abnormal psychology

n. The study of persons whose behavior causes significant distress to them or others; the behavior’s cause is believed to be the pathological functioning of the mind. This field includes the development, classification, diagnosis, treatment, and prevention of mental disorders. The term abnormal psychology is not applied in a statistical sense to both the highest and lowest functioning persons but only to the lowest functioning ones, and so the term is usually used in a pejorative sense rather than a statistical one, causing significant confusion among laypersons.