Medical Dictionary

mental illness


Medical Definition of mental illness

  1. :  any of a broad range of medical conditions (such as major depression, schizophrenia, obsessive compulsive disorder, or panic disorder) that are marked primarily by sufficient disorganization of personality, mind, or emotions to impair normal psychological functioning and cause marked distress or disability and that are typically associated with a disruption in normal thinking, feeling, mood, behavior, interpersonal interactions, or daily functioning <Some homeless families are also hindered by substance abuse and mental illness.—Ellen L. Bassuk, Scientific American, December 1991> <Catatonia is usually an expression of mental disorders like bipolar disorder or schizophrenia, but it could also come from other medical problems, such as a brain tumor.—Forrest Wickman, The Pittsburgh Post-Gazette, 31 May 2012> <… mental diseases such as schizophrenia and manic depression may either involve more than one gene or may result from a complex mix of genetic predisposition and environmental rotten luck.—Natalie Angier, The New York Times Book Review, 12 Aug. 1990>

mentally ill

adjective <mentally ill patients> <Mental health workers … perform a wide variety of therapeutic, supportive, and preventative functions for persons who are mentally ill and developmentally disabled.—Barbara M. Swanson, Careers in Health Care, 1989>

Variants of mental illness


mental disorder


mental disease

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