Obsessive–compulsive disorder

Obsessive–compulsive disorder

Obsessive–compulsive disorder (OCD) is ananxiety disorder characterized by intrusive thoughtsthat produce uneasiness, apprehension, fear or worry (obsessions), repetitive behaviors aimed at reducing the associated anxiety (compulsions), or a combination of such obsessions and compulsions. Symptoms of the disorder include excessive washing or cleaning, repeated checking, extreme hoarding, preoccupation with sexual, violent or religious thoughts, relationship-related obsessions, aversion to particular numbers and nervous rituals such as opening and closing a door a certain number of times before entering or leaving a room. These symptoms are time-consuming, might result in loss of relationships with others, and often cause severe emotional and financial distress. The acts of those who have OCD may appear paranoid and potentiallypsychotic. However, people with OCD generally recognize their obsessions and compulsions as irrational and may become further distressed by this realization. Despite the irrational behaviour, OCD is associated with high verbal IQ.

Causes

Psychological

An evolutionary psychology view is that moderate versions of compulsive behavior may have had evolutionary advantages. Examples would be moderate constant checking of hygiene, the hearth, or the environment for enemies. Similarly, hoarding may have had evolutionary advantages. In this view OCD may be the extreme statistical "tail" of such behaviors possibly due to a high amount of predisposing genes.

Biological

OCD has been linked to abnormalities with the neurotransmitter serotonin, although it could be either a cause or an effect of these abnormalities. Serotonin is thought to have a role in regulating anxiety. To send chemical messages from one neuron to another, serotonin must bind to thereceptor sites located on the neighboring nerve cell. It is hypothesized that the serotonin receptors of OCD sufferers may be relatively understimulated. This suggestion is consistent with the observation that many OCD patients benefit from the use of selective serotonin reuptake inhibitors(SSRIs), a class of antidepressant medications that allow for more serotonin to be readily available to other nerve cells.^[35]

A possible genetic mutation may contribute to OCD. A mutation has been found in the human serotonin transporter gene, hSERT, in unrelated families with OCD.^[36] Moreover, data from identical twins supports the existence of a "heritable factor for neurotic anxiety".^[37] Further, individuals with OCD are more likely to have first-degree family members exhibiting the same disorders than do matched controls. In cases where OCD develops during childhood, there is a much stronger familial link in the disorder than cases in which OCD develops later in adulthood. In general, genetic factors account for 45–65% of OCD symptoms in children diagnosed with the disorder.^[38] Environmental factors also play a role in how these anxiety symptoms are expressed; various studies on this topic are in progress and the presence of a genetic link is not yet definitely established.