Sensationalist headlines concerning the alleged cancer-busting abilities of cannabis have sparked a huge amount of interest in this once maligned plant, with polls suggesting that more people than ever before now support the use of medical cannabis. Accordingly, governments around the world have been busy repealing prohibitionist laws in order to allow for increased access to the drug, which is now commonly used to treat a range of conditions including neuropathic pain and epilepsy.
However, the science behind the medical properties of cannabis is in fact much more complex than many people might think, and the reality is that huge gaps still exist in our knowledge of how the plant works.
More Than Just THC And CBD
By now, most people have heard of the compounds tetrahydrocannabinol (THC) and cannabidiol (CBD), both of which are commonly cited as the source of weed’s medical efficacy. The truth, however, is that cannabis contains more than 500 compounds, all of which are thought to contribute to the plant’s pharmacological properties. Of these, around 100 are classed as phytocannabinoids, which means they bind to the cannabinoid receptors within our central nervous systems.
Both THC and CBD are phytocannabinoids, with the former being largely responsible for the psychoactive effects of cannabis thanks to its binding affinity for the cannabinoid 1 (CB1) receptor, while the latter is often credited with treating inflammation, anxiety, and depression by reacting with the cannabinoid 2 (CB2) receptor. Yet a number of other phytocannabinoids – including cannabigerol (CBG) and cannabichromene (CBC) – are also believed to play a role in shaping the drug’s effects, with new discoveries continually adding to our understanding of these compounds.
Last year, for instance, researchers identified a previously unknown phytocannabinoid called tetrahydrocannabiphorol (THCP), which has a binding affinity for the CB1 receptor that is 33 times that of THC. This discovery cast doubt on everything we thought we knew about weed, leading some to suggest that it may be THCP, rather THC, that gets users high.
On top of all that, the plant is also loaded with terpenes, which are essential oils that not only give each cannabis strain its unique smell and taste but also generate an array of pharmacological and medical effects. Though way more research is needed in order to determine the true value of each of these compounds, it is generally believed that the overall properties of a given strain are shaped by the interactions between its various ingredients rather than by any one particular molecule. The combined action of these compounds is often referred to as the entourage effect.
Cannabis and Cancer
While stories about cannabis curing cancer abound, it’s worth pointing out that no proper clinical trials into the drug’s anti-cancer properties have ever been conducted. However, a great deal of preclinical evidence, mostly involving animals, has indicated that several of the compounds in cannabis may help to treat the condition.
For example, THC has been found to slow the development of colitis-associated colon cancer in mice, predominantly by inhibiting the release of the pro-inflammatory protein interleukin-22. In a separate study, the same cannabinoid-induced apoptosis in breast cancer cells, though a more recent paper concluded that only cannabis strains that are high in CBD are effective at treating certain types of cancer. Conflicting findings such as these have sparked a huge amount of confusion and debate regarding the mechanisms underlying weed’s medical properties while adding weight to the entourage effect theory.