Effectiveness of Internet-based Self-help Cognitive Behavioural Therapy in Reducing Insomnia Among Adult Population

Change from Baseline Assessment in General Sleep Disturbances on the Pittsburgh Sleep Quality Index (PSQI) at Post-Intervention Assessment and Follow-up Assessment

The PSQI assesses the change in a 4-point Likert scale, ranging from 1 (not during the past month/ very good) to 4 (three or more times a week/ very poor).

Time frame: Before intervention, Immediately after intervention, and 4 weeks after intervention

Change from Baseline Assessment in Daily Sleep-Wake Schedule on the 7-Day Consensus Sleep Diary at Post-Intervention Assessment and Follow-up Assessment

The 7-day consensus sleep diary will calculate the change of participants' sleep parameters from the diary data.

Time frame: Before intervention, Immediately after intervention, and 4 weeks after intervention

Change from Baseline Assessment in Cognitive and Somatic Manifestations of Arousal on the Pre-sleep Arousal Scale (PSAS) at Post-Intervention Assessment and Follow-up Assessment

The PSAS assesses the change in a 5-point Likert scale, ranging from 1 (not at all) to 5 (extremely).

Time frame: Before intervention, Immediately after intervention, and 4 weeks after intervention

Change from Baseline Assessment in Sleep Habits on the Sleep Hygiene Practice Scale (SHPS) at Post-Intervention Assessment and Follow-up Assessment

The SHPS assesses the change in a 6-point Likert scale, ranging from 1 (never) to 6 (always).

Time frame: Before intervention, Immediately after intervention, and 4 weeks after intervention

Change from Baseline Assessment in Sleep Related Cognition on the Dysfunctional Beliefs and Attitudes about Sleep (DBAS) at Post-Intervention Assessment and Follow-up Assessment

The DBAS assesses the change in a 10-point Likert scale, ranging from 0 (strongly disagree) to 10 (strongly agree).

Time frame: Before intervention, Immediately after intervention, and 4 weeks after intervention

Change from Baseline Assessment in Psychological Wellbeing on the World Health Organisation-Five Well-Being Index (WHO-5) at Post-Intervention Assessment and Follow-up Assessment

The WHO-5 assesses the change in a 6-point Likert scale, ranging from 1 (never) to 6 (all of the time).

Time frame: Before intervention, Immediately after intervention, and 4 weeks after intervention

Change from Baseline Assessment in Psychological Distress on the Short Form of the Depression, Anxiety, and Stress Scale (DASS-21) at Post-Intervention Assessment and Follow-up Assessment

The DASS-21 assesses the change in a 4-point Likert scale, ranging from 0 (did not apply to me at all) to 3 (applied to me very much, or most of the time).

Time frame: Before intervention, Immediately after intervention, and 4 weeks after intervention

Change from Baseline Assessment in Quality of Life on the Twelve-Item Short-Form (SF-12) Health Survey at Post-Intervention Assessment and Follow-up Assessment

The SF-12 assesses the change in a combination of 5-point and 3-point Likert scale, ranging respectively from 1 (poor/ never) to 5 (excellent/ very much), and 1 (never) to 3 (very much).

Time frame: Before intervention, Immediately after intervention, and 4 weeks after intervention

Change from Baseline Assessment in Functional Impairment of Insomnia on the Work and Social Adjustment Scale (WSAS) at Post-Intervention Assessment and Follow-up Assessment

The WSAS assesses the change in a 9-point Likert scale, ranging from 1 (not at all) to 9 (very severely).

Time frame: Before intervention, Immediately after intervention, and 4 weeks after intervention

Change from Baseline Assessment in Cognitive Failure on the Measure of Insight into Cognition-Self Report (MIC-SR) at Post-Intervention Assessment and Follow-up Assessment

The MIC-SR assesses the change in a 4-point Likert scale, ranging from 1 (never) to 4 (almost daily).

Time frame: Before intervention, Immediately after intervention, and 4 weeks after intervention

Change from Baseline Assessment in Expectation toward Intervention on the Credibility of Treatment Rating Scale (CTRS) at Post-Intervention Assessment and Follow-up Assessment

The CTRS assesses the change in a 6-point Likert scale, ranging from 1 (not at all confident) to 6 (very confident).

Time frame: Before intervention, Immediately after intervention, and 4 weeks after intervention

Insomnia Treatment Acceptability assessed the Insomnia Treatment Acceptability Scale (ITAS) at the Interview after Post-Intervention Assessment

The ITAS assesses the insomnia treatment acceptability in a 10-point Likert scale, ranging from 1 (not at all acceptable) to 10 (very acceptable).

Time frame: Immediately after Post-Intervention Assessment

Treatment Adherence at the Interview after Post-Intervention Assessment

Participants report the number of sessions they had read, how long they had spent on the CBT program, and how far they had followed the instructions.

Time frame: Immediately after Post-Intervention Assessment

Treatment Satisfaction at the Interview after Post-Intervention Assessment

Participants report on whether they like, found it useful, and improvement of the intervention in a 10-point Likert scale, ranging from 0 (not at all suitable) to 10 (very suitable).

Time frame: Immediately after Post-Intervention Assessment

Treatment Satisfaction in internet (Acceptability of the Internet for delivering CBT) at the Interview after Post-Intervention Assessment

Participants report on how suitable, how convenient, how much they liked, and how worried they were about their privacy in a 10-point Likert scale, ranging from 0 (not at all suitable) to 10 (very suitable).

Time frame: Immediately after Post-Intervention Assessment