OCD and Focussed Attention
What we focus on is important. We have approx 70,000 thoughts a day. When we focus our attention on a distressing thought this tells the brain that thought is important. The brain then sends one, more of the distressing thoughts. When you change your response to thought, you then are showing the brain that the thought is not important and the brain will stop bombarding you. Attention is one of the problems for an OCD sufferer because they give the thought much attention. Ruminating checking avoidance are all attention.
You are not your thoughts! Dont attach meaning to a meaningless thought. There is no such thing as the Thought police!