Smoking high-strength cannabis might harm never fibres in brain: Study
28 Nov 2015
High-strength cannabis might harm nerve fibres handling the flow of messages across the two halves of the brain, according to scientists.
In brain scans of regular skunk-like cannabis smokers, doctors identified subtle differences in the white matter that connected the left and right hemispheres and carries signals from one side of the brain to the other.
Skunk, a more potent form of cannabis, has a strong smell and contains higher levels of the main active ingredient delta-9-tetrahydrocannabinol (THC).
The changes were absent in people who never used cannabis or smoked only the less potent forms of the drug, the researchers found.
The researchers said they are among the first to study the effects of cannabis potency on brain structure, and suggests that greater use of skunk might cause more damage to the corpus callosum, making communications across the brain's hemispheres less efficient.
According to Paola Dazzan, a neurobiologist at the Institute of Psychiatry at King's College London, the effects appeared to be linked to the level of active ingredient, tetrahydrocannabinol (THC), in cannabis. While traditional forms of cannabis contain 2 to 4 per cent THC, the more potent varieties (of which there are about 100), could contain 10 to 14 per cent THC, according to the DrugScope charity.
''If you look at the corpus callosum, what we're seeing is a significant difference in the white matter between those who use high potency cannabis and those who never use the drug, or use the low-potency drug,'' said Dazzan, The Guardian reported.
Studies had increasingly associated the use of skunk cannabis with increased risk of psychosis - a term used for describing hallucinations and delusions that arose from certain mental disorders, such as schizophrenia.
According to the study frequent use of high potency cannabis was linked to significantly higher mean-diffusivity (MD), a marker of damage in white matter structure.
''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'', Dazzan, said in a press release.
