Obsessive-Compulsive Disorder (OCD)
Both biological and psychological causes have been found in OCD.
The key features of this disorder include obsessions (persistent, often irrational, and seemingly uncontrollable thoughts) and compulsions (actions which are used to neutralize the obsessions). A good example of this would be an individual who has thoughts that he is dirty, infected, or otherwise unclean which are persistent and uncontrollable. In order to feel better, he washes his hands numerous times throughout the day, gaining temporary relief from the thoughts each time. For these behaviors to constitute OCD, it must be disruptive to everyday functioning (such as compulsive checking before leaving the house making you extremely late for all or most appointments, washing to the point of excessive irritation of your skin, or inability to perform everyday functions like work or school because of the obsessions or compulsions).
Medication is often prescribed for individuals with OCD. Psychotherapy can be helpful in learning ways to feel more in control, cope better with stressors, and explore the underlying issues associated with the obsessive thoughts.
Prognosis for this disorder has a wide range, depending upon how the individual responds to medication and how deep rooted the underlying issues are.