RESUMO
BACKGROUND: It has been shown that higher levels of trait gratitude are associated with better self-reported sleep quality, possibly due to differences in presleep cognitions. However previous studies have not taken into account the role of depressive symptoms in this relationship. PARTICIPANTS AND METHODS: In this study, 88 nonclinical 18-29-year-olds completed the Gratitude Resentment and Appreciation Test (GRAT) as a measure of trait gratitude. The Glasgow Content of Thought Inventory (GCTI) was used to measure the intrusiveness of cognitions prior to sleep onset, the Motivation and Energy Inventory (MEI) assessed daytime fatigue, and the Pittsburgh Sleep Quality Index (PSQI) was used to assess self-reported sleep quality. The BDI-II assessed self-reported depressive symptoms. RESULTS: Consistent with previous work, GRAT scores were positively associated with higher daytime energy and greater number of hours of sleep per night. Importantly, however, we further observed that depressive symptoms mediated the relationships between gratitude scores and sleep metrics. CONCLUSIONS: Depressive mood state appears to mediate the association between gratitude and self-reported sleep quality metrics. We suggest, as one plausible model of these phenomena, that highly grateful individuals have lower symptoms of depression, which in turn leads to fewer presleep worries, resulting in better perceived sleep quality. Future work should aim to disentangle the causal nature of these relationships in order to better understand how these important variables interact.
