Not a good point AT ALL. LSD tolerance builds up over absurdly short times. If you take a dose today, and another tomorrow, you'll experience drastically fewer effects. Thus, you never hear of "LSD addicts". There may be other psychological dangers involved for certain individuals, but addiction is not going to be a concern, for purely physiological reasons.
Seriously? People take too much acid, get real into drug culture and end up living in a bus down by the river. Over time psychedelics can erode the mind.
Perhaps they're suffering from HPPD, which can happen to some people. LSD is not 100% safe. Regardless, I think it is more likely they moved on to other drugs as hallucinogens aren't the kind of thing you'd want to take every day or get addicted to.
Dopamine agonists (heroin, cocaine, Farmville, et al.) are the kinds of drugs that people get addicted to. They are not the kinds of things you would want to get addicted to. Heroin and cocaine have other actions beyond dopamine, but Farmville and friends are a rather beautiful example of pure dopamine engines. The attached money pump increases the evil factor.
