In psychiatry, deterioration denotes a progressive impairment or decline of intellectual and personality functions such as memory, reasoning, concentration, communication, and emotional response.The deteriorated patient gradually loses his ability to think clearly, express himself coherently, recall events (especially recent events), make decisions, and solve problems. His condition may degenerate into severe dementia, in which he becomes confused and disoriented. Along with the loss of intellectual functions there is usually an emotional deterioration, characterized by such symptoms as apathy, shallowness of affect, lability (emotional instability), and inappropriate response.Mental deterioration may be due to brain pathology, as in cerebral arteriosclerosis, toxic conditions, senile brain disease, and cerebral tumors. It may also be functional in origin, as it is believed to be in chronic, advanced schizophrenia. The term “deteriorative psychosis” is sometimes applied to disorders in which progressiveimpairment of mental functions takes place. In many cases, particularly the organic conditions, the deterioration is considered permanent. Recent studies, however, have indicated that irreversible changes occur less frequently in deteriorated schizophrenics than had been assumed. In reports by Foulds and Dixon, Lubin et al., and Griffith et al., published in 1962, there was no definite evidence of permanent deterioration among schizophrenic patients when they were given standardized psychological tests.