Bridging Disciplinary Boundaries (January 11 - 14, 2007)

Purpose: There is evidence that individuals who experience trauma are more likely to report drinking to cope with negative emotions, but less is known about associations between trauma and drinking for enhancement, social, or conformity reasons. This analysis investigates associations of trauma history and depression with each of four drinking motives, and examines potential genetic influences on drinking motives. Methods: Subjects are female twins born in Missouri between 1975 and 1987. Responses from 2238 twins who reported having drunk any alcohol and for whom there was complete data on trauma and drinking motive items were used in this analysis. Factor analysis was used to derive drinking motives from 20 items about reasons for drinking. Latent class analysis was used to define trauma classes based on type and number of traumatic events endorsed by each twin. Genetic effects were modeled as the interaction between twin zygosity and co-twin drinking motives. General linear models were used to examine associations between each of the drinking factors and trauma classes. Results: Factor analysis of drinking motive items derived four factors analogous to a model reported in the literature (Cooper, M., 1994). Four trauma classes provided the best fit to the trauma items. Class 1 was characterized by low trauma endorsement, Class 2 by endorsement of nonassaultive events (e.g., accident, disaster), and Classes 3 and 4 by a high endorsement of childhood sexual and physical abuse and other assaultive events (e.g., being threatened with a weapon). Rates of depression were significantly higher in Classes 3 and 4 compared to Classes 1 and 2. Women in Classes 2 and 4, compared to women in Class 1, were more likely to be regular drinkers, and African American women were over-represented in classes 2 and 4. Drinking to cope was associated with membership in trauma Classes 3 and 4, and was the only drinking motive with evidence of genetic influence. Although overall African American women were less likely to drink regularly than were Caucasian women, those who did were more likely to drink to cope with negative emotions. Drinking to obtain positive social rewards had a negative association with Class 3 and, for African American women only, with Class 2. Drinking to enhance positive mood had a negative association with membership in Class 3. Implications: The association of childhood trauma with drinking to cope suggests that alcohol prevention and treatment for women with histories of trauma should introduce alternative means of coping with negative emotions, whether or not directly addressing trauma history. The negative association of childhood trauma with drinking to enhance positive mood and drinking for social rewards may be associated with findings that suggest that early trauma contributes to long-term emotional dysregulation and vulnerability to depression.