Is cannabis use feeding anxiety disorders? Young men especially at risk, study says

While cannabis is generally considered a calming drug, a recent study found heavy use could have the opposite effect — potentially worsening anxiety and associated disorders.

The large-scale Canadian study, published Feb. 5 in The Lancet’s journal eClinicalMedicine, analyzed the health records of more than 12 million people in Ontario from 2008 to 2019, none of whom had previously received care or treatment at a hospital due to anxiety.

“Our findings … suggest both an association between cannabis use and the risk of anxiety disorders as well as with the severity of anxiety symptoms,” researchers said.

“These findings have important clinical and policy implications given the increasing use of cannabis over time and trend towards legalization of cannabis.”

A Gallup poll, for example, found that 17% of Americans reported smoking marijuana, which is legal for recreational use in 24 U.S. states, in 2023, compared to 7% who said the same a decade earlier. Another 2023 poll from Gallup, meanwhile, found that 50% of Americans admitted to trying marijuana at least once in their lives, while just 38% said the same in 2013.

Out of 12 million people recorded in the study, records showed nearly 35,000 visited emergency rooms because of cannabis.

Within three years, more than 12% of those 35,000 people were back in the ER for an anxiety disorder — despite having no previous anxiety-related incidents on their medical records, according to researchers. If outpatient visits for anxiety are included, the number is much higher, at 27.5%.

In other words, these people were almost four times more likely to be diagnosed with a new anxiety disorder, the study said.

The risk isn’t equal across the board, researchers said. Young people, and young men in particular, were more likely to be diagnosed with an anxiety disorder within the three year period.

“For example, amongst individuals aged 10–18 years, the increased risk … relative to the general population was almost double in men compared to women,” the study said.

Younger age groups appear to be the most likely to consume cannabis, with the Gallup poll finding 26% of Americans ages 18 to 34 saying they smoke marijuana — compared to 18% of 35- to 54-year-olds and 11% of those 55 or above who said the same. Men across age groups were also more likely to say they smoke marijuana than women, the poll found.

Previous studies looking for a link between cannabis use and anxiety have had “mixed findings,” researchers said, but added that those studies “generally had small sample sizes” or “relied on self-reported cannabis use” instead of health records.

Researchers said they found a strong correlation, but admitted other factors could be at play, including the possibility that some individuals may have already had an undiagnosed anxiety disorder, and were using cannabis as a way to self-medicate.

It’s also possible that some were genetically predisposed to their disorder, or suffered “adverse life experiences,” which would increase their likelihood of not only developing an anxiety disorder due to trauma, but also using marijuana, the study said.

This story was originally published February 7, 2024 at 2:35 PM with the headline "Is cannabis use feeding anxiety disorders? Young men especially at risk, study says."