Typic and Atypic Antipsychotic Drugs: Comparison of Their Effects on Blood Sugar in Schizophrenic Patients

Antipsychotic drugs are the cornerstone of schizophrenia treatment. Glucoregulatory abnormalities have been associated with the use of antipsychotic medications. There are some reports of weight gain and glucose intolerance in patients with schizophrenia receiving atypical antipsychotic medications. The purpose of this study is to compare the effect of various antipsychotic therapies on glycemic control in patients with schizophrenia.

Eighty-one patients with schizophrenia were enrolled in the study and underwent glucose-tolerance test. Patients were divided in to two groups، with one group (n=43) receiving typical and the other group (n=38) receiving atypical medication. Demographical and historical data were collected with a questionnaire.

There was a marginally significant difference in the first hour glucose level between typical and atypical drugs (mean 132. 12 vs. 151. 76، respectively، p=0. 07). Also، marginal significant difference was present comparing the first hour glucose level between typical antipsychotics and clozapine consumers (mean 132. 12 vs. 153. 67، p=0. 06). This difference was not present when typical antipsychotics were compared with risperidone (mean 132. 12 vs. 149. 41، p=0. 230). Fasting blood sugar and second- hour glucose tolerance results did not show a statistically significant difference. The increased GTT of the first hour blood sugar in patients who received clozapin may indicate the early stages of insulin resistance in this group.

This study suggests that patients under atypical antipsychotic treatment are more vulnerable to diabetes mellitus (DM). Across atypical medications; we observed a greater glycemic effect from clozapin compared to risperidone.