Investigators at the University of California at Davis, in conjunction with the University of California Center for Medical Cannabis Research (CMCR), assessed the efficacy of inhaled cannabis on pain intensity among 38 patients with central and/or peripheral neuropathic pain in a randomized, placebo-controlled, crossover trial. Researchers reported that smoking low-grade (3.5 percent THC) and mid-grade (7 percent THC) cannabis equally reduced patients’ perception of spontaneous pain.

"[A] significant … reduction in [a 100-point visual analog scale of] pain intensity per minute was noted from both 3.5 percent and 7 percent cannabis compared to placebo," authors wrote. "Separate appraisals using the patient global score and multidimensional [eleven-point neuropathic pain scale also] revealed that both active agents alleviated pain compared with placebo."

Investigators added: "[N]o participant withdrew because of tolerability issues. Subjects receiving active agent endorsed a ‘good drug effect’ more than a ‘bad drug effect.’"

They concluded: "In the present experiment, cannabis reduced pain intensity and unpleasantness equally. Thus, as with opioids, cannabis does not rely on a relaxing or tranquilizing effect, but rather reduces both the core component of nociception (nerve pain) and the emotional aspect of the pain experience to an equal degree."

The study is the second clinical trial conducted by CMCR investigators to conclude that inhaled cannabis significantly reduces chronic neuropathy, a condition that is typically unresponsive to both opioids and non-steroidal anti-inflammatory drugs such as ibuprofen.

Commenting on the study’s the findings, NORML Deputy Director Paul Armentano said: "With the results of each published study it becomes increasingly apparent why the US government has tried consistently to stonewall clinical research on the therapeutic effects of inhaled cannabis. Each new trial the Feds approve provides additional evidence undermining the government’s ‘flat Earth’ position that cannabis is without medical value."