The term "psychiatric" is defined by Dorland's Medical Dictionary as:
Pertaining to or within the purview of psychiatry—the branch of medicine, which deals with the study, treatment, and prevention of mental disorders.
The American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV) outlines the criteria by which specific mental disorders are diagnosed and is the main diagnostic reference tool used by mental health practitioners in the US, today. According to the DSM-IV, a mental disorder is:
A clinically significant behavioral or psychological syndrome or pattern that occurs in an individual and that is associated with present distress (a painful symptom) or disability (impairment in one or more important areas of functioning) or with significantly increased risk of suffering death, pain or disability.