Subtypes of family history and conduct disorder: effects on P300 during the stroop test.

The goal of the present study was to identify neurophysiological differences associated with a family history of substance dependence, and its subtypes (paternal alcohol, cocaine, or opiate dependence), and with conduct disorder, and its subtypes (aggression, deceitfulness/theft, and rules violations). P300 event-related brain potentials were recorded from 210 males and females, aged 15-20 years while they performed the Stroop color-word compatibility test. Analyses revealed no significant effects of familial substance dependence on P300. However, an elevated number of conduct disorder problems was associated with a statistically significant reduction in P300 amplitude. The P300 amplitude reduction was related to the severity of the "rules violation" subtype, but was unrelated to aggression or deceitfulness and theft. It is concluded that conduct disorder can explain many of the P300 findings previously attributed to a family history of alcohol dependence. Furthermore, it appears that conduct disorder may be a heterogenous classification comprised of neurophysiologically different subtypes.