A recent study shows , schizophrenics treated with clozapine and olanzapine may be at an increased risk for developing type 2 diabetes. Patients taking these antipsychotic agents resisted insulin and had impairment of glucose effectiveness compared with patients taking another drug under study.

Researchers evaluated 36 non-obese people with schizophrenia or schizoaffective disorder who were treated with clozapine (Clozaril), olanzapine (Zyprexa, Zydis), or risperidone (Risperdal). The participants followed a certain diet to maintain body weight and fasted before having a glucose tolerance test. Schizophrenics were found to have a much shorter life expectancy than the general population attributable to many factors, including cardiovascular disease.

Thus researchers conclude, that psychiatrists and primary care professionals should be aware that patients treated with clozapine and olanzapine may be at increased risk for insulin resistance, even if not obese and patients treated with these agents should be routinely screened and counseled to reduce risk, and provided early interventions.