We introduced the concept of behavior chains above in the section on altering behavior. Thought habits can take the form of behavior chains as well, with one automatic thought leading to another unhelpful thought, that can ultimately lead people towards biased, mistaken conclusions which cause them to feel or act badly. One cognitive technique previously popular in the scientific literature that you may see in many self-help books is called "thought stopping" or "thought suppression." This technique uses a variety of strategies in order to help a person deliberately try and stop thinking certain thoughts. For instance, you will see advice encouraging people to silently think "STOP!" when they find themselves engaging in unwanted thoughts or habits, or to wear a rubber band around their wrist, that can be snapped (to create a sharp stinging sensation that is painful) in order to interrupt the "bad thought" habit.
There have been a large number of studies investigating the usefulness of thought stopping techniques across a wide variety of people (e.g., people without mental disorders, people with depression, and people with anxiety disorders such as phobias or obsessive compulsive disorder). Even though the results of these studies are a bit confusing (e.g., some of the studies seem to disagree with other studies), overall, the data suggests that thought stopping techniques are not a particularly useful cognitive strategy. In fact, the research suggests that this type of technique may actually prove HARMFUL to some people in the long run. For some, across time, the thoughts that they are trying to suppress may end up occurring more frequently (a so-called "rebound effect").
Hopefully, you can understand how problematic this rebound effect would be for individuals with anxious or depressive thoughts. A person who is worried about recurring thoughts of suicide, uses thought stopping techniques to get rid of them, and then goes on to experience an increase in the frequency of suicidal thoughts will be significantly worse off than if they didn't attempt this type of cognitive technique at all.
Several other issues can make this type of cognitive strategy problematic. First, people can't use thought stopping until they have become enough aware of their automatic thoughts that they can identify them while they are happening. Thus, thought stopping must be preceded by self-monitoring if it is to be an effective tool. A second problem is that thought stopping doesn't help people to know what to do once they have succeeded in interrupting their automatic thought chain. It isn't enough to simply interrupt a thought chain. Without some other behavior or thought to replace it with once interruption has occurred, it is highly likely that you will go back to thinking your automatic thoughts in short order. Last, behavioral research with individuals who experience anxiety disorders suggests that facing an anxiety-provoking thought and confronting it (rather than trying to suppress it) can actually be quite helpful. For instance, a technique called systematic desensitization is highly successful in treating phobias. In this technique, a person is gradually introduced to thinking about and experienced something that they intensely fear (e.g., spiders, bridges, elevators, etc). Cognitive techniques that center on confronting anxiety provoking thoughts are best left to professionals, however, as there are specific steps designed to increase the likelihood that you experience ultimate success in decreasing unwanted thoughts and feelings. If you are interested in learning how to confront anxiety provoking thoughts, find a cognitive behavioral therapist in your area that specializes in the treatment of anxiety disorders for more help.