LONDON, Nov. 27 (UPI) -- In scanning the brains of drug users, researchers at Kings College London found smokers of high-potency pot had smaller amounts of white brain matter inside their corpus callosum, a neural pathway connecting the left and right halves of the brain.

While pot smokers generally showed more damage to the corpus callosum than non-smokers, those who smoked super strong weed known as 'skunk' showed more significant white matter loss.


Scientists performed MRI scans on the brains of 56 patients who had visited a London hospital reporting a first episode of psychosis. The brains of 43 healthy participants were also scanned. All the participants were surveyed about their drug habits.

"We found that frequent use of high-potency cannabis significantly affects the structure of white matter fibres in the brain, whether you have psychosis or not," Paola Dazzan, a neurobiologist at Kings College, said in a press release. "This reflects a sliding scale where the more cannabis you smoke and the higher the potency, the worse the damage will be."

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The main psychoactive ingredient in weed, tetrahydrocannabinol (THC), is much more concentrated in modern skunk strains as compared to traditional pot and hash -- up 14 percent as compared to 4 percent.

Researchers say their new findings, published this week in the journal Psychological Medicine, are proof that healthcare workers need to pay greater attention to the type of marijuana patients are using.

"As we have suggested previously, when assessing cannabis use it is extremely important to gather information on how often and what type of cannabis is being used," Dazzan said. "These details can help quantify the risk of mental health problems and increase awareness on the type of damage these substances can do to the brain."

Previous studies have found a link between instances of psychosis and high-potency marijuana use.

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