Hypochondriasis, which affects up to 5 percent of medical outpatients, is defined as a persistent fear or belief that one has a serious, undiagnosed medical illness. Except for one large-scale clinical trial, few well-designed studies have investigated the efficacy of treatment. Barsky and Ahern hypothesized that a cognitive behavior therapy (CBT) intervention would be more effective than usual care in alleviating hypochondriacal symptoms.

Subjects were recruited from physician practices and through a public announcement seeking volunteers. Hypochondriasis was assessed using a hypochondriasis questionnaire and included patients who met the Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV) criteria for hypochondriasis and those with subthreshold scores. Patients were included if they were older than 18 years, fluent in English, and had visited a primary care physician in the previous 12 months. CBT was provided in six 90-minute sessions, focusing on cognitive and behavioral amplification of symptoms, health beliefs, illness and sick role behaviors, and mood. The primary outcome variable was the hypochondriasis questionnaire, while secondary outcomes included health-related anxiety, frequency of hypochondriacal thoughts, hypochondriacal somatic symptoms, DSM-IV clinical diagnosis of hypochondriasis, role impairment, and functional status.

Of 187 eligible patients, 102 were randomized to treatment (allocation designated through the primary care physician), while 85 patients received usual care. Patients in the CBT group attended zero to six sessions, with 61.8 percent of patients attending all six sessions. Participants, most of whom were middle-aged women, were followed at six months and 12 months in person or by telephone. With respect to the primary outcome, measures of treatment effect and time showed a statistically significant interaction effect, with improvement in the treatment group compared with the control group at six- and 12-month follow-up.

Similarly, statistically significant interaction effects were noted for hypochondriacal thought frequency, health anxiety, somatosensory amplification, and improvements at six and 12 months in all secondary outcomes except hypochondriacal somatic symptoms. Functional status showed inconsistent improvements and interaction effects at six months but greater effect at 12 months for social activities.

The authors conclude that a six-session CBT intervention modestly but significantly improves a range of hypochondriacal symptoms, beliefs, and attitudes at six and 12 months. It is unclear whether these results are generalizable to all patients with hypochondriasis, because patients most amenable to treatment also may have been more willing to participate—only 30 percent of eligible patients entered the trial. Also, it is not known whether the CBT itself is effective, or whether any six-session program would be equally effective. The authors note that hypochondriasis often is refractory to treatment and, in this study, improvement involved better coping methods rather than cure.