Somatic Symptom Disorder and Illness Anxiety Disorder

Risk factors

• Childhood adversity (abuse, neglect, chronic illness)
• Family history of somatization or anxiety disorders
• Comorbid depression and anxiety
• History of medical illness in self or family
• Personality traits: high neuroticism, alexithymia
• Female sex (SSD)
• Online health-information seeking (cyberchondria as IAD subset)

Pathophysiology

Heightened interoceptive perception with maladaptive cognitive appraisal — benign sensations interpreted as dangerous. Insular cortex and anterior cingulate hyperactivity. HPA-axis dysregulation in some patients. Learned illness behavior and reinforcement contribute.

Clinical presentation

Differential diagnosis

• Undiagnosed medical illness — Always perform appropriate workup — SSD/IAD do NOT exclude real disease; a patient can have both
• Conversion disorder — Neurologic symptoms incompatible with known disease (e.g., functional weakness, nonepileptic seizures)
• Factitious disorder — Intentional production of symptoms for sick role; deception present
• Malingering — Intentional production for external incentive (disability, drugs); not a mental disorder
• Generalized anxiety disorder — Worry spans multiple domains, not focused on health/symptoms
• Major depressive disorder — Somatic complaints common; mood symptoms predominate
• Obsessive-compulsive disorder (illness obsessions) — Obsessions are ego-dystonic; rituals beyond checking
• Body dysmorphic disorder — Focus is on perceived appearance defect, not illness
• Delusional disorder, somatic type — Fixed false belief held with delusional intensity

Diagnostic workup

Diagnostic algorithm

Treatment

Complications

• Iatrogenic harm from repeated testing, procedures, and polypharmacy
• Substance use, especially opioid and benzodiazepine dependence
• Major depression, suicide
• Functional disability, occupational loss
• Damaged therapeutic relationships and provider burnout

PANCE pearls

• DSM-5-TR eliminated the requirement that symptoms be 'medically unexplained' — the disorder is defined by the disproportionate response, not by absence of disease.
• Patients with SSD or IAD CAN have real medical illness; do not anchor diagnostically.
• The most effective intervention is a structured, regular relationship with one primary care provider.
• CBT is more durable than medication; combine when comorbid mood/anxiety disorders are present.
• Cyberchondria (compulsive online symptom searching) is a modern variant of IAD and predicts higher distress.

References

• DSM-5-TR — American Psychiatric Association. DSM-5-TR. 2022.
• AAFP 2016 — Kurlansik SL, Maffei MS. Somatic Symptom Disorder. Am Fam Physician 2016;93(1):49-54.
• Cochrane 2014 — van Dessel N et al. Non-pharmacological interventions for somatoform disorders and medically unexplained physical symptoms in adults. Cochrane Database Syst Rev 2014;11:CD011142.