Marijuana smokers who experience an overwhelming urge to raid the refrigerator are responding to active ingredients in the psychoactive drug that cause the appetite-suppressive part of the brain to reverse, a new study claims.

Researchers headed by Dr. Tamas Horvath of Yale University,
activated the appetites of mice by manipulating the same
molecular pathways that regulate cannabis use in the human brain.

"We found that these neurons, under the influence of
cannabinoids, switch the chemicals that they release,"
Horvath told Live Science. Under normal conditions, the brain
cells examined in the study, known as pro-opiomelanocortin (POMC)
neurons, release chemicals that give the sensation of being full.
But when the neurons were exposed to cannabinoids, the chemical
found in marijuana, they release chemicals that induce hunger, he
explained.

Horvath compared the change to when “you’re driving your car
downhill and you push your brakes, and all of a sudden the brake
becomes the accelerator.”

"We were surprised to find that the neurons we thought were
responsible for shutting down eating were suddenly being
activated and promoting hunger, even when you are full. It fools
the brain's central feeding system."

The findings were published in the February 18
issue of Nature journal.

The research team hopes their findings may be used to find new
ways to treat the loss of appetite commonly found among cancer
patients, who experience eating disorders due to the disease
itself, or to the treatments they receive, such as chemotherapy.

Such patients may suffer from a severe type of weight loss known
as cachexia, which the medical use of cannabinoids may help
reverse.

Researchers Sachin Patel and Roger D. Cone of Vanderbilt
University Medical Center wrote in a related editorial that the
most significant part of the findings is that marijuana can alter
the brain, basically telling the body it’s still hungry even when
it is really full.