► crazy mentally ill: I feel so alone, sometimes I wonder if I’m going crazy. She was acting crazy, and we were worried.
► mentally ill having an illness of the mind that affects the way you behave: Her father had been mentally ill and spent time in a psychiatric hospital.
► unstable having an emotional state that changes very suddenly: Her mother was mentally unstable and could not keep a job.
► disturbed not behaving in a normal way because of mental or emotional problems: Susan teaches in a program for emotionally disturbed children.
► insane seriously and usually permanently mentally ill: A psychiatrist said that he was insane at the time of the crime.
► demented crazy or very strange: His demented fantasies involved killing other people.
► psychotic formal relating to having a serious mental illness: His family was frightened by his psychotic behavior.