Scientists have found that a widely used antipsychotic drug may influence overeating, weight gain and insulin resistance by lowering body temperature.
In the study, Dutch researchers studied olanzapine (brand name Zyprexa), an atypical antipsychotic drug approved by the FDA for the treatment of schizophrenia and bipolar disorder. Olanzapine has been associated with weight gain and impaired blood sugar levels in humans and experimental animals.
In a series of studies, researchers sought to reveal underlying mechanisms for olanzapine’s metabolic effects by studying healthy adult male volunteers. Co-author Dr. Anton Scheurink, said they sought to examine the “mysterious interaction between schizophrenia and diabetes.”
Their findings confirmed previous observations that olanzapine induces weight gain by increasing caloric intake. But it was also found to reduce body temperature, an action which contributes to decreased energy expenditure.
The finding that olanzapine treatment reduces body temperature may explain many of its side effects. The authors also found that olanzapine alters peripheral glucose metabolism, which may contribute to impaired insulin sensitivity.
According to lead author Simon Evers, “Our research group believes that reduced body temperature is the foremost direct and consistent effect of olanzapine in humans and in experimental animals.
“Reduced body temperature might explain several of olanzapine’s metabolic side effects, including increased food intake, reduced energy expenditure, sedation, high blood sugar, body weight gain, and insulin resistance.”