Comorbidity of conduct disorder and bipolar disorder in clinically referred children and adolescents

The co-occurrence of conduct disorder (CD) and bipolar disorder (BD) has been frequently reported in referred children and adolescents. We address the implications of this comorbidity in a naturalistic sample of youths with BD, CD, and CD+BD. The sample consisted of 307 patients (216 males and 91 females, age range 8-18 years, mean age 13.5 +/- 2.6 years) referred during a 5-year period and followed-up for at least 6 months, 106 with CD without BD, 109 with BD without CD, and 92 with CD+BD, diagnosed with a structured clinical interview (K-SADS-PL). Patients with CD alone were more predominantly males and with the lowest socio-economic status. Patients with CD without BD were the least severe at the baseline, while patients with BD alone presented the greatest improvement during the follow-up, and those with CD+BD had the poorest response. Patients with CD+BD presented higher rates of global aggression at the baseline, namely impulsive aggression, compared with CD alone, and the highest risk of substance abuse. Patients with BD alone presented higher rates of comorbid panic disorder and obsessive compulsive disorder, while patients with CD, with or without BD, had higher rates of ADHD. Bipolar-conduct disorder comorbidity may have meaningful implications in children and adolescents, in terms of presentation, course, and treatments.