Differentiating hypochondriasis from panic disorder.

Hypochondriasis and panic disorder are both characterized by prevalent health anxieties and illness beliefs. Therefore, the question as to whether they represent distinct nosological entities has been raised. This study examines how clinical characteristics can be used to differentiate both disorders, taking the possibility of mixed symptomatologies (comorbidity) into account. We compared 46 patients with hypochondriasis, 45 with panic disorder, and 21 with comorbid hypochondriasis plus panic disorder. While panic patients had more comorbidity with agoraphobia, hypochondriasis was more closely associated with somatization. Patients with panic disorder were less pathological than hypochondriacal patients on all subscales of the Whiteley Index (WI) and the Illness Attitude Scales (IAS) except for illness behavior. These differences were independent of somatization. Patients with hypochondriasis plus panic had higher levels of anxiety, more somatization, more general psychopathology and a trend towards increased health care utilization. Clinicians were able to distinguish between patient groups based upon the tendency of hypochondriacal patients to demand unnecessary medical treatments. These results confirm that hypochondriasis and panic disorder are distinguishable clinical conditions, characterized by generally more psychopathology and distress in hypochondriasis.