Since the Middle Ages, there were asylums which served the sole function of locking up people with severe mental illness. Among the oldest was Bethlem Royal Hospital, the first asylum for the mentally ill in England, founded in the 13th century.

The predominant treatment- if one could call it that - was based on the notion that "madness" was a disease of the physical body which could be cured by purging the individual of "melancholic humours" by inducing repeated bouts of vomiting and diarrhoea, and by bloodletting - often inadvertently killing the patients.