Muscle Abnormalities in Acute Psychoses

SERUM creatine phosphokinase (CPK) and aldolase activities are increased in many acutely psychotic patients of a variety of diagnostic types.¹⁻³CPK 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.⁴Much smaller amounts are present in many tissues.⁵Only the type III isoenzyme of CPK was found in the sera of psychotic patients.¹,²A 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 process²weight loss²,⁸; hypersecretion of steroids²or epinephrine⁸; and muscle tension.⁷These have been considered to be not responsible for the increased serum enzyme activity in most acutely psychotic patients. Increased activity of serum