Definition and DSM-5 criteria
Illness anxiety disorder (IAD) — historically “hypochondriasis” — is preoccupation with having or acquiring a serious illness in the near-absence of somatic symptoms. The defining contrast with somatic symptom disorder is the symptom burden: in IAD bodily symptoms are absent or mild, and the distress is driven by the fear of illness rather than by the symptoms themselves. About a quarter of patients formerly labelled hypochondriacal map to IAD; the remainder, who have prominent somatic symptoms, map to SSD.
The DSM-5 criteria are:
- Criterion A — preoccupation with having or acquiring a serious illness.
- Criterion B — somatic symptoms are not present or, if present, are only mild; if another medical condition is present or there is a high risk of developing one, the preoccupation is clearly excessive or disproportionate.
- Criterion C — a high level of anxiety about health, and the person is easily alarmed about personal health status.
- Criterion D — excessive health-related behaviours (e.g. repeatedly checking the body for signs of illness) or maladaptive avoidance (avoiding appointments and hospitals).
- Criterion E — illness preoccupation present for at least 6 months, though the specific feared illness may change.
- Criterion F — not better explained by another mental disorder (e.g. SSD, panic, OCD, generalized anxiety, body dysmorphic disorder).
Specify type: care-seeking or care-avoidant.
Clinical features
In adolescents IAD presents as repeated reassurance-seeking, frequent internet symptom-searching (“cyberchondria”), body-checking, and either heavy or pointedly avoided medical contact. A child may fixate on a feared diagnosis after a relative’s illness or a media story. Normal physiological sensations — a heartbeat, a swollen lymph node — are catastrophically misinterpreted. Reassurance helps only transiently, then the cycle resumes. Comorbid anxiety, depression and OCD are common.
Diagnosis
IAD is a positive diagnosis made on the pattern of disproportionate illness fear with minimal somatic symptoms, sustained ≥6 months. Distinguish it from SSD (prominent somatic symptoms), generalized anxiety disorder (broader worry), panic disorder (acute episodic fear), and OCD/body dysmorphic disorder. A focused, time-limited work-up excludes serious disease, but repeated investigation is itself reinforcing and should be limited.
See the full criteria: Illness Anxiety Disorder
Red flags
- Genuine new objective signs (mass, weight loss, fever, focal deficit) — investigate appropriately rather than attributing to anxiety
- The care-avoidant child who is dangerously avoiding necessary care for a real condition
- Suicidality or severe functional impairment — mental-health referral
- Escalating, family-driven demands for invasive testing
- Diagnostic overshadowing — do not let an IAD label delay work-up of a new, genuinely concerning symptom
Management overview
Begin by validating the distress — the fear is real and exhausting — while gently reframing the problem as one of anxiety about health rather than undiagnosed disease. Avoid the two common errors: endless reassurance and repeat testing (which entrench the cycle) and dismissiveness (which ruptures trust). Set a single coordinating clinician and scheduled, time-based reviews rather than symptom-triggered visits.
The evidence-based core is cognitive-behavioural therapy targeting catastrophic misinterpretation, reassurance-seeking and body-checking, with graded exposure and response prevention. Psychoeducation, limiting symptom-searching, and family involvement (parental modelling matters) are central. Treat comorbid anxiety or depression; an SSRI may be considered by a child mental-health specialist where comorbidity warrants it. Coordinate firmly but compassionately to reduce iatrogenic harm from over-investigation.
References
- American Psychiatric Association. DSM-5-TR. 2022.
- MSD Manual Professional. Illness Anxiety Disorder. 2024.
- Axelsson E, Hedman-Lagerlof E. Health anxiety. Curr Opin Psychiatry. 2019.
Decision support for qualified clinicians only — verify against current primary guidelines and your clinical judgement.