See also distinguish mental illness from demon possession

In general, mental illness is considered to be a disorder affecting one’s mood, thinking, and behavior. The term mental illness covers a broad range of disorders from mild depression to schizophrenia, but for the purposes of this article, we will define mental illness as a condition that impairs a person’s ability to think, feel, process, and respond to life situations in appropriate ways. Our brains are physical organs like lungs and kidneys and are subject to illness and damage just as other organs are.