People with illness anxiety disorder, previously known as hypochondriasis, are chronically anxious about their health and are convinced that they have or are developing a serious medical illness, despite the absence of somatic symptoms (see Table 10-5). They repeatedly check their body for signs of illness and misinterpret various bodily events as signs of serious medical problems. Typically the events are merely normal bodily changes, such as occasional coughing, sores, or sweating. Those with illness anxiety disorder persist in such misinterpretations no matter what friends, relatives, and physicians say. Some such people recognize that their concerns are excessive, but many do not.

Although illness anxiety disorder can begin at any age, it starts most often in early adulthood, among men and women in equal numbers. Between 1 and 5 percent of all people experience the disorder (Abramowitz & Braddock, 2011). Their symptoms tend to rise and fall over the years. Physicians report seeing many cases (Dimsdale et al., 2011). As many as 7 percent of all patients seen by primary care physicians may display the disorder.

Theorists typically explain illness anxiety disorder much as they explain various anxiety disorders (see Chapter 5). Behaviorists, for example, believe that the illness fears are acquired through classical conditioning or modeling (Marshall et al., 2007). Cognitive theorists suggest that people with the disorder are so sensitive to and threatened by bodily cues that they come to misinterpret them (Witthöft & Hiller, 2010; Williams, 2004).

People with illness anxiety disorder usually receive the kinds of treatments that are used to treat obsessive-compulsive disorder (see pages 164–169). Studies reveal, for example, that clients with the disorder often improve considerably when given the same antidepressant drugs that are helpful in cases of obsessive-compulsive disorder (Bouman, 2008). Many clients also improve when treated with the behavioral approach of exposure and response prevention, often combined with cognitive interventions (Abramowitz & Braddock, 2011). In this approach, the therapists repeatedly point out bodily variations to the clients while, at the same time, preventing them from seeking their usual medical attention. In addition, cognitive therapists guide the clients to identify, challenge, and change their beliefs about illness that are helping to maintain their disorder (Hedman et al., 2011).