Serum creatine kinase level in unmedicated nonpsychotic, psychotic, bipolar and schizoaffective depressed patients

Creatine kinase (CK) level was previously found to be increased in the majority of hospitalized acute psychotic patients. We aimed to asses the possible differences in CK level in various forms of depression: major with and without psychotic symptoms, of bipolar depression and schizoaffective depression. Unmedicated hospitalized patients participated: nonpsychotic major depression (n = 39), psychotic major depression (n = 23), bipolar depression (n = 23) and schizoaffective depression (n = 24). The severity of depression was assessed by the Hamilton Depression Rating Scale (Ham-D) and blood samples were collected in the morning of admission day, prior to any treatment. Ham-D yielded a significantly higher score for psychotic major depression group, compared with all other groups which showed similar score. CK serum level was significantly higher in nonpsychotic major depression than in all other forms of depression. The results indicate a biological difference between the nonpsychotic major depression and the "psychotic" cluster of depressive syndromes.