psychiatry psy·chi·a·try (sĭ-kī'ə-trē, sī-)
The branch of medicine that deals with the diagnosis, treatment, and prevention of mental and emotional disorders.
The medical science that studies and treats mental illness and mental maladjustment. Psychiatrists treat mental disorders; psychologists study mental activities, whether healthy or disordered. In the United States, psychiatrists usually hold the degree of doctor of medicine (M.D.) and may prescribe medication for their patients.