Rumination-Focused CBT
Rumination-focused cognitive behavioural therapy is a version of CBT built to attack the habit of ruminating rather than the content of any particular thought. It works on the move from the brooding kind of thinking to the reflective kind, and it is the only treatment in this area designed for the habit itself. Edward Watkins developed it. It has a trial in people whose depression had not shifted on medication, and a prevention trial in students who were not yet depressed.
What it is
Ordinary cognitive behavioural therapy tends to work on what a thought says: is this true, what is the evidence, what would you tell a friend. This version works on what the thinking is doing. The target is the process, the returning to it, the abstract "why am I like this" framing, rather than any single belief.
The distinction it is built on is the brooding and reflective pondering split, and the therapy trains the shift from the first style to the second: from unanswerable questions about what kind of person you are, to answerable ones about what happened and what you would do next time.
It is clinician-delivered and clinician-guided. Describing it is not advising it, and nothing on this page is a technique to try from an article.