Sleep Restriction Treatment for Insomnia

With a prevalence of about 10% chronic insomnia is a common problem. The standard treatment for insomnia is cognitive behavioral therapy. According to many, the core element within this treatment is sleep restriction. This element has been examined separately in a couple of studies and also appears to be effective in isolation. In the current study the aim is to get more information about the effectiveness of this core element of the treatment. For this reason, a randomized study is conducted to compare sleep restriction with a diary control condition. The second aim in this study is to determine mechanisms behind treatments. Network intervention analysis will be used to determine which specific symptoms are associated with therapy success. This is the reason that throughout the study weekly and daily measures will be conducted. The expectations are that: Participants in the sleep restriction condition will improve more on insomnia complaints than the sleep diary control condition (primary outcome) Participants in the sleep restriction condition will improve more on sleep diary outcomes and other secondary outcomes compared to the sleep diary control condition (secondary outcome)

This is a randomized controlled trial where participants are allocated to either a sleep restriction treatment condition or a sleep monitoring control condition. All participants keep a daily sleep diary and fill out weekly questionnaires

Treatment consists of sleep restriction treatment for insomnia. In this treatment, participants limit their bedtimes to the time they actually sleep. If they sleep most of the time in bed again then bedtimes are slowly built up again. This treatment technique has already been studied in several trials and found to be effective. Mode of delivery is an online booklet, online exercises and weekly telephone support

As an active control condition people monitor their sleep with a sleep diary (also included in the sleep restriction intervention)

The Insomnia Severity Index is a seven item-scale scored on a five-point Likert scale (Bastien et al. 2001). The total score ranges from 0 to 28. Higher scores indicate more insomnia.

Sleep onset latency is assessed with the Carney (2012) consensus sleep diary. This is measured in minutes (higher scores indicating longer sleep onset latency).

Sleep onset latency is assessed with the Carney (2012) consensus sleep diary. This is measured in minutes (higher scores indicating longer sleep onset latency).

Wake after sleep onset is assessed with the Carney (2012) consensus sleep diary. This is measured in minutes (higher scores indicating longer wake after sleep onset).

Wake after sleep onset is assessed with the Carney (2012) consensus sleep diary. This is measured in minutes (higher scores indicating longer wake after sleep onset )

Terminal wakefulness is assessed with the Carney (2012) consensus sleep diary. This is measured in minutes (higher scores indicating longer terminal wakefulness).

Terminal wakefulness is assessed with the Carney (2012) consensus sleep diary. This is measured in minutes (higher scores indicating longer terminal wakefulness).

Sleep efficiency is assessed with the Carney (2012) consensus sleep diary. This is measured in percentage (higher scores indicating better sleep efficiency).

Sleep efficiency is assessed with the Carney (2012) consensus sleep diary. This is measured in percentage (higher scores indicating better sleep efficiency).

Total sleep time is assessed with the Carney (2012) consensus sleep diary. This is measured in minutes (higher scores indicating longer total sleep time).

Total sleep time is assessed with the Carney (2012) consensus sleep diary. This is measured in minutes (higher scores indicating longer total sleep time).

Time in bed is assessed with the Carney (2012) consensus sleep diary. This is measured in minutes (higher scores indicating longer time in bed).

Time in bed is assessed with the Carney (2012) consensus sleep diary. This is measured in minutes (higher scores indicating longer time in bed).

The Insomnia Severity Index is a seven item-scale scored on a five-point Likert scale (Bastien et al. 2001). The total score ranges from 0 to 28. Higher scores indicate more insomnia.

Sleep safety behaviors are measured with the Dutch translation of the 32-item Sleep-Related Behaviors Questionnaire-SRBQ (Ree & Harvey, 2004). The total score ranges from 0 (no safety behaviors) to 128 (severe safety behaviors).

Sleep safety behaviors are measured with the Dutch translation of the 32-item Sleep-Related Behaviors Questionnaire-SRBQ (Ree & Harvey, 2004). The total score ranges from 0 (no safety behaviors) to 128 (severe safety behaviors).

To assess daytime sleepiness the Epworth Sleepiness Scale (ESS) is used. The ESS consists of 8-items on a 4-point Likert scale (range 0-24) with higher scores indicating more sleepiness.

To assess daytime sleepiness the Epworth Sleepiness Scale (ESS) is used. The ESS consists of 8-items on a 4-point Likert scale (range 0-24) with higher scores indicating more sleepiness.

Sleep-related arousal was measured with the Pre-sleep Arousal Scale (PSAS) (Nicassio et al. 1985). The PSAS consists of 16 items that range from 1 ('not at all') to 5 ('extremely'), higher scores indicating more arousal (range 16-80).

Sleep-related arousal was measured with the Pre-sleep Arousal Scale (PSAS) (Nicassio et al. 1985). The PSAS consists of 16 items that range from 1 ('not at all') to 5 ('extremely'), higher scores indicating more arousal (range 16-80).

Sleep-bed association is measured with a newly constructed scale of 5 items on a 7-point Likert scale (0-6). Higher scores indicating a stronger sleep-bed association (range 0-30)

Sleep-bed association is measured with a newly constructed scale of 5 items on a 7-point Likert scale (0-6). Higher scores indicating a stronger sleep-bed association (range 0-30)

Dysfunctional beliefs about sleep are measured using the 16-item Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS-16) (Morin et al. 2017). Items are scored on an 11-point Likert scale (0-10). Higher scores indicating more dysfunctional beliefs (range 0-160).

Dysfunctional beliefs about sleep are measured using the 16-item Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS-16) (Morin et al. 2017). Items are scored on an 11-point Likert scale (0-10). Higher scores indicating more dysfunctional beliefs (range 0-160).

Depression is measured with the Dutch version of a nine-item depression scale, the Patient Health Questionnaire-9 (PHQ-9; range 0-27, Cronbach's α = 0.94; Spitzer et al., 1999). Higher scores indicating more depression.

Depression is measured with the Dutch version of a nine-item depression scale, the Patient Health Questionnaire-9 (PHQ-9; range 0-27, Cronbach's α = 0.94; Spitzer et al., 1999). Higher scores indicating more depression.

Anxiety is measured with the Anxiety section of the Hospital Anxiety and Depression Scale (HADS-A; Cronbach's α = 0.84, seven items on a four-point Likert scale, scores ranging 0-21; Spinhoven et al., 1997). Higher scores indicating more anxiety.

Anxiety is measured with the Anxiety section of the Hospital Anxiety and Depression Scale (HADS-A; Cronbach's α = 0.84, seven items on a four-point Likert scale, scores ranging 0-21; Spinhoven et al., 1997). Higher scores indicating more anxiety.

Acceptance is measured with 10-items of the 'flexibiliteits index test'. Items are scored on a 7-point Likert scale (0-6) and higher scores indicate more acceptance (range 0-60).

Acceptance is measured with 10-items of the 'flexibiliteits index test'. Items are scored on a 7-point Likert scale (0-6) and higher scores indicate more acceptance (range 0-60).

Participants asked to report adverse events ("Did anything unpleasant happen to you that was related to your sleep or participation in the trial?"

Treatment quality is rated with a single question 'how do you rate the treatment'. This is rated on an 11-point Likert scale (0-10) with higher scores indicating more satisfaction (intervention only)

Coaches are rated with a single question 'how satisfied were you with your coach during the treatment'. This is rated on an 11-point Likert scale (0-10) with higher scores indicating more satisfaction

Inclusion Criteria: Insomnia Severity Index Score ≥ 10 18 years or older Self reported insomnia complaints: being awake ≥30 minutes per night, ≥3 nights per week, ≥ 3 months Daytime problems related to sleep complaints Sleep efficiency < 85% Dutch speaking Exclusion Criteria: (1) No acces to internet (2) Pregnant or breastfeeding (3) working in night shifts (4) currently in psychological treatment (started < 6 months) or on wait-list for treatment (5) cognitive behavioral treatment for insomnia in last 12 months (6) concrete suicidal ideation (7) schizophrenic or psychotic disorder (8) high level of depressive complaints (BDI-II > 28) (9) Instable medication use (medication should not be tampered in last 6 weeks) incidental sleep-medication use is allowed