Cannabidiol, or CBD, is an active ingredient in the drug cannabis, also known as marijuana. CBD is the second-most widely recognized element of marijuana, after delta-9-tetrahydrocannibinol, or THC. Marijuana contains over 400 different active substances, with THC and CBD being just two of its 60 different cannabinoid molecules.
There is increasing evidence that CBD may have potential therapeutic benefits, including anticonvulsive, sedative, hypnotic, antipsychotic, and neuroprotective properties. It also has an anti-inflammatory effect, which in animal studies has been found to be several hundred times that of aspirin (acetysalicylic acid). Because CBD produces its biological effects without acting significantly on the brain's cannabinoid receptors, it does not cause the unwanted psychotropic effects that are characteristic of other marijuana derivatives. This gives it a particularly high potential to be used in the development of various forms of medical marijuana.
A study comparing THC with CBD showed that some of the unpleasant aspects of the marijuana high, such as anxiety and paranoia, appear to be caused by THC, and alleviated by CBD. Although complex, studies have shown some neuroprotective effects of CBD. Research comparing the brains of chronic marijuana smokers and the amount of THC and CBD on hair samples indicated that, while THC appears to have a neurotoxic effect, diminishing grey matter in areas of the brain, CBD appears to have a neuroprotective effect on the same areas of the brain.
Another study looking at the effects of various drugs on the development of dementia showed that CBD may have some positive effects, including the reduction of symptoms of psychosis in people with Parkinson's Disease. However, it is too early to say whether CBD could be used to prevent dementia, a condition which the medical system is struggling to cope with as it is reaching epidemic proportions among the aging population. There is also some research to suggest that CBD may reduce symptoms of psychosis in people with Parkinson's disease.
Despite the current view that CBD appears to be both a positive agent in and of itself, and a potential modifier of some of the negative aspects of THC, reports of how the constituents of cannabis have changed over the first decade of the 21st century are concerning. Typical reports of the amount of THC and CDB in cannabis has been around 4% of each substance. In contrast, "high potency" strains of marijuana that have been developed more recently, such as sinsemilla, or "skunk," are reported to contain 16-22% of THC, and less than 0.1% CBD. This might explain the recent increase in cannabis-related cases of psychosis.
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