A comparison was made between the efficacy of eight laboratory tests and three rapid interviews in the detection of excessive drinking and alcoholism among 385 psychiatric patients. gamma-glutamyl transpeptidase, the best of the laboratory tests, detected only a third of those consuming more than 16 "drinks" per day or independently diagnosed as alcoholic. In contrast, the Brief MAST, the Cage, and the Reich interviews each identified nine out of ten alcoholics, and the Cage and Reich interviews detected 93% and 98% of excessive drinkers respectively. The three interviews, each of which takes less than 1 min to administer, have considerable potential for use in the routine screening of high-risk groups, such as hospital patients.