SERUM creatine phosphokinase (CPK) and aldolase activities are increased in many acutely psychotic patients of a variety of diagnostic types.1-3 CPK exists in three molecular forms (isoenzymes). Type I is found almost exclusively in the brain, type II in cardiac muscle, and type III in skeletal and cardiac muscle.4 Much smaller amounts are present in many tissues.5 Only the type III isoenzyme of CPK was found in the sera of psychotic patients.1,2 A number of possible causes of an increased activity in serum of type III CPK have been evaluated: orally or intramuscularly administered psychotropic medications2,6; physical activity2,7; severe emotional distress not part of a psychotic process2 weight loss2,8; hypersecretion of steroids2 or epinephrine8; and muscle tension.7 These have been considered to be not responsible for the increased serum enzyme activity in most acutely psychotic patients. Increased activity of serum
Meltzer HY, Moline R. Muscle Abnormalities in Acute Psychoses. Arch Gen Psychiatry. 1970;23(6):481–491. doi:10.1001/archpsyc.1970.01750060001001
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