Substance dependence (SD) and antisocial personality disorder (ASPD) are highly comorbid and aggregate in families. Mating assortment may be an important process contributing to this familial aggregation.
Hypothesis: Symptom counts of substance dependence, antisocial personality disorder, and retrospectively assessed conduct disorder (CD) will be correlated significantly among parents of youth in treatment for substance use and conduct problems and, separately, among parents of community controls.
Methods: We examined SD, ASPD, and CD among 151 pairs of parents of adolescents in treatment for substance use and conduct problems, and in 206 pairs of parents of control subjects.
Results: For average dependence symptoms (ADS) (the sum of across-drug substance dependence symptoms divided by the number of substance categories meeting minimum threshold use) mother-father correlations were 0.40 for patients and 0.28 for controls. Mother--father correlations for ASPD symptom count were 0.33 for patients and 0.26 for controls and for CD symptom count were 0.31 for patients (all P < 0.01) and 0.10 for controls (P = 0.14).
Conclusions: Spousal correlations for ADS and ASPD, suggest substantial non-random mating. Results support gender differences in homogamy for SD. Behavior genetic studies of these disorders need to account for assortment to avoid biases in estimates of genetic and environmental effects.