CHICAGO — People who smoke marijuana to calm their nerves take heed: Low levels of tetrahydrocannabinol (THC), the main psychoactive ingredient found in cannabis, can reduce stress, but high levels of the compound do the opposite, a new study finds.
Scientists from the University of Illinois at Chicago and the University of Chicago studied 42 healthy volunteers 18 to 40 years old who’ve used marijuana previous, but don’t consider themselves daily users. Patients were divided into three groups — one group that took a pill containing a small dose of THC, another that took a pill with higher levels of THC, and a control group that took a placebo.
“The doses used in the study produce effects that are equivalent to only a few puffs of a cannabis cigarette,” says Emma Childs, associate professor of psychiatry at UIC and author of the study, in a press release. “We found that THC at low doses reduced stress, while higher doses had the opposite effect, underscoring the importance of dose when it comes to THC and its effects.”
Though it is common to associate marijuana use with lowered stress, Childs says there aren’t many scientific studies that back up that claim.
The researchers reached their findings by running a series of experiments where they placed the research participants in different social situations — such as a mock job interview or playing a game — and gave them varying doses of THC or a placebo. To help rattle nerves, they were also told to pick a five-digit number and count backwards by thirteens — a tool that’s known to induce stress.
The results showed that those who took 7.5 milligrams of THC reported less stress after taking a psychosocial test than those who were given a placebo, while those who received 12.5 milligrams reported greater negative mood both before and after the test.
Participants who took the higher dose also reported taking more pauses during their mock interviews.
“Our findings provide some support for the common claim that cannabis is used to reduce stress and relieve tension and anxiety,” says Childs. “At the same time, our finding that participants in the higher THC group reported small but significant increases in anxiety and negative mood throughout the test supports the idea that THC can also produce the opposite effect.”
The tests showed no effect on heart rate or blood pressure before, during, or after the tasks.
The study is published in the journal Drug and Alcohol Dependence.