Imagine you are suffering day in and day out in crushing poverty, that you see nothing but crime and hopelessness all around you, that your friends and family have been killed or are rotting away in jail, that you are looked down upon, spat upon, and despised, that you see no hope of bettering or escaping your situation.

Then imagine you've taken something that infinitely transforms your world and makes you feel amazing to such a degree that's absolutely unimaginable to someone who hasn't tried some of these substances ("better than sex" is an extreme understatement). All your pain is gone, all your misery forgotten, amazing vistas open before you, all is good.

After that brief stay in paradise, you come crashing down and back in to your miserable life. Everything is as before, your passion is back, only you now know it's possible for you to get back to that exalted state, to escape that prison of a life you've been living in, even if for a moment.

Is it evidence of a disease for someone who's gone through this to desperately want to experience that escape again? To be free and feel great?

Is the cause of such a desire -- the misery, the poverty, the hopelessness, the fantastic way these substances make you feel and the escape they offer -- can all that be justly summed up in the word "disease", or is there something else going on?