Does a Group CBT-Course for Depressed Youth also Reduce Aggression? Results from a Cluster Randomized Controlled Trial

Abstract Aggression and depression are two of the most common forms of psychosocial difficulties in adolescents. High prevalence and disabling effects stress the need for more cost-effective interventions. Studies show that the two difficulties are closely linked regarding comorbidity, risk factors, consequences and theoretical background, making it interesting to investigate whether an intervention targeting one of them could also reduce the other. The aim of this study was therefore to assess the association between aggression and depression and to investigate whether a treatment that has been found effective in reducing depression—“Adolescents coping with depression course” (ACDC), a group-based cognitive behavioural intervention-, could also reduce aggression, either directly, or indirectly via reducing depression. The data came from a randomized control trial, with a pre- post- and follow-up longitudinal design. In total 228 youth participated in the study, of which 133 received the ACDC-intervention and 95 received usual care. Correlation analysis showed that aggression and depression were associated at all time points. Structural equation modelling showed that the intervention did have neither direct nor indirect effect on aggression. Our conclusion is that future CBT interventions with a primary aim to reduce depression might have to design intervention components that are more directly targeted toward aggression if also this potential comorbid difficulty should be addressed. Previous studies have found higher levels of comorbid aggression among depressed boys than girls. Few boys in our sample may thereby have reduced statistical power to detect potential influences on aggression. Trial Registration : ISRCTN registry ISRCTN19700389. Registered 6 October 2015. Full Protocol: https://doi.org/10.1186/s12888-016-0954-y