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Title: An explanatory randomised controlled trial testing the effects of improving sleep on mental health: an interventionist-causal model approach with mediation analysis
Authors: Brugha, Traolach S.
Freeman, Daniel
Espie, Colin
et al
First Published: 2018
Publisher: Elsevier
Citation: Lancet Psychiatry, in Press.
Abstract: Background: Sleep difficulties may be a contributory causal factor in the occurrence of mental health problems. If this is true, improving sleep should benefit psychological health. Our primary objective was to determine whether treating insomnia leads to a reduction in paranoia and hallucinations. The effects on other mental health outcomes were also tested. Methods: For our parallel group, single blinded, explanatory randomised controlled trial (called OASIS), we randomised university students with insomnia to digital cognitive behaviour therapy for insomnia or usual practice. Online assessments were at 0, 3, 10 (post-treatment), and 22 weeks. The primary outcomes were insomnia, paranoia, and hallucinatory experiences. The secondary outcomes included anxiety, depression, nightmares, and psychological well-being. The trial was registered (ISRCTN61272251). Findings: 3,755 people were randomised between 5th March 2015 to 17th February 2016. Compared to usual practice, the sleep intervention at 10 weeks reduced insomnia, adjusted difference=4.78 (95% C.I. 4.29;5.26), p<.0001, d=1.11, paranoia, adjusted difference=-2.22 (95% C.I. -2.98;-1.45), p<.0001, d=0.19, and hallucinations, adjusted difference=-1.58 (95% C.I. -1.98;-1.18), p<.0001, d=0.24. Insomnia was a mediator of change in paranoia and hallucinations. There were improvements in other mental health outcomes. No adverse events were reported. Interpretation: This is the largest randomised controlled trial of psychological intervention for a mental health problem. It provides strong evidence that insomnia is a causal factor in the occurrence of psychotic experiences and other mental health problems. Whether the results generalise beyond a student population requires testing. The treatment of disrupted sleep may require a higher priority in mental health provision.
ISSN: 2215-0366
eISSN: 2215-0374
Embargo on file until: 1-Jan-10000
Version: Post-print
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © Elsevier, 2018. After an embargo period this version of the paper will be an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License (, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Description: The file associated with this record is under embargo until publication, in accordance with the publisher's self-archiving policy. The full text may be available through the publisher links provided above.
Appears in Collections:Published Articles, Dept. of Health Sciences

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