Obsessive-compulsive disorder Health Article

Definition

Obsessive-compulsive disorder (OCD) is currently classified as an anxiety disorder marked by the recurrence of intrusive or disturbing thoughts, impulses, images or ideas (obsessions) accompanied by repeated attempts to suppress these thoughts through the performance of certain irrational and ritualistic behaviors or mental acts (compulsions). The obsessions and compulsions take up large amounts of the patient's time (an hour or longer every day) and usually cause significant emotional distress for the patient and difficulties in his or her relationships with others.

Some researchers have questioned whether OCD really belongs with the other anxiety disorders. They think that it should be grouped with the spectrum of such obsessive-compulsive disorders as Tourette's syndrome, which are known to have biological causes.

OCD should not be confused with obsessive-compulsive personality disordereven though the two disorders have similar names. Obsessive-compulsive personality disorder is not characterized by the presence of obsessions and compulsions; rather, it is a lifelong pattern of insistence on control, orderliness, and perfection that begins no later than the early adult years. It is possible, however, for a person to have both disorders.

Description

Obsessive-compulsive disorder is a mental disorder with two components: obsessions, which consist of thoughts, impulses, or mental images; and compulsions, which are repetitive behaviors that the person feels driven to perform in response to the obsessions. In some cases, the compulsionmay represent a strict rule that the patient must apply rigidly in every situation (tying one's shoes a certain number of times, for example) in order to feel "right." The exact content of obsessions varies from person to person, although certain themes are common. People with OCD experience their disturbing thoughts and images as intrusive and troublesome, but they recognize that their thoughts are products of their own minds. Obsessive thoughts are different from worries about such real-life problems as losing one's job or bad grades in school. In addition, obsessive thoughts are not usually related to any real-life problems.

The most common types of obsessions in persons with OCD in Western countries are:

• fear of contamination (impurity, pollution, badness)
• doubts (worrying about whether one has omitted to do something)
• an intense need to have or put things in a particular order
• aggressive or frightening impulses
• recurrent sexual thoughts or images

It is important to understand that patients diagnosed with OCD do not perform their compulsions for pleasure or satisfaction. A compulsive behavior becomes linked to an obsessional thought because the behavior lowers the level of anxiety produced by the obsession(s).

The most common compulsions in Western countries are:

• washing/cleaning
• counting
• hoarding
• checking
• putting objects in a certain order
• repeated "confessing" or asking others for assurance
• repeated actions
• making lists

Although descriptions of patients with OCD have been reported since the fifteenth century in religious and psychiatric literature, the condition was widely assumed to be rare until very recently. Epidemiological research since 1980 has now identified OCD as the fourth most common psychiatric illness, after phobias, substance use disorders, and major depressive disorders. OCD is presently classified as a form of anxiety disorder, but current studies indicate that it results from a combination of psychological, neurobiological, genetic, and environmental causes.

Causes

PSYCHOSOCIAL.In the early part of the century, Sigmund Freud theorized that OCD symptoms were caused by punitive, rigid toilet-training practices that led to internalized conflicts. Other theorists thought that OCD was influenced by such wider cultural attitudes as insistence on cleanliness and neatness, as well as by the attitudes and parenting style of the patient's parents. Cross-cultural studies of OCD indicate that, while the incidence of OCD seems to be about the same in most countries around the world, the symptoms are often shaped by the patient's culture of origin. For example, a patient from a Western country may have a contamination obsessionthat is focused on germs, whereas a patient from India may fear contamination by touching a person from a lower social caste.

Studies of families with OCD members indicate that the particular expression of OCD symptoms may be affected by the responses of other people. Families with a high tolerance for the symptoms are more likely to have members with more extreme or elaborate symptoms. Problems often occur when the OCD member's obsessions and rituals begin to control the entire family.

BIOLOGICAL.There is considerable evidence that OCD has a biological component. Some researchers have noted that OCD is more common in patients who have suffered head trauma or have been diagnosed with Tourette's syndrome. Recent studies using positron emission tomography(PET) scanning indicate that OCD patients have patterns of brainactivity that differ from those of people without mental illness or with some other mental illness. Other studies using magnetic resonance imaging(MRI) found that patients diagnosed with OCD had significantly less white matter in their brains than did normal control subjects. This finding suggests that there is a widely distributed brain abnormality in OCD. Some researchers have reported abnormalities in the metabolism of serotonin, an important neurotransmitter, in patients diagnosed with OCD. Serotonin affects the efficiency of communication between the front part of the brain (the cortex) and structures that lie deeper in the brain known as the basal ganglia. Dysfunction in the serotonergic system occurs in certain other mental illnesses, including major depression. OCD appears to have a number of features in common with the so-called obsessive-compulsive spectrum disorders, which include Tourette's syndrome; Sydenham's chorea; eating disorders; trichotillomania; and delusional disorders.

There appear to be genetic factors involved in OCD. The families of persons who are diagnosed with the disorder have a greater risk of OCD and tic disordersthan does the general population. Childhood-onset OCD appears to run in families more than adult-onset OCD, and is more likely to be associated with tic disorders. Twin studies indicate that monozygotic, or identical twins, are more likely to share the disorder than dizygotic, or fraternal twins. The concordance (match) rate between identical twins is not 100%, however, which suggests that the occurrence of OCD is affected by environmental as well as genetic factors. In addition, it is the general nature of OCD that seems to run in families rather than the specific symptoms; thus, one family member who is affected by the disorder may have a compulsion about washing and cleaning while another is a compulsive counter.

Large epidemiological studies have found a connection between streptococcal infections in childhood and the abrupt onset or worsening of OCD symptoms. The observation that there are two age-related peaks in the onset of the disorder increases the possibility that there is a common causal factor. Patients with childhood-onset OCD often have had one of two diseases caused by a group of bacteria called Group A beta-hemolytic streptococci ("strep" throat and Sydenham's chorea) prior to the onset of the OCD symptoms. The disorders are sometimes referred to as pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections, or PANDAS. It is thought that antibodies in the child's blood cross-react with structures in the basal ganglia, producing or worsening the symptoms of OCD or tic disorders.