This disorder is characterized by a preoccupation with having or acquiring a serious illness. While bodily symptoms may be present, they are often mild, or if there is a high risk of developing a medical condition (for example, there is a family history of a specific medical condition), the preoccupation is clearly excessive and disproportionate.

Those of us with Illness Anxiety Disorder experience a high level of anxiety about our health, become easily alarmed about our health, and often perform excessive health-related behaviors to reduce our anxiety or avoid health-related behaviors entirely (also to reduce our anxiety). Excessive health-related behaviors may be as subtle as checking our bodies for symptoms or as explicit as repeatedly contacting our primary care provider to seek reassurance about an ambiguous symptom.