Triggers and Clinical Presentations of Functional Neurological Disorders: Lessons from World War 1

The psychological contribution to functional neurological and somatic symptom disorders is a major topic in current medical debate.

For an understanding of the processes leading to functional somatic symptoms, it is paramount to explore their relationship with stress and life events and to elucidate the contribution of cultural factors.

A total of 937 case records of civilian and military patients with functional somatic disorders treated in London during World War 1 were analysed. Group differences in symptom profiles and contemporaneous diagnoses were tested with χ2 tests.

Paralyses and speech disturbances were significantly more common in soldiers (43.3 and 17.2% of cases) than in civilian male (28.1 and 6.5%) and female patients (32.4 and 7.5%), whereas female patients had the highest rates of pain (48.6%) and somatic symptoms (67%). Triggers were identified in around two-thirds of cases and included accidents, physical illness, and work stress, in addition to the combat experience of the soldier patients. The nature of the trigger influenced symptom expression, with acute (combat and noncombat) events being particularly prone to trigger loss of motor function. Symptom profiles showed a great deal of multi-morbidity and overlap, although some symptom clusters were more (motor and speech disturbance) or less common (pain and loss of energy) in soldiers than civilians. Triggering life events in civilians were similar to those reported by patients with somatic symptom disorders today, with an important role of physical factors. Patterns of multi-morbidity and symptom clusters also resembled those of modern cohorts.

Analysis of historical records, illness trajectories, and treatments can enhance the understanding of the presentation, mechanisms, and course of functional neurological and related disorders and their consistency over time.