Does change in positive affect mediate and/or moderate the impact of symptom distress on psychological adjustment after cancer diagnosis? A prospective analysis.

Physical symptom distress is one of the commonest correlates of psychological adjustment in cancer patients. Positive affect (PA) can be a dynamic resource for patients to cope with the cancer-related physical demands. The present study examined whether differential patterns of change in PA were associated with anxiety and depressed mood, and whether PA modified the association between change in symptom distress and psychological distress in 215 Chinese people newly diagnosed with colorectal cancer (CRC). Participants completed measures of physical symptoms, PA, and anxiety and depression at diagnosis and again at 3-month follow-up. Multivariate analyses of covariance revealed that at follow-up, people reporting higher anxiety and depressed mood demonstrated loss in PA, whereas those reporting lower depressed mood demonstrated a gain in PA. Structural equation modelling revealed that change in PA significantly mediated and moderated the associations between increased symptom distress and anxiety and depressed mood. We conclude that in line with Hobfoll's conservation of resources theory, continuous physical symptom distress depletes PA of newly diagnosed cancer patients, resulting in higher levels of anxiety and depressed mood. Effectiveness of symptom management intervention could be enhanced by preserving or enhancing PA in patients.