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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Date results information initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Do Treatment Interventions for Obstructive Sleep Apnoea Reduce Depressive Symptoms in Patients with Comorbid Depression?
Scientific title
Does Continuous Positive Airway Pressure (CPAP) Treatment for Obstructive Sleep Apnoea improve Depression?
Secondary ID [1] 283771 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Obstructive Sleep Apnoea 290745 0
Depression 290746 0
Condition category
Condition code
Respiratory 291104 291104 0 0
Sleep apnoea
Mental Health 291105 291105 0 0

Study type
Description of intervention(s) / exposure
CPAP therapy. CPAP treatment involves wearing a mask that is attached to a pump that forces air into the airway to hold the airway open during sleep. The dosage will be individually determined during an in-laboratory CPAP implementation sleep study at the start of the trial. This treatment should be used every night, for 12 months for the CPAP group, or 8 months for the wait-list group. Usage data is recorded automatically by the device and can be downloaded by the researchers at each visit. The CPAP group will be provided with a 1-hour CPAP and sleep education session by a sleep scientist or psychologist (either one-on-one or in small groups), a CPAP information booklet, and follow up phone call from a sleep scientist after night 1 and night 7 at home to troubleshoot any problems (~5 minutes duration). The treatment as usual (TAU) group will receive CPAP without additional follow up procedures or education.
Intervention code [1] 288455 0
Treatment: Devices
Comparator / control treatment
Wait-list for 4 months, after which this group will receive the CPAP treatment.
Control group

Primary outcome [1] 291092 0
Depression score - (Center for Epidemiology - Depression scale)
Timepoint [1] 291092 0
1, 2, 4 and 12 months
Primary outcome [2] 291093 0
Daytime Sleepiness (Epworth Sleepiness Scale (ESS)
Timepoint [2] 291093 0
1, 2, 4 and 12 months
Secondary outcome [1] 305992 0
Emotional Reactivity Scale and Difficulties in Emotional Regulation Scale
Timepoint [1] 305992 0
1, 2, 4, 12 months

Key inclusion criteria
Untreated OSA patients who have been recommended to start CPAP therapy; English fluency; not pregnant or possibility of being pregnant; CES-D score >16. Patients with a current clinical diagnosis of depression, and who are on antidepressants will also be included.
Minimum age
18 Years
Maximum age
60 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
History of or current psychiatric or medical condition (except depression) including epilepsy, recent stroke, myocardial infarction (in last 6 months); excessive daytime sleepiness (ESS>16); head injury with loss of consciousness >15 mins; learning disability; alcohol or drug dependence; shiftwork; and any neurological disorder or inability to complete the trial at the judgment of the clinician investigator.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Participants will be stratified by depression and daytime sleepiness score, and randomized into one of three conditions: a new CPAP treatment group (CBT), the current CPAP treatment group (TAU) or a wait-list group. Group allocation is concealed between the TAU and CBT groups. Allocation is conducted via centralized randomisation by computer
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
After each subject has been assessed for depression and sleepiness, they will be assigned a random number using an on-line number generator program into the CPAP, TAU or wait-list group.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Partial cross-over - CPAP group will not cross over to waitlist.
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
An intention-to-treat principle will be employed. Statistical analysis will be in the form of a repeated measures ANCOVA model with CES-D score, memory sensitivity and sleepiness as the primary outcome measures, with baseline depression score as a covariate. Treatment group (CPAP vs TAU vs. wait list) and time (1, 2, 4 and 12 months) will be included in the model as independent variables. Secondary analyses will be performed to evaluate effect modification across levels of the depression stratification factor (MDD vs. mild-no depression) to examine a potential interaction between treatment group and baseline depression category. Regression analyses will be conducted to determine whether quality of relationship, personality and/or depression scores at baseline differ between those participants who continue CPAP and those who stop treatment.

We plan to recruit 120 OSA patients. This sample size is calculated assuming an SD of 8 for change in CES-D score over 3 months as estimated using individual patient data (Baron, Smith et al. 2008). A change in CES-D score of 5 or more constitutes a clinically significant change (Jacobson and Truax 1991). Therefore, we need a total 33 patients in each group to detect an effect size of 5, assuming an SD of 8, Beta = 0.80 and alpha less than or equal to 0.05. We estimate 20% attrition; therefore we will recruit 40 participants in each group.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 288434 0
Name [1] 288434 0
The University of Melbourne
Address [1] 288434 0
Redmond Barry Building
Level 12
Parkville, Vic, 3010
Country [1] 288434 0
Funding source category [2] 294029 0
Name [2] 294029 0
Austin Medical Research Foundation
Address [2] 294029 0
Austin Health
145 - 163 Studley Rd
Heidelberg 3084 VIC
Country [2] 294029 0
Primary sponsor type
Royal Melbourne Institute of Technology
PO Box 17
Bundoora 3083
Secondary sponsor category [1] 287137 0
Name [1] 287137 0
Address [1] 287137 0
Country [1] 287137 0
Other collaborator category [1] 277731 0
Name [1] 277731 0
Austin Health
Address [1] 277731 0
Studley Rd Heidelberg, Vic, 3084
Country [1] 277731 0

Ethics approval
Ethics application status
Ethics committee name [1] 290309 0
Austin Health
Ethics committee address [1] 290309 0
Studley Rd Heidelberg, Vic, 3084
Ethics committee country [1] 290309 0
Date submitted for ethics approval [1] 290309 0
Approval date [1] 290309 0
Ethics approval number [1] 290309 0

Brief summary
Obstructive Sleep Apnoea (OSA) is a common respiratory disease, caused by collapse of the airway during sleep, which produces oxygen desaturations and sleep disruption. OSA is associated with cognitive deficits, reduced quality of life, and depressed mood. The prevalence of both depressive symptoms and major depressive disorder (MDD) are significantly higher in OSA patients compared to the general community. Currently there is little clinical evidence to support whether treatment of OSA improves depressive symptoms in OSA patients with comorbid depressive symptoms or MDD. The aim of this study is to determine whether CPAP treatment improves depressive symptoms and cognitive functioning over the short and long term. This project is a prospective, randomised controlled trial of an enhanced CPAP treatment program for OSA patients with comorbid MDD and depressive symptoms, compared to a wait list control group, and treatment as usual. This study will provide much-needed clinical evidence of the efficacy of CPAP therapy for improving both depression and cognitive functioning in OSA.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 44978 0
Dr Melinda Jackson
Address 44978 0
Turner Institute for Brain and Mental Health
School of Psychological Sciences
Monash University
18 Innovation Walk, Clayton, Vic 3164
Country 44978 0
Phone 44978 0
+613 99050206
Fax 44978 0
Email 44978 0
Contact person for public queries
Name 44979 0
Dr Melinda Jackson
Address 44979 0
Turner Institute for Brain and Mental Health
School of Psychological Sciences
Monash University
18 Innovation Walk, Clayton, Vic 3164
Country 44979 0
Phone 44979 0
+61 399050206
Fax 44979 0
Email 44979 0
Contact person for scientific queries
Name 44980 0
Dr Melinda Jackson
Address 44980 0
Turner Institute for Brain and Mental Health
School of Psychological Sciences
Monash University
18 Innovation Walk, Clayton, Vic 3164
Country 44980 0
Phone 44980 0
+61 399050206
Fax 44980 0
Email 44980 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
Do not have ethics approval for this
What supporting documents are/will be available?
No other documents available
Summary results
Have study results been published in a peer-reviewed journal?
Journal publication details
Publication date and citation/details [1] 2303 0
Jackson ML, Tolson T, Bartlett D, Varma P, Berlowitz D, Barnes M. Clinical depression in untreated Obstructive Sleep Apnea: examining predictors and a meta-analysis of prevalence rates. Sleep Medicine. Accepted 21/3/2019
Attachments [1] 2303 0
Other publications
Have study results been made publicly available in another format?
Other publication details
Citation type [1] 2304 0
Conference abstract
Citation/DOI/link/details [1] 2304 0
Tolson J, Barnes M, Bartlett DJ, Trinder J, Rochford P, Jackson ML. (2016). A CPAP adherence program to improve treatment adherence and sleep-efficacy in patients with obstructive sleep apnea. Journal of Sleep Research, 25 (Supp 2): 48.
Attachments [1] 2304 0
Citation type [2] 2305 0
Citation/DOI/link/details [2] 2305 0
Jackson ML, Tolson J, Bartlett DJ, Barnes M. (2016). Does continuous positive airway pressure treatment for obstructive sleep apnea improve mood in patients with comorbid clinical depression? Journal of Sleep Research, 25 (Supp 2): 42.
Attachments [2] 2305 0
Results – basic reporting
Results – plain English summary