Marijuana and medical research: what may happen in medical research if marijuana is rescheduled, and why our understanding of marijuana's impact is now limited. The Biden administration recently proposed reclassifying marijuana from a Schedule I controlled substance to a Schedule III controlled substance, a change that acknowledges the medical benefits of the drug and would get rid of a lot of research red tape. While we currently have a basic understanding of how marijuana impacts the body and the brain, rescheduling the substance will bring more researchers to the table and make it easier to study the THC products people are currently using today.