I live in Europe. There is plenty of work done on health risks of canabis. Smoking is strongly associated with lung cancer, yes weed too. That should not be surprising. If you think otherwise you are reading the wrong Internet. Smoking is also strongly associated with mental disorders. There is a lot of evidence. Huge numbers. If you smoke weed you _must_ have friends that's have had a bad one on weed at some point, even if you never have yourself, which I doubt, if you are over 18 and live in the US I would be very surprised to hear you have no anacdotal evidence of mental health effects. If you really don't go talk to a psychiatrist and ask them what they do all day. Weed is part of the culture we all know it's ups and downs. I am in favour of legalization but you have to be honest to discuss it. If _you_ have a lack of evidence about the effects of weed read more, ask your friends, about 70% of my friends smoke weed regularly. Those that do don't have regular issues with it, naturally, but that is a long way from saying there is no evidence of health effects or the lack of evidence itself _is_ the health risk. That's crazy talk. Depression and demotivation is normal, and documented. Of course, if you smoke, you don't need a doctor to tell you that. Smoking weed is so common the numbers are very good.
Large numbers make good averages.
Psych health care workers deal with people with drug problems on a daily basis, that's pretty much all they do. Psychs know _which_ drug each patient has issues with. A huge percentage of psychiatric work is related to drugs and alcohol. The percentage that is weed is well known.
If you deny that, no one will ever take anything you say seriously because everyone one else is basing health care policy on these numbers.
Your trouble is probably that you are looking for a study that says that weed is good for mental health,
and there isn't one.
It's fun, you get high, but it does have negative health consequences. That is essentially it, no one has yet found a control group that got better exam results from smoking bifters in the park.
The difference between high thc weed and weed as gaia intended exacerbates the issue, modified indoor weed does most of the damage. Natural weed has anti-psychotics and skunk messed up the balance.