Medical Marijuana Alters Your Brain Connections to Relieve Pain

Medical marijuana could ease chronic nerve pain by loosening specific connections in the brain, according to the latest study uncover the potential therapeutic benefits of the drug.

Tetrahydrocannabinol (THC), the psychoactive ingredient in cannabis, was the focus of the study, carried out by researchers based in Israel.

To shed light on nerve pain that centers around the spine and legs, also known as radicular pain, the team sought the help of 15 men who had lived with the condition for at least six months. The participants of the small study had an average age of 33. Only men qualified to take part in the project to eliminate the risk of hormones released during the menstrual cycle, which would alter perceptions of pain and affect the results.

First, the participants rated their pain levels on a scale of zero to 100. Researchers then scanned their brains using functional magnetic resonance imaging equipment.

Medical marijuana could be used to treat nerve pain, according to research. Getty Images

The scientists gave nine of the participants 15mL of THC under their tongue, while the remaining took a placebo oil that didn't contain the cannabinoid. An hour later, the researchers asked the participants about their pain levels. Two hours later, they scanned their brains again.

A week later, the scans were repeated and those who had the placebo were given the THC oil, while those first given the drug took the placebo.

When patients consumed THC they experienced less pain than those who were given a placebo, at a 35 out of 100 average pain rating versus 43 out of 100. Before taking THC, the volunteers rated their pain at 53 out of 100 on average.

The results of the scans suggested those who experienced less pain after taking THC had a reduction in the connections in parts of the brain that process the sensation: the anterior cingulate cortex and the sensorimotor cortex.

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The research was published in the journal Neurology.

Dr. Haggai Sharon, study author who researches the subjectivity of pain at the Sagol Brain Institute, Tel Aviv Medical Center, explained in a statement: "Pain is a complex experience that involves both the senses and emotions.

"Our study results link pain relief from THC with a reduction in the connections between areas of the brain otherwise heavily connected, suggesting that THC may alleviate pain by disrupting signals between these pain processing pathways."

"Interestingly, our results also show that the more connected the areas of the brain that process emotion and sensory prior to treatment, the greater the pain relief experienced when taking THC," said Sharon.

To confirm their findings, research involving more people will be needed in the future, Sharon acknowledged. Other lines of inquiry include studying different chemicals in cannabis, such as cannabidiol.

In the U.S., medical marijuana is currently legal in 30 states with California the first to give the drug a green light. The drug is prescribed for a variety conditions, from nausea to stress and schizophrenia.

Last month, researchers found cannabidiol, the plant's ingredient that is not psychoactive, could ease the symptoms of inflammatory bowel disease after studying its effects in mice.

The authors of the study published in The Journal of Clinical Investigation concluded a molecule in cannabis had similarities to one the body naturally releases to soothe gut inflammation.