Cannabis use may strengthen, rather than weaken, the relationships between pain and depression and pain and anxiety, according to a US observational study.
Many patients who are being treated for opioid addiction in a medication-assisted treatment clinic use marijuana to help manage their pain and mood symptoms. But research led by Dr Marian Wilson, of the Washington State University College of Nursing found that frequent marijuana use seems to strengthen the relationship between pain and depression and anxiety, not ease it.
"For people who are using cannabis the most, they have a very strong relationship between pain and mood symptoms, and that's not necessarily the pattern you'd want to see," Wilson said. "You would hope, if cannabis is helpful, the more they use it the fewer symptoms they'd see."
The research involved 150 patients being seen at an opioid treatment clinic. Previous studies have shown that nearly two-thirds of patients receiving medication-assisted treatment for opioid addiction also have chronic pain, and many experience depression and anxiety.
About 67% of the clinic patients surveyed by Wilson and her team said they had used marijuana in the past month. "Some are admitting they use it just for recreation purposes, but a large number are saying they use it to help with pain, sleep, and their mood," Wilson said. "We don't have evidence with this study that cannabis is helping with those issues." In fact, the relationship between pain and depression and anxiety increased with the frequency of marijuana use.
In most cases, people reported they were self-medicating with marijuana, Wilson noted, yet only a small number had a medical marijuana card.
The study noted that opioid overdose rates have more than tripled in the past two decades and are now the second-leading cause of accidental death in the US. There are many questions about the relationship between marijuana use and opioid addiction and treatment – such as why opioid death rates are 25% lower in states that have legalized medical marijuana – but the primary purpose of Wilson's study was to see whether cannabis use affects the relationship between pain and depression and anxiety.
Patients believe using marijuana helps them with their symptoms, but the study's results could indicate the opposite is true for those in addiction treatment – that by strengthening the connection between feelings of pain and emotional distress, it makes it harder for them to manage their symptoms.
"The effectiveness of cannabis for relieving distressing symptoms remains mixed and requires further research," the study concludes.
Introduction: Adults in Medication-Assisted Treatment (MAT) for opioid addiction are at risk for substance use relapse and opioid overdose. They often have high rates of cannabis use and comorbid symptoms of pain, depression, and anxiety. Low levels of self-efficacy (confidence that one can self-manage symptoms) are linked to higher symptom burdens and increased substance use. The effects of cannabis use on symptom management among adults with MAT are currently unclear. Therefore, the primary purpose of this study is to examine whether cannabis use moderates the relationships between pain and negative affect (i.e., depression and anxiety) and whether self-efficacy influences these interactions.
Methods: A total of 150 adults receiving MAT and attending one of two opioid treatment program clinics were administered a survey containing measures of pain, depression, anxiety, self-efficacy, and cannabis use.
Results: Cannabis use frequency moderated the relationships between pain and depression as well as pain and anxiety. Specifically, as cannabis use frequency increased, the positive relationships between pain and depression and pain and anxiety grew stronger. However, cannabis use was no longer a significant moderator after controlling for self-efficacy.
Conclusions: Results suggest that cannabis use strengthens, rather than weakens, the relationships between pain and depression and pain and anxiety. These effects appear to be driven by decreased self-efficacy in cannabis users. It is important to understand how self-efficacy can be improved through symptom self-management interventions and whether self-efficacy can improve distressing symptoms for people in MAT.
Marian Wilson, Hannah Y Gogulski, Carrie Cuttler, Teresa L Bigand, Oladunni Oluwoye, Celestina Barbosa-Leiker, MaryLee A Roberts