Clinical characteristics of patients with motor disability due to conversion disorder: a prospective control group study

Abstract

Objectives: Previous studies have suggested associations between conversion and many different clinical characteristics. This study investigates these findings in a prospective design including a control group.

Methods: Thirty consecutive patients with a recent onset of motor disability due to a conversion disorder were compared with a control group of patients with corresponding motor symptoms due to a definite organic lesion. Both groups had a similar duration of symptoms and a comparable age and sex profile and were assessed on a prospective basis. Background information about previous somatic and psychiatric disease was collected and all patients were assessed by means of a structured clinical interview linked to the diagnostic system DSM III-R, the Hamilton rating depression scale, and a special life events inventory.

Results: The conversion group had a higher degree of psychopathology with 33% of the patients fulfilling the criteria for psychiatric syndromes according to DSM-III-R axis I, whereas 50% had axis II personality disorders compared with 10% and 17% respectively in the control group. Conversion patients also had significantly higher scores according to the Hamilton rating depression scale. Although patients with known neurological disease were not included in the conversion group, a concomitant somatic disorder was found in 33% of the patients and 50% complained of benign pain. The educational background in conversion patients was poor with only 13% having dropped out of high school compared with 67% in the control group. Self reported global assessment of functioning according to the axis V on DSM IV was significantly lower in conversion patients, who also registered significantly more negative life events before the onset of symptoms than controls. Logistic regression analysis showed that low education, presence of a personality disorder, and high Hamilton depression score were significantly associated with conversion disorder.

Conclusion: The importance of several previously reported predisposing and precipitating factors in conversion disorder is confirmed. The results support the notion that conversion should be treated as a symptom rather than a diagnosis and that efforts should be made in diagnosing and treating possible underlying somatic and psychiatric conditions.