For what I understand the idea is to change where that thought eventually leads to, so instead of trying to get rid of it which is what makes it come back, you can redirect it.
For example, "I feel that I ruined my life", instead of actually believing that you extend that thought so it incorporates something like, "well, this is drug induced, I should wait it out and see how it goes". I find this more useful the less word bounded you make it in your mind, full meditation being optimal.
A word that encoded this for me back when my LTC started was "detachment", for me it meant forgetting about the things I wanted so I could want the things I have.
Its really just a trick to change your thought patterns, finding your own way to reconect with yourself, if that makes sense to you.