The epidemiology of bipolar affective disorder

There are three reasons why a review of the existing data on the epidemiology of bipolar affective disorder may be indicated: (1) to summarize the general differences between unipolar and bipolar affective disorder; (2) to illustrate the similarities and differences in biopolar disease (especially mania) and chronic schizophrenia, and (3) to look more closely at the depression of bipolar and unipolar disease.