Psychiatry: the medical specialty devoted to the diagnosis, prevention, study, and treatment of mental disorders. These include various abnormalities related to mood, behaviour, cognition, and perceptions. People seek psychiatric help for many reasons. The problems can be sudden, such as a panic attack, frightening hallucinations, thoughts of suicide, or hearing "voices." Or they may be more long-term, such as feelings of sadness, hopelessness, or anxiousness that never seem to lift or problems functioning, causing everyday life to feel distorted or out of control.