Long-lasting leukocytosis in patients with schizophrenia treated with clozapine after electroconvulsive therapy: ECT stabilizes white blood cell count

INTRODUCTION: The present study was conducted to investigate the possible hematologic impact of long-term electroconvulsive therapy (ECT) in patients with drug-resistant schizophrenia and receiving clozapine therapy. SUBJECTS AND METHODS: In this retrospective study, clinical charts of 57 hospitalized patients with schizophrenia who required clozapine therapy because of active psychotic symptoms resistant to other antipsychotics were examined. For 18 who underwent ECT, the first assessment was conducted at the end of that therapy (average two months after start, 7.68 sessions) and the second two months later. As for the 39 patients who did not undergo ECT, the first and second assessment points were at two and four months, respectively, after a randomly chosen time point. RESULTS: Multiple regression analysis revealed that modified ECT (m-ECT) (ß = 0.346, p = 0.005), gender (males showed greater increase) (ß = 0.273, p = 0.023), and disease duration (longer associated with greater increase) (ß = 0.258, p = 0.033) were correlated with a change in white blood cell (WBC) count (ΔR2 = 0.277, p < 0.001) at the first assessment point. At the second assessment point, multiple regression analysis showed that m-ECT (ß = 0.262, p = 0.039), gender (males showed greater increase) (ß = 0.264, p = 0.036), and disease duration (longer associated with greater increase) (ß = 0.234, p = 0.068) were again correlated with changed WBC count (ΔR2 = 0.203, p < 0.007). DISCUSSION: An increase in leukocytes may have a protective influence against the adverse myelosuppressive effects of clozapine. However, a simple mobilization of leukocytes from bone marrow to peripheral circulation may not enhance the immune system, leading to only a masking of the effects of a potential immuno-insufficient state in the treated patient. In either case, should leukocytosis be induced and then remain for an extended period, hematologists, as well as psychiatrists involved in electroconvulsive intervention for clozapine-treated patients, must keep this factor in mind.