Obsessive repetition of thoughts, phrases, or conversations; can be a symptom of Obsessive-Compulsive Disorder.
Example: Whenever the patient becomes agitated, she calms herself by repeating a specific phrase in her head. She also has a habit of mentally reviewing past conversations, worrying about whether she said anything inappropriate.
Grinnell, R. (2008). Mental Rituals. Psych Central. Retrieved on April 21, 2015, from http://psychcentral.com/encyclopedia/2008/mental-rituals/