From Longman Dictionary of Contemporary Englishmentally illˌmentally ˈill adjective having an illness that affects your mind and your behaviourTHESAURUSmentally ill having an illness that affects your mind and your behaviourMany mentally ill people are treated in the community.He was declared mentally ill and unfit to stand trial.crazy informal mentally illI couldn’t think straight. I felt like I was going crazy (=becoming crazy).mad old-fashioned mentally ill. This word is now usually considered offensive, and is usually used in a different meaning, when you think that someone’s ideas are not sensibleSwift himself went mad (=became mad) later in life.a mad old womaninsane [not before noun] old-fashioned having a serious and permanent mental illnessShe went insane after her two young sons were murdered.a hospital for the criminally insanedisturbed not behaving in a normal way because of mental or emotional problems, especially problems that are caused by bad experiencesShe teaches emotionally disturbed children.Her experiences left her deeply disturbed.unstable having an emotional state that often changes very suddenlyHer mother was mentally unstable.He lived in a small Putney flat with his ageing Aunt Bunny, and his emotionally unstable sister, Nancy.He was too unstable to be a leader. deranged behaving in a crazy or dangerous way, usually because of being mentally illA deranged young woman entered the school and took the life of one young boy.psychopathic having a serious and permanent mental illness that causes violent or criminal behaviourThe film is about a psychopathic killer.psychotic suffering from or caused by a serious mental illness that changes your character and makes you unable to behave in a normal waypsychiatric services for chronic psychotic patients.There is a tendency for psychotic illnesses to be inherited.neurotic relating to or suffering from a mental illness that makes you unreasonably worried of frightenedHis mother was neurotic and insecure.She’s neurotic about her weight.A bored or lonely horse may become so neurotic that it chases itself around in circles.
