A meta-study from the US National Academies of Science, Engineering, and Medicine looked at over 10,000 studies to see what we actually know about marijuana. The study reviewed the results from all these studies in aggregate in order to find out which claims have the most evidence and which don't.
Others say marijuana has helped them recover from abusing alcohol and hard drugs. Even if the person ends up replacing their habit with marijuana, it's a significantly better choice. Marijuana is nearly impossible to overdose on and has far fewer detrimental effects than alcohol and other drugs.
Some swear by certain strains of marijuana to lessen their anxiety. Many people are turned off by the idea of turning to pharmaceuticals. They think marijuana's a better alternative because at least it's natural—people have been smoking it for ages.
Many think the benefits of marijuana are outweighed by the negative effects the drug has on a person and society. Plenty of drugs have medical purposes but are kept on strict control because of the potential for abuse. Marijuana should be treated the same way.
The dangers of marijuana are very real. The meta-study also found some evidence marijuana can cause respiratory distress, worsen anxiety and other mental illnesses, harm a person's capacity learn, their attention span, memory and is associated with abusing other substances. It's by no means a harmless drug.
Others worry about the harm marijuana causes to society. Many think that popularizing a drug that makes people sluggish and lazy is a horrible idea. We should be trying to find ways to get people to work and engage in society—not giving people new ways to mentally check out. Here's what Attorney General Jeff Sessions thinks about marijuana:
“I realize this may be an unfashionable belief in a time of growing tolerance of drug use. But too many lives are at stake to worry about being fashionable. I reject the idea that America will be a better place if marijuana is sold in every corner store. And I am astonished to hear people suggest that we can solve our heroin crisis by legalizing marijuana—so people can trade one life-wrecking dependency for another that’s only slightly less awful,” Sessions said. “Our nation needs to say clearly once again that using drugs will destroy your life.”