Rumination as a transdiagnostic factor underlying transitions between internalizing symptoms and aggressive behavior in early adolescents.

The high degree of comorbidity among mental disorders has generated interest in identifying transdiagnostic processes associated with multiple types of psychopathology. Susan Nolen-Hoeksema conceptualized rumination as one such transdiagnostic process associated with depression, anxiety, substance abuse, binge eating, and self-injurious behavior. The degree to which rumination accounts for the co-occurrence of internalizing and externalizing psychopathology, however, has never been tested. We used a sample of early adolescents (N = 1,065) assessed at 3 time points spanning 7 months to examine (a) the reciprocal prospective associations between rumination and aggressive behavior in adolescents, (b) whether rumination explained the longitudinal associations of aggressive behavior with depression and anxiety symptoms, and (c) gender differences in these associations. Rumination predicted increases over time in aggressive behavior, and aggression was associated with increases in rumination over time only for boys. Rumination fully mediated the longitudinal association of aggression with subsequent anxiety symptoms and of both depression and anxiety symptoms with subsequent aggression in boys but not girls. Rumination did not explain the association between aggression and subsequent depressive symptoms for either boys or girls. These findings provide novel evidence for the role of rumination as a transdiagnostic factor underlying transitions between internalizing and externalizing symptoms among males during early adolescence. Interventions aimed at reducing rumination may have beneficial influences on multiple forms of psychopathology and on the development of comorbidity. (PsycINFO Database Record (c) 2014 APA, all rights reserved).