A new study from the University of Bristol is providing new insight into the likelihood of developing a psychological disorder from cannabis use. The researchers determined that high potency strains of marijuana greatly increase the risk of mental health problems.

The study showed that high-potency cannabis users are four times more likely to report mental health issues. Stronger strains of marijuana were also found to double the risk of developing an anxiety disorder compared to cannabis strains that are less intoxicating. 

“We know that people who use cannabis are more likely to report mental health problems than those who don’t use cannabis, but we don’t fully understand how recent increases in the strength and potency of cannabis affects this,” said lead author Dr. Lindsey Hines.

“This study gives us an estimate of the increased likelihood of mental health problems from use of high-potency cannabis, compared to use of lower-potency cannabis, and we are able to account for the effect that people’s early adolescent mental health symptoms may have on this relationship.”

The investigation was focused on data from a long-term health survey, Children of the 90s, which involved more than 14,000 pregnant women and their babies. The participants have continued to report on their health and development since the early 1990s. 

The current analysis is the first to examine the association between marijuana potency and coinciding mental health in a general population sample.

The design of the Children of the 90s study made it possible for the Bristol team to account for whether mental health symptoms were present before the individuals started using marijuana. The researchers also accounted for the frequency of cannabis use.

“The strength of association between the use of cannabis and mental health outcomes is increased when cannabis use is frequent; consequently, increased frequency of use may confound the association between cannabis potency and mental health outcomes,” wrote the study authors. 

Among participants 24 and older who reported using cannabis in the previous year, 13 percent had used high-potency cannabis. These individuals were more than four times as likely to have experienced recent psychological problems associated with their cannabis use.

In addition, high-potency marijuana users were twice as likely to report frequent and distressing psychotic experiences and symptoms of generalized anxiety disorder. 

“People who use cannabis are more likely to report mental health problems than those who don’t use cannabis, but reducing the potency and regularity of their cannabis use may be effective for lessening the likelihood of harms from use,” said Dr. Hines.

“In countries where cannabis is sold legally, limiting the availability of high-potency cannabis may reduce the number of individuals who develop cannabis use disorders, prevent cannabis use escalating to a regular behavior, and reduce impacts on mental health.”

“In countries like the UK, where we are not able to limit the availability of high-potency cannabis, we should make sure there is good treatment and support for those who develop problems from cannabis use.”

The study is published in the journal JAMA Psychiatry.

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By Chrissy Sexton, Earth.com Staff Writer