Medical marijuana patients tend to reduce their use of prescription opioid pain medications, according to new research.

The study, published in the Journal of Psychopharmacology, investigated whether there was a “substitution effect” for medical cannabis — meaning that people with legal access to marijuana decide to use it instead of other medications. The researchers found that patients reduced their use of opioids and a number of other types of drugs after being provided with medical cannabis.

“Among 1,500 medical cannabis patients, three-quarters that used opioids reported a reduction in their use after starting medical cannabis,” explained Brian J. Piper of Geisinger Commonwealth School of Medicine, the study’s corresponding author. “Over-two thirds also reported a reduction in anti-anxiety, migraine, and sleep medications. More broadly, there is much that doctors and biomedical researchers can learn about medical cannabis, and the conditions that it is used to treat, from patients.”

Piper told PsyPost he was interested researching the topic, in part, because of the ongoing opioid addiction epidemic.

“I was teaching neuropharmacology courses and invited Becky DeKeuster, MEd as a guest-lecturer to present about medical cannabis and its role in health care. At the same time, I was also doing pharmacoepidemiology research looking at the tremendous rates of prescription drug use and misuse. The state I was in when this project began (Maine) was, and continues to be, battling the opioid epidemic. Also, my wife is an oncology nurse and has had to find a balance between her patient’s needs and the complex legal status of medical cannabis.”

“After carefully reading what had already been done, all of these factors converged for me, and other members of the research team (including a pharmacist and two anesthesiologists) to start a research project on this timely topic,” Piper said.

The patients in the study were members of medical marijuana dispensaries in Maine, Vermont, and Rhode Island. Data was collected by sending them an online survey.

Piper told PsyPost the study had four main caveats: “It was completed in close collaboration with, and funded partially by, the marijuana dispensaries — 4 of the 9 authors have dispensary affiliations. All data was self-reported and the majority of patients had chronic pain. Also, this study (like all studies) is not conclusive, and further research is needed on this important, and quickly evolving, topic.”

“I would like to follow up this investigation using data from medical records and looking at other populations including those with post-traumatic stress disorder, alcoholics, and patients addicted to prescription pain medications,” he added.

Previous research has found that many patients would rather turn to cannabis instead of their prescribed opioid medication to treat pain.

“The finding that medical cannabis patients reduce their use of opioid-type medications has been shown many, many times using various methodologies including patient surveys and epidemiological studies (e.g. decreased rates of opioid overdoses in states that have legalized medical cannabis),” Piper explained. “This repeatedly replicated result is supported by basic science studies in rats and mice which show a cross-talk between the brain’s opioid and cannabinoid neurotransmitter systems. The most novel part of this study was that this substitution effect may also apply to other classes of medications.”

Piper and his colleagues also found that a patient’s friends and family were more likely to know about their use of marijuana than their primary care provider. More than one in seven patients had not told their primary care provider about their medical cannabis use.

“There is currently a stigma associated with medical cannabis,” Piper told PsyPost. “Patients, doctors, and pharmacists need to do a better job of regularly and openly discussing this topic. This is especially important if patients are considering discontinuing a prescribed medication like an antidepressant or an antianxiety drug.”

“From a biological standpoint, medical cannabis is a drug. The principles of pharmacology regarding dosage, potential interactions with other drugs, risks and benefits apply to medical cannabis just like they would with any other substance. Rather than view this topic from only a social or cultural viewpoint, this broader perspective may be helpful, especially as new information continues to be obtained about medical cannabis.”

The study, “Substitution of medical cannabis for pharmaceutical agents for pain, anxiety, and sleep“, was also co-authored by Rebecca M DeKeuster, Monica L Beals, Catherine M Cobb, Corey A Burchman, Leah Perkinson, Shayne T Lynn, Stephanie D Nichols and Alexander T Abess.