Just as we associate two things together, like “up and down” and “left and right,” a well-worn pathway in the brain associates two things that follow each other, and they become connected (what psychologists call “conditioned”). If a thought is followed by an anxious experience, the pathway from thought to fear gets established. When this happens repeatedly, your brain becomes conditioned to react anxiously and automatically to that thought. This sets up the conditions for unwanted intrusive thoughts to take hold.
