title: Chronotype and Improved Sleep Efficiency Independently Predict Depressive Symptom Reduction after Group Cognitive Behavioral Therapy for Insomnia.
abstract: OBJECTIVE
  Cognitive behavioral therapy for insomnia (CBT-I) has been shown to improve both sleep and depressive symptoms, but predictors of depression outcome following CBT-I have not been well examined. This study investigated how chronotype (i.e., morningness-eveningness trait) and changes in sleep efficiency (SE) were related to changes in depressive symptoms among recipients of CBT-I.
  
  
  METHODS
  Included were 419 adult insomnia outpatients from a sleep disorders clinic (43.20% males, age mean ± standard deviation = 48.14 ± 14.02). All participants completed the Composite Scale of Morningness and attended at least 4 sessions of a 6-session group CBT-I. SE was extracted from sleep diary; depressive symptoms were assessed using the Beck Depression Inventory (BDI) prior to (Baseline), and at the end (End) of intervention.
  
  
  RESULTS
  Multilevel structural equation modeling revealed that from Baseline to End, SE increased and BDI decreased significantly. Controlling for age, sex, BDI, and SE at Baseline, stronger evening chronotype and less improvement in SE significantly and uniquely predicted less reduction in BDI from Baseline to End. Chronotype did not predict improvement in SE.
  
  
  CONCLUSIONS
  In an insomnia outpatient sample, SE and depressive symptoms improved significantly after a CBT-I group intervention. All chronotypes benefited from sleep improvement, but those with greater eveningness and/or less sleep improvement experienced less reduction in depressive symptom severity. This suggests that evening preference and insomnia symptoms may have distinct relationships with mood, raising the possibility that the effect of CBT-I on depressive symptoms could be enhanced by assessing and addressing circadian factors.
authors.affiliation: School of Psychological Sciences, Faculty of Biomedical and Psychological Sciences, Monash University, Australia.|Melbourne School of Psychological Sciences, University of Melbourne, Australia.|Centre for Women's Mental Health, Royal Women's Hospital, Parkville, Australia.
authors.forename: Bei
authors.initials: B
authors.lastname: Bei
authors.affiliation: Stanford University School of Medicine, Department of Psychiatry and Behavioral Science.|Rush University Medical Center, Department of Behavioral Sciences.
authors.forename: Jason C
authors.initials: JC
authors.lastname: Ong
authors.affiliation: School of Psychological Sciences, Faculty of Biomedical and Psychological Sciences, Monash University, Australia.
authors.forename: Shantha M W
authors.initials: SM
authors.lastname: Rajaratnam
authors.affiliation: Stanford University School of Medicine, Department of Psychiatry and Behavioral Science.
authors.forename: Rachel
authors.initials: R
authors.lastname: Manber
mesh_terms: D015928:Cognitive Behavioral Therapy; D003866:Depressive Disorder / Q000150:complications / Q000523:psychology* / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011615:Psychotherapy, Group; D012307:Risk Factors; D012720:Severity of Illness Index; D012893:Sleep Wake Disorders / Q000150:complications / Q000523:psychology* / Q000628:therapy*; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
keywords: CBT-I; chronotype; circadian; depression; insomnia; mood; morningnesseveningness
references.citation: Chronobiol Int. 2006;23(1-2):497-509
references.pmid: 16687322
references.citation: Clin Psychol Rev. 2005 Jun;25(4):487-510
references.pmid: 15914266
references.citation: Sleep. 2008 Apr;31(4):489-95
references.pmid: 18457236
references.citation: Front Neurol. 2010 Nov 01;1:137
references.pmid: 21188265
references.citation: Sleep. 2013 Jul 1;36(7):1059-1068
references.pmid: 23814343
references.citation: J Psychosom Res. 2008 Apr;64(4):419-25
references.pmid: 18374742
references.citation: J Clin Sleep Med. 2011 Dec 15;7(6):645-52
references.pmid: 22171204
references.citation: Annu Rev Psychol. 2009;60:577-605
references.pmid: 18817479
references.citation: Arch Gen Psychiatry. 1997 Nov;54(11):1016-24
references.pmid: 9366658
references.citation: J Consult Clin Psychol. 2006 Aug;74(4):658-70
references.pmid: 16881773
references.citation: Clin Psychol Rev. 2007 Apr;27(3):318-26
references.pmid: 17184887
references.citation: Psychiatry Res. 2009 Aug 15;168(3):259-61
references.pmid: 19524304
references.citation: J Clin Sleep Med. 2007 Apr 15;3(3):289-94
references.pmid: 17561599
references.citation: Sleep. 2006 Nov;29(11):1398-414
references.pmid: 17162986
references.citation: JAMA. 2006 Jun 28;295(24):2851-8
references.pmid: 16804151
references.citation: J Affect Disord. 2008 May;108(1-2):11-23
references.pmid: 17950467
references.citation: Sleep. 2014 May;37(5):911-7
references.pmid: 24790269
references.citation: Lancet. 2011 Aug 13;378(9791):621-31
references.pmid: 21596429
references.citation: Chronobiol Int. 2011 Apr;28(3):248-57
references.pmid: 21452920
references.citation: Chronobiol Int. 2009 Feb;26(2):337-47
references.pmid: 19212845
references.citation: J Child Psychol Psychiatry. 2014;55(2):180-90
references.pmid: 24889207
references.citation: Arch Gen Psychiatry. 1961 Jun;4:561-71
references.pmid: 13688369
references.citation: Behav Res Ther. 2001 Jan;39(1):45-60
references.pmid: 11125723
references.citation: Sleep. 2015 Mar;38(3):453-61
references.pmid: 25325471
references.citation: J Affect Disord. 1997 Feb;42(2-3):209-12
references.pmid: 9105962
references.citation: Behav Sleep Med. 2007;5(3):210-28
references.pmid: 17680732
references.citation: Science. 1980 Dec 12;210(4475):1264-7
references.pmid: 7434029
references.citation: J Behav Med. 2002 Apr;25(2):135-53
references.pmid: 11977435
references.citation: Annu Rev Clin Psychol. 2011;7:297-319
references.pmid: 21166537
references.citation: J Affect Disord. 2009 Dec;119(1-3):100-6
references.pmid: 19285347
references.citation: Neuropsychopharmacology. 2010 May;35(6):1279-89
references.pmid: 20072116
references.citation: Chronobiol Int. 2011 Nov;28(9):771-8
references.pmid: 21895489
references.citation: Psychol Methods. 2005 Sep;10(3):259-84
references.pmid: 16221028
references.citation: Sleep Med. 2012 May;13(5):469-75
references.pmid: 22357064
references.citation: J Sleep Res. 2006 Jun;15(2):162-6
references.pmid: 16704571
references.citation: Psychiatry Clin Neurosci. 2009 Jun;63(3):283-90
references.pmid: 19566758
references.citation: J Appl Psychol. 1989 Oct;74(5):728-38
references.pmid: 2793773