Drug Addict Cure Castle

I am imagining a future in which a castle is built that allows for the cure of human drug
addicts.

The drugs which have the addicts hooked are available for free in this castle.  There is a catch,
however.  The drugs are mixed with a substance that modifies the brain of the addict so that he
or she will want to quit.  These drugs come in bottles which are labeled as to their side-effects
in the fine print.  But who reads the fine print, anyway?  The added substances might be a
gene therapy that affects the pineal gland and brain in such a way that the addiction
disappears.