Somatoform Disorders
Somatoform disorders involve physical symptoms that cannot be fully explained by a medical condition. They cause significant distress and functional impairment.
Key Facts
Somatic symptom disorder (DSM-5) replaces older terms — excessive thoughts, feelings, or behaviours related to somatic symptoms Prevalence ~5-7% in primary care; F:M 2:1 Physical symptoms are genuinely experienced — not feigned (unlike factitious disorder/malingering) Common presentations: Pain, fatigue, GI symptoms, neurological symptoms (functional neurological disorder) NICE CG127 addresses recognition of medically unexplained symptoms in primary care CBT is the most effective psychological treatment — reduces symptom burden and disability Avoid unnecessary investigations — they reinforce health anxiety and illness behaviour Comorbid anxiety and depression in >50% of cases
Overview
Key Facts
Somatoform/somatic symptom disorders involve physical symptoms accompanied by excessive and disproportionate thoughts, feelings, or behaviours. The symptoms are not intentionally produced.
Epidemiology
Approximately 15-30% of primary care consultations involve medically unexplained symptoms. Somatic symptom disorder affects ~5-7% of primary care patients. More common in women and lower socioeconomic groups.
Aetiology
- Biological: Central sensitisation, altered pain processing, autonomic dysregulation, inflammation
- Psychological: Health anxiety, catastrophic misinterpretation of symptoms, somatisation as emotional expression, childhood adversity
- Social: Illness modelling, secondary gain (not conscious), sick role reinforcement
Pathophysiology
- Central sensitisation amplifies normal bodily sensations
- Selective attention to bodily symptoms increases their perceived intensity
- Cortical processing of interoceptive signals is altered — functional MRI shows differences in insular and prefrontal cortex activation
- HPA axis dysregulation and autonomic dysfunction may produce real physiological symptoms
Clinical Presentation
Common Presentations
- Pain: Chronic widespread pain, headache, back pain, abdominal pain
- GI: IBS, non-cardiac chest pain, globus sensation
- Neurological: Functional neurological disorder (weakness, tremor, seizures, sensory loss)
- Fatigue: Chronic fatigue without medical explanation
- Multiple symptoms: Multiple organ systems involved
Key Clinical Features
- Symptoms are disproportionate to any identified pathology
- Excessive time and energy devoted to health concerns
- High healthcare utilisation (frequent GP visits, A&E attendances)
- Persistent despite medical reassurance
- Significant functional impairment
Red Flags
- Exclude organic disease before diagnosing — thorough but focused investigation
- Psychiatric comorbidity: Depression (~50%), anxiety (~50%), personality disorder
- Suicide risk if severe functional impairment and despair
- Iatrogenic harm from unnecessary investigations and treatments
Differential Diagnosis
| Diagnosis | Key Features | Investigation |
|---|---|---|
| Organic disease | Objective findings matching symptoms | Guided investigation |
| Health anxiety (illness anxiety disorder) | Fear of having disease despite minimal symptoms | Clinical assessment |
| Depression | Low mood, anhedonia, somatic symptoms | PHQ-9 |
| Factitious disorder | Intentional production of symptoms for sick role | Clinical observation |
| Malingering | Intentional symptom production for external gain | Medico-legal context |
| Functional neurological disorder | Neurological symptoms with positive clinical signs | Hoover's sign, clinical assessment |
Diagnosis / Investigation
Bedside
- PHQ-15: Somatic symptom severity scale (15 items)
- PHQ-9, GAD-7: Comorbid depression and anxiety
- Functional assessment: Impact on daily life, work, relationships
Bloods
- Focused investigation based on presenting symptoms — avoid shotgun approach
- FBC, TFTs, inflammatory markers as reasonable baseline
- Stop investigating when adequate exclusion of serious pathology achieved
Special Tests
- Guided by clinical presentation — principle of 'just enough' investigation
- Avoid unnecessary imaging and specialist referrals that reinforce illness behaviour
Management
Non-pharmacological
- Therapeutic relationship: Continuity of care with single GP, regular scheduled appointments (not symptom-driven)
- Validation: Acknowledge symptoms are real and distressing
- Explanation: Sensitisation model, stress-symptom link, biopsychosocial framework
- CBT: Most effective treatment — addresses catastrophic thinking, illness behaviour, avoidance; 12-16 sessions
- Graded exercise/activity: Gradual return to function
- Reduce secondary gain: Minimise reinforcement of sick role
Pharmacological
- SSRIs: Sertraline 50-200mg or duloxetine 60-120mg — effective for somatic symptoms even without depression
- Low-dose TCAs: Amitriptyline 10-50mg ON for pain-predominant symptoms
- Pregabalin: 150-600mg/day for pain (off-label in this context)
- Avoid: Opioids, benzodiazepines, unnecessary polypharmacy
Referral Criteria
- Specialist liaison psychiatry/psychological medicine if severe functional impairment
- Persistent symptoms despite primary care management
- Complex comorbidity
Prognosis
- Chronic course in many cases; ~50% improve with treatment, ~20% have poor long-term outcomes
- CBT improves symptoms in ~50-60% of patients
- Comorbid depression and personality disorder worsen prognosis
- Iatrogenic harm from unnecessary investigations/treatments is a significant risk
- Early intervention and explanation improve outcomes
Other Relevant Information
DSM-5 Classification Changes
| Old Term | New Term |
|---|---|
| Somatisation disorder | Somatic symptom disorder |
| Hypochondriasis | Illness anxiety disorder (or somatic symptom disorder) |
| Conversion disorder | Functional neurological symptom disorder |
| Pain disorder | Somatic symptom disorder with predominant pain |