The goal of this clinical trial is to evaluate whether adding rumination-tailored, rule-based personalized feedback to guided internet-based cognitive behavioral therapy for insomnia (iCBT-I) improves treatment outcomes in university students with insomnia symptoms.

The main questions it aims to answer are:

Does rumination-tailored feedback improve insomnia severity compared to standard guided iCBT-I? Does the addition of personalized feedback improve rumination, treatment adherence, and treatment satisfaction compared to standard guided iCBT-I? Researchers will compare three conditions: (1) standard guided iCBT-I, (2) guided iCBT-I with additional rumination-tailored feedback, (3) waitlist control group, to determine whether the enhanced intervention leads to superior clinical and behavioral outcomes.

Participants will:

complete an online screening and baseline assessment be randomly assigned to one of three study conditions receive either guided iCBT-I, guided iCBT-I with rumination-tailored feedback, or no intervention (waitlist condition) complete a structured internet-based CBT-I program over several weeks (for intervention arms) receive weekly guidance according to group allocation complete post-treatment and follow-up questionnaires assessing sleep, rumination, and treatment experience

This study is a pilot randomized controlled trial with three parallel arms. Participants will be randomly assigned to either (1) guided internet-based cognitive behavioral therapy for insomnia (iCBT-I), (2) guided iCBT-I with additional rumination-tailored, rule-based personalized feedback, or (3) a waitlist control group. The study aims to evaluate the feasibility and preliminary efficacy of integrating targeted cognitive feedback into a digital insomnia intervention.

The study will recruit university students with clinically relevant insomnia symptoms. Participants will be included if they are university students, 18 years of age or older, fluent in Persian and able to read and understand online study materials, reporting clinically relevant insomnia symptoms, and willing to complete online questionnaires and use the internet-based intervention platform.

Participants will be excluded if they have a current severe psychiatric condition requiring immediate treatment, such as psychosis, mania, or active suicidal intent; are currently receiving another structured insomnia treatment or CBT-I program; have a diagnosed sleep disorder other than insomnia that would better explain the sleep problem, such as sleep apnea, restless legs syndrome, or narcolepsy; work regular night shifts or have a highly irregular sleep-wake schedule that would make the intervention unsuitable; have a substance use problem severe enough to interfere with participation; or have a cognitive or language problem that prevents completion of the online materials or questionnaires.

The base intervention consists of a structured guided internet-based CBT-I program including standard components such as sleep restriction, stimulus control, cognitive restructuring, sleep hygiene education, and relaxation techniques. Participants receive weekly brief supportive guidance during the intervention period (for intervention arms only).

In the experimental condition, participants additionally receive rumination-tailored, rule-based personalized feedback generated based on their levels of repetitive negative thinking and sleep-related cognitive arousal. The feedback is predefined according to decision rules and is not dynamically generated. The feedback targets repetitive negative thinking patterns, sleep-related worry and cognitive arousal, and maladaptive pre-sleep cognition. Feedback is delivered in written format alongside standard CBT-I guidance and is designed to complement, not replace, core therapeutic components.

Participants in the waitlist control condition will not receive immediate intervention during the study period. After study completion, they will be offered access to the guided iCBT-I program.

The primary outcome is insomnia severity measured using a validated insomnia questionnaire. Secondary outcomes include repetitive negative thinking (rumination), treatment adherence, treatment satisfaction, and dropout rate.

Participants will be randomly allocated to one of three study conditions using a parallel group randomized design with balanced allocation. Due to the nature of the intervention, participants and intervention providers cannot be blinded. Outcome assessment is based on self-report measures, and participants will be aware of their group allocation.

Assessments will be conducted at baseline, post-intervention, and follow-up. Data collection will be fully online through a secure platform. Participants will complete weekly monitoring measures during the intervention period.

Feasibility will be evaluated through recruitment rate, retention, and adherence to intervention modules. Acceptability will be assessed using self-reported treatment satisfaction.

Insomnia is frequently maintained by cognitive arousal and repetitive negative thinking, particularly rumination before sleep. While standard CBT-I is effective, variability in treatment response suggests a need for personalization. This study investigates whether augmenting CBT-I with structured rumination-focused feedback can improve engagement and outcomes in a scalable digital format.

Inclusion Criteria:

• University students
• Aged 18 years or older
• Fluent in Persian and able to read and understand online study materials
• Reporting clinically relevant insomnia symptoms as indicated by screening measures
• Willing to complete online questionnaires and participate in an internet-based intervention program

Exclusion Criteria:

• Current severe psychiatric condition requiring immediate clinical attention (e.g., psychosis, mania, or active suicidal ideation)
• Current participation in another structured psychological treatment for insomnia (including CBT-I)
• Presence of a diagnosed sleep disorder other than insomnia that better explains sleep problems (e.g., sleep apnea, restless legs syndrome, narcolepsy)
• Regular night-shift work or highly irregular sleep-wake schedule that would interfere with CBT-I protocols
• Severe substance use problems that may interfere with participation or adherence
• Cognitive, language, or technological limitations that prevent completion of online assessments or intervention materials

De-identified individual participant data (IPD) collected in this study will include demographic information, baseline characteristics, questionnaire responses (e.g., insomnia severity, rumination, sleep quality), treatment adherence indicators, and treatment outcome measures. No directly identifiable personal information will be shared. All data will be fully anonymized prior to sharing.

De-identified IPD and supporting documents will become available after publication of the primary study results or within 12 months after study completion, whichever occurs first. Data will remain available for a minimum of 5 years following publication.

Access to de-identified individual participant data and supporting documents will be granted upon reasonable request to qualified researchers for academic and non-commercial purposes. Requests will be reviewed by the principal investigator. Data will be shared under a data use agreement to ensure confidentiality, ethical use, and compliance with institutional and ethical guidelines. Only de-identified datasets will be shared.