Psychological dysfunction in patients with reflex sympathetic dystrophy

Patients with reflex sympathetic dystrophy (RSD) often present with pain and disability that cannot be explained on the basis of objective physical findings. This has led some to speculate that RSD may be caused or mediated by non-organic factors. Unfortunately, there have been few studies using standardized measures of mood and illness behavior that have compared patients with RSD to patients with other chronic pain disorders. The goal of the present study, therefore, was to compare the pattern of psychological dysfunction in patients with RSD to the pattern of dysfunction in patients with chronic back pain and local neuropathic pain. Patients with back pain resemble those with RSD in that both may report symptoms that cannot be reconciled with objective physical findings. Patients with local neuropathy, by contrast, report pain that is both circumscribed and consistent with a known organic cause. The records of 253 patients attending a tertiary pain service were retrospectively reviewed and three distinct (non-overlapping) diagnostic groups were formed: 25 were assigned to the RSD group; 44 to the back pain group; and 21 to the local neuropathy group. Using a set of stringent criteria to diagnose RSD and an analysis of covariance to control for differences in symptom duration and age, the present study found no evidence to suggest that patients with RSD were psychologically unique. Instead, RSD patients were remarkably similar to those with local neuropathy in terms of their symptom reporting, illness behavior, and psychological distress. The only exception was that RSD patients had more disability days during the preceding 6 months than those with local neuropathy (P < 0.05). The back pain group, on the other hand, presented with more diffuse pain complaints (P < 0.05) and had a greater number of non-specific medical symptoms (P < 0.05) compared to either the RSD or local neuropathy group. In contrast to previous research using less stringent diagnostic criteria, there was no evidence of higher pain scores or lower levels of psychological distress among patients with RSD. In addition, a validated survey of childhood trauma found that sexual abuse, physical abuse, emotional abuse, and cumulative trauma were evenly distributed among all three diagnostic groups. The burden of proof would appear to be upon those who advocate the non-organic hypothesis to provide credible evidence of psychological involvement in the etiology of RSD.