Colorado State University Study Shows Marijuana May Not Help Depression

The medicinal uses of marijuana span a wide variety of diseases and disorders, but a recent study conducted by Colorado State University indicates that cannabis may not be as useful for treating depression and anxiety.

In December 8, researchers in the Department of Psychology at Colorado State University published a study regarding the relationship between marijuana use and depression and anxiety in study participants. Led by professor Lucy Troup, a cognitive neuroscientist at CSU, the study focused on the residual effects of marijuana over time on three groups of students — casual users, chronic users and non-users — and observed how individuals assessed their levels of depression and anxiety.

“A large number of people who use cannabis medically say they use it for psychological disorders — depression and anxiety being two classic examples of this,” Troup says. “I wanted to find out if it really helps these. And it doesn’t, I don’t think."

Using three examination tools — the Recreational Cannabis Use Examination (R-CUE), the Center for Epidemiologic Studies Depression Scale and the State-Trait Anxiety Inventory — Troup and her team of graduate students evaluated 178 participants. The results indicated that the residual effects of marijuana appeared to be counterproductive to aiding in depression and anxiety treatment. In fact, many of the participants who claimed to use marijuana to treat their depression or anxiety were found to have misconceptions of how helpful marijuana actually was.

“I don’t want to demonize cannabis, but at the same time I don’t want to glorify it," says Troup. "I wish people would say, ‘I like getting high, and that’s why I do it.' I mean, marijuana does more, perhaps, for anxiety than depression, but it isn't necessarily a cure-all for those things, and in fact, it can increase those behaviors, especially in young people."

Troup’s research goes against the grain of popular consensus, as well as other research published within the past five years. In February 2015, for example, neuroscientists at the University of Buffalo’s Research Institute found that marijuana may be useful in treating depression caused by chronic stress. But according to Troup, opposing results from various studies is common because of the lack of research on cannabis and its effects.

“It absolutely has potential for things like helping anti-inflammatory, or helping people with their appetite, but I can guarantee you that for every paper and bona fide study that says it’s good for something, there’s another one that says it has the opposite effect,” she notes.

And not much work has been done on the psychological and emotional effects of marijuana on users. A majority of the Colorado Department of Public Health and Environment's research grants approved in 2015 focused on specific diseases, disorders and cancers, but few concern themselves entirely with the psychological effects of marijuana use.

“There’s so much more research needed, and if you look at the neuro side of it, we have no idea how [marijuana] affects the brain," Troup says. "We are only just starting to understand how it affects the brain at the level of neurotransmission."

The study, which was published through PeerJ, followed an earlier study by Troup that looked into the residual effects of marijuana on users' ability to process emotions. And it won't be the last study done: Troup and her team of graduate students are now conducting more marijuana research, including the effects on learning and exposure to concentrates and hash oils.

"We want to study these effects on the brain and gain a better understanding of how marijuana really works," Troup says.
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