Researchers at King’s college London and Sapienza University of Rome have reported some worrying findings about high-potency “skunk like” cannabis strains. In their research, it was found that skunk-like cannabis could damage a crucial region of the brain that communicates between the two brain hemispheres.

The research, published in Psychological Medicine, is the first to examine the changes in brain structure due to the effect of cannabis potency. It gains relevance due to the increasingly potent skunk cannabis of today as compared to nearly a decade ago. “Skunk-like” cannabis products have shown to contain higher quantities of delta-9-tetrahydrocannabinol (THC) than before.

Paola Dazzan, reader in Neurobiology of Psychosis from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King's College London, and senior researcher on the study, said, “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,” in a King’s College London press release. “This reflects a sliding scale where the more cannabis you smoke and the higher the potency, the worse the damage will be,” she added.

A technique of MRI called Diffusion Tensor Imaging (DTI) was used in the study. The white matter in 56 patients’ brains who had reported psychosis at the South London and Maudsley NHS Foundation Trust (SLaM), as well as 43 local participants who were healthy, were examined. The largest white matter structure in the brain, called the corpus callosum, was specifically examined. Communication between right and left hemispheres of the brain is carried out by this region. The region is also particularly rich in cannabinoid receptors that are acted upon by THC in marijuana.

It was found that high potency marijuana used frequently was linked to significantly high mean-diffusivity (MD) – a parameter to measure white matter damage, linking high potency skunk weed to brain damage.

“This white matter damage was significantly greater among heavy users of high potency cannabis than in occasional or low potency users, and was also independent of the presence of a psychotic disorder,” said Tiago Reis Marques, a senior research fellow at King’s College London.

Skunk weed comprises strains of cannabis that are hybrids between Cannabis indica and Cannabis sativa. According to Dutch Passion, its origins date back to the 1970s. These strains are strong-smelling and highly potent with their odour likened to the spray from a skunk.

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