Background: Elevated serum creatine phosphokinase (CPK)MM level is frequently found in acute psychosis. Theories relate this CPKemia to psychomotor agitation and medication. We hypothesized that psychosis-related CPKemia observed in individual patients is relatively consistent.
Methods: Ninety psychotic patients were studied; 83% were schizophrenics (Brief Psychiatric Rating Scale scores > or = 40) whose serum CPKMM levels were recorded during two or more different acute psychoses. The serum CPKMM levels used were the maximal levels monitored during the beginning of each hospitalization. The last CPK measurement in a circumscribed period was defined as the index serum CPK level (IndCPK). The mean of all other individual maximal CPK measurements during other psychotic episodes was defined as the average CPK (AvgCPK).
Results: Multiple linear regression analysis showed a significant correlation of natural logarithm (Ln) of (IndCPK with Ln(AvgCPK), as well as with gender (coefficient = .65 and .63, p < .0001 and p < .01, respectively). There were significantly higher IndCPK levels among male patients than among female patients (p < or = .001). A relatively consistent individual pattern of serum CPKMM levels during repeated acute psychotic episodes was observed.
Conclusions: Serum CPKMM levels and gender were found to be good predictors of maximal serum CPKMM levels during every repeated acute psychotic episode. High IndCPK levels are probably risk factors for neuroleptic malignant syndrome.