Classification accuracy was 45 percent for alcohol abuse, 48.8 percent for marijuana use, and 66 percent for related multiple substance use. There were few differences in functioning as measured by the California Psychological Inventory between true positives and false negatives. Subjects exhibited adolescent qualities, such as irresponsibility, attraction to pleasure seeking, and minor rebelliousness. False negatives appeared to be slightly less impulsive and somewhat less secure about themselves. Alcohol was used to enhance a sense of well-being; i.e., to gain pleasure and to reduce dysphoric effect, but not to reduce inhibitions in social relationships. However, true positives tended to use alcohol to help cope with problems in personal relationships, such as rejection. Some limitations of the study, especially in relation to recent formulations of female alcoholism by MacAndrew, were discussed. 2 tables and 19 references. (Author abstract modified)