Neuromuscular dysfunction in schizophrenia

Measurement of serum CPK activity in psychiatric patients may occasionally be of value for the differential diagnosis of psychotic from nonpsychotic psychiatric patients. But because the duration of any increases in often brief, because those with less florid symptomatology have increases significantly less frequently than the more severely ill psychotic, and because some nonpsychotic patients may have increases caused by injections, trauma, or alcoholism, the main value of determining serum CPK activity for psychiatry may be heuristic. It has already led to studies that have demonstrated a variety of pathologic changes in the neuromuscular system of psychotics, including morphologic changes in muscle fibers and subterminal motor nerves and physiologic abnormalities in nerve conduction velocity and spinal cord reflex mechanisms. Other techniques for investigating the spinal cord, motor nerves, and muscle fibers should be employed in the study of psychotic patients and may yield further information about the extent of involvement of the neuromuscular apparatus in psychosis. Collectively, these studies contribute to the evidence for an organic component of the major psychoses. Perhaps, they will also provide significant insight into the causes of the major psychoses as well. It is possible that the causes of the neuromuscular dysfunction may be related to the causes of the psychoses themselves. Conceivably, determining the causes of the neuromuscular dysfunction can be useful to test current theories of the etiology of the schizophrenic and affective psychoses or to generate new hypotheses.