To examine the mediating role of catastrophizing in the relationship between pain and disability among patients with carpal tunnel syndrome (CTS).

Cross-sectional register of 141 patients with CTS. Pain Catastrophizing Scale (PCS) was used. Mediation analysis was used to assess the indirect effect of pain catastrophizing on pain-related disability.

The average age was 54.0 (SD 16.1) years and 89 (63 %) were women. For the total PCS score, the indirect effect was responsible for 31 % (95 % CI 15 %–47 %) to 33 % (95 % CI 15 %–52 %). The highest proportion was observed in the helplessness domain, 37 % (95 % CI 19 %–55 %). The lowest effect of 11 % (95 % CI 0 %–23 %) was seen for the magnification domain.

The mediating effect of catastrophizing was responsible for over 30 % of the total effect seen in correlation between pain and disability experienced by patients with CTS. While the effect of magnification sub-score was borderline and could probably be ignored in clinical context, domain of helplessness reached the effect size of almost 40 %. The results suggest that catastrophizing should be considered when treating or rehabilitating people with CTS. Catastrophizing may play a significant role in the development of pain-related disability.