A study published in the Journal of Anaesthesia's May 2004 issue found that marijuana extracts help people who suffer from "chronic, stable pain." The double-blind, randomized, and placebo-controlled study recruited patients with a variety of underlying illnesses including MS, spinal fusion, degenerative disk disease, and massive trauma. Patients were dosed alternately with tetrahydrocannabinol (THC), cannabidiol (CBD) and a mixture of both.
The study found that patients who used the cannabinoids were rewarded with better quality sleeps, elevated moods and relief from neuropathic pain. Furthermore, patients who suffered pain from "failed spinal surgery" ? a notoriously difficult to treat group ? received significant pain relief from the application of CBD alone, a pot substance with low psychoactive effects.

A separate study recently published in the Journal of Clinical Psychopharmacology found that doses of 15 mg THC made people sleepy, while doses of 15 mg CBD made people feel more alert.