Abstract
The relationship between age of onset for conduct disorder (CD) and the externalizing disorder attention-deficit hyperactivity disorder (ADHD) is well researched. However, little is known about associations between age of CD onset and comorbid internalizing disorders. This study examined whether age of CD onset significantly predicted the presence of a comorbid mood or anxiety disorder in a community-based sample of adolescents (n = 147). Results showed each one-year increase in age of CD onset was significantly associated with increased probability of comorbid depression, but not significantly associated with the probability of a comorbid anxiety disorder. Analyses were replicated in subsamples of youth with (n = 77) and without (n = 70) ADHD. The significant positive relationship between age of CD onset and comorbid depression held in youth with ADHD only, while a negative relationship with anxiety emerged as significant in youth without ADHD.