Also, write the troublesome thoughts down the moment they occur. The combination of jotting them down—which acts to ventilate them and dispose of them—and setting a later time to think about them works well; it takes advantage of the reason ruminations exist—to remind you of themselves—and so undercuts them. If you write them down and set a time to think about them, they no longer have any purpose, and purposelessness lessens their strength.
