Insomnia and eating disorders are highly prevalent among adolescents, often co-occur, and are associated with somatic and mental comorbidities and functional impairment. The first aim of this project is to longitudinally monitor psychological functioning and sleep- and eating-related behaviours in a large sample of students aged 14-17 yrs. (N = 854), to identify the variables that predict transition from a prodromal phase to a clinical stage, and signpost individuals at risk or with clinical symptoms to self-help materials and clinical support. The second aim is to test whether increased emotional reactivity to disease-related stimuli (stimuli related to sleep or eating) in a virtual reality environment can discriminate between individuals at risk or with clinical symptoms and healthy peers. The third goal is to conduct a pilot randomized controlled trial to test a virtual reality self-help exposure-based intervention to remediate eating or sleep difficulties in individuals at risk or exhibiting clinical symptoms of eating disorders or insomnia.

The present study aims:

1. To measure eating- and sleep-related behaviours and psychological functioning over time (6-9 months) in a large sample of secondary school students aged 14 to 17 years old and identify individuals at risk or exhibiting clinical symptoms in order to signpost them to self-help written materials and clinical support;
2. To establish whether increased emotional reactivity to disease-related stimuli (sleep- or eating-related) in a virtual reality environment discriminates between individuals at risk or with clinical levels of eating and/or insomnia and healthy peers;
3. To conduct a pilot randomized controlled trial to test a virtual reality self-help exposure-based intervention for eating or sleep difficulties, targeting increased emotional reactivity to disease-related stimuli.

A minimum of 854 adolescents will be recruited and assessed at baseline, 3- and 6-to-9 months follow-up.

A mobile application has been specifically designed for this study, incorporating gamified elements to enhance engagement and adherence. The app can be downloaded for free on participants' mobile devices and will play a crucial role throughout the study, serving multiple purposes. It will be first used as an assessment tool: participants will complete baseline and follow-up questionnaires. Moreover, they will receive notifications to collect Ecological Momentary Assessment (EMA) data. Finally, it will provide access to self-help written materials on sleep and eating habits and disorders that participants will be able to read and download from the beginning of the study.

The sample size was estimated based on the recommendations for sample size calculation in prevalence studies. The calculation was performed using the Scalex sample size calculator and was based on four parameters: level of confidence, which was set at 95%; level of precision of the estimated prevalence, which was set at 3%, the recommended threshold for large scale studies likely to gain attention from policy makers; estimated prevalence of the disorder, which was established at 20% based on prevalence of sleep and eating problems among Italian adolescents; anticipated loss, which was set at 20% based on the loss of data at six months in previous studies.

Assessment phase.

Students whose parents will have given informed consent to participate in the study will complete the baseline assessment through the App and provide information on:

• gender, age, family composition, and history of mental health disorders;
• sleep behaviours and insomnia symptoms: Insomnia Severity Index (ISI); Sleep Health Dimensions Questionnaire
• eating behaviours and symptoms: Screening Tool for Eating Disorders (SCOFF); Eating Disorder Examination Questionnaire (EDE-Q 6.0)
• history of weight-based victimization
• depression, anxiety, and stress symptoms: Depression, Anxiety and Stress Scales (DASS-21)
• strengths and difficulties regarding emotional functioning: Cognitive Emotion Regulation Questionnaire (CERQ-IS)
• emotional, behavioural and interpersonal difficulties and prosociality: Strengths and Difficulties Questionnaire (SDQ)
• social media usage: Bergen Social Media Addiction Scale (BSMAS).

They will also undergo a 4-day EMA to assess sleep and eating behaviours, sleepiness, eating disorder symptoms, and emotional states multiple times/day.

At three- and six-to-nine months follow-up, participants will complete a subset of measures completed at baseline:

• Insomnia Severity Index (ISI)
• Eating Disorder Examination Questionnaire (EDE-Q 6.0)
• Screening Tool for Eating Disorders (SCOFF)
• Depression, Anxiety and Stress Scales (DASS-21)
• 4-day Ecological Momentary Assessment; EMAs

Self-help written materials have been developed by the research team for the purposes of the present study. They consist of a short booklet about sleep and eating behaviours and disorders, providing strategies to cope with them. Contents will be available to participants from the beginning of the study. They will be able to both read and download them directly from the application on their mobile devices.

Individuals identified as at high-risk for, or with insomnia (ISI, total score min=0; max=28, cut-off= 8 for high-risk individuals, cut-off=15 for clinical levels of insomnia)/eating disorder symptoms (SCOFF, total score min=1; max=5, cut-off 3) at baseline and at 3 months will be invited to take part in a 15-min virtual reality exposure session to measure emotional reactivity to eating and/or sleep-related stimuli. Individuals at high-risk for/with insomnia will be exposed to a virtual bedroom, while individuals at high-risk for/with eating disorders will be exposed to a virtual kitchen. A control group (with no symptoms of eating disorders or insomnia) will also be recruited and exposed to both the virtual bedroom and virtual kitchen in randomized order.

Intervention phase. Participants in the high-risk/clinical group (approximately N=100) will be randomly allocated to an intervention or a control condition. Those in the intervention condition will be asked to use the virtual reality scenario for a week, at home, with the aim of reducing emotional reactivity associated with sleep or eating-related stimuli. Those in the control condition will only have received access to the self-help written materials. Visual analogue scales will be presented to evaluate anxiety levels before and after the exposure. Feasibility and acceptability of the virtual reality environments will be assessed through visual analogue scales and a qualitative interview. Participants across groups will also complete EMAs of eating and/or sleep behaviours during the week.

Inclusion Criteria:

• age ≥ 14; ≤ 17 years old
• knowledge of Italian language
• own a device with internet connection

a plan will be established by the research team for data sharing following publication of the first manuscript

Each participant will be assigned an identification code (ID-code) randomly generated by a computer. The outcome assessors will be blind to which group (intervention or control) conditions 1 and 2 will correspond to.