A chemical found in cannabis, known as tetrahydrocannabinol, or THC, has been found to potentially slow the process in which mental decline can occur in up to 50 percent of HIV patients, says a new study.

Scientists discovered that the compounds in cannabis were able to act as anti-inflammatory agents, reducing the number of inflammatory white blood cells, called monocytes, and decreasing the proteins they release in the body.

The scientists took blood samples from 40 HIV patients who reported whether or not they used cannabis. Then, they isolated the white blood cells from each donor and studied inflammatory cell levels and the effect cannabis had on the cells.

They have studied the effects of cannabis on the immune system since 1990. The lab was the first to identify the proteins that can bind cannabis compounds on the surface of immune cells. Up until then, it was unclear how these mixes, also known as cannabinoids, affected the immune system.

HIV, which stands for human immunodeficiency virus, infects and can destroy or change the functions of immune cells that defend the body. With antiretroviral therapy — a standard form of cure that includes a cocktail of drugs to ward off the virus — these cells have a better chance of staying intact. Yet, even with this therapy, certain white blood cells can still be overly stimulated and eventually become inflammatory.

Knowing more about this interaction could ultimately lead to new therapeutic agents that could help HIV patients specifically maintain their mental function. It might not be people smoking cannabis. It might be people taking a pill that has some of the key compounds found in the cannabis plant that could help.