MILWAUKEE — Chronic pain patients who used both prescription opioids and recreational marijuana showed higher levels of mental health and substance abuse problems than those who used opioids alone, survey results presented here showed.
Anxiety and depression scores were significantly higher for patients who used both drugs, as were measurements of opioid-dependence severity and alcohol and cocaine involvement, reported Andrew Rogers, of the University of Houston, and colleagues, at the 2019 American Pain Society Scientific Meeting.
“The things psychologists would be most worried about were worse, but the thing patients were using the cannabis to hopefully help with — namely pain — was no different,” Rogers said.
“This study provides further evidence that cannabis may not be an effective substitute or alternative to opioids for pain management,” added Abhiram Bhashyam, MD, MPP, of Massachusetts General Hospital in Boston, who was not involved with the research.
“Studies like these are important for clinicians as patients increasingly ask about opioid-cannabis co-use for managing their pain,” he told MedPage Today. “We lack robust evidence to provide appropriate guidance due to a paucity of research on this topic at present.”
In a 2018 study, Bhashyam and colleagues looked at cannabis-opioid co-use in acute pain patients after traumatic musculoskeletal injury and found that marijuana use during recovery was associated with increased quantity and duration of opioid use.
For their study, Rogers and colleagues surveyed people with moderate to severe chronic pain through Qualtrics, an online survey company, in the summer of 2018. They screened individuals in an online panel and invited them to participate in a confidential survey, classifying people who reported using recreational cannabis in the past 3 months as cannabis users.
All participants (n=450) currently used opioids for pain, and had current chronic pain that persisted for at least 3 months and pain levels that were moderate to severe during the past 4 weeks. Most participants were female (75%) and white (79%); their average age was 39. Nearly four in ten (39%, or 176 respondents) reported using recreational cannabis in the past 3 months in addition to opioids.
More women than men reported opioid use only, and people who reported opioid use only were significantly older. Compared with opioid use alone, opioid and cannabis co-use was associated with elevated anxiety and depression symptoms, as well as opioid, tobacco, alcohol, cocaine, and sedative use problems (all P<0.001), but not pain severity (P=0.20) or pain disability (P=0.13). The magnitude of effects for all substance-related variables was medium-to-large, and small-to-medium for anxiety and depression.
“There may be no effect from cannabis on pain combined with opioids,” Rogers noted. While this study provides novel assessment and intervention targets for this population, these individuals may be more difficult to treat for their pain and other problems, he added.
“These results are not surprising and indeed replicate other studies showing that cannabis use by pain patients is associated with higher doses of opioids and no pain relief benefits,” observed Keith Humphreys, PhD, of Stanford University in California, who was not involved in the study.
Previous research by Humphreys and colleagues showed that people who used medical cannabis also had higher rates of opioid use and misuse. “This is one of many examples where claims about the benefits of medical cannabis are not supported by evidence,” Humphreys told MedPage Today.
The current study had several limitations: it relied on cross-sectional, self-reported data and was subject to possible selection bias and confounding. It also did not assess the frequency or quantity of cannabis or opioid use, or the type of chronic pain.
Rogers disclosed no relevant relationships with industry.