Distinctions between organic brain syndrome and functional psychiatric disorders: based on the geriatric mental state interview.

Discriminant function analysis was employed to study the ability of the Geriatric Mental Status interview to distinguish between patients diagnosed by the project as having an organic brain syndrome or a functional psychiatric disorder. In both New York and London, patients with organic brain syndrome scored significantly higher (p less than 0.05) than those with functional disorders on the factors of impaired memory, disorientation and incomprehensibility and significantly lower on the factors of depression and somatic concerns. Discriminant functions calculated from data on the New York and London patients separately significantly distinguished not only the patients on whom the functions were based but the patients in the other sample as well.