How Antipsychotic Drugs Influence Weight Gain

An in-depth scientific study indicates the primary mechanism through which antipsychotic medication can influence processes such as weight gain, overeating and resistance to insulin, among others.

Scientists have determined that a number of widely used drugs from this class tend to lower the temperature of the human body, leading to a host of unpleasant effects. The team says that more work is needed in order to understand the intricacies of this mechanism in more detail.

Dutch investigators decided to focus their attention on the atypical antipsychotic drug olanzapine, which is sold in the United States under the brand name Zyprexa. The US Food and Drug Administration (FDA) approved this chemical for the treatment of bipolar disorder and schizophrenia.

Olanzapine is known to cause a host of side-effects in both human clinical trials, and in assessments carried out on experimental animals in the lab. The most common manifestation of consuming the chemical are impaired blood sugar levels and weight gain.

“Our research group believes that reduced body temperature is the foremost direct and consistent effect of olanzapine in humans and in experimental animals,” explains researcher Simon Evers, who is the lead author of the new study.

“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,” he goes on to say.

The findings will soon be presented at a meeting of the Society for the Study of Ingestive Behavior (SSIB), which is the foremost society for research into all aspects of eating and drinking behaviors.

The investigation was conducted by a collaboration of researchers from the University of Groningen and PRA International, both in the Netherlands. Top Institute Pharma provided the funds needed to conduct the research, PsychCentral reports.

“The research was motivated by observations of what co-author Anton Scheurink described as 'a mysterious interaction between schizophrenia and diabetes',” a press release on the SSIB website informs.

“Their results confirmed previous findings that olanzapine induces weight gain by increasing caloric intake, but also revealed that olanzapine reduces body temperature, which contributes to decreased energy expenditure,” the statement concludes.