It depends on how a person uses it. Its all in your mind. Some people consider it one of the most effective nootropics.
This is a major reason I no longer keep any on hand. Once in a while I can dig but the mental lethargy induced from daily use turns me into an able bodied invalid.
I only know two heavy users personally....one will keep talking long after I walk away....and the other laughs at the end of EVERY SENTENCE
I'm sure this has already been said but... No smoking pot doesn't make you go permantly stupid, maybe temperarily, like me, I exaggerate ALOT when I'm stoned. Weed paralyzese brain cells it doesn't actually kill them, and even when brain cells die they weaker cells die first.