Serum creatine phosphokinase in acute psychosis.

Fifty-four patients suffering from a variety of psychotic states were graded by their degree of psychomotor activity. Serum creatine phosphokinase (cpk) levels were found to be related to the degree of psychomotor activity, irrespective of the diagnostic category. Retarded and withdrawn patients had normal serum CPK, but on their return to normal psychomotor activity the CPK levels tended to rise transiently. It appears that unphysiological motor activity has a more direct relationship to the rise of serum CPK than motor activity per se.