Abstract
INTRODUCTION: Alcohol dependence (AD) presents with substantial clinical heterogeneity, including concurrent use of non-alcohol drugs. Here, we examine specific patterns of concurrent non-alcohol substance use during the previous year among a nationally representative sample of adults with DSM-IV AD, and estimate their population prevalence in the U.S. We then evaluate alcohol use behavior and comorbid psychopathology among respondents with AD according to their patterns of concurrent non-alcohol substance use. METHODS: These analyses utilized data from Waves 1 and 2 of the National Epidemiologic Survey on Alcohol and Related Conditions. Latent class analyses classified respondents with AD into four clinically meaningful patterns of concurrent substance use: (1) use of alcohol only; (2) use of alcohol and tobacco only; (3) use of alcohol, tobacco and cannabis; and (4) use of alcohol, tobacco, cannabis, cocaine, and other illicit drug(s). RESULTS: Among AD respondents, the most prevalent pattern was the use of alcohol and tobacco only (weighted percentage, 32.4%), followed by the use of alcohol only (weighted percentage, 27.5%). AD respondents who used alcohol, tobacco, cannabis, cocaine, and other illicit drug(s) (weighted percentage, 25.3%) manifested the most severe pattern of alcohol consumption, and had significant overrepresentations of major depression, panic, and other anxiety disorders as well as paranoid, schizotypal, borderline, antisocial, and histrionic personality disorders compared with those who used alcohol alone. CONCLUSIONS: Specific patterns of concurrent substance use convey important information regarding the clinical presentation and prognosis for AD. In particular, concurrent use of illicit drugs over the past year by AD individuals was associated with greater severity and comorbid psychopathology. These data suggest the need for pragmatic trials of AD interventions that take into account patterns of substance use behavior in addition to an AD diagnosis.