mental illness

noun

variants or mental disorder or less commonly mental disease
: 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
mentally ill adjective

Examples of mental illness in a Sentence

Recent Examples on the Web Rooms average $400 a month, but because they’re not directly subsidized with homeless housing vouchers, Abode chooses its own tenants and there are fewer with severe addiction and mental illness. Liam Dillon, Los Angeles Times, 19 Mar. 2024 The Tempe Democrat said his family petitioned for involuntary treatment for his younger brother, who was diagnosed with severe mental illness and developed a drug addiction. The Arizona Republic, 13 Mar. 2024 Later, in 2020, the developer, Affirmed Housing, secured a $10 million, zero-interest construction loan from San Diego County’s No Place Like Home program that required the project to include housing for people with severe mental illness. Phil Diehl, San Diego Union-Tribune, 13 Mar. 2024 About 181,000 people were considered homeless in the state's 2023 count, and most are suffering from drug addiction or mental illnesses. Jamie Joseph, Fox News, 11 Mar. 2024 The report referenced health records that said Hart has a history of severe mental illness, which includes delusional ideations, hyper-religious beliefs, aggressive conduct and paranoia. Elliot Hughes, Journal Sentinel, 7 Mar. 2024 The show is doing a good job of highlighting stigma, which actually ends up de-stigmatizing mental health and mental illness. Joan MacDonald, Forbes, 28 Feb. 2024 More than 50% of the homeless have severe mental illness and/or substance use disorder issues. Letters To The Editor, The Mercury News, 27 Feb. 2024 Within their rural, predominantly masculine culture that values stoicism and self-sufficiency, mental health and mental illness remain heavily stigmatized. Sophia Liang, The Courier-Journal, 27 Feb. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'mental illness.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1724, in the meaning defined above

Time Traveler
The first known use of mental illness was in 1724

Dictionary Entries Near mental illness

Cite this Entry

“Mental illness.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mental%20illness. Accessed 28 Mar. 2024.

Medical Definition

mental illness

noun
variants or mental disorder also mental disease
: 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
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
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
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

Legal Definition

mental illness

noun
mental ill·​ness
1
2
: a mental condition marked primarily by sufficient disorganization of personality, mind, and emotions to seriously impair the normal psychological and often social functioning of the individual

called also mental disorder

More from Merriam-Webster on mental illness

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!