Yes. Smoking pot is a very good example of it. Most potheads I knew in college stopped at some point. But for those with addictive personalities... They didn't graduate and I lost track of them. I can only guess at where they are now, but my best guess would be that they slid down a slippery slope. Yes, I went to a very liberal school and no, I'd never be able to stand it today. I'm sure it's much worse.