CRP and major depressive disorder: Due to scarce data on changes in CRP levels and pain impairment in relation to mental disorders over time, this cross-sectional study investigated differences in mental health, QoL, and pain-related impairments depending on pain status and time intervals.<h4>Methods</h4>A cross-sectional survey was conducted among cancer patients in an academic hospital pain clinic and members of support groups to assess CRP, pain-related impairment (Von Korff Severity Scale), depression, anxiety, stress (Depression, Anxiety, and Stress Scale [DASS]), and QoL (EORTC-QLQ-C30 Version 3).