Diagnosis and course of affective psychoses: was Kraepelin right?

Kraepelin's basic attitude to the classification of psychoses was data-oriented and flexible. In his latter years he was close to revising his own celebrated dichotomy between manic-depressive insanity and dementia praecox in order to take account of a large group of intermediate psychoses, which today are called schizo-affective. His concept of a continuum from healthy to ill has stood the test of time and corresponds to modern epidemiological findings. Kraepelin's unitarian concept of manic-depressive insanity did not survive. It was differentiated and broken down into several subgroups, and a proportional diagnostic spectrum with a continuum from mania via bipolar disorders to depression has recently even been proposed. Bipolar disorders would in that case be comorbid disorders of mania plus depression. In contrast to Kraepelin's unitarian view the long-term prognosis of subgroups of mood disorders varies considerably. Overall it is nevertheless astonishing how much of Kraepelin's legacy has survived.