Fatigue and depression in cancer patients undergoing chemotherapy: an emotion approach

Fatigue and depressive symptoms are common in cancer patients, but the nature of the relationship between the two remains unclear. We examined the degree to which two dimensions of emotion assessed as psychological factors (i.e., arousal and valence) predicted changes in fatigue and depressive symptoms over four cycles of chemotherapy in cancer patients who participated in a randomized clinical trial. Among 549 patients enrolled in the study, 525 provided data from a minimum of two treatments and were included in the multilevel modeling analyses. Multilevel models were used to identify significant predictors of initial levels and changes of fatigue and depressive symptoms and to determine the relationship between fatigue and depressive symptoms independent of other predictors proposed in this study. Multiple factors, including age, gender, and cancer site, predicted the initial levels. More importantly, the two dimensions of psychological factors significantly predicted changes in fatigue and depressive symptoms, in similar patterns but to different degrees. Specifically, changes in fatigue depended more on the valence dimension, whereas changes in depressive symptoms depended on both the valence and arousal dimensions. Theoretical and practical implications of the current findings are discussed and suggestions for interventions to alleviate fatigue and depressive symptoms in cancer patients are proposed.