Ernst Kretschmer

Ernst Kretschmer was a German psychiatrist and neurologist, one of the leading figures of academic psychiatry in the first half of the twentieth century. He is remembered above all for proposing a link between bodily build and temperament, an idea that shaped personality typology for decades.

Born near Heilbronn, he studied medicine at Tübingen and trained under Robert Gaupp, later becoming professor of neurology and psychiatry at the same university. After the Second World War he helped revive the German neuropsychiatric congresses and for many years presided over the German Society of Neurology and Psychiatry. In 1933 he left the International General Medical Society for Psychotherapy for political reasons and, according to the record, afterwards signed the pledge of loyalty to Hitler made by German university professors, a chapter that still weighs on his legacy.

His major book, Physique and Character, set out a classification of body types (asthenic, athletic, pyknic and dysplastic) and linked them with temperaments. He observed that manic-depressive psychosis appeared mostly in pyknic people and schizophrenia in asthenic people, and distinguished cyclothymic from schizothymic temperaments. In medical psychology he described hyponoic and hypobulic mechanisms, and in psychiatry he helped redefine sensitive paranoid delusion. Other works include Medical Psychology and The Psychology of Men of Genius.

His studies inspired later researchers such as William Herbert Sheldon. Today psychiatry accepts some of his descriptions, but it firmly questions whether the link between body type and mental illness is as direct as he claimed.