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
Founder Carolyn Halpin-Healy started the program in 2009 using art to help provide positivity and community for people struggling with mental illness.
—
Cindy Hsu, CBS News, 3 Apr. 2026
Melendez, whose defense team stated has a history of mental illness, reported KOMO News, was ordered to undergo mental health evaluations during his arraignment on Tuesday, March 31.
—Julia Gomez, USA Today, 3 Apr. 2026
The psychiatric facility provides services for severe mental illness, behavioral and emotional problems for children 13 to 17 years old.
—Laura Tillman, Hartford Courant, 2 Apr. 2026
Since mental illnesses can be linked to genetics, relatives of patients with schizophrenia and bipolar disorder were also invited to participate in a study funded by India’s Cognitive Science Research Initiative’s Department of Science & Technology.
—IEEE Spectrum, 2 Apr. 2026
See All Example Sentences for mental illness
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Cindy Hsu, CBS News, 3 Apr. 2026
Melendez, whose defense team stated has a history of mental illness, reported KOMO News, was ordered to undergo mental health evaluations during his arraignment on Tuesday, March 31.
—Julia Gomez, USA Today, 3 Apr. 2026
The psychiatric facility provides services for severe mental illness, behavioral and emotional problems for children 13 to 17 years old.
—Laura Tillman, Hartford Courant, 2 Apr. 2026
Since mental illnesses can be linked to genetics, relatives of patients with schizophrenia and bipolar disorder were also invited to participate in a study funded by India’s Cognitive Science Research Initiative’s Department of Science & Technology.
—IEEE Spectrum, 2 Apr. 2026
See All Example Sentences for mental illness
Cite this Entry
“Mental illness.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mental%20illness. Accessed 5 Apr. 2026.
Copy CitationMedical 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
Ellen L. Bassuk, Scientific AmericanCatatonia 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
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
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
Barbara M. Swanson, Careers in Health Care
Love words? Need even more definitions?
Merriam-Webster unabridged
