Family history and antisocial traits moderate naltrexone's effects on heavy drinking in alcoholics.

Naltrexone's (NAL) effects on alcohol consumption are generally modest, so identifying patients likely to benefit would improve treatment utility. Several studies indicate that potentially significant moderators of NAL's effects might include family history of alcohol problems (FH), age of onset of alcohol problems, degree of antisocial traits, and comorbid drug use. Data from 128 alcoholic patients enrolled in a 12-week NAL treatment study (50 mg/day) were reanalyzed to determine the role of FH, age of onset, antisocial traits, and comorbid drug use in NAL's treatment effects on heavy drinking days. Dichotomized FH, age of onset of alcohol problems, and comorbid cocaine or marijuana use had no interaction effect with medication. Percentage of relatives with problem drinking (family history percentage [FHP]) moderated the effects of NAL on drinking such that NAL resulted in lower drinking rates only for patients with higher FHP. Antisocial traits also moderated the effects of medication on drinking for patients compliant with =70% of medication. Patients with more antisocial traits had less heavy drinking on NAL than on placebo, whereas patients low on antisocial traits had no benefit from NAL. Covarying antisociality in regressions of drinking outcome on FHP showed that the effects of FHP were not attributable to antisociality. Thus, NAL may selectively benefit alcoholics with antisocial traits or 20% or more relatives with problem drinking.