Longitudinal associations between family identification, loneliness, depression, and sleep quality

Objectives: The prevalence of depression and loneliness are increasing in Western nations, and both have been shown to cause poor sleep quality, with evidence suggesting that loneliness also predicts depression. The Social Cure perspective can shed light on these relationships, and thus informs the present study. Specifically, it was hypothesised that the extent of participants’ identification with a significant social group, their family, would positively predict sleep quality, and that this relationship would be mediated by loneliness and depression. Design: A two-wave longitudinal online survey was used. Methods: Participants completed an online survey at T1 (N = 387) and one year later at T2 (N = 122) assessing the extent to which they identified with their family. Their loneliness, depressive symptomology, and sleep quality/insomnia severity were also measured. Results: Consistent with predictions, cross-sectional and longitudinal serial mediation models indicated that family identification was a negative predictor of loneliness, which in turn was a positive predictor of depression, which predicted poor sleep quality/insomnia. Conclusions: This is the first Social Cure study to explore the mediated relationship between social identification and sleep quality. As well as advancing the Social Cure perspective, these results have implications for how health professionals understand, prevent, and treat sleep problems.