Many people use cannabis to cope with anxiety. But a new study suggests that regular use of cannabis products containing a high concentration of THC, the substance's psychoactive ingredient, could lead to heightened anxiety.
The study, published on May 27 in the journal JAMA Psychiatry, looked at data from 1,087 people that was collected between June 2015 and October 2017. All study participants were from the United Kingdom, were 24 years old, and reported using cannabis in the past year.
The authors asked participants the type of cannabis they consumed most often over the past year (herbal cannabis, "strong" herbal cannabis, or resin, a cannabis concentrate that comes in a solid form). They were also asked about frequency of use and their mental health.
Those who used high-potency cannabis used it more frequently, and were more likely to have anxiety
Herbal cannabis and resin with less than 10% THC content was considered low-potency and herbal cannabis with more than 10% THC content was considered high-potency.
The researchers found that 12.8% of the study participants reported using high-potency cannabis the most often, and 87.2% used low-potency cannabis.
Men were also more likely to use the more concentrated forms of the substance.
After controlling for socioeconomic status and conditions like anxiety and depression that participants were diagnosed with prior to starting a cannabis-use habit, the researchers found that people who used high-potency cannabis were both more likely to use the substance often and more likely to have generalized anxiety disorder than low-potency users.
There were caveats to the study. The researchers relied on self-reported results and only used subjects of a specific age and demographic, so they may not be applicable to the population at large. The researcher didn't collect mental health data from non-cannabis users, so it's also possible cannabis use only correlates with anxiety, but does not cause it.
Researchers suggested limiting high-THC cannabis strains that dominate the legal market today
The researchers suggested limiting the availability of potent cannabis to prevent people from becoming dependent on the substance due to anxiety or other mental health issues.
These high-potency strains are commonplace in today's legal cannabis market.
A 2017 survey of Colorado marijuana dispensaries found their most-sold strains had between 17% and 28% THC, and THC content in marijuana increased 212% between 1995 and 2015.
