20 May 2016

The press release reveals

Kelly Cosgrove, associate professor of psychiatry, radiology and biomedical imaging, and neuroscience, will receive the Wendy U. and Thomas C. Naratil Pioneer Award to examine how smoking cannabis affects the brain in women and men. As Cosgrove notes, there are differences in the ways males and females initiate use of cannabis, progress to dependence, and experience withdrawal symptoms. Her focus will be to determine the sex-specific mechanisms underlying the drug’s rewarding properties and the potential for addiction.

“Cannabis is generally thought of as a safe drug despite a substantial number of studies showing negative, potentially long‐term effects on the brain, including cognitive dysfunction and mental illness,” Cosgrove said. “Over the past 30 years, cannabis has become increasingly potent, with its major psychoactive ingredient content growing from an average of 1.5% before the 1980s to current strains that contain upwards of 25%.”

Over the last 20 years, 24 states and the District of Columbia passed laws making cannabis legal for medical or recreational use, even as it remains illegal under federal law. Moreover, cannabis is the most commonly used illicit drug in the United States, with about 22 million people reporting having used it in the previous month. While use of other drugs has declined in recent years, cannabis use has grown.

According to a 2014 national survey, 4.2 million Americans have a marijuana use disorder, defined as use that causes significant problems with health or the ability to meet responsibilities.

Cosgrove’s team has developed a way of using a type of brain scan to show sex differences in the neurochemical response to smoking a tobacco cigarette. They plan to adapt this method and scan men and women smoking cannabis, expecting to see a faster reward response in women at the brain’s suspected hub of drug reinforcement.

“Neurochemical sex differences have been documented for tobacco smoking and alcohol dependence, and we need to find out if there are sex differences in the neurochemistry of cannabis use in humans,” Cosgrove said. “We need to investigate these differences so people can understand what cannabis does to their brains and — for people who become addicted — allow for the development of gender-sensitive treatments.”