ERP is predicated on the idea that a therapeutic effect is achieved as subjects confront their fears, but refrain from engaging in the escape response or ritual that delays or eliminates distress. In the case of individuals with OCD or an anxiety disorder, there is a thought or situation that causes distress. Individuals usually combat this distress through specific behaviors that include avoidance or rituals. However, ERP involves purposefully evoking fear, anxiety, and or distress in the individual by exposing him/her to the feared stimulus. The response prevention then involves having the individual refrain from the ritualistic or otherwise compulsive behavior that functions to decrease distress. The patient is then taught to tolerate distress until it fades away on its own, thereby learning that rituals are not always necessary to decrease distress or anxiety. Over repeated practice of ERP, patients with OCD expect to find that they can have obsessive thoughts and images but not have the need to engage in compulsive rituals to decrease distress.