Obsessive-compulsive disorder or OCD Is one of the most common types of psychological disorder. OCD is most commonly defined by its symptoms. OCD sufferers experience recurrent, invasive thoughts or repetitive actions that are understood to be irrational and unnecessary. These recurring, invasive thoughts, calledobsessions, and uncontrollable, repetitive actions, called compulsions, cause the person significant stress and disruption in their daily life. Regardless of the name, not all people with OCD suffer from both obsessions and compulsions, even though it is most common together. OCD can take many forms. The following are only a few of the common types of OCD: Seeking cleanliness, orderliness or symmetry Performing repetitive acts that are thought to be protective, such as counting or praying Repeatedly checking, often for the purpose of safety Hoarding