Background: Disinhibitory personality traits such as high novelty seeking (NS) are moderately heritable, and individuals with substance use disorders (SUDs) frequently exhibit such traits. However, recent studies have cast doubt on the supposition that such traits are true familial risk factors for SUD and particularly for alcohol dependence. Another possibility is that familial risk interacts with personality-associated risk, in which case the association between personality and familial risk might depend on sample composition, accounting for the lack of consensus among studies to date. We examined this possibility by analyzing the association between NS and alcohol dependence in individuals at intermediate and high levels of familial risk for alcohol dependence.
Methods: Data from the Collaborative Study on the Genetics of Alcoholism, a multisite family study, were examined. Subjects were 1,111 adult siblings of alcohol-dependent index cases. Parental diagnoses of alcohol dependence and personality scores of NS from the Tridimensional Personality Questionnaire were used to predict alcohol dependence.
Results: A significant interaction between NS and familial risk for alcoholism was seen, such that NS was a significantly stronger predictor of alcohol dependence in subjects with one or more parents with alcohol dependence than in subjects without alcohol-dependent parents.
Conclusions: Novelty seeking and familial risk interact so that the risk associated with high NS is magnified in families with parental alcohol dependence and NS is a moderator of familial risk. Accordingly, high NS is strongly associated with alcohol dependence in subjects with a parent diagnosed with alcohol dependence, but low NS may protect against the risk associated with familial alcoholism. This interaction may account for conflicting findings from studies that have examined this question previously.