My psyc told me that it can cause psychosis and blamed my last episode on weed a few mths ago.It actually wasnt the case i got mania because i was stressed about things it was not the pot.I was smoking for about 6 yrs before that and it always calmed me rather than make me psycho.I just think everyone is different and i havent had any bad affects.But other drugs such as speed will fuck your brain beyond repair.