It may be one of the world's most widely used recreational drugs, but scientists from the University of South Carolina believe they have discovered how smoking cannabis might suppress the body's immune system. And that, they say, could lead to the development of certain types of cancers and infections.
The researchers investigated compounds in cannabis called cannabinoids, which includes THC (delta-9 tetahydrocannabinol), the substance that's already used in medical cannabis products for pain relief.
Cannabinoids, they claim, trigger the mass production of a type of cell called MDSCs (myeoloid-derived suppressor cells), which scientists believe actively suppress the immune system. Cancer patients, for instance, are known to have a higher count of MDSCs than people who don't have cancer.
Another study by Paris-based researchers also links the production of MDSCs and cancer growth. Scientists from the Institut Pasteur have discovered that cancer cells produce a molecule called interleukin-1 beta, which triggers MDSCs.
The studies, both published in the European Journal of Immunology, could offer some explanation as to why smoking cannabis has been linked with lung cancer. One study, for instance, has claimed smoking a joint is as bad as smoking 20 cigarettes in terms of increasing your risk for the disease.
If your immune system is depressed, it may leave you more susceptible to infections and viruses too. However, there are several easy ways to boost your resistance.
What are your views on cannabis? Do you think it should be legalised? Or are the health risks - both physical and mental - too great?