Too much of it is wrong. Even Ambrosia, as the saying goes. Can be reasonably sure Pharma companies have done research over it. After all, it's in their interest if it appears bad. But they also use some of its contents. THC for instance. Seems good business.

Too much water will kill you eventually. Funnily enough, we know how much water it takes to kill you, but we haven't discovered that limit on cannabis yet... but there surely is one.

In any case, the question isn't so much how it affects you while it's active, but how it affects you long-term. Transitory effects of any nature are not a concern, unless we're talking about rage fits or other behavioral changes that are actively and directly harmful to others.

Well, at my high school, the "stoners" were also drinking, sniffing glue, eating nutmeg, smoking banana peels, etc. In adult life, the few people I've met who only smoke weed have been pretty level-headed. There's some selection bias because I try to avoid people who appear to be of the glue-sniffing variety. Maybe they're just big reefer junkies after all.

The research is at its very basic level now. There are many different types with different affects. Studies that generalize all strains are inheritly flawed.

It will take awhile for accurate research to produce hard truths