OK,OK. It took me a long time to get here but I do not believe marijuana should be illegal. There, I said it. Not because it doesn't have health harms (it does -- both physical and cognitive). Not because it has no addictive risk (it does -- approximately marijuana 9% of users develop addiction -- highest risk in those with personal or family history of addictive and other psychiatric disorders). But because the criminalization of marijuana has far outpaced any biological harm caused by the drug. It continues to undermine therapeutic benefits of marijuana that cannot be refuted and disproportionately criminalizes individuals of low socioeconomic status and non-white race. That said, individuals who begin smoking marijuana before age 18 experience persistent declines in IQ, problem solving and other measures of cognitive functioning and are at higher risk of psychosis, so still JUST SAY NO! (at least until you turn 18, but hopefully forever) will be what I continue to teach my children.
On a serious note, it may surprise you considering my specialty is Addiction Medicine, but I have been dismayed at the medical profession's un-objective and clearly propaganda-driven vilification of marijuana. But happily, I just finished watching an EXCELLENT webinar sponsored by the California Society of Addiction Medicine on Marijuana's Effects on Health. Dr. Itai Danovitch gives a data-based review on the biology of marijuana, patient perceptions and the medical literature that exists on the health harms and benefits of marijuana. I've pasted a few of the salient slides below, however, I would strongly encourage you to watch the entire presentation. It is (finally!) an unbiased review on a topic that is very politically charged at the moment. It is a full hour so grab some popcorn and your fuzzy slippers before you click this link to watch: Clearing the Air: Marijuana's Effects on Health.