Intrusive thoughts like that are present in OCD, PTSD
and GAD. In OCD you have obsessive thoughts that only seem to be eased by actions, such as researching, cleaning, locking, counting, many things. For instance I used to have a constant anxiety of having a medical condition, so I would regularly check my pulse, look at my skin color, check my temp ( I would carry around a thermometer) and kept a medical diagnosis book beside my bed that I would read everyday.