# Complex regional pain syndrome and use of psychotropic drugs as a proxy for psychological health

## TL;DR

This study finds that people with complex regional pain syndrome, especially type 2, are more likely to use psychotropic drugs, suggesting poorer psychological health compared to the general population.

## Contribution

The study introduces psychotropic drug use as a novel proxy for psychological health in CRPS patients, revealing significant associations with disease type and socioeconomic factors.

## Key findings

- CRPS type 2 patients had higher prevalence ratios of psychotropic drug use compared to the general population.
- Higher absolute risk differences were observed in CRPS type 2 across income and occupational status levels.
- Immigrants with CRPS type 2 showed the highest risk differences for psychotropic drug use.

## Abstract

We aimed to investigate the association between psychotropic drug use (proxy for psychological health) and Complex Regional Pain Syndrome (CRPS) type 1 and type 2 in upper and lower limbs. We also assessed the impact of demographic and socioeconomic factors. From a national record linkage database [4,706,821 individuals (25–64 years); CRPS type 1 = 809; type 2 = 225], prevalence ratios (PR), absolute risk (AR), and AR difference (ARD) [95% confidence intervals (CI)] were estimated by logistic and Cox regressions with constant time at risk. About 36% of CRPS individuals consumed psychotropic drugs (reference: general population 15%). Unadjusted PRs were two times higher in nerve injuries/disorders without CRPS [PR = 1.78; 95% CI: 1.73–1.82] and CRPS type 1 [2.33 (2.07–2.62)] and almost three times higher in CRPS type 2 [2.79 (2.27–3.42)]. Higher ARDs were observed in type 2, independent of level of income, and were higher for the high-income category. In type 2, ARDs were higher for middle-high/high occupational status levels. Higher ARDs were observed in nerve injuries/nerve disorders, CRPS type 1, and type 2 in immigrants, especially high for type 2. Regarding most age intervals, ARDs were higher for individuals with CRPS type 2. Individuals with CRPS, especially type 2, have high risk of impaired psychological health.

The online version contains supplementary material available at 10.1038/s41598-025-09701-9.