Anxiety, often accompany Obsessive Compulsive Disorder. If you understand the cause it is easy to see why.
There are glands which sit on top of each of your kidneys called adrenal glands. During times of stress, these glands go into a primitive survival mode. They produce adrenaline to help you fight or flee from the stressor. However, most of our stressors today are not something like a animal, that we can fight or run away from to protect our lives, rather they are bosses, co-workers, teenagers, spouses, bill collectors etc.