodsA two-phase cross-sectional study was conducted on 9,806 children. During the screening phase, 8848 children (90.23%) and their mothers and teachers were interviewed using the Strengths and Difficulties Questionnaire (SDQ). During the diagnostic phase, 1129 children with a positive SDQ and 804 randomly selected children with a negative SDQ (11%), and their mothers and teachers, were interviewed using the Development and Well-Being Assessment (DAWBA).ResultsThe overall prevalence of DSM-IV disorders was 9.49% (95% CI = 8.10–11.10%). Anxiety disorders were the most common (6.06%, 95% CI = 4.92–7.40), followed by depression (1.32%, 95% CI = 0.91–1.92%), oppositional defiant disorder (1.21%, 95%CI = 0.77–1.87) and attention-deficit hyperactivity disorder (0.84%, 95% CI = 0.52–1.36%). Of the 805 children with a psychiatric disorder, 15.2% had two or more comorbid disorders.ConclusionsApproximately one in ten Chinese school children has psychiatric disorders involving a level of distress or social impairment likely to warrant treatment. Prevention, early identification and treatment of these disorders are urgently needed and pose a serious challenge in China.

Background To measure the effects of using different combinations of multiple informants and the impact score on the estimated prevalence of mental health problems in Chinese schoolchildren. Methods Complete information on the Strengths and Difficulties Questionnaire (SDQ) were obtained from students (S), parents (P), and teachers (T) for 4986 schoolchildren (11–17 years-old). We used 3 criteria to determine the prevalence of mental health problems: SDQ cut-off value (previously established in the United Kingdom), SDQ cut-off value plus an impact score of 1 or more, or plus an impact score of 2 or more. A student was defined as having a mental health problem if any informant (S, P, or T) classified the child as ‘abnormal’. We compared the prevalence of mental health problems determined from 1 informant, 2 informants, and 3 informants. Results The prevalence of overall mental health problems increased with rising number of informants, but decreased with increasing impact score. When the impact score was not considered, the prevalence was 8.2% to 14.2% when rated by 1 informant, 18.8% to 24.7% when rated by 2 informants, and 28.3% when rated by all 3 informants. Failure to measure the impact score led to a two to threefold greater estimate of the prevalence of mental health problems. Conclusions The types, number, and combinations of multiple informants and use of the impact score must be considered when comparing the results of different studies. It is preferable to use multiple informants and have the impact score taken the impact into account to reflect the real burden of mental health burden in children and adolescent.