The role of physical injury in motor and sensory conversion symptoms: a systematic and narrative review.
Stone J., Carson A., Aditya H., Prescott R., Zaubi M., Warlow C., Sharpe M.
OBJECTIVES: Conversion symptoms are currently conceptualized as physical symptoms induced by psychological trauma, conflict, or stress. Historical accounts also included physical injury as an important precipitant. We aimed to determine (a) the frequency of reported physical injury prior to onset in published studies of patients with motor or sensory conversion symptoms and (b) the clinical characteristics of patients in whom onset was associated with physical injury. METHODS: Firstly, we employed a systematic review of all reports of adults with motor or sensory conversion symptoms published between 1965 and 2005. Secondly, we used a narrative review of the literature on this topic, especially possible mechanisms. RESULTS: A total of 133 eligible studies, which recorded precipitating factors, including 869 patients, were found. Physical injury prior to symptom onset was reported in 324 patients (37%). Clinical features associated with physical injury included younger age, weakness (vs. movement disorder), paraparesis (vs. hemiparesis), and neurological versus psychiatric study settings. CONCLUSIONS: Despite the current dominance of a psychological view of conversion symptoms, physical injury prior to onset has been frequently reported in papers published since 1965. While the data are of low quality, they nevertheless suggest that physical trauma has a role in many patients in the onset of motor and sensory conversion symptoms. We discuss possible mechanisms for this association.