IME: Increase in artist-like traits like creativity, magical beliefs, and odd behavior. I've seen a couple of Youtubers like this and remember some heavy weed smokers in undergrad who started to go off the rails.

He is referencing delta 9, which has a lot of the same similarities as what we refer to colloquially as "weed".

Delta 9 is much different physiologically and psychologically and can induce this abhorrent behaviors.

Also in the mid to early 2000's over 50.3% of US adults (Pew Research Center) had tried cannabis, I can assure you someone in your "circle" has smoked in their life.