Obsessive-Compulsive Disorder

Prevalence

The 12-month prevalence of OCD in the United States is 1.2%, with a similar prevalence internationally (1.1%-1.8%).
Females are affected at a slightly higher rate than males in adulthood, although males are more commonly affected in childhood.

Physical and sexual abuse in childhood and other stressful or traumatic events.
Some children may develop the sudden onset of obsessive-compulsive symptoms, which has been associated with different environmental factors, including various infectious agents and a post-infectious autoimmune syndrome.

The rate of OCD among first-degree relatives of adults with OCD is approximately two times that among first-degree relatives of those without the disorder;
However, among first-degree relatives of individuals with onset of OCD in childhood or adolescence, the rate is increased 10-fold.
Familial transmission is due in part to genetic factors (e.g., a concordance rate of 0.57 for monozygotic vs. 0.22 for dizygotic twins).
Dysfunction in the orbitofrontal cortex, anterior cingulate cortex, and striatum have been most strongly implicated.

Obsessions are defined by:

1. Recurrent and persistent thoughts, urges, or images that are experienced, at some time during the disturbance, as intrusive and unwanted, and that in most individuals cause marked anxiety or distress.
2. The individual attempts to ignore or suppress such thoughts, urges, or images, or to neutralize them with some other thought or action (i.e., by performing a compulsion).

Compulsions are defined by:

1. Repetitive behaviors (e.g., hand washing, ordering, checking) or mental acts (e.g., praying, counting, repeating words silently) that the individual feels driven to perform in response to an obsession or according to rules that must be applied rigidly.
2. The behaviors or mental acts are aimed at preventing or reducing anxiety or distress, or preventing some dreaded event or situation; however, these behaviors or mental acts are not connected in a realistic way with what they are designed to neutralize or prevent, or are clearly excessive.

The obsessions or compulsions are time-consuming (e.g., take more than 1 hour per day) or cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.
The obsessive-compulsive symptoms are not attributable to the physiological effects of a substance (e.g., a drug of abuse, a medication) or another medical condition.
The disturbance is not better explained by the symptoms of another mental disorder.