A Longitudinal Study of Psychosis due to a General Medical (Neurological) Condition: Establishing Predictive and Construct Validity

A sample of 44 patients with a neurological disorder and a DSM-IV diagnosis of Psychosis due to a General Medical Condition were followed on average for 4 years and their response to treatment and clinical course noted. Outcome was more benign than in schizophrenia, with most patients having a brief duration of psychosis and good response to small doses of neuroleptics. One-fourth of patients suffered a single, brief psychotic episode with return to full premorbid function. None required maintenance neuroleptic treatment. The outcome and descriptive profile of the disorder also differed from late-onset schizophrenia. Thus, Psychosis due to a General Medical (Neurological) Condition does appear to have predictive validity. However, no temporal association was found between the neurological illness and psychosis. Possible reasons for this are discussed.