Daytime Sleepiness

This study tests whether a week of morning bright light therapy changes how well healthy young adults sleep and how alert, positive, and mentally sharp they feel during the day. Morning light is the body's main signal for keeping its internal clock and sleep-wake timing on track. Many university students keep irregular hours and spend most of the day indoors, where light is far dimmer than daylight. This study asks whether adding a short, bright morning light session can help. Each participant takes part for two weeks. For one week they use a bright light box for 30 minutes each morning, shortly after waking; for the other week they keep their usual lighting. The order of the two weeks is decided at random, and each person serves as their own comparison. Throughout both weeks, sleep is tracked with a wrist-worn Fitbit and a short daily diary. Participants also rate their sleepiness and mood, complete brief computer-based attention and memory tasks, and take part in a short interview at the end about their experience. The study compares the bright-light week with the usual-light week to see whether morning bright light improves sleep regularity and efficiency, reduces daytime sleepiness, lifts mood, or affects thinking performance. The trial is being conducted in waves; a first wave has completed and a second wave is planned, pending additional funding.

The overall aim of this project is to evaluate the effectiveness of two school-based programs that have the potential to promote adolescent sleep and prevent future depressive symptoms. The programs will be offered to students aged 13-19 at Swedish high schools and upper secondary schools at the classroom level. The students will be compared to teaching as usual (control group).

The study will be a prospective randomized, controlled clinical study. There will be interventional treatment for a total of 30 days. The subjects will complete questionnaires throughout the study at pre-specified timepoints.