BACKGROUND Sleep problems are particularly common among adolescents and young adults, a developmental period characterized by biological, psychological, and social changes that increase vulnerability to insomnia. In Denmark, youth aged 16-24 report the highest prevalence of sleep difficulties, and similar trends are seen internationally. Short or disturbed sleep is linked not only to daytime fatigue, impaired academic performance, and social difficulties, but also to increased risk of stress-related disorders, anxiety, depression, and later chronic insomnia. Despite these risks, existing treatment options remain limited. Cognitive-behavioral therapy for insomnia (CBT-I) is effective but resource-intensive, while pharmacological treatments carry risks of side effects and dependency. Safe, accessible, and scalable non-pharmacological alternatives are urgently needed.
Special blankets represent one such potential intervention. These blankets can be designed to stimulate tactile and proprioceptive systems, which may reduce hyperarousal, promote relaxation, and regulate stress-related mechanisms. Preliminary observations suggest beneficial effects on sleep initiation and maintenance, as well as reductions in anxiety and stress. However, robust randomized controlled trials (RCT) in general youth populations with clinically relevant insomnia are lacking.
AIMS AND HYPOTHESES
Primary aim Aim 1: To test the efficacy of different blankets on insomnia severity (primary outcome) in adolescents and young adults with insomnia.
Exploratory aims Aim 2: To test the effect of different blankets on actigraphy-based sleep (sleep efficiency, total sleep time and wake after sleep onset) in a sub-group of adolescents and young adults.
Aim 3: To explore the effect of different blankets on self-report measures of mental and physical health and well-being (i.e., stress, depression, anxiety, cognition, daytime sleepiness, health status and quality of life) in adolescents and young adults.
Aim 4: To explore the effect of different blankets on potential stress-related mechanisms (i.e., the diurnal cortisol response and self-reported pre-sleep arousal) and to test for potential mediation of the effect of special blankets on insomnia severity.
Aim 5: To explore the continued use of different blanket for 8 weeks after intervention completion and to track associated changes in insomnia severity and self-reported mental health and physical well-being in an open trial design.
METHODS
The present project aims to fill this knowledge gap through a rigorous, two-phase study design. In Phase 1, a randomized controlled trial (RCT) will test the efficacy of different special blankets compared with an observation group receiving no blanket. Eligible participants will be young people aged 16-24 with clinically relevant sleep problems, defined as an Insomnia Severity Index (ISI) score \>10. After baseline screening and consent, participants will be randomized via REDCap into one of three groups:
Group 1: receives Blanket A for home use over 4 weeks.
Group 2: receives Blanket B for 4 weeks.
Group 3 (observation group): receives no blanket during the same period but completes identical assessments.
Assessments will take place at baseline (week 0), mid-intervention (week 2), and post-intervention (week 4). Primary outcomes will be insomnia severity and sleep quality, assessed by validated questionnaires. Secondary outcomes include mental health indicators (stress, anxiety, depressive symptoms), physical health, and well-being. To explore potential mechanisms, the first 40 participants in Groups 1 and 2 will also provide salivary cortisol samples and wear actigraphy devices to measure circadian rhythm and sleep-wake patterns.
In Phase 2, an open-label extension phase, participants in Groups 1 and 2 may continue using their blanket or revert to regular bedding for an additional 8 weeks. At week 12, follow-up questionnaires will assess long-term sleep outcomes, user experience, satisfaction, and perceived barriers. Participants from the observation group will then be offered the opportunity to try a special blanket for 8 weeks, ensuring equal access.
The investigators plan to recruit 672 participants, which will provide sufficient statistical power to detect clinically meaningful effects while accounting for potential dropout. Inclusion criteria are age 16-24 years and ISI \>10. Exclusion criteria include significant somatic, psychiatric, or neurological disorders affecting sleep; ongoing use of medications influencing sleep; pregnancy; shift or night work; prior use of special blankets for sleep; and insufficient Danish language proficiency to complete questionnaires.
SIGNIFICANCE AND RELEVANCE This project will be the first large-scale, randomized evaluation of special blankets in a general youth population with insomnia symptoms. By integrating subjective measures, objective circadian monitoring, and biological stress markers, the study will not only test efficacy but also shed light on underlying mechanisms. Results will have direct clinical relevance: recent guidelines for managing sleep problems in children and adolescents emphasize non-pharmacological approaches and highlight the potential of special blankets as a first-line option. If proven effective, special blankets could represent a safe, inexpensive, and easily disseminable intervention with the potential to substantially reduce the personal and societal burden of insomnia.
