illness anxiety disorder

**Definition (DSM-5):** Illness anxiety disorder (IAD) requires: (1) preoccupation with having or acquiring a serious illness; (2) somatic symptoms absent or only mild (if another medical condition or a high risk for one is present, the preoccupation is clearly excessive or disproportionate); (3) high level of anxiety about health, with easy alarm over personal health status; (4) excessive health-related behaviors (repeated checking of the body for signs of illness) or maladaptive avoidance (avoiding doctors and hospitals); (5) illness preoccupation present for at least 6 months (the feared illness may change over time); (6) not better explained by another mental disorder (somatic symptom disorder, panic disorder, GAD, body dysmorphic disorder, OCD, delusional disorder, somatic type).

**Subtypes:** - Care-seeking type: frequent doctor visits, tests, and referrals. - Care-avoidant type: avoids medical care because of fear of a diagnosis.

**Key distinction from related disorders (high-yield):** - Somatic symptom disorder: one or more distressing somatic symptoms are present, with excessive thoughts, feelings, or behaviors about them for ≥6 months. The main problem is the symptom. In IAD the main problem is the fear of having a disease, and symptoms are minimal or absent. - Conversion disorder (functional neurologic symptom disorder): neurologic deficits (weakness, blindness, pseudoseizures) incompatible with known neurologic disease. Patients may show "la belle indifférence." - Factitious disorder: intentional symptom production for the sick role (primary gain), with no external reward. In malingering, symptoms are intentionally produced for external gain (money, avoiding work). - Delusional disorder, somatic type: fixed false belief about illness without insight. IAD patients can usually be briefly reassured, though the reassurance does not last. - Panic disorder: health fears occur during discrete panic attacks. - OCD: intrusive thoughts and compulsions are not limited to health fears.

**Pathophysiology and epidemiology:** The cause is multifactorial. Proposed contributors are a cognitive model of catastrophic misinterpretation of normal bodily sensations, heightened somatic awareness, past childhood illness or a family member's serious illness, and abuse history. It is associated with comorbid anxiety, depression, and OCD. Prevalence is about 1-5%, with roughly equal rates in men and women. The course is usually chronic and waxing and waning.

**Clinical features:** Reassurance after a negative workup gives only brief relief. Patients repeatedly check their bodies, research symptoms online ("cyberchondria"), and seek repeated reassurance. This causes distress and functional impairment. Physical exam and testing are normal or show only mild findings that cannot account for the level of concern.

**Management:** - Establish a long-term relationship with a single primary care physician. Schedule regular, brief visits rather than symptom-driven ones. Limit unnecessary testing and specialist referrals. - CBT is first-line psychotherapy. It addresses catastrophic thinking and reduces checking and reassurance-seeking. - SSRIs are helpful, especially with comorbid anxiety, depression, or OCD. - Screen for and treat comorbid psychiatric disorders. - Avoid dismissing the patient ("it's all in your head"), because this damages the alliance.

**Board pearl:** A patient who is convinced they have cancer or another serious disease despite repeated negative workups, with no or minimal symptoms, for ≥6 months has illness anxiety disorder. Best next step: regular scheduled visits with the same physician, plus CBT.