Cannabis products high in CBD are more effective at reducing anxiety than THC-dominant alternatives — and carry a lower side effect burden — according to new research out of the University of Colorado Boulder.
The randomised trial looked at how legal, commercially available cannabis products in the US affect people living with anxiety. Researchers enrolled 300 participants with the condition, 258 of whom had prior experience with cannabis. The other 42 had never used it.
Those in the cannabis-using group were each assigned one of three flower varieties — THC-dominant (24% to 1% CBD), CBD-dominant (24% to 1% THC), or balanced (12% to 12%).
Throughout the four-week study, participants were free to use their assigned product as often and in whatever quantity they wished, with the typical usage averaging three times a week. A mobile laboratory was brought to each participant's home, where researchers conducted assessments both before and immediately after cannabis was smoked.
By the end of the trial, all four groups — including non-users — reported lower anxiety levels. However, the cannabis groups experienced greater reductions overall, and participants using CBD-dominant products showed the most pronounced improvement.
Those in the CBD-dominant group did not report feeling cognitively impaired, yet they did notice a reduction in tension right after smoking. They were also less likely to experience paranoia immediately following use compared to participants in either of the other two cannabis groups.
Anxiety is among the top three reasons American adults report turning to cannabis for medical purposes, alongside sleep and pain management, yet the evidence on its effectiveness for treating anxiety has been inconsistent.
Senior author Cinnamon Bidwell noted that CBD has stronger anti-inflammatory properties than THC, suggesting CBD-dominant products may ease anxiety by reducing inflammation in the brain and nervous system.
Although a range of prescription medications exists for treating anxiety, many carry side effects and carry dependency risks. Bidwell also noted that early and frequent THC use can heighten the likelihood of cannabis-related harms, including problematic use patterns and cognitive impairment.
She added: "Our study suggests that CBD products may be able to relieve anxiety in the moment for adults who use them, and possibly longer-term, in a way that is meaningful and doesn't necessarily produce the same risks or harms of THC or prescription medications.
"We need more data before we can make conclusive recommendations, but this is promising news."