Stigma is one of the factors contributing to inadequate recognition and treatment of recurrent mood disorders, including unipolar depression and bipolar disorder. In addition, the potential seriousness of these illnesses is often underestimated. This Viewpoint describes an analogy to the development and spread of a malignancy as a way of trying to emphasize the pernicious course of bipolar disorder in particular, but many of the comments are also relevant to recurrent depression.