Comparative effects of clozapine and risperidone monotherapy on levels of immunoglobulins in patients with schizophrenia – A 12 weeks' longitudinal study

Background: Schizophrenia is among the most puzzling yet disabling of all brain diseases. The finding of immunity-related genes seems to vindicate theories about the involvement of neuroimmunological processes in the pathogenesis of schizophrenia. Moreover, antipsychotics used in the treatment of schizophrenia have been shown to have effects on serum immunoglobulin levels. Aim: The aim of this study was to assess and compare the effect of risperidone and clozapine on the immunoglobulins at 6 weeks and 12 weeks in patients with schizophrenia and its clinical correlation. Materials and Methods: It was an open-label, randomized, comparative, and prospective study. Patients with International Classification of Diseases-11th Revision diagnosis of schizophrenia who were not on any antipsychotic drug for more than 2 weeks, were randomized to two groups, i.e., A (risperidone) and B (clozapine) after baseline assessment of sociodemographic and clinical parameters on the Positive and Negative Syndrome Scale (PANSS). Baseline blood investigations (complete hemogram, liver and renal function tests, lipid profile, and fasting blood sugar) and immunoglobulin estimation were done. Patients were followed at 6 weeks and 12 weeks and levels of immunoglobulin were reassessed at 6 weeks and 12 weeks along with PANSS and Glasgow Antipsychotic Side-Effect checklist. Results: A total of 32 patients were inducted into the study – 16 in the risperidone group and 16 in the clozapine group. There was no statistically significant difference in terms of the duration of illness or period of exacerbation between the two groups though the baseline total PANSS score was significantly higher in the clozapine group. In both the groups, there was no statistically significant difference in the baseline immunoglobulin levels at baseline and over 12 weeks in terms of the immunoglobulin G (IgG), IgM, and IgE levels. Within the clozapine group, a significant difference over 12 weeks was noted in IgG level. Conclusion: It can be concluded from the index study that the immunoglobulin levels in the patients with schizophrenia do not differ much concerning the effect of risperidone and clozapine. Clozapine is associated with a significant increase in IgG levels indicating the immunologic response of clozapine in schizophrenia.