MedGen

Obsessive-compulsive disorder (OCD) is characterized by recurring obsessions and/or compulsions and has been estimated to affect nearly 5 million people in the United States (Karno et al., 1988). Evidence for a strong genetic component in OCD comes from twin studies, family genetics studies, and segregation analyses, as reviewed by Alsobrook et al. (2002). Zhang et al. (2002) suggested that hoarding is likely to be an evolutionarily conserved trait that, in times of adversity, was associated with increased survival and reproductive fitness. However, extreme forms of this trait are associated with marked disability and poor response to treatment (Black et al., 1998; Mataix-Cols et al., 1999). [from OMIM]

Intense feelings of nervousness, tension, or panic often arise in response to interpersonal stresses. There is worry about the negative effects of past unpleasant experiences and future negative possibilities. Individuals may feel fearful, apprehensive, or threatened by uncertainty, and they may also have fears of falling apart or losing control. [from HPO]