What Causes OCD?

The old belief that OCD was the result of life experiences has been weakened before the growing evidence that biological factors are a primary contributor to the disorder. The fact that OCD patients respond well to specific medications that affect the neurotransmitter serotonin suggests the disorder has a neurobiological basis. For that reason, OCD is no longer attributed only to attitudes a patient learned in childhood--for example, an inordinate emphasis on cleanliness, or a belief that certain thoughts are dangerous or unacceptable. Instead, the search for causes now focuses on the interaction of neurobiological factors and environmental influences, as well as cognitive processes.

OCD is sometimes accompanied by depression, eating disorders, substance abuse disorder, a personality disorder, attention deficit disorder, or another of the anxiety disorders. Co-existing disorders can make OCD more difficult both to diagnose and to treat.

In an effort to identify specific biological factors that may be important in the onset or persistence of OCD, NIMH-supported investigators have used a device called the positron emission tomography (PET) scanner to study the brains of patients with OCD. Several groups of investigators have obtained findings from PET scans suggesting that OCD patients have patterns of brain activity that differ from those of people without mental illness or with some other mental illness. Brain-imaging studies of OCD showing abnormal neurochemical activity in regions known to play a role in certain neurological disorders suggest that these areas may be crucial in the origins of OCD. There is also evidence that treatment with medications or behavior therapy induce changes in the brain coincident with clinical improvement.

Recent preliminary studies of the brain using magnetic resonance imaging showed that the subjects with obsessive-compulsive disorder had significantly less white matter than did normal control subjects, suggesting a widely distributed brain abnormality in OCD. Understanding the significance of this finding will be further explored by functional neuroimaging and neuropsychological studies (Jenike et al, 1996).

Symptoms of OCD are seen in association with some other neurological disorders. There is an increased rate of OCD in people with Tourette's syndrome, an illness characterized by involuntary movements and vocalizations. Investigators are currently studying the hypothesis that a genetic relationship exists between OCD and the tic disorders.

Other illnesses that may be linked to OCD are trichotillomania (the repeated urge to pull out scalp hair, eyelashes, eyebrows or other body hair), body dysmorphic disorder (excessive preoccupation with imaginary or exaggerated defects in appearance), and hypochondriasis (the fear of having--despite medical evaluation and reassurance--a serious disease). Genetic studies of OCD and other related conditions may enable scientists to pinpoint the molecular basis of these disorders.

Other theories about the causes of OCD focus on the interaction between behavior and the environment and on beliefs and attitudes, as well as how information is processed. These behavioral and cognitive theories are not incompatible with biological explanations.

Do I Have OCD?

(link to OCD screening test)

A person with OCD has obsessive and compulsive behaviors that are extreme enough to interfere with everyday life. People with OCD should not be confused with a much larger group of individuals who are sometimes called "compulsive" because they hold themselves to a high standard of performance and are perfectionistic and very organized in their work and even in recreational activities. This type of "compulsiveness" often serves a valuable purpose, contributing to a person's self-esteem and success on the job. In that respect, it differs from the life-wrecking obsessions and rituals of the person with OCD.

Treatment of OCD; Progress Through Research

Clinical and animal research sponsored by NIMH and other scientific organizations has provided information leading to both pharmacologic and behavioral treatments that can benefit the person with OCD. One patient may benefit significantly from behavior therapy, while another will benefit from pharmacotherapy. Some others may use both medication and behavior therapy. Others may begin with medication to gain control over their symptoms and then continue with behavior therapy. Which therapy to use should be decided by the individual patient in consultation with his or her therapist.

Pharmacotherapy

Clinical trials in recent years have shown that drugs that affect the neurotransmitter serotonin can significantly decrease the symptoms of OCD. The first of these serotonin reuptake inhibitors (SRIs) specifically approved for the use in the treatment of OCD was the tricyclic antidepressant clomipramine (AnafranilR). It was followed by other SRIs that are called "selective serotonin reuptake inhibitors" (SSRIs). Those that have been approved by the Food and Drug Administration for the treatment of OCD are flouxetine (ProzacR), fluvoxamine (LuvoxR), and paroxetine (PaxilR). Another that has been studied in controlled clinical trials is sertraline (ZoloftR). Large studies have shown that more than three-quarters of patients are helped by these medications at least a little. And in more than half of patients, medications relieve symptoms of OCD by diminishing the frequency and intensity of the obsessions and compulsions. Improvement usually takes at least three weeks or longer. If a patient does not respond well to one of these medications, or has unacceptable side effects, another SRI may give a better response. For patients who are only partially responsive to these medications, research is being conducted on the use of an SRI as the primary medication and one of a variety of medications as an additional drug (an augmenter). Medications are of help in controlling the symptoms of OCD, but often, if the medication is discontinued, relapse will follow. Indeed, even after symptoms have subsided, most people will need to continue with medication indefinitely, perhaps with a lowered dosage.