It surprised the researchers who published their findings in The Journal of Studies on Alcohol and Drugs.
“We expected that persons receiving both cannabis and prescription opioids would have greater levels of involvement with alcohol and other drugs. However, that wasn’t the case,” said lead author Brian Perron, PhD, who is an Associate Professor in the University of Michigan’s School of Social Work.
The researchers examined 273 patents in the upper Midwest who were seeking medical cannabis certification or recertification at a clinic. All of the subjects had used cannabis within the past month for pain relief, and 172 (63%) of them had also taken prescription pain medications in that time period.
Prescription opioid users reported having higher levels of current pain and lower levels of physical functioning than those who did not take opioids.
Opioid users also reported cannabis was more effective at treating pain than prescription painkillers, and they expressed a desire to reduce their medication intake for pain or non-medical reasons. The majority of this group admitted to some form of opioid misuse.
“Although persons who were receiving both medical cannabis and prescription opioids reported higher levels of pain, they showed very few differences in their use of alcohol and other drugs compared to those receiving medical cannabis only,” Dr. Perron added.
About 40% of the study population reported combining alcohol and cannabis, though there was no significant difference between opioid users and nonusers. However, there was evidence of more lifetime and past 3 months’ use of alcohol and other drugs than the general population.
In examining co-occurring substance abuse of drugs such as cocaine, sedatives, and amphetamines, there was no significant difference between opioid users and nonusers.
“These data provide preliminary results that use of [prescription opioids] among cannabis users might not be a reliable risk indicator for more serious forms of drug involvement,” the researchers wrote.
They called for more longitudinal studies to provide further evidence of this finding.