Originally Posted by Nosu3
Brushing of teeth doesn't have the same method of action as cannabis. Cannabis alters brain chemistry and activity in a totally different way. One way being reducing acetylcholine output of the hippocampus by up to 40% which the effects are attributed to aspects of the high. Then there is the question of how it is performing this action and whether that method can cause permanent or semi-permanent effects in people with a certain biological make-up.
There is only anecdotal evidence linking it as a cause, because at this time that's the only evidence possible to obtain.
Derrrr my comment was obvious snark.
Here's something less snarky.
Take a group of disaffected children just entering puberty and compare them to a group of more well adjusted kids. Which group do you think would be more likely to have recently used cannabis? Quite likely the less well adjusted group. Which group is more likely to suffer from mental illness? Again the less well adjusted group?
Now consider that anti-cannabis governments around the world have been pumping billions of dollars into anti-drug research for over 50 years and yet there is still no evidence that cannabis use causes long term physiological harm to humans and that animal trials show that cannabis is in fact not brain toxic.
Then ask yourself which conclusion is more likely, A: that disaffected children prone to mental illness are more likely to smoke weed or B: that smoking weed causes mental illness.
Again, not advocating that kids be allowed to smoke weed anymore than I would advocate allowing them to drink.
Just because anecdotal evidence is the only evidence available doesn't make it good evidence. It isn't the only evidence by the way, there are plenty of animal trials that show the opposite of what you believe. This allied with a sensible reading of the anecdotal evidence should lead to the conclusion that it is more likely that cannabis is safe than harmful and that there is little or no case for the argument that cannabis causes brain injury in adults. And even less of a case for it's prohibition especially when compared to the deleterious effects of other legal drugs such as alcohol.