Alison Mack, a science and medical writer, and Janet Joy, PhD, Senior Program Officer at the US Institute of Medicine, wrote in their 2000 book Marijuana As Medicine?: The Science Beyond the Controversy:

“[C]annabinoid-induced euphoria or sedation may simply mask symptoms, leading some users to the false belief that marijuana improves their medical conditions. That is a problem if it causes patients to choose marijuana over more effective conventional medicines that have fewer undesirable side effects.”