Sociodemographic and clinical characteristics in child and youth mental health; comparison of routine outcome measurements of an Australian and Dutch outpatient cohort.

Aims: Although of great value to understand the treatment results for mental health problems obtained in clinical practice, studies using naturalistic data from children and adolescents seeking clinical care because of complex mental health problems are limited. Cross-national comparison of naturalistic outcomes in this population is seldomly done. Although careful consideration is needed, such comparisons are likely to contribute to an open dialogue about cross-national differences and may stimulate service improvement. The aim of this observational study is to investigate clinical characteristics and outcomes in naturalistic cohorts of specialized child and adolescent mental health outpatient care in two different countries.

Methods: Routinely collected data from 2013 to 2018 of 2715 outpatients in the Greater Area of Brisbane, Australia (CYMHS) and 1158 outpatients in Leiden, the Netherlands (LUMC-Curium) were analysed. Demographics, clinical characteristics and severity of problems at start and end of treatment were described, using Children's Global Assessment Scale (CGAS), Health of the Nation Outcome Scales for Children and Adolescents (HoNOSCA) and the parental Strength and Difficulties Questionnaire (SDQ-P).

Results: Routine outcome measures (CGAS, HoNOSCA, SDQ-P) showed moderate to severe mental health problems at start of treatment, which improved significantly over time in both cohorts. Effect sizes ranged between 0.73-0.90 (CYMHS) and 0.57-0.76 (LUMC-Curium). While internalizing problems (mood disorder, anxiety disorder and stress-related disorder) were more prevalent at CYMHS, externalizing developmental problems (ADHD, autism) prevailed at LUMC-Curium. Comorbidity (>1 diagnosis on ICD10/DSM-IV) was relatively similar: 45% at CYMHS and 39 % at LUMC-Curium. In both countries, improvement of functioning was lowest for conduct disorder and highest for somatoform/conversion disorders and obsessive-compulsive disorders (OCD). Overall, 20-40% showed clinically significant improvement (shift from clinical-range at start to a non-clinical-range at the end of treatment), but nearly half of patients still experienced significant symptoms at discharge.

Conclusions: This large-scale outcome study showed both cohorts from Australia and the Netherlands improve during the course of treatment on clinician- and parent-reported measures. Although samples were situated within different contexts and differed in patient profiles, they showed similar trends in improvement per diagnostic group. While 20-40% showed clinically significant change, many patients experienced residual symptoms reflecting increased risk for negative outcome into adulthood. We emphasize cross-national comparison of naturalistic outcomes faces challenges, although it can similarly reveal trends in treatment outcome providing direction for future research: what factors determine discharge from specialized services; and how to improve current treatments in this severely affected population.