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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Behavioural Sleep Therapy for Insomnia
Scientific title
Sleep Restriction Therapy (SRT) for chronic insomnia disorder: physiological, cognitive & objective sleep alterations after six weeks of therapy intervention - a pilot study
Secondary ID [1] 273497 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Insomnia Disorder 279292 0
Condition category
Condition code
Mental Health 279488 279488 0 0
Other mental health disorders

Study type
Description of intervention(s) / exposure
Sleep Restriction Therapy for Insomnia Disorder -
Initially, the first treatment session (one hour face to face with researcher at the Woolcock Institute) involves a managed reduction of time in bed in line with the average subjective total sleep time derived from a one week sleep diary. But with no less than five hours total time in bed.

Participants are instructed to keep a stable bedtime and wake-up time for the length of the intervention. The researcher will come up with a "sleep window" that is approved by the participant.

This sleep window will be evaluated every week for six weeks via telephone. Time in bed may be modified at weekly intervals by the achievement of 90% sleep efficiency (SE) = Total sleep time / Time in bed * 100) from a one week sleep diary (15 - 30 minute session per week via telephone).

If 90% SE is achieved on average for any week of the therapy then Time in Bed is expanded by 15 minutes (either at bedtime or in the morning, depending on the participant). If <85% SE is achieved Time in bed is reduced by 15 minutes (but not if it is at the minimum of five hours). If SE = 85-90% Time in bed is held constant. The intervention will end after six weeks of this treatment
Intervention code [1] 283814 0
Intervention code [2] 284007 0
Treatment: Other
Comparator / control treatment
Within subjects design - subjects will act as their own controls pre and post intervention.
Control group

Primary outcome [1] 286052 0
Reduction in insomnia severity via the Insomnia Severity Index, the Epworth Sleepiness Scale, Sleep Arousal Scale, & the Flinders Fatigue Scale
Timepoint [1] 286052 0
Baseline, 6 weeks, 15 weeks
Secondary outcome [1] 295044 0
Changes in Sleep Polysomnography
Timepoint [1] 295044 0
Baseline & 6 weeks
Secondary outcome [2] 295045 0
Changes in overnight measures of hourly cortisol secretion (22:00-06:00) via Venepuncture. We will collect blood half-hourly during an overnight sleep study before the intervention and again after the SRT intervention at six weeks. This will be achieved from a small catheter for measurement of Cortisol concentrations. The total amount of blood taken will be less than a standard blood donation.
Timepoint [2] 295045 0
Baseline & 6 weeks
Secondary outcome [3] 317642 0
Changes in overnight measures of core body temperature (22:00-06:00) via an indigestible temperature monitoring pill device. We will collect temperature every minute during an overnight sleep study before the intervention and again after the SRT intervention at six weeks. This will be achieved from a small wireless core body temperature monitoring system.
Timepoint [3] 317642 0
Baseline & 6 weeks

Key inclusion criteria
1. Symptoms of Insomnia Disorder as diagnosed by the Diagnostic and
Statistical Manual of Mental Disorders, Fifth Edition criteria for insomnia
disorder (APA, 2013) specifically: Difficulty initiating or maintaining sleep or
waking up too early for at least 3 nights per week, for at least 3 months,
with adequate opportunity and circumstances for sleep
2. Stable sleep/wake schedule with no shift work
3. Able to give informed, written consent
4. Fluent speaker of English
5. Referred by a sleep physician to have a routine sleep study as part of Medicare
Minimum age
25 Years
Maximum age
65 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
1. Active illicit substance use or alcohol dependence
2. Psychiatric disorders, other than mild to moderate depression (on the Depression Anxiety Stress Scales)
3. Previous history of depressive episode
4. Sleep disorders (other than insomnia)
5. Learning disabilities
6. Dementia
7. Neurological problems
8. Pregnancy or lactation

Study design
Purpose of the study
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
All participants receive 5 weeks access to sleep restriction therapy for insomnia immediately on completion of the baseline in-laboratory overnight assessment.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Single group
Other design features
Within subjects pre to post intervetion design
Not Applicable
Type of endpoint(s)
Statistical methods / analysis

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] 284292 0
Name [1] 284292 0
University of Sydney
Address [1] 284292 0
Woolcock Institute of Medical Research
431 Glebe Point Road, Glebe NSW 2037
Country [1] 284292 0
Funding source category [2] 284293 0
Name [2] 284293 0
University of Sydney CIRUS
Address [2] 284293 0
Woolcock Institute of Medical Research
431 Glebe Point Road, Glebe NSW 2037
Country [2] 284293 0
Primary sponsor type
University of Sydney
The University of Sydney
NSW 2006
Secondary sponsor category [1] 283243 0
Name [1] 283243 0
Woolcock Institute of Medical Research
Address [1] 283243 0
431 Glebe Point Road, Glebe NSW, 2037
Country [1] 283243 0

Ethics approval
Ethics application status
Ethics committee name [1] 286468 0
Sydney Local Health District Ethics Review Committee
Ethics committee address [1] 286468 0
c/- Research Development Office
Royal Prince Alfred Hospital
Missenden Road
Ethics committee country [1] 286468 0
Date submitted for ethics approval [1] 286468 0
Approval date [1] 286468 0
Ethics approval number [1] 286468 0

Brief summary
This project aims to discover the contribution of certain mechanisms of action within sleep restriction therapy for insomnia disorder. Insomnia disorder can be treated by the use of Cognitive Behavioural Therapy for insomnia (CBT-I). Within this Sleep Restriction Therapy is considered a key component. Yet, a lack of evidence exists to determine the mechanisms of action within this treatment option. Therefore, this study will look to examine changes in the contribution of certain sleep-wake mechanisms. Namely, the circadian drives for sleep and the homeostatic sleep drive or ‘pressure’ for sleep. In addition, we will also look to measure subjective changes in the perception of sleep through questionnaire response.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 33463 0
A/Prof Delwyn Bartlett
Address 33463 0
Woolcock Institute of Medical Research
M77, Missenden Road, NSW, 2050
Country 33463 0
Phone 33463 0
+61 2 9114 0460
Fax 33463 0
Email 33463 0
Contact person for public queries
Name 16710 0
Dr Christopher Miller
Address 16710 0
Woolcock Institute of Medical Research
431 Glebe Point Road,
NSW 2037
Country 16710 0
Phone 16710 0
+61 (2) 9114 0411
Fax 16710 0
+ 61 2 9114 0014
Email 16710 0
Contact person for scientific queries
Name 7638 0
A/Prof Delwyn Bartlett
Address 7638 0
Woolcock Institute of Medical Research
431 Glebe Point Road,
NSW 2037
Country 7638 0
Phone 7638 0
+61 2 9114 0460
Fax 7638 0
+ 61 2 9114 0014
Email 7638 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary