Papers of the Week

Self-efficacy, fear of movement, and depression may mediate the sequential pathway of how pain leads to disability in nonspecific low back pain. Participants with chronic (>13 weeks) non-specific low back pain were included. They were prospectively monitored for eight consecutive weeks. Each second day, all participants filled in a survey (30 surveys pp). Questionnaires on current back pain intensity (NRS) and disability (PDI) were completed in each survey. One out of three standardized questionnaires on self-efficacy (SES), fear of movement, kinesiophobia (TSK), or depression (PHQ-9) were randomly completed each time. Multilevel mediation analyses on the within-(temporal changes) and between-patients total and indirect (mediated by SES; TSK and PHQ-9) effect of pain on disability were conducted for three temporal associations: No time delay, Simple temporal delay, and Double delay. In total, 280 questionnaires were filled in by 10 participants (m = 4; 34.4 ± 12.2 years). A moderate to strong effect of pain on disability in the no delay-model for the within-patients (0.436), and (all models) in the between-patients (0.595-0.627) models was found. The way how pain affects kinesiophobia was influenced by the time passed. Kinesiophobia itself predicted disability. Further, depression was affected by (within and between) pain intensity (NRS). In the simple delay effects mediation, depression affects disability (within) and is itself affected by the pain (between). No indirect effect of self-efficacy, fear of movement and depression in the pain-disability relationship was found. Understanding underlying mechanisms of how and when pain leads to disability might help to find accurate measures in therapy setting.