Reports of drinking to self-medicate anxiety symptoms: Longitudinal assessment for subgroups of individuals with alcohol dependence

Background Self-medication with alcohol is frequently hypothesized to explain anxiety and alcohol dependence comorbidity. Yet, there is relatively little assessment of drinking to self-medicate anxiety and its association with the occurrence or persistence of alcohol dependence in population-based longitudinal samples, or associations within demographic and clinical subgroups. Methods Hypothesizing that self-medication of anxiety with alcohol is associated with the subsequent occurrence and persistence of alcohol dependence, we assessed these associations using data from the National Epidemiologic Survey on Alcohol and Related Conditions, and examined these associations within population subgroups. This nationally representative survey of the US population included 43,093 adults surveyed in 2001-2002, and 34,653 reinterviewed in 2004-2005. Logistic regression incorporating propensity score methods was used. Results Reports of drinking to self-medicate anxiety was associated with the subsequent occurrence (adjusted odds ratio (AOR) = 5.71, 95% confidence interval (CI) = 3.56-9.18, P <.001) and persistence (AOR = 6.25, CI = 3.24-12.05, P <.001) of alcohol dependence. The estimated proportions of the dependence cases attributable to self-medication drinking were 12.7 and 33.4% for incident and persistent dependence, respectively. Stratified analyses by age, sex, race-ethnicity, anxiety disorders and subthreshold anxiety symptoms, quantity of alcohol consumption, history of treatment, and family history of alcoholism showed few subgroup differences. Conclusions Individuals who report drinking to self-medicate anxiety are more likely to develop alcohol dependence, and the dependence is more likely to persist. There is little evidence for interaction by the population subgroups assessed. Self-medication drinking may be a useful target for prevention and intervention efforts aimed at reducing the occurrence of alcohol dependence.