Abstract
A 24-year-old black woman with probable manic-depressive illness was found to have central cores in all type I muscle fibers in a biopsy of the gastrocnemius muscle and in some type I fibers in a biopsy of the vastus lateralis muscle. Both biopsy specimens were differenteated into two main fiber types. The ultrastructural changes in the cores were more profound than in other cases of central core disease. Small atrophic fibers indicative of denervation or loss of the neurotrophic influence were also present. An electromyogram had both myopathic and neurogenic features. The question of whether the etiology of the muscle abnormalities in at least some acutely psychotic patients is neuropathic or myopathic, or a mixture of both, is discussed.