Background This meta-analysis aimed to determine the overall prevalence of emotional and behavioural disorders among children and adolescents in Germany, the dependence of prevalence estimates upon the methods employed and potential secular trends.

Methods Primary studies were subjected to meta-analytical analyses using a random effects model. Mean estimates of primary study effects were averaged using the precision-weighted method and were subsequently subjected to sensitivity analyses using hierarchical regression and (co-)variance analyses.

Results The precision-weighted average primary study prevalence for the 33 studies included was M=17.6%. The effect size primarily depended on the case definition employed, with studies applying questionnaire criteria showing, on average, lower primary study effects. Moreover, a negative relationship was found between study validity and primary study effect.

Conclusion Half a century of research efforts indicate that approximately every sixth child shows signs of emotional or behavioural disorders, and conclusions regarding period effects are not robust.