Dr Michael Lee of Oxford University's
Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB) and his
colleagues have revealed that they have the information regarding the neural
basis of the pain relief brought about cannabis.
Long-term pain, which is
capable of occurring without a clear cause, is a complex healthcare problem and
various types of methods are required to manage it. They include medications,
physical therapy or physiotherapy, and psychological support. Cannabis
are very useful for some people in managing pain, especially when all other
medications have failed.
The study by Lee and his
group was carried out to understand how cannabis brings about pain relief. The
small study was carried out in controlled settings involving 12 healthy men.
For the study, the researchers used only one of many derivative compounds of cannabis
-- THC or delta-9-tetrahydrocannabinol, which is the active psychotropic
compound providing the "high"! Each of the twelve volunteers was administered
either a 15 mg tablet of THC or a placebo.
To induce pain, the
volunteers were required to rub either a cream containing 1% capsaicin or a
dummy cream onto the skin of one leg. The former caused burning and a painful
sensation, while the dummy cream was used for comparison purpose.
Each subject had four MRI
tests to cover each combination of THC or placebo, and pain-inducing cream or
dummy cream, and was asked to report the degree of discomfort or pain they were
The participants were asked
to report the intensity and unpleasantness of the pain and to the extent to
which it bothered them. It was found that those who had taken THC reported that
the pain bothered them less although they didn't report any change in the pain
The brain imaging studies
carried out on these patients support these findings. They showed reduced
activity in the areas controlling the emotional aspects of pain in the brain.
They also found that it is possible to determine who would benefit from
This study was different,
in that it dealt with healthy subjects and not patients, but it remains to be
seen how the findings of the study impacts cannabis -based pain relief therapy.
More research is required to evaluate the clinical outcomes and to understand
the quality of life of patients with chronic pain.
The results of the study have been reported in the journal Pain