Instructing a psychiatric expert in chronic pain and medically unexplained symptoms

Chronic pain claims are frequently instructed to orthopaedic, pain medicine or neurological experts, and rightly so where there is a clear physical injury with an established mechanism. A psychiatric instruction becomes necessary, or additionally necessary, where the pain has persisted well beyond the expected healing time for the physical injury, where the reported disability is disproportionate to identifiable pathology, where mood or anxiety symptoms have developed alongside the pain, or where the presentation raises a question of somatic symptom disorder — a recognised psychiatric diagnosis in which physical symptoms, including pain, are genuinely experienced but are not fully explained by, or are out of proportion to, demonstrable physical disease.

Instructing agents sometimes hesitate to raise a psychiatric instruction in a pain case for fear it will be read as an allegation that the pursuer is exaggerating or fabricating. That is a misunderstanding of what the diagnosis addresses. Somatic symptom disorder and related presentations describe a genuine clinical phenomenon, recognised in ICD-11 and DSM-5, in which psychological factors amplify, maintain or are expressed through physical symptoms. The opinion is not a finding of dishonesty; it is a diagnosis with its own treatment implications and its own bearing on prognosis and quantum.

The assessment addresses several questions that a pain medicine or orthopaedic opinion does not: whether the pursuer meets criteria for a depressive or anxiety disorder secondary to or associated with the pain; whether the presentation meets criteria for somatic symptom disorder, illness anxiety disorder or a related diagnosis; the psychological mechanisms — hypervigilance to bodily sensation, fear-avoidance, catastrophising, or depression lowering pain threshold — that may be maintaining or amplifying the pain experience; and the treatment implications, since pain that is being maintained or amplified by psychological factors responds poorly to physical treatment alone and may require a structured psychological or pain-management programme instead of, or alongside, further physical intervention.

The psychiatric opinion also has a direct bearing on prognosis and quantum. Where pain is substantially maintained by identifiable and treatable psychological factors, the prognosis with appropriate treatment may be materially better than the pursuer's current presentation suggests, which affects both the schedule of damages and the treatment costs properly claimed. Conversely, where a somatic symptom disorder has become entrenched over a period of years, that has its own implications for prognosis that differ from those of a resolving injury.

Chronic pain and somatisation cases are more heavily contested than most other categories of psychiatric injury, and the report should anticipate this. Two evidential issues recur.

The letter of instruction should ask directly whether the pursuer's presentation is consistent with a psychiatric diagnosis such as somatic symptom disorder, whether psychological factors are contributing to the severity or persistence of the pain reported, and what treatment — psychological or otherwise — is indicated and with what expected effect on function and prognosis. Where the pursuer has already been assessed by a pain specialist, that report should be provided in full, since the psychiatric opinion is more useful when it engages with, rather than duplicates, the physical findings already established.

Joint working between disciplines is often appropriate in these cases. Where both a pain medicine expert and a psychiatric expert are instructed, each report should identify clearly which questions fall to which discipline, so that the two opinions are complementary rather than overlapping in ways that create apparent inconsistency for no substantive reason.

Assessment in these cases is usually best conducted in person, since the interaction between reported pain behaviour, mood and function is more reliably observed face to face than by video. Where remote assessment is proposed for logistical reasons, that should be discussed at the outset, and the considerations relevant to remote assessment generally are addressed in a separate article on this site.