Prevalence of mental health problems in Chinese schoolchildren: The influence of measuring impact score and combining information from multiple informants.

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.