You wont see me disagree on alcohol, its a shame prohibition failed.
The effect of pot in the 60s and 70s may have been peace, but modern hydroponics and strains can produce pot with THC content in excess of 30%, compared to the stuff I admit I smoked in the 70s, which had a THC content of between 2-4%.
Hydroponic pot can and increasingly does (as the stuff just gets stronger and stronger) aggravate the condition for anyone who is predisposed to schizophrenia... and thats a lot more people than you may think. Sure, they might be peaceful when on the stuff, but when they run out, the mood swings, paranoia and desperation to feed their addiction kicks in. This is absolute proven medical fact, so dont even try to defend that one.
Schizophrenics are NOT usually peaceful people when they have a psychotic episode. I've personal experience with a family member who is a pot-induced schizophrenic and I can assure you he isnt fun to be around when he is losing it.
That doesnt even take into account the proven loss of IQ for regular smokers, the total lack of motivation it causes, the loss of any drive, initiative or work ethic that comes with the 'wow man look at the pretty lights' thing.
A song from a stoner, admitting what its done to his life. Most of you just stick your head in the sand and think it doesnt apply to you.