Adults who use opioids for chronic pain often use marijuana too, believing it helps them sleep better or provides more pain control, according to a study recently published in Nursing Outlook.

Other participants reported perceived adverse effects from their cannabis use, such as weight gain, a lack of concentration, and high cost.

The study was led by Teresa Bigand, who was awarded a doctoral degree from the WSU College of Nursing in May. Bigand’s co-investigators were doctorate candidate Cristina Lee Anderson, Research Associate Mary Lee Roberts, Associate Professor Michele Rose Shaw, and Assistant Professor Marian Wilson, senior scientist on the project, all of the WSU College of Nursing.

The study’s 150 participants were enrolled through three pain management clinics in Washington. Their ages ranged from 19 to 85, and the average amount of time they had been taking prescription opioids for pain was about six years.

About 70 percent of the participants told researchers they have used cannabis, with a third reporting they’d used it within the past month. Only 11 percent were registered medical marijuana patients at the time.

The number of participants who said they’d used cannabis wasn’t surprising, given other studies that have reported similar numbers, Bigand said. But, “we were surprised to see that so few participants had current medical marijuana cards, meaning that a majority of cannabis users were likely using without medical supervision or oversight,” she said.

The biggest reason cited for using marijuana was pain relief, at 67 percent. About 58 percent of participants said cannabis helps them sleep, though the study notes “there is little corroborating evidence in literature that cannabis can actually improve sleep.” And about half those surveyed said they use cannabis for recreational purposes, in addition to other perceived benefits or adverse effects.

Participants said cannabis use both helps and hurts their mental health, with some saying it reduces anxiety, while others said it increases anxiety and paranoia. And the cost was a real concern; 56 percent of those surveyed have household income of under $20,000 a year. Said one participant, “I am low-income and it’s (cannabis) kind of expensive so I don’t do it often. Only on really bad days.”

Bigand said the research is important given the growing number of states legalizing recreational use of marijuana. Health care professionals need to understand why their patients might be using cannabis, and build trusting relationships that allow them to discuss cannabis with their patients.

“So little is known about the short- and long-term effects of cannabis use, especially in conjunction with medications such as opioids,” she said. “Patients should be cautioned that while there is potential for positive benefits, there may also be negative aspects of that use that should be considered and shared with the healthcare provider.”

Media contact: