Abstract

Background: Abnormalities in glucose metabolism were noticed in schizophrenia patients even before the era of antipsychotics. Studies have also found development of new onset diabetes mellitus in patients treated with antipsychotics. The current study was conducted to assess insulin resistance in schizophrenia patients receiving typical or atypical antipsychotics, as well as, those who were not taking any antipsychotic drug.
Method: In this cross sectional study, conducted in a tertiary referral centre, 120 male patients with diagnosis of Schizophreina, Schizotypal and Delusional disorders (ICD-10 DCR), were divided into three groups: those who were receiving typical antipsychotic (haloperidol, chlorpromazine) (N=37), those who were receiving atypical antipsychotic (olanzapine, clozapine, risperidone) (N=43) and those who were not receiving any antipsychotic (N=40) for a period of at least three months preceding the study. Patients were assessed for fasting plasma glucose, fasting serum insulin and the level of insulin resistance.
Results: Patients in the groups receiving antipsychotics (typical or atypical) were found to have higher level of insulin resistance and fasting serum insulin in comparison to those not receiving any antipsychotic (p=0.009). The mean value was highest in those treated with risperidone. However, the difference in fasting glucose was not significant.
Conclusion: Both typical and atypical antipsychotics are associated with higher level of insulin resistance and certain atypical agents are implicated more than other antipsychotics.

Keywords: Schizophrenia; Antipsychotic; Level of insulin resistance