Family and Environment in the Choice of Opioid Dependence or Alcoholism

From interviews with 235 opioid-dependent probands, the lifetime prevalence of opioid dependence among their family members was found to be 8.4%, markedly exceeding the estimated lifetime prevalence of 0.9% in the general adult population. Gender-specific lifetime prevalence rates of alcoholism among family members did not consistently exceed rates in the general adult population as estimated from epidemiologic studies based on direct interviews. Because interviews with probands alone tend to underestimate family prevalence of alcoholism, the family rates may have exceeded the general population rates. The probands themselves had a high lifetime prevalence (56%) of alcoholism. A trend toward association of alcoholism in the probands with alcoholism in the parents was found. An intergenerational increase in availability of heroin and in heroin-using peers was accompanied by an intergenerational reversal in prevalence of alcoholism and opioid dependence. The parents of probands had higher rates of alcoholism than of opioid dependence, while the siblings of probands had higher rates of opioid dependence than of alcoholism. This study and preceding studies demonstrate that opioid dependence clusters in families of opioid-dependent probands. Familial clustering is consistent with but not equivalent to familial transmission. The findings suggest that the extrafamilial environment affected choice of alcohol or opioid as the principal substance of dependence.