The mediating role of catastrophizing in the relationship between pain intensity and depressed mood in older adults with persistent pain: A longitudinal analysis.

BACKGROUND AND AIMS

Depression is common in older adults with persistent pain. Cognitive-behavioural models of pain propose that the relationship between pain and depression is influenced or mediated by interpretations of events (cognitions), rather than by the event itself. Almost exclusively, the evidence for this position has come from studies of people aged less than 65 years. The role of cognitions in the pain experience of older adults has been unclear due to the limited and conflicting evidence available. The aim of our study was to examine the role of catastrophizing in mediating the relationship between pain intensity and depressed mood in older adults with persistent pain using reliable and valid measures for this population.

METHODS

In a two-wave longitudinal design, a sample of 141 patients (89 women, 52 men) 65 years and over with persistent pain participating in an evaluation of a pain self-management programme completed questionnaires measuring usual level of pain intensity (NRS), depressed mood (DASS-21) and the catastrophizing factors of magnification and helplessness (PRSS) at the beginning of the programme and 6 months later. Demographic data and pain history were collected by self-completion questionnaires, which were mailed to patients prior to participating in the programme and returned by post.

RESULTS

Change scores for usual level of pain intensity (NRS), depressed mood (DASS-21) and the magnification and helplessness factors on the PRSS-Catastrophizing were calculated by subtracting the scores at 6 months after completion of the study (Time 2) from the scores at the beginning of the study (Time 1). In the longitudinal analyses of mediation, using a series of regression analyses, change scores for both factors (magnification, helplessness) of the measure of catastrophizing (PRSS) totally and significantly mediated the relationship between change scores for pain intensity and depressed mood. The significant relative magnitude of beta between pain intensity and depression reduced from 0.22 to 0.13 and became non-significant after introducing magnification as a mediating variable, whilst the significant relative magnitude of beta reduced from 0.22 to 0.12 and also became non-significant after introducing helplessness as a mediating variable.

CONCLUSIONS

These results support a cognitive-behavioural model and highlight the importance of cognitive factors, in this case catastrophizing, in the relationship between pain intensity and depressed mood in older adults with persistent pain.

IMPLICATIONS

These findings also have important clinical implications for the treatment of older adults with persistent pain. They highlight the importance of targeting interventions to reduce the influence of catastrophizing as a prerequisite for reducing depressive symptoms in this growing population.