The science of cannabis
As of March 2023, 21 states and the District of Columbia permit the recreational use of marijuana, according to the Congressional Research Service. Thirty-seven states and the District of Columbia allow medicinal use of marijuana, and 10 states allow “limited access to medical cannabis,” defined as low-THC cannabis or cannabidiol (CBD) oil.
THC is the main psychoactive compound in cannabis. It creates a high feeling after binding with receptors in the brain that control pain and mood. CBD is another chemical found in cannabis, but it does not create a high.
Some research suggests cannabinoids may help reduce anxiety, reduce inflammation, relieve pain, control nausea, reduce cancer cells, slow the growth of tumor cells, relax tight muscles, and stimulate appetite.
The drug also carries risks, according to Mayo Clinic. Use of marijuana is linked to mental health problems in teens and adults, such as depression, social anxiety, and temporary psychosis, and long-lasting mental disorders, such as schizophrenia.
In the worst cases, CIP can persist for weeks or months – long after a negative drug test – and sometimes does not subside at all, according to Ken Finn, MD, president and founder of Springs Rehabilitation, PC, a pain medicine practice in Colorado Springs, Colo.
Dr. Finn, the co–vice president of the International Academy on the Science and Impact of Cannabis, which opposes making the drug more accessible, said educating health care providers is an urgent need.
Studies are mixed on whether the legalization of cannabis has led to more cases of CIP.
A 2021 study found that experiences of psychosis among users of cannabis jumped 2.5-fold between 2001 and 2013. But a study published earlier this year of more than 63 million medical claims from 2003 to 2017 found no statistically significant difference in rates of psychosis-related diagnoses or prescribed antipsychotics in states that have legalized medical or recreational cannabis compared with states where cannabis is still illegal. However, a secondary analysis did find that rates of psychosis-related diagnoses increased significantly among men, people aged 55-64 years, and Asian adults in states where recreational marijuana has been legalized.
Complicating matters, researchers say, is the question of causality. Cannabis may exacerbate or trigger psychosis, but people with an underlying psychological illness may also be more likely to use cannabis.
Dr. Finn said clinicians in Colorado and other states with legalization laws are seeing more patients with CIP. As more states consider legalizing recreational marijuana, he expects the data will reflect what doctors experience on the ground.
Cannabis-induced “psychosis is complicated and likely underdiagnosed,” Dr. Finn said.
Talking to teens
Clinicians outside the emergency department can play a role in aiding young people at risk for CIP. Primary care physicians, for instance, might explain to young patients that the brain only becomes fully developed at roughly age 26, after which the long-term health consequences of using cannabis become less likely. According to the CDC, using cannabis before age 18 can change how the brain builds connections and can impair attention, memory, and learning.