Categorical and dimensional psychopathology in Dutch and US offspring of parents with bipolar disorder: A preliminary cross-national comparison

Objective: Accumulating evidence suggests cross-national differences in adults with bipolar disorder (BD), but also in the susceptibility of their offspring (bipolar offspring). This study aims to explore and clarify cross-national variation in the prevalence of categorical and dimensional psychopathology between bipolar offspringin the US and The Netherlands. Methods: We compared levels of psychopathology in offspring of the Pittsburgh Bipolar Offspring Study (n=224) and the Dutch Bipolar Offspring Study (n=136) (age 10-18). Categorical psychopathology was ascertained through interviews using the Schedule for Affective Disorders and Schizophrenia for School Age Children (K-SADS-PL), dimensional psychopathology by parental reports using the Child Behavior Checklist (CBCL). Results: Higher rates of categorical psychopathology were observed in the US versus the Dutch samples (66% versus 44%). We found no differences in the overall prevalence of mood disorders, including BD-I or -II, but more comorbidity in mood disorders in US versus Dutch off spring (80% versus 34%). The strongest predictors of categorical psychopathology were maternal BD (OR: 1.72, p<.05), older age of the offspring (OR: 1.19, p<.05), and country of origin (US; OR: 2.17, p<.001). Regarding comorbidity, only country of origin (OR: 7.84, p<.001) was a significant predictor. Ingeneral, we found no differences in dimensional psychopathology based on CBCL reports. Limitations: Preliminary measure of inter-site reliability. Conclusions: We found cross-national differences in prevalence of categorical diagnoses of non-mood disorders in bipolar offspring, but not in mood disorder diagnoses nor in parent-reported dimensional psychopathology. Cross-national variation was only partially explained by between-sample differences. Cultural and methodological explanations for these findings warrant further study. (C) 2016 Elsevier B.V. All rights reserved.