Subterminal motor nerve abnormalities in psychotic patients

THERE is considerable evidence of neuromuscular dysfunction in most patients with all types of the functional psychoses. Examples of such dysfunction are (1) increased activity of skeletal-muscle-type creatine phosphokinase (CPK) in serum in the acute stage of psychosis^1-4; (2) abnormally large increases in serum CPK activity with a standardised exercise test performed by patients in symptomatic remission⁵; (3) morphological abnormalities in skeletal muscle fibres at biopsy, particularly scattered atrophic fibres and extensive areas of Z-band streaming^6-8; and (4) abnormalities of eye movements in tracking a pendulum⁹. The skeletal muscle fibre abnormalities found in psychotic patients are likely to be neurogenic in origin¹⁰.