Cannabis has become more popular across the U.S. in recent years, but new research this month shows that one group has especially gravitated to it: people living with depression. And it’s not clear whether that’s a good thing.
The study, published in the journal Addiction, looked at over 10 years of data from a nationally representative, government-run annual survey of Americans’ drug and lifestyle habits, collectively involving more than 700,000 volunteers.
Between 2005 to 2017, the overall percentage of people who admitted to recent cannabis use (meaning in the past 30 days) rose steadily, they found. But the climb was far more pronounced among people who reported having clinical depression. While about 9 per cent of people without depression reported any amount of weed use in the past 30 days, for instance, the same was true for 19 per cent of people with depression. Seven per cent of those depressed also said they used cannabis daily, compared to 3 per cent without depression.
Studies like this can’t tell us why exactly depressed people are more likely to use cannabis, though the drug has certainly earned a reputation for mellowing people out. One key reason for the general uptick in cannabis’ popularity, the authors noted, is that people have become more likely to believe that cannabis is relatively harmless—a trend that was also greater among people with depression in their study sample.
While it’s true that cannabis isn’t as dangerous as say, alcohol, that doesn’t mean it’s harmless, especially to young people.
“As brain development is ongoing until at least age 25, and young persons with depression are especially vulnerable, this is a group who may need attention in terms of prevention and intervention,” said study co-author Renee Goodwin, a researcher at Columbia University’s Mailman School of Public Health, in a statement released by the university.
Scientifically, the evidence is very mixed on whether cannabis can help treat depression or other mental health problems. A 2018 study found that medical marijuana users experienced a short-term boost in mood, for instance, but also that the long-term use of cannabis explicitly to treat depression was linked to worsening symptoms over time.
A review earlier this year also found a link between teen cannabis use and later depression in adulthood, though these studies can only suggest a connection between two factors, not prove that one causes the other (maybe people more likely to be depressed as adults are also more likely to use cannabis, for other reasons).
Obviously, the occasional puff or edible isn’t the end of the world. But there might be reason to worry about an increase in people self-medicating as recreational cannabis use becomes increasingly legalised, the authors said.