Nearly a third of people who went to the emergency room for cannabis-related problems developed a new anxiety disorder within three years, according to research published Monday.
The study, published today in That of the Lancet open access journal eClinical Medicine—said to be the most comprehensive examination to date of the relationship between cannabis use and anxiety.
Canadian researchers examined the medical records of more than 12 million people who lived in Ontario between 2008 and 2019 and who had no record of an anxiety disorder or had received treatment for one. Those who went to the emergency room for cannabis use during that period were three times more likely to be diagnosed with a new anxiety disorder – during an office, emergency room or hospital visit – within three years, he said. the study found. They were also nine times more likely to require another health care visit – an outpatient or emergency room visit, or a hospital stay – for an anxiety disorder in the future.
Young cannabis users – aged 10 to 24 and particularly males – were at particularly high risk, the researchers noted.
Does Cannabis Help or Hurt Anxiety? Expert opinions are conflicting
Scientists are unsure whether cannabis use leads to anxiety, or whether anxiety symptoms in many cannabis users are pre-existing but underdiagnosed, prompting users to attempt to self-medicate.
Regardless, the study authors cautioned against using cannabis to treat anxiety. Evidence of its effectiveness is lacking, they wrote. Additionally, its use may delay the initiation of evidence-based treatments such as prescription medications and/or therapies, or worsen symptoms.
A 2020 study published in Journal of Translational Medicine noted that THC, the main psychoactive ingredient in cannabis, increases anxiety, while CBD, a cannabis derivative that is non-psychoactive, decreases it.
An April 2023 study published in Cureo documented an increase in emergency room visits for the psychiatric effects of cannabis after Michigan legalized the drug in 2018. Nearly 20% of emergency room visits over a two-year period at an unnamed hospital in the state resulted in to a diagnosis of cannabis-induced anxiety, the researchers found.
In a 2018 note published on New England Journal of Medicine Newspaper Clock, Dr. Peter Roy-Byrne, the publication’s senior consultant editor for psychiatry, called the use of cannabis a “band-aid” strategy for those with symptoms of mood and anxiety disorders that can temporarily improve the way they they feel, but worsen the long-term results.
“Absolutely no studies suggest the use of cannabis as a viable therapeutic strategy for anxiety and depression,” he wrote. “…Continued, rather than occasional, use would likely harm therapeutic outcomes, whereas cessation or marked reduction of use to a weekly maximum would likely improve them.”