The MAC scale in a normal population: the meaning of "false positives"

The MAC scale has been very successful in identifying alcoholics and, in studies of clinical populations, is often considered a test for predisposition to alcoholism. MacAndrew, however, holds that the MAC scale assesses a more general personality trait characterized by sociability, boldness, rebelliousness and pleasure seeking. The present study examines the distribution of MAC scale scores in a normal population and tests for correlates of high MAC scores other than alcohol-related problems (e.g., arrest history). The sample consisted of 1,117 men, participants in the Normative Aging Study (mean age = 61.6). As expected, heavier drinkers and problem drinkers reported significantly higher MAC scale scores than did lighter and nonproblem drinkers. However, arrestees without drinking problems had MAC scale scores nearly identical to those of problem drinkers without arrest histories (23.19 and 23.42, respectively). Further, 36% of the sample without problem drinking or arrest histories had MAC scale scores of 24 or above, the clinical indicator of alcoholism, and more than 32% of these had scores above 27. In the entire sample, of the 152 men who had MAC scores above 27, 71% had no problems, either with arrest or drinking. Results are interpreted as supporting MacAndrew's interpretation of the meaning of the MAC scale as a general personality measure rather than a specific alcoholism instrument.