Rumination is a type of obsessive over-thinking in which a person will mentally replay a past negative event again and again but make no real progress toward resolution. It is similar to worry in that a person will obsess over the potential causes and consequences of an event; however, worry is related to future events, while rumination is related to the past.
Rumination is commonly associated with mental health disorders that involve negative and anxious thinking patterns, such as obsessive-compulsive disorder (OCD), post-traumatic stress disorder (PTSD), generalized anxiety disorder (GAD), and major depressive disorder (MDD).
Rumination plays a major role in the circular thinking pattern found in OCD. The OCD sufferer ruminates in an attempt to alleviate anxiety and “resolve” the intrusive thought, although resolution never occurs because the disturbing thought is being fueled by the anxiety itself.
Similarly, people who suffer from depression have a hard time letting go of negative thinking patterns. They will often dwell on negative scenarios from their past, wishing that things could have turned out differently in their lives.
Example: A man with OCD obsessively ruminates over how he may have struck someone with his car on the way home from work. He replays the scenario over and over again in an attempt to relieve his anxiety by proving this could never really happen without his knowing.