Abstract
OBJECTIVE: The aim of this study was to assess how fatigue is related to mood among youth with sickle cell disease (SCD) by evaluating if the cognitive appraisal of stress moderates the impact of fatigue on emotional functioning consistent with the Risk-and-Resistance Model of Chronic Illness. METHODS: Daily diaries assessing fatigue (Numerical Rating Scale), pain intensity (Numerical Rating Scale), mood (Positive and Negative Affect Schedule for Children), and cognitive appraisal of stress (Stress Appraisal Measure for Adolescents) were collected from 25 youth with SCD (ages 11-18 years) for 8 consecutive weeks resulting in 644 daily diaries for analyses. RESULTS: When measured concurrently, higher fatigue was associated with higher negative mood controlling for pain and prior-night sleep quality. Fatigue predicted next-day negative mood through its interaction with primary and secondary appraisal of stress, consistent with stress appraisal as a protective factor. A similar pattern was observed for pain, which, like fatigue, is a common SCD-related stressor. CONCLUSION: Fatigue and negative mood are inter-related when concurrently assessed, but their temporal association in SCD suggests that mood changes are not an inevitable sequalae of increased fatigue; fatigue influenced subsequent levels of negative mood, but only in the presence of less adaptive cognitions about stress; specifically, a higher perceived threat from stress and a lower belief in the ability to manage stress. The results suggest specific cognitive targets for reducing the negative impact of fatigue on mood in SCD.