CBD Reduced Opioid Reward and Fentanyl Intake in Female Rats
A 2023 study in Addiction Neuroscience found that inhaled, high-CBD cannabis vapor reduced several opioid-related behaviors in female rats. The preclinical study, conducted by researchers at Washington State University and Legacy Research Institute, tested a whole-plant extract containing 64.2% cannabidiol (CBD) and 7.1% tetrahydrocannabinol (THC). The control group received the vapor ingredients propylene glycol and vegetable glycerin without the cannabis extract.
The researchers examined 196 female rats, including animals with neuropathy-related pain. The extract produced modest relief from cold allodynia—a painful response to stimuli that would not normally cause pain—but it did not enhance morphine’s pain-relieving effects or prevent the development of morphine tolerance.
Its clearest effects involved opioid reward and intake. CBD-rich vapor prevented the usual preference associated with morphine, reduced fentanyl self-administration in rats with and without neuropathic pain, and blocked the return of morphine-seeking behavior after extinction. However, it did not reduce fentanyl-seeking behavior in a separate reinstatement test. That distinction matters: the experiments measured behavioral models of drug reward, intake and relapse—not subjective craving as it is experienced by people.
The study also found no detectable changes in lung structure or estrous cycling after chronic exposure, and the vapor did not appear to produce cognitive impairment, social withdrawal or reinforcing effects in the animals. Those findings provide preliminary safety information for this specific extract and delivery method, but they cannot establish that commercial CBD vaping products are safe or that the results will translate to people.
There is some human evidence supporting further investigation. In a 2019 randomized, placebo-controlled trial, people with heroin use disorder who had been abstinent received 400 or 800 milligrams of oral CBD for three days. CBD reduced anxiety and craving triggered by heroin-related cues, with some effects still measurable seven days after the final dose. The trial was exploratory and relatively small; it did not show that CBD treats opioid use disorder or prevents relapse.
Other findings are similarly preliminary. A 2013 pilot study of 24 tobacco smokers found that participants using a CBD inhaler smoked about 40% fewer cigarettes during the one-week treatment period than those receiving placebo. Separately, a 2022 review of CBD and opioid withdrawal concluded that CBD might eventually help address symptoms such as anxiety, pain, insomnia and nausea, but emphasized that much of the evidence came from animal research or small clinical studies.
Together, these results suggest that CBD may influence opioid reward, cue-induced craving and some withdrawal-related symptoms. They do not yet support replacing established treatment. In the United States, buprenorphine, methadone and naltrexone remain the FDA-approved medications commonly used to treat opioid use disorder. Any role for CBD would need to be determined through larger, well-controlled human trials that establish effective doses, interactions with opioid medications, long-term safety and whether reduced craving leads to fewer relapses or overdoses.
