Obsessive–compulsive disorder
Anxiety is one of the most common symptoms. It can lead the person to believe that if a task is not done, something bad will happen. Such a task may be washing hands many times, keeping the lights on, or keeping their surrounding clean. This belief leads to more anxiety and tension. The actions that someone takes to stop the thoughts and feelings may take more than an hour every day. Excessive hand washing is a sign of OCD.