14th February 2025

Diagnosis of somatic symptom disorders

Presentation of somatic symptom disorders

The presence of a medically unexplained physical (or ‘somatic’) symptom is not sufficient for diagnosis. It must be accompanied by a set of maladaptive cognitive, emotional and behavioural responses for the diagnosis to apply. These responses may perpetuate or emphasise the physical symptom. 

The DSM-5 requires all three of the following criteria to be met for diagnosis of somatic symptom disorder:

• Presence of physical symptom(s) that cause distress or disruption to daily life 
• Thoughts, anxiety or time/energy spent in relation to the symptom(s), which is excessive for severity
• A continuous symptomatic state, usually for at least 6 months, even if no single symptom is continuous for this time (i.e. different symptoms may feature across this period)

The most well-known examples of somatic symptom disorders involve symptoms in the neurological domain:

• Conversion disorder: sensory or motor function deficit, e.g. limb paralysis, vision loss
• Non-epileptic seizures, also known as pseudoseizures, functional or psychogenic seizures

However, somatic symptom disorders can affect any organ system and can be non-specific. For example, unexplained cough, swallowing difficulty, abdominal pain, nausea or tiredness. Terminology is often controversial and multiple in relation to these disorders, as in the case of non-epileptic seizures, due to varying and controversial focus on the psychological origin of the condition.

Examination in somatic symptom disorders

This varies according to the symptom. In conversion disorder, examination reveals ‘pseudo-neurological’ signs:

• Variability, e.g. movement disorders with erratic patterns of movement
• Distractibility: variation in symptoms when the patient’s attention is directed elsewhere
• Inconsistency, e.g. leg weakness on formal examination that does not limit mobility as much as expected
• Unusual distribution, not in keeping with physiology, e.g. motor deficit in an abnormal distribution

Investigations in somatic symptom disorders

Somatic symptom disorder is a diagnosis of exclusion: there is no diagnostic test for it. Instead, clinicians need to first search for any objectively measurable medical conditions that could explain the condition.

The extent of investigations will heavily depend on the organ system involved. Conversion disorder is one of the best understood somatic symptom disorders because objective neurological testing is more readily available than in other body systems. For example, nerve conduction studies and electromyogram (EMG) can objectively demonstrate functional peripheral nerves and muscles to rule out disorders originating there. Video-EEG can objectively capture or rule out epileptic seizures.