Somatic symptom and illness anxiety disorders !

Excessive worry about physical symptoms or about having a serious illness, causing distress and repeated medical visits, whether or not a disease is present.

Updated 2026-11-01

Structures involved

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What it is

In somatic symptom disorder, one or more distressing physical symptoms are accompanied by excessive thoughts, feelings and behaviours about them (disproportionate concern, high health anxiety, excessive time spent) for at least 6 months. In illness anxiety disorder, the person is preoccupied with having or acquiring a serious illness while bodily symptoms are absent or mild. The symptoms are not faked.

Who gets it

Somatic symptom disorder is estimated in about 5–7% of the general population and is much more frequent in primary care. Illness anxiety disorder affects about 1–5%. Both are common reasons for repeated consultations, tests and emergency visits in health systems of Latin America.

Causes

Heightened attention to and catastrophic interpretation of normal bodily sensations
Childhood experience of serious illness in self or family
Childhood adversity or trauma
Learned illness behaviour reinforced by attention or medical testing

Risk factors

Anxiety or depressive disorders
History of childhood abuse or neglect
Recent stressful life events
Chronic medical illness
Fewer years of formal education and lower socioeconomic level (somatic symptom disorder)

Pathophysiology

Thought to involve amplified processing of bodily signals (interoception) in the insula and anterior cingulate cortex, together with anxious, catastrophic beliefs about health. Checking, reassurance seeking and repeated testing reduce anxiety briefly but reinforce the cycle.

Classification

Somatic symptom disorder: distressing somatic symptoms plus disproportionate thoughts, feelings or behaviours; mild, moderate or severe; with predominant pain specifier
Illness anxiety disorder, care-seeking type: frequent consultations and tests
Illness anxiety disorder, care-avoidant type: avoids doctors and hospitals because of fear

Symptoms and signs

One or more physical symptoms (pain, fatigue, gastrointestinal, neurological) that cause distress
Persistent, disproportionate worry about the seriousness of symptoms
Preoccupation with having a serious illness despite reassurance
Frequent body checking, internet searches and requests for tests
Doctor shopping or, conversely, avoidance of medical care

Diagnosis

Clinical: Diagnosis is based on positive features (excessive thoughts, feelings and behaviours about symptoms or illness for at least 6 months), not merely on the absence of a medical explanation. A thorough initial history and examination should rule out medical disease; the presence of a disease does not exclude the diagnosis if the response is disproportionate.
Tests: Reasonable baseline tests guided by the symptoms; avoid repeated testing driven only by the patient's anxiety.
Imaging: Only when clinically indicated by new or objective findings.

Differential diagnosis

Undiagnosed medical illness (multiple sclerosis, lupus, thyroid disease, porphyria)
Panic disorder and generalised anxiety disorder
Major depressive disorder
Functional neurological symptom disorder (conversion disorder)
Factitious disorder and malingering (symptoms are intentionally produced)

Goal of treatment

Reduce distress and health-related anxiety, improve functioning and avoid unnecessary tests and harm, rather than eliminate every symptom.

Treatment

Conservative: A single, consistent primary care provider with regular scheduled visits (not only when symptoms arise), a brief examination each time and validation that the symptoms are real.
Conservative: Cognitive behavioural therapy, including mindfulness-based approaches, is the treatment with best evidence; it targets catastrophic thinking and checking or reassurance seeking.
Medical: Antidepressants (SSRIs or SNRIs) when depression, anxiety or pain coexist.
Follow-up: Coordination between services to limit unnecessary tests and procedures, careful review of medicines and periodic reassessment for new organic disease.

Complications

Iatrogenic harm from unnecessary tests, procedures and medicines
Depression and anxiety disorders
Disability and loss of work
High health care costs

Prognosis

Often chronic with fluctuations, especially with many symptoms and comorbid depression or anxiety. Outcomes improve with a stable therapeutic relationship and cognitive behavioural therapy; illness anxiety disorder may remit in a substantial proportion of people.

Test yourself

Think of the answer, then tap the question to see it.

Does the presence of a real medical disease exclude somatic symptom disorder?

No; the diagnosis rests on disproportionate thoughts, feelings and behaviours about the symptoms.

How does illness anxiety disorder differ from somatic symptom disorder?

In illness anxiety disorder somatic symptoms are absent or mild; the problem is the fear of having a serious illness.

What is the key management strategy in primary care?

One consistent provider with regular scheduled visits, avoiding unnecessary tests.

In which disorders are symptoms intentionally produced?

Factitious disorder (to assume the sick role) and malingering (for external gain).

Which psychotherapy has the best evidence?

Cognitive behavioural therapy.

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Educational information, not medical advice. For any symptom, see a health professional.

Sources: Somatic symptom disorder (MedlinePlus (U.S. National Library of Medicine), 2025); Illness anxiety disorder (MedlinePlus (U.S. National Library of Medicine), 2025).

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Representative model, for educational purposes only.

Insula highlighted on the Durgical 3D model