It has been long known that certain antipsychotics cause so much weight gain that often led to serious complications such as heart disease and diabetes. The exact link could not be established until recently when the researchers from the Johns Hopkins School of Medicine in Baltimore found that a certain class of antipsychotics triggers an overreaction in AMPK, an enzyme in brain cells that controls appetite.

They are suspecting that histamine may be to blame for the weight gain in patients taking these specific drugs.

In order to prove their theory, the researchers injected mice with clozapine. It is a drug usually prescribed to patients with schizophrenia and bipolar disorders. The drug caused AMPK levels to quadruple in the mice during the study.

They went further on and managed to establish a link between a histamine receptor, clozapine, AMPK activity and appetite. When the mice that had lacked histamine receptor got injected with clozapine, they showed no increase in AMPK activity.

The connection made between histamine receptor and appetite control gives hope for finding a newer generation of drugs without the weight-gain side effects as well as drugs that would suppress appetite safely.