• Posted September 5, 2025

Self-Medicating With Weed Might Make Things Worse

Folks who start using weed to cope with anxiety, depression or pain might end up with a worse mental state than before, a new study says.

People self-medicating with marijuana had higher levels of paranoia, anxiety and depression, researchers reported recently in the journal BMJ Mental Health.

By comparison, those using weed for “fun” or “curiosity” had lower scores for paranoia and anxiety, results showed.

“Our study provides vital evidence on how the reason someone first starts using cannabis can dramatically impact their long-term health,” lead researcher Edoardo Spinazzola said in a news release. He’s a research assistant at the Institute of Psychiatry, Psychology & Neuroscience at King’s College London.

“This research suggests that using cannabis as a mean to self-medicate physical or mental discomfort can have a negative impact on the levels of paranoia, anxiety and depression,” Spinazzola said.

People using weed to self-medicate also tended to use more than those imbibing recreationally, researchers found.

For the study, researchers surveyed nearly 3,400 former and current cannabis users 18 and older living in the London area. Participants were asked the reasons for their first and continued use of marijuana, and also answered questions related to their mental health.

Each week, the average participant consumed 206 units of THC, the compound in weed that causes intoxication, researchers said. That’s roughly 10 to 17 joints a week, assuming the cannabis contained the average 20% THC concentrations found commonly in London weed.

However, people using cannabis to deal with anxiety or depression used much more weed – on average, 248 and 255 units of THC a week, respectively.

Further, people tended to demonstrate higher levels of paranoia if they first started using weed to self-medicate pain, anxiety, depression or illness, researchers found.

Most also “had average scores of depression and anxiety which were above the threshold for referral to counseling,” Spinazzola said.

Senior research Dr. Marta Di Forti pointed to real-life examples.

“My experience in clinic tells me that there are groups of people who start to use cannabis as a means of coping with physical and emotional pain,” Di Forti, a professor of drug use, genetics and psychosis at King’s College London, said in a news release.

“My research has confirmed that this is not without significant further risk to their health and well-being, and policy makers across the world should be mindful of the impact that legalization, without adequate public education and health support, could have on both the individual, as well as on health care systems more broadly,” Di Forti added.

More information

The Mayo Clinic has more on marijuana.

SOURCE: King’s College London, news release, Aug. 26, 2025