I am 48 yo and have been a chronic case off and on since my teens. I was diagnosed with what was called a learning disability (now ADD/ADHD)But that was well before I ever picked up a joint. I guess what I am trying to express is that you can't make generalizations. Actually as a nurse who detoxes alcoholics on a regular basis I'd have to say that booze kills a fuck of alot more neurons than ganja ever will.