HEALTH/CANNABIS – RESPONSE TO PAIN
CANNABIS AFFECTS EMOTIONAL RESPONSE TO PAIN
For some patients who struggle with chronic pain, cannabis (also known as marijuana) and cannabis-based medications have been found to be effective. However, others find that it fails to reduce their pain, only bringing about the side effects associated with its use, which, according to the National Institute on Drug Abuse, include “distorted perceptions, impaired coordination, difficulty with thinking and problem solving, and disrupted learning and memory.”
A new study by the University of Oxford, published in the journal Pain, aims to get a better look at what exactly occurs in the brain when someone uses cannabis as a therapy for pain relief. Researchers found that, although some people reported changes in their levels of pain, there appeared to be no significant changes in the parts of the brain that account for the experience of pain. It did, however, appear that cannabis affects the emotional response the patients to pain, but it does not do so in a consistent fashion.
The Expert Take
Dr. Michael Lee of the University of Oxford’s Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB), who was involved with the study, spoke with Healthline about how the study was conducted, as well as its implications for patients suffering from chronic pain.
Although the study was limited to a small group of men and examined only one possible THC compound, the study was intended to begin scratching the surface of what occurs in the brain during the use of THC (the psychoactive ingredient in cannabis).
“Patients may be prescribed multiple doses and for much longer periods of time to help them manage pain,” explains Lee. “We studied effects from a single dose of THC in healthy, drug-naïve volunteers for ethical and scientific reasons.”
“Cannabis may influence the emotional aspect (‘the hurt’), rather than the sensation of pain,” explains Lee. “This sort of pain relief may depend on how the amygdala (the brain region linked to fear) reacts to the drug. That means that not everyone can benefit from the effects of cannabis on the brain.”
The researchers found an apparent correlation between the effectiveness of THC for pain relief and a certain connection in the brain—namely, the strength of the connection between the right amygdala and the primary sensorimotor area, which is part of the brain’s cortex. If this correlation is, in fact, present, it may allow doctors to determine in advance whether THC will be effective as a form of pain relief for certain patients. This will, however, require long-term studies, and would also require the participation of patients suffering from chronic pain.