Yes it does..
Psychedelic (users) can be just as bad if not worse.
I am in complete agreement with this. If one more bloke tells me about how he's in communication with deities and gods when he smokes DMT I'm going to do something drastic.
As for weed, I find that the majority of smokers are great, they're just normal people.
But weed extremists who claim Marijuana is the perfect, healthiest thing in the world are wrong. It has positive and negative effects. It's just a drug, not a way of life.
I used to smoke everyday but now I only get high with people I'm really close to or when I have nothing to do for a day and I've found cutting back like that has really improved my productivity.