Dual diagnosis: impact of family history.

Psychiatric outpatients with severe and persistent mental illness and a current or past substance use disorder (N = 89) were interviewed. Information from the Family Informant Schedule and Criteria was configured in three ways to capture the degree of familial substance abuse: biological parents only, all first-degree biological relatives, and all caregivers. All three configurations predicted the severity of lifetime drug abuse on the Inventory of Drug Use Consequences, controlling for any gender and non-substance-related Axis I diagnosis. Differences in means represent low to very low substance abuse severity for those without family history and low to medium severity for those with family history. The clinical implications are discussed.