Much of the medical literature is dominated by goal-seeking fraud, sponsored by prohibitionists in government and competitors in the alcohol and pharmaceutical industries (and in the original, the paper industry). It can’t be believed any more than fake news, or “climate change” nonsense.
The fact that people who make it to the top of society are quite often pot smokers is conclusive proof that it is not anywhere near as dangerous as prohibitionists claim. Contrast to, say, heroin, where the only people who made it to the top who use it are now-elderly rock stars from a previous era.
With 200 trillion solder points the human brain is the most complex mechanism in the known universe. Everyone knows playing around with its complex communication chemistry will almost certainly cause permanent damage of some kind, as will publicly defending doing so.