Why was this research done?

Neuropathic pain is sometimes described as shooting pain or burning pain or a sensation of electrical shock. It is caused by injury or dysfunction of nerves within the central nervous system (brain or spinal cord) or peripheral nervous system (nerves outside of the brain or spinal cord). Cannabinoids refer to a group of chemicals that are related to the cannabis (marijuana) plant. Different cannabinoid products contain different chemicals (for example, THC, CBD) that act on the nervous system. It is thought that CBD might improve sleep while THC improves pain.

Reviewers wanted to know if cannabinoids improve sleep and reduce pain in people with chronic neuropathic pain. They found moderate quality evidence that cannabinoids do improve sleep and pain, but there is also high quality evidence that they increase daytime sleepiness, dizziness, and nausea. Concerns about this study include combining participants with central and peripheral neuropathic pain together (they are not the same), inability to come to a conclusion on the best dose of THC:CBD, and the fact that the studies allowed participants to continue on other medications for pain at the same time as study drugs (so we don't know for certain that all of the benefits or all of the adverse effects were due to the cannabinoids).