Decades ago, friends of mine at U.C. Berkeley were pre-law majors. They were good students, politically well informed and very focused on righting all the wrongs in the world. In the beginning, bright eyed and bushy tailed, they took to occasional social smoking at parties, etc. Then as time progressed, they slowly became less interested in their studies and politics while getting more focused on their smoking. Eventually that's all they did: scoring big buys, growing their plants, cleaning the stuff of seeds and stems, reselling, fiddling around with their bongs, etc. You could watch their I.Q.s diminish (it was very noticeable). The analogy to Alzheimer's disease is very apt.

Gary