Great answer, Ron C. I was just going to say that about the rubber band trick. I have used it and found it very effective, and the good news is that I didn't have to do it for long because it hurt!!!. . Another idea is to have something to substitute for the negative thought. When I quit smoking (many years ago), every time I would think I wanted a cigarette, I would say "Don't be silly." Helped me.. . And, just one more, spend some time looking for good things in life - even just the beauty of a flower or the sky or even a spiderweb wet with dew. Well, two more - I also watch funny movies to get me out of a negative spell.. . If none of this helps, you might want to see a therapist for some help.