In my teens/20s, I would have advocated for legalization of marijuana and thought any argument against it was some antiquated, puritanical nonsense.

In the decade+ since, there's no way I'd do so.

I know three personal friends that are long time (allegedly not addicted) heavy marijuana users that all suffer from Cannabinoid hyperemesis syndrome to the extent that it's effected their daily lives substantially.

Two of the aforementioned are roughly my age, and are half as bright as they were as teens. Neither of them can follow a train of thought particularly well and are difficult to hold conversations with.

How much of this is attributable to how much more powerful "modern" strains (or whatever the geo-engineered differences are) is unknown, but I can't imagine it's not a factor. This is not the dopey "get stoned and play XBox and eat a whole pizza" stuff we had in the 00s.

I'm sure there's plenty of counterexamples or something, but my perspective on this has completely changed, influenced by examples like this.