Exploring Diagnostic Classification Prevalence in German and Dutch Child and Adolescent Psychiatry: An International Cross-Sectional Comparative Study

= 3.82). A multivariate analysis compared primary classifications between the two samples, which were further stratified into three age groups: early childhood (0-5 years), middle childhood (6-12 years), adolescence (13-18 years). The main factor influencing classification was the country. Age and sex showed moderate to low effect sizes, respectively. The impact varied across different age groups and sexes. Patients in the German sample were generally older and had a higher proportion of girls than those in the Dutch sample. Mood, anxiety, disruptive/impulsive-control and conduct, and trauma and stressor-related disorders were more prevalent in the German sample, while autism spectrum disorder and attention-deficit/hyperactivity disorder were more common in the Dutch sample. Our findings suggest that the primary classifications of mental disorders in Dutch and German children and adolescents largely depend on the country. This may have implications for cross-country comparisons and highlights the potential influence of national mental healthcare systems and cultural contexts on classification practices, which could impact policy decisions.