Among the skin diseases that have been of interest to both dermatology and neuropsychiatry, exclusive of the entities commonly called psychosomatic, are syphilis, adenoma sebaceum, neurofibromatosis, and the Sturge-Weber syndrome.1 We would like to add Darier's disease (keratosis follicularis) to this list. Since brain and epidermal tissue are both derived from ectoderm, some of the intrinsic pathological processes that are not influenced by exogenous factors may involve both organ systems. If the hypothesis has some degree of validity we might then expect to find some organic involvement in the central nervous system in certain dermatological disease states. We reviewed the records at the University of Illinois since 1940 and at the Veterans Administration Hospital, Hines, Ill., since 1950, and found a total of 6 cases of keratosis follicularis proven by biopsy. We were able to study 5 of these patients both dermatologically and psychologically. Report of Cases Case 1.—A