The Effects of Bright Light Therapy on Adolescent's Sleep Quality and Well-being

Primary outcomes

1. ActTrust: Sleep/wake activity

   Time frame: Up to 9 months

   Measure of night-time and daytime sleep (combined minutes of sleep, sleep-onset latency, and sleep efficiency. Recorded by a wrist actigraph (ActTrust).

2. ActTrust: Circadian Activity Rhythms

   Time frame: Up to 9 months

   Rest-activity patterns (amplitude, acrophase, mesor) recorded by a wrist actigraph (ActTrust), combined into a circadian activity variable.

3. ActTrust: Daily physical activity

   Time frame: Up to 9 months

   Measure recorded by a wrist actigraph (ActTrust) showing activity levels of participants.

4. ActTrust: Environmental light exposure

   Time frame: Up to 9 months

   Measure recorded by a wrist actigraph (ActTrust), showing the types of light a participant is exposed to.

5. Pittsburgh Sleep Quality Index

   Time frame: Up to 9 months

   The Pittsburgh Sleep Quality Index assesses sleep quality. his measure is composed of 19 items that generate seven component scores (subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleep medication, and daytime dysfunction). The sum of the seven component scores yields one global score. A person with a global score above 5 is considered to have sleep disturbances. The scale has the test-retest reliability of r=.85 and estimated internal consistency of α=.80.

6. The Warwick-Edinburgh Mental Well-being Scale

   Time frame: Up to 9 months

   The Warwick-Edinburgh Mental Well-being Scale (WEMWBS), 7 item short version will be used to assess overall well-being during the last two weeks. Each item on the list is rated on a 5-point Likert scale ranging from "never" to "very often".

7. Munich Chronotype Questionnaire (MCTQ)

   Time frame: Up to 9 months

   The Munich Chronotype Questionnaire (MCTQ) is a self-reported measure of chronotype that addresses questions related to sleep and wakefulness. The participants were asked to answer the list based on experience of a typical week in their current situation.

8. PROMIS cognitive function and cognitive abilities 8a

   Time frame: Up to 9 months

   PROMIS® (Patient-Reported Outcomes Measurement Information System) cognitive function and cognitive abilities 8a consist of 8 self-report item rated on a five point Likert scale ranging from "never" to "very often" on the Cognitive Function scale and "not at all" to "very much" on the Cognitive Abilities scale. Both PROMIS item banks show good psychometric properties, such as a high internal consistency (α =.94 for each).

9. Depression Anxiety Stress Scales (DASS 21)

   Time frame: Up to 9 months

   The Depression, Anxiety and Stress Scale - 21 Items (DASS-21) is a set of three self-report scales designed to measure the emotional states of depression, anxiety and stress. The participants were asked to read the following statement and circle a number 0, 1, 2 or 3 which indicates how much the statement applied to the participant over the past week.

10. The Cleveland Adolescent Sleepiness Questionnaire

    Time frame: Up to 9 months

    The Cleveland Adolescent Sleepiness Questionnaire (CASQ), a brief, self-completed instrument to measure excessive daytime sleepiness in adolescents. For each statement, the participants were asked to mark the circle under the response that best fits with how often it applies to them. Each item on the list is rated on a 5-point Likert scale ranging from "never" to "almost daily".

11. Adolescents Daytime Naps

    Time frame: Up to 9 months

    Adolescents Daytime Naps measure how often participants fall asleep daily. If they rest or fall asleep during the day, it is called a day-nap, whether they have planned to go to bed or not. Daytime hours also cover shorter periods of time when they rest or fall asleep, for example over a computer / television or reading. First participants are asked about daytime hours on weekdays and then about daytime hours on weekends. If participants go to bed more than once a day, they should record the total time staying in bed.

12. Adolescents Screen Time

    Time frame: Up to 9 months

    The participants were asked how long time they spend on a computer, tablet, game console, television, phone or other display device in the following: school lessons, work/internship, computers or social media. The answer possibilities are 0-23 hours and 0-50 minutes.

13. Physical activity

    Time frame: Up to 9 months

    The participants were asked two questions about their physical activity during the last seven days. The participants were asked how long time per one day they usually spend participating in physical activity. Include the time they spent waking, jogging, running, cycling, exercising or doing some kind of sport. The answer possibilities range from "less than 1/2 hour a day" up to "more than 6 hours a day" The participants were also asked how many days of the last seven days they participated in physical activity for at least 60 minutes so that their heart rate increased and they sometimes got out of breath. The participation may include physical activity, workout, brisk walking, cycling in free time or transportation between different locations. The answers range from "almost never" up to "seven days".

14. Sedentary behaviour

    Time frame: Up to 9 months

    The participants were asked how long time they usually spend sitting the last seven days. The period starts when they wake up in the morning and ends when they goes to bed for the night. Include time spent at work, at school, at home, and in their free time. This can include time spent at a desk, dining table, visiting, watching movies, reading, or in front of a television, computer, or other monitor. The answer possibilities range from "30 minutes per day" up to "more than 16 hours per day".