In the U.S., cannabis remains a Controlled Substances Act Schedule 1 drug like heroin and LSD, which means that it has no currently accepted medical use, has a high potential for abuse, and lacks accepted safety for use under medical supervision. This places extreme limits on scientific research.
Despite being a substance that targets the brain, if and how long-term cannabis use alters brain structure and function remain unknown. There are some known adverse effects. It acutely impairs mental functions and may exacerbate depression, bipolar disorder, anxiety, post-traumatic stress disorder and use of other substances. Whether it is more harmful than substances such as alcohol or nicotine is still undetermined. On the plus side, there is conclusive evidence that cannabis provides relief from symptoms related to chemotherapy and multiple sclerosis. Other potential benefits remain unknown.
So why don’t we know more? Because federal policies seemingly put more stock in public opinion than