Findings indicated that various categories of more specifically defined parental drug abuse (e.g., drug abuse in fathers) were related to severe aggressive or destructive behavior, conduct disorders, or both in their children. Findings also indicated that parental abuse of nonalcohol substances appeared to be more important than parental alcohol abuse in predicting severe aggressive and antisocial behavior. Drug abuse in fathers, especially abuse of drugs other than alcohol, also seemed to be more important than drug abuse in mothers in predicting severe aggression and conduct disorder. Tables and 40 references (Author abstract modified)