A general cover term for a number of severe mental
disorders of organic or emotional origin. In contemporary psychiatric
terminology, the defining feature of these disorders is gross impairment in
reality testing. That is, the person makes incorrect inferences concerning
external reality, makes improper evaluations of the accuracy of his or her
thoughts and perceptions, and continues to make these errors in the face of
contrary evidence. Classic symptoms include delusions, hallucinations, severe
regressive behaviors, dramatically inappropriate mood, and markedly incoherent
speech. The standard clinical literature lists as psychoses: manic-depression
(or bipolar disorder), paranoia, schizophrenia, various organic mental
disorders, pervasive developmental disorder, and some of the affective
disorders.