Association between poor sleep and mental health issues in Indigenous communities across the globe: a systematic review.

Study Objectives: Evidence from studies among non-Indigenous populations has established the association of poor sleep to mental health issues and supported how improving sleep could reduce the risk of mental ill health. In contrast, for Indigenous people, who experience disproportionate rates of mental ill health, the association between sleep and mental health and the potential of sleep health in reducing the risk and severity of mental health issues have never been fully reviewed. Considering the literature gap, this review assesses the association between sleep and mental health in Indigenous people. Methods: Following PRISMA guidelines, a study was submitted to the PROSPERO database for registration (293798) prior to commencing the review. Then academic databases were searched for relevant studies published up till 19 February 2023. Studies with quantitative data on sleep and mental health association in Indigenous people were included and a narrative review/synthesis was conducted. Results: Seven studies, using carer/self-reports (six cross-sectional, one longitudinal) among three Indigenous groups (N = 3066) met the inclusion criteria. In Indigenous Australian children, arousal problems were associated with aggression, and withdrawn behavior, while early bedtime was associated with a lower risk of behavioral problems. In Native American young people, insomnia symptoms were associated with depressive symptoms in adults, short sleep was associated with affective disorders. Clinical sleep issues, i.e. restless leg and apnea, were associated with depression. In Amerindian/Mestizo adults, restless leg syndrome was associated with depression and anxiety. Overall, findings report the prevalence of poor sleep and mental health issues among Indigenous communities across the globe. Six studies scored "moderate quality" and one study scored "high quality" in quality assessment. Conclusions: While there is limited research available, our finding suggests an association between poor sleep and mental health issues in Indigenous people. Further investigation of the potential role of, and investing in, sleep health could help support mental health.