This review focuses on human studies of caffeine in subjects with & without psychiatric disorders. Besides the possibility of mild drug dependence, caffeine may bring benefits that contribute to its widespread use. Moderate caffeine intake (less than 6 cups per day) has been associated with less depressive symptoms, fewer cognitive failures, & lower risk of suicide. More population (cross-sectional & prospective) & experimental studies are necessary to establish the role of caffeine intake in psychiatric disorders, especially its putative efficacy on depressive mood & cognitive/attention disorders. (126 refs.) JA