as usual, there is no answer. any experimentation on the subject is always clouded by an agenda. ask 20 different "authorities" and you'll get 20 different answers. make your own decisions based on your own experience and don't expect some lab coated fool to give you any truth. for myself, i choose to believe that a few brain cells here or there are no big deal. after decades of getting high my iq is still in the high 140s so if i'm missing a few cells -who gives a shit. brain cells die every day of their own accord so if you kill a few on purpose and improve your enjoyment of life along the way, i'd say that's an even trade. but what the fuck do i know, i'm just an aging hippie with delusions of normality!!