In my experience that is the case. I haven't gone to the gym for a few weeks now, because after years of doing it, I no longer feel anything. I go to Walmart every day and buy Apple juice and Kit Kat, and that does very little, incomparable to taking pleasure-optimized drugs.
You just get used to chemicals as well and need more and more, and stronger ones. Alcoholics are not happy when drinking, they are miserable if they are not drinking. That's a completely different world.
