mental illness

mental illness Any disease that affects the central nervous system, causing disturbances of thought or behavior. Mental illnesses can be caused by genetic, metabolic, structural, infectious, or environmental causes. The term mental illness is also used to describe emotional disturbances caused by traumatic or distressing events or by poor adjustment to normal life stresses. Treatment depends on the root cause of the illness and may include use of medication, surgery (as in the case of brain tumors and some types of epilepsy), and various forms of therapy to help rebuild life skills.