Do psychological factors influence recovery from complex regional pain syndrome type 1? A prospective study.

Previous studies have shown that the outcomes of complex regional pain syndrome (CRPS) vary significantly between patients, but few studies have identified prognostic indicators. The aim of this study was to determine whether psychological factors are associated with recovery from recently onset CRPS amongst patients followed prospectively for 1 year. Sixty-six patients with CRPS (type 1) were recruited within 12 weeks of symptom onset and assessed immediately and at 6 and 12 months, during which time they received treatment as usual. At each assessment, the following were measured: signs and symptoms of CRPS, pain, disability, depression, anxiety, stress, pain-related fear, pain catastrophising, laterality task performance, body perception disturbance, and perceived ownership of the limb. Mixed-effects models for repeated measures were conducted to identify baseline variables associated with CRPS severity, pain, and disability over the 12 months. Results showed that scores for all 3 outcome variables improved over the study period. Males and those with lower levels of baseline pain and disability experienced the lowest CRPS severity scores over 12 months. Those with lower baseline anxiety and disability had the lowest pain intensity over the study period, and those with lower baseline pain and pain-related fear experienced the least disability over the 12 months. This suggests that anxiety, pain-related fear, and disability are associated with poorer outcomes in CRPS and could be considered as target variables for early treatment. The findings support the theory that CRPS represents an aberrant protective response to perceived threat of tissue injury.