1. The clinical and post-mortem findings in an unusual case of Cushing's syndrome are described. There existed in this patient a depressive psychosis and an extrapyramidal neurologic disorder, the overt development of both being associated temporally with that of the specific endocrine disorder. It is suggested that the etiology of the complex clinical picture observed in this case may be a neuroendocrine disorder on an encephalitic basis.2. A review of the literature reveals that mental symptoms not infrequently occur in Cushing's syndrome and that mental depression of varying degree has been a prominent feature in these psychiatric disorders. The mental symptoms may be a direct manifestation of the underlying specific endocrinopathy although the mechanism of their production remains obscure. The possibility that the form of psychiatric disorder, namely depression, in these cases bears a close relationship to manic depressive and involutional psychoses is pointed out.3. Patients hospitalized with depressive psychoses should be carefully examined for evidence of Cushing's syndrome.