Skip to main content

Research Repository

Advanced Search

The effects of improving sleep on mental health (OASIS): a randomised controlled trial with mediation analysis

Freeman, Daniel; Sheaves, Bryony; Goodwin, Guy M.; Yu, Ly-Mee; Nickless, Alecia; Harrison, Paul J.; Emsley, Richard; Luik, Annemarie I.; Foster, Russell G.; Wadekar, Vanashree; Hinds, Christopher; Gumley, Andrew; Jones, Ray; Lightman, Stafford; Jones, Steve; Bentall, Richard; Kinderman, Peter; Rowse, Georgina; Brugha, Traolach; Blagrove, Mark; Gregory, Alice M.; Fleming, Leanne; Walklet, Elaine; Glazebrook, Cris; Davies, E. Bethan; Hollis, Chris; Haddock, Gillian; John, Bev; Coulson, Mark; Fowler, David; Pugh, Katherine; Cape, John; Moseley, Peter; Brown, Gary; Hughes, Claire; Obonsawin, Marc; Coker, Sian; Watkins, Edward; Schwannauer, Matthias; MacMahon, Kenneth; Siriwardena, A. Niroshan; Espie, Colin A.

The effects of improving sleep on mental health (OASIS): a randomised controlled trial with mediation analysis Thumbnail


Daniel Freeman

Bryony Sheaves

Guy M. Goodwin

Ly-Mee Yu

Alecia Nickless

Paul J. Harrison

Richard Emsley

Annemarie I. Luik

Russell G. Foster

Vanashree Wadekar

Christopher Hinds

Andrew Gumley

Ray Jones

Stafford Lightman

Steve Jones

Richard Bentall

Peter Kinderman

Georgina Rowse

Traolach Brugha

Mark Blagrove

Alice M. Gregory

Leanne Fleming

Elaine Walklet

Cris Glazebrook

Professor of Child and Adolescent Psychiatry and Digital Mental Health

Gillian Haddock

Bev John

Mark Coulson

David Fowler

Katherine Pugh

John Cape

Peter Moseley

Gary Brown

Claire Hughes

Marc Obonsawin

Sian Coker

Edward Watkins

Matthias Schwannauer

Kenneth MacMahon

A. Niroshan Siriwardena

Colin A. Espie



Sleep difficulties might be a contributory causal factor in the occurrence of mental health problems. If this is true, improving sleep should benefit psychological health. We aimed to determine whether treating insomnia leads to a reduction in paranoia and hallucinations.


We did this single-blind, randomised controlled trial (OASIS) at 26 UK universities. University students with insomnia were randomly assigned (1:1) with simple randomisation to receive digital cognitive behavioural therapy (CBT) for insomnia or usual care, and the research team were masked to the treatment. Online assessments took place at weeks 0, 3, 10 (end of therapy), and 22. The primary outcome measures were for insomnia, paranoia, and hallucinatory experiences. We did intention-to-treat analyses. The trial is registered with the ISRCTN registry, number ISRCTN61272251.


Between March 5, 2015, and Feb 17, 2016, we randomly assigned 3755 participants to receive digital CBT for insomnia (n=1891) or usual practice (n=1864). Compared with usual practice, the sleep intervention at 10 weeks reduced insomnia (adjusted difference 4·78, 95% CI 4·29 to 5·26, Cohen's d=1·11; p

Journal Article Type Article
Acceptance Date Sep 6, 2017
Online Publication Date Sep 6, 2017
Publication Date Sep 6, 2017
Deposit Date Dec 11, 2018
Publicly Available Date Dec 12, 2018
Print ISSN 2215-0366
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 4
Issue 10
Pages 749-758
Public URL
Publisher URL


You might also like

Downloadable Citations