Introduction
Sleep and mental health go hand-in-hand; however, the extent to which sleep is causally related to the experience of mental health difficulties is unclear. One way to test whether there is a causal link is to evaluate the extent to which interventions that improve sleep also improve mental health over time.
Methods
We conducted a systematic review and meta-analysis of 54 randomised controlled trials (N = 6,876) that reported the effects of interventions that successfully improved sleep on overall composite mental health, as well as on six specific mental health difficulties including depression, anxiety, stress, psychosis spectrum experiences, suicidal ideation, and PTSD.
Results
Improving sleep had a medium-sized effect on composite mental health (g+ = -0.47), and depression (g+ = -0.54), small-to-medium sized effects on anxiety (g+ = -0.40), and stress (g+ = -0.42), and small effects on positive psychosis spectrum experiences (g+ = -0.26). We also found a significant dose response relationship, in that greater improvements in sleep were associated with greater improvements in composite mental health.
Conclusion
Taken together, the findings suggest that sleep is causally related to the experience of mental health difficulties. Improving sleep leads to better mental health, especially for experiences of depression, anxiety, and stress. Future research might profitably consider how interventions that improve sleep be better incorporated into routine mental health care, as well as the possible mechanisms of action that might explain how sleep exerts its effects on mental health.
Support (if any)
This research was funded by the National Institute for Health Research (NIHR) under its Research for Patient Benefit (RfPB) Programme (Grant Reference Number PB-PG- 0817-20027). The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care.