Check out this fantastic article Quartz put together to help debunk several marijuana myths:
The march of marijuana legalization continues, and so do the questions about its effect on the health of smokers. Kevin Hill, an addiction psychiatrist at McLean Hospital in Harvard Medical School and author of Marijuana: The Unbiased Truth about the World’s Most Popular Weed, recently took to Reddit to answer questions from the public. Quartz has condensed and edited the highlights of the discussion.
What medical uses of marijuana are backed by evidence?
The two commercially available cannabinoids are FDA-approved for nausea and appetite stimulation. Beyond that, I think there is strong evidence supporting the use of marijuana or cannabinoids for chronic pain, neuropathic pain, and spasticity associated with multiple sclerosis.
What are the downsides of using marijuana? How often do people get addicted?
Most who use marijuana do not become addicted to it. Published data say that 9% of adults and 17% of young people who use it become addicted.
How do you diagnose marijuana addiction? What are the risks of withdrawal?
Does inhaling marijuana have different risks from eating it?
Is there a marijuana drug test?
Is marijuana getting more potent?
Potency has increased dramatically. Average THC content—which is the active substance in marijuana—in 1960s was 3-4%. Latest published data puts potency at 13%.
Where do you stand on the legalization of marijuana?
I want to emphasize, though, that in many states, like Massachusetts, that will have legalized marijuana on the ballot soon, the real question is no longer who is in favor and who is not, but rather, if it gets passed, what should the laws look like. More and more states will legalize marijuana, so we need to work hard to craft policy that gives people what the want while limiting risk.
What is the most dangerous marijuana myth?
Most researchers agree that early, regular use of marijuana—young people below 25 whose brains are developing—is a bad idea. Major negative effects of long-term use include cognitive difficulties, worsening anxiety, worsening depression, and increased likelihood of expressing a psychotic disorder (not causing one).