Numerous reports suggest that medical school has adverse psychological effects on medical students, although not all students are affected equally. The authors examined the effects of two social motives, the need for power and the need for intimacy, on measures of well-being and distress obtained throughout the undergraduate years. Medical students high in both power and intimacy motivation were more depressed, neurotic, fatalistic, and self-doubting than were their classmates. These effects began at the end of year 1, peaked in year 2, and disappeared by the end of clerkships. High intimacy-low power students had the highest levels of well-being. These effects were equally true in men and women and both support and render more precise prior role conflict explanations.