The relationship between types of life events and the onset of functional neurological (conversion) disorder in adults: a systematic review and meta-analysis

Adverse life events precede the onset of functional neurological disorder (FND, also known as conversion disorder) more commonly than other neuropsychiatric conditions, but their aetiological role is unclear. We conducted a systematic review and quantitative analysis of the type, timing and number of life events preceding the onset of FND in adults, and a meta-analysis of the proportions of types of events in controlled studies. Fifty-one studies of different designs, covering 4247 patients, were eligible for inclusion. There was no clear majority of any type of preceding event. Family problems were the most common category of events, followed by relationship problems. Females were more likely to experience preceding family/relationship problems than males, who reported more work problems. Family problems were the commonest type of preceding event in studies in developing countries, whereas family and health problems were equally common in developed countries. Abuse was associated with early symptom onset, while patients with later onset were more likely to report family problems. The median number of events was one, and the events occurred closer to onset than in controls. Meta-analysis found that family, relationship and work events were all relatively more common in patients than pathological controls, as were events where symptoms might provide a solution to the stressor. In conclusion, although a range of events precede the onset of FND, they do not appear to do so uniformly. This may support a different aetiological role for stressors than in other disorders, although the support is indirect and the quality generally low.