Drug abuse by alcoholics and problem drinkers: a literature review and evaluation.

The estimate of drug abuse by alcoholics and problem drinkers in the literature varies from a low of 1% to a high of 90%. These studies, coupled with data from the National Drug/Alcohol Collaborative Project (NDACP), led us to estimate the figure to lie somewhere between 60 and 80%, being somewhat higher for individuals under 40 than over 40. Some explanations for the increased occurrence of this form of multiple substance abuse are provided. Problems associated with investigating this phenomenon are discussed and illustrated. Physiological and medical complications associated with drug and alcohol abuse are also cited.