exactly, cannabis is a plant, jus like valerian, kava, anything you can think of. how you use it determines if you will "burnout" i think it too a myth. do your friends take asprin when they have headache? asprin is proven to kill brain cells. documeted facts. ask them if either(all) if they have/know sum1 who has add, ask them if they found a replacement, a natural replacement for ritalin*(not sure, baked) if they would drink an herbal tea for example, once a day, would they do it or consider it. if they have a common regard for the long term health of their boddies, they'll say yeah. then tell them it was cannabis
p.s. be sure to bring that up 1 day when you arent talking about cannabis and pick your moment and you'll be suprised at thier responses