Dual dependence: assessment of dependence upon alcohol and illicit drugs, and the relationship of alcohol dependence among drug misusers to patterns of drinking, illicit drug use and health problems.

Abstract

The study investigates severity of alcohol dependence among drug misusers. Specifically, it investigates the inter-relationship of alcohol and drug dependence and associations with alcohol consumption, drug consumption and substance-related problems. The sample comprised 735 people seeking treatment for drug misuse problems, who were current (last 90 days) drinkers. Data were collected by structured face-to-face interviews. Dependence upon illicit drugs and upon alcohol was measured by the Severity of Dependence Scale (SDS). Three groups of drinkers were identified: non-alcohol-dependent drug misusers (63%); low-dependence (19%); and high-dependence (18%). Many drug misusers were drinking excessively and alcohol dependence was related to patterns of alcohol and drug consumption. High-dependence drinkers were more likely to drink extra-strength beer; they were less frequent users of heroin and crack cocaine but more frequent users of benzodiazepines, amphetamines and cocaine powder; they reported more psychological and physical health problems. The SDS was found to have good reliability and validity as a measure of alcohol dependence. SDS scores for alcohol and drug dependence were unrelated. Alcohol use is an important and under-rated problem in the treatment of drug misusers. A comprehensive assessment of alcohol use among drug misusers should include separate assessments of alcohol consumption, alcohol-related problems and severity of alcohol dependence.