Illness Anxiety Disorder

The DSM-5 Successor to Hypochondriasis: Diagnosis, Subtypes, and Treatment

Illness Anxiety Disorder (IAD) is the DSM-5 diagnosis characterized by preoccupation with having or acquiring a serious illness, despite the absence — or only mild presence — of somatic symptoms. It replaces and refines the older diagnosis of hypochondriasis, which was discarded in DSM-5 due to its stigmatizing connotations. IAD is distinguished by the central role of cognitive preoccupation rather than physical complaints.

For a broader, lay-friendly overview of health-related fears, see health anxiety. This page focuses specifically on the formal DSM-5 disorder.

Key Facts

  • Prevalence: 1.3–10% in primary care; ~3–8% community estimates
  • Equal gender distribution
  • Onset typically in early to middle adulthood
  • Roughly 75% of former hypochondriasis cases reclassified as Somatic Symptom Disorder; the remainder as IAD
  • Two specifiers: care-seeking type and care-avoidant type
  • CBT is first-line; SSRIs are second-line

DSM-5 Diagnostic Criteria

Illness Anxiety Disorder (300.7 / F45.21) requires all of the following:

  1. Preoccupation with having or acquiring a serious illness
  2. Somatic symptoms are not present, or if present, are only mild in intensity. If another medical condition is present, the preoccupation is clearly excessive or disproportionate
  3. High level of anxiety about health, with the individual easily alarmed about personal health status
  4. Excessive health-related behaviors (e.g., repeated body checking, doctor visits) or maladaptive avoidance (e.g., avoiding appointments, hospitals, or sick relatives)
  5. Illness preoccupation has been present for at least 6 months, though the specific feared illness may change
  6. The illness-related preoccupation is not better explained by another mental disorder

Subtypes

Care-Seeking Type

  • Frequent medical visits and procedures
  • Excessive online symptom checking
  • Repeated requests for tests, scans, and second opinions
  • Persistent reassurance-seeking from family or providers
  • Body-checking behaviors (palpation, mirror examination, pulse monitoring)

Care-Avoidant Type

  • Avoidance of routine medical care, screenings, and check-ups
  • Avoidance of hospitals, ill relatives, or media coverage of disease
  • Refusal to discuss bodily symptoms
  • Avoidance can lead to delayed diagnosis of genuine medical problems

IAD vs. Somatic Symptom Disorder

The DSM-5 split former hypochondriasis into two diagnoses based on whether somatic symptoms are prominent:

  • Illness Anxiety Disorder: Preoccupation drives the picture; somatic symptoms are absent or mild
  • Somatic Symptom Disorder (SSD): One or more distressing somatic symptoms are prominent and accompanied by excessive thoughts, feelings, or behaviors related to them

Roughly 75% of patients formerly diagnosed with hypochondriasis are now classified as having SSD, with the remaining 25% meeting criteria for IAD.

Cyberchondria

Cyberchondria refers to repeated, escalating online searching for health information that intensifies rather than alleviates illness anxiety. While not a formal diagnosis, it is a common maintenance behavior in IAD. Features include:

  • Compulsive symptom checking on search engines and forums
  • Catastrophic interpretation of common symptoms
  • Brief reassurance followed by renewed searching
  • Increased anxiety and reduced functioning over time

Targeting cyberchondria is often a key element of CBT for IAD.

Differential Diagnosis

  • Somatic Symptom Disorder: Distinguished by prominent somatic complaints
  • Generalized Anxiety Disorder: Worry spans many domains, not exclusively health
  • OCD: Health worries take an obsessive-compulsive form (e.g., contamination); see OCD
  • Body Dysmorphic Disorder: Preoccupation focuses on appearance defects, not illness
  • Major Depressive Disorder: Health worries occur within a depressive episode and remit with mood improvement
  • Panic Disorder: Fears center on the panic episode itself rather than long-term illness
  • Delusional Disorder, Somatic Type: Beliefs about illness are held with delusional intensity and are not amenable to reassurance

Etiology and Maintenance

Predisposing Factors

  • Childhood illness (personal or in caregivers)
  • History of medical trauma or misdiagnosis
  • Family modeling of illness behavior
  • High trait anxiety, neuroticism, intolerance of uncertainty

Cognitive Maintenance Model

  1. Normal bodily sensations are detected (selective attention)
  2. Sensations are catastrophically misinterpreted as signs of serious disease
  3. Anxiety amplifies sensations (vicious cycle)
  4. Safety behaviors (checking, reassurance, searching) provide brief relief
  5. Relief reinforces the cycle, preventing disconfirmation of illness fears

Assessment

  • Short Health Anxiety Inventory (SHAI): 18-item validated screen
  • Whiteley Index: Classic measure of illness preoccupation
  • Illness Attitudes Scale (IAS): Multidimensional
  • Functional analysis: triggers, body-checking, reassurance-seeking, avoidance
  • Review of medical record: prior tests, specialist consultations, ER visits
  • Coordination with primary care to set boundaries on testing

Evidence-Based Treatment

Cognitive-Behavioral Therapy (First-Line)

CBT for IAD has the strongest evidence base. Core components include:

  • Psychoeducation on the cognitive maintenance model
  • Cognitive restructuring of catastrophic illness appraisals
  • Exposure to feared bodily sensations (interoceptive exposure)
  • Exposure to illness-related cues (hospitals, medical content)
  • Response prevention: eliminating checking, reassurance-seeking, and online searching
  • Behavioral experiments to test illness predictions
  • Mindfulness-based approaches for tolerating uncertainty

Pharmacotherapy

  • SSRIs (fluoxetine, paroxetine, fluvoxamine) show efficacy
  • Often combined with CBT for moderate-to-severe cases
  • Doses often higher than for major depression, similar to OCD ranges

Primary Care Management

  • Scheduled rather than symptom-driven appointments
  • Brief, focused visits emphasizing function over diagnosis
  • Avoidance of unnecessary tests that fuel the cycle
  • Consistent messaging across providers
  • Acknowledgment that distress is real, even when illness fears are not

Course and Prognosis

  • Without treatment, IAD tends to be chronic with waxing and waning intensity
  • The specific feared illness may change over time
  • Comorbidity is the rule, particularly with depression and other anxiety disorders
  • CBT response rates: 60–75%, with durable gains at 1-year follow-up
  • Care-avoidant patients face risk of delayed diagnosis of genuine medical conditions

Conclusion

Illness Anxiety Disorder represents a meaningful diagnostic refinement over hypochondriasis, distinguishing patients whose central problem is preoccupation and anxiety from those with prominent somatic symptoms. The shift acknowledges that what drives suffering and impairment is the cognitive and behavioral cycle of illness fear, not the symptoms themselves.

Effective treatment hinges on a single therapeutic insight: reassurance, in any form — medical testing, online searching, body checking — is the engine that keeps illness anxiety running. Eliminating reassurance, while building tolerance for uncertainty, is the path out.

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