Obsessive-Compulsive Disorder: Contamination

Contamination

Contamination obsessions are the most frequently encountered obsessions in OCD. Such obsessions are usually character-ized by a fear of dirt or germs. Contamination fears may also involve toxins or environmental hazards (e.g., asbestos or lead) or bodily waste or secretions. Patients usually describe a feared consequence of contacting a contaminated object, such as spread-ing a disease or contracting an illness themselves. Occasionally, however, the fear is based not on a fear of disease but on a fear of the sensory experience of not being clean. The content of the contamination obsession and the feared consequence commonly changes over time; for example, a fear of cancer may be replaced by a fear of a sexually transmitted disease.

Many patients with contamination fears use avoidance to prevent contact with contaminants, as is illustrated by a 58-year-old housewife who spent the entire day sitting in a chair to avoid touching anything in the house that might be dirty. In some cases, a specific feared object and associated avoidance become more generalized. For example, a woman with a fear of acquired im-munodeficiency syndrome (AIDS) initially avoided anything that looked like dried blood but eventually avoided anything red.

Excessive washing is the compulsion most commonly as-sociated with contamination obsessions. This behavior usually occurs after contact with the feared object; however, proximity to the feared stimulus is often sufficient to engender severe anxiety and washing compulsions, even though the contaminated object has not been touched. Most patients with washing compulsions perform these rituals in response to a fear of contamination, but these behaviors occasionally occur in response to a drive for perfection or a need for symmetry. Some patients, for example, repeatedly wash themselves in the shower until they feel “right” or must wash their right arm and then their left arm the same number of times.

Need for Symmetry

Need for symmetry is a term that describes a drive to order or arrange things perfectly or to perform certain behaviors sym-metrically or in a balanced way. Patients describe an urge to repeat motor acts until they achieve a “just right” feeling that the act has been completed perfectly. Patients with a prominent need for symmetry may have little anxiety but rather describe feeling unsettled or uneasy if they cannot repeat actions or order things to their satisfaction. In addition to a need for perfection, the drive to achieve balance or symmetry may be connected with magical thinking. The desire to “even up” or balance movements may be present in patients with tapping or touching rituals. Such a patient may, for example, feel that the right side of the chair must be tapped after the left side has been tapped. Such urges and behaviors are frequently seen in patients with comorbid tic disorders, who may, for example, describe an urge to tic on the right side of their body after experiencing a tic on the left side. Patients with a need for symmetry frequently present with obses-sional slowness, taking hours to perform acts such as grooming or brushing their teeth.