The authors examined the impact of life stress on the course of bipolar disorder over a 2-year period in a group of 61 outpatients. The patients were followed prospectively with ongoing assessments of stressful life events, symptoms, levels of maintenance medication, and compliance with treatment regimens. As predicted, survival analyses indicated a significant association between life events and relapse or recurrence of the disorder. These effects could not be explained by differences in levels of medication or compliance. Further research is recommended to examine which specific subgroups of bipolar patients are most susceptible to stress.