Bright Light Intervention to Reduce Students' Stress

Study Overview
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Brief Summary
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Increased stress levels are a significant problem for many students and represent a risk factor for impaired mental and physical health as well as academic performance. Stress levels are particularly high during the preparation phase for major exams. There is good evidence that light therapy is an effective treatment option to improve mood in affective disorders. The present study aims at investigating the psychophysiological effects of a 3-week morning bright light exposure in reducing stress and stress-related problems in students preparing for major exams.

Detailed Description
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Increased students' stress represents a significant risk factor for impaired mental and physical health as well as academic performance. The World Mental Health Survey (WHO) reports a 12-month prevalence of mental illness of 20.3% among students, with anxiety disorders (14.7%), affective disorders (9.9%), and substance abuse (6.7%) being particularly prominent. Moreover, six out of 10 students suffer from impaired sleep quality. Offering an effective treatment for stress-related symptoms in students is a challenge. In situations of intense stress, conventional methods such as relaxation and mindfulness-based programs often fail because of poor prior practice. Only a few students apply cognitive behavioral interventions. Although medication might decrease stress symptoms within days, the side effects of drugs cannot be ignored. Therefore, there is a need for effective and efficient treatment of acute stress symptoms in students. Bright light therapy is an effective treatment for several mental disorders, e.g. affective disorders and sleep disorders. There is some evidence, that exposure to bright light may even reduce stress in patients with burnout symptoms. Thus, exposure to bright light may be a promising new option to reduce academic stress and improve mood and sleep parameters. In the present study, a large-area desk lamp, which emits diffuse light and is controllable in its luminance and correlated color temperature is used. Study participants are randomly assigned to one of three study arms: (i) exposure to polychromatic light of 5,000 lux and 5,300 Kelvin, (ii) exposure to polychromatic light of 50 lux and 2,200 Kelvin, or (iii) no light intervention. Data collection takes place in winter periods.

Official Title
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Effects of Bright Morning Light Exposure on Students' Stress, Mood, Anxiety, Sleep and, Circadian Rest-activity Cycle

Conditions
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Psychological Stress, Physiological Stress, Sleep Disorders, Circadian Rhythm

Intervention / Treatment
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* Other: Bright light intervention
* Other: Reddish placebo light


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: students from the faculty of medicine, pharmacy, and law major exam at least 5 weeks ahead possession of smartphone and data plan Exclusion Criteria: major depressive disorder (PHQ-9): Score > 4 suicidal ideation (BDI, Item i): Rating > 1 seasonal affective disorder (PIDS-A): Score > 11 taking medication which increases photo-sensitivity taking medication to increase cognitive performance starting or changing pharmacotherapy for affective disorders and anxiety disorders within the last two weeks changing of all kinds of medication within the last two weeks headache (PHQ-D, Item f): Rating severly impaired increased light sensitivity: Item Wearing sunglasses outside on sunny days is answered with 'often' or 'very often' currently undergoing psychotherapeutic treatment the presence of an eye disease for which light therapy is contraindicated

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: placebo-controlled, randomized trial
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: bright white light intervention<br>exposure to 5,000 lux with polychromatic white light with 5,300 Kelvin at eye level; light exposure starts immediately after awakening; light exposure takes place on weekdays (Monday till Friday) over a period of 3 weeks | Other: Bright light intervention<br>* Exposure with 5,000 lux at eye level for one hour and a Correlated Color Temperature of 5,300 Kelvin every morning for three weeks.<br>|
| Placebo Comparator: dim reddish light intervention<br>exposure to 50 lux with polychromatic reddish light with 2,200 Kelvin at eye level; light exposure starts immediately after awakening; light exposure takes place on weekdays (Monday till Friday) over a period of 3 weeks | Other: Reddish placebo light<br>* Exposure with 50 lux at eye level for one hour and a Correlated Color Temperature of 2,200 Kelvin every morning for three weeks.<br>|
| No Intervention: no light intervention<br>no light intervention takes place in the morning; the study participants follow their natural rhythm of life | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| subjective stress level - baseline/post | Perceived Stress Scale (PSS-10); scale: PSS-10 sum score; range:0 - 40; higher scores mean a higher subjective stress level | Change from baseline PSS-10 sum score at the end of week 3 | 
| subjective stress level - baseline/post | Perceived Stress Questionnaire (PSQ-20); scale: PSQ-20 sum score; range: 20 - 80; higher scores mean a higher subjective stress level | Change from baseline PSQ-20 sum score at the end of week 3 | 
| subjective stress level - on weekdays | Perceived Stress Questionnaire (PSQ-20); scale: PSQ-20 sum score; range: 20 - 80; higher scores mean a higher subjective stress level | Change of daily PSQ-20 sum score at each weekday during the light intervention period up to 3 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| anxiety | State-Trait Anxiety Inventory (STAI - form Y) - 20 trait items; scale: STAI-trait sum score; range: 20 - 80; higher scores mean a higher subjective anxiety level | Change from baseline STAI-trait sum score at the end of week 3 | 
| mood | Center for Epidemiologic Studies Depression Scale (CES--D); scale: CES-D sum score; range: 0 - 60; higher scores mean a higher subjective depression level | Change from baseline CES-D sum score at the end of week 3 | 
| sleep quality | Pittsburgh Sleep Quality Index (PSQI); scale: global PSQI score; range: 0 - 21; higher scores mean a lower subjective sleep quality | Change from baseline global PSQI score at the end of week 3 | 
| sleep quality - total sleep time | Wrist actimetry to measure daily total sleep time (TST); scale: sleep duration; range: >0 (minutes); higher TST means longer sleep period | Change of TST at each night during the light intervention period up to 3 weeks | 
| sleep quality - sleep onset latency | Wrist actimetry to measure daily sleep onset latency (SOL); scale: duration to fall asleep; range: >0 (minutes); higher SOL means longer period to fall asleep | change of SOL at each night during the light intervention period up to 3 weeks | 
| sleep quality - wake after sleep onset | Wrist actimetry to measure daily wake after sleep onset (WASO); scale: duration of being awake during sleep period; range: greater than or equal to 0 (minutes); higher WASO means longer wake periods after sleep onset | change of WASO at each night during the light intervention period up to 3 weeks | 
| sleep quality - sleep efficiency | Wrist actimetry to measure daily sleep efficiency (SE); scale: percentage; range: 0 - 100; higher SE means a higher undisturbed sleep | change of SE at each night during the light intervention period up to 3 weeks | 
| circadian rest/activity rhythm - interdaily stability | Circadian rest-activity cycle parameter interdaily stability (IS) derived from weekly wrist actimetry data; scale: real number; range: 0 -1; higher IS means a higher stability in daily rest-activity cycles | change of IV at each of the three light intervention weeks up to 3 weeks | 
| circadian rest/activity rhythm - intradaily variability | Circadian rest-activity cycle parameter intradaily variability (IV) derived from averaged wrist actimetry data over a period of 1 week; scale: real number; range: 0 - 2; higher IV means a higher variability in 24-h rest-activity cycle | change of IS at each of the three light intervention weeks up to 3 weeks | 
| physiological stress reaction | cortisol level measured from hair sample; scale: real number (pg/mg); range: >0; higher hair cortisol level means higher physiological stress | Change from baseline hair cortisol level at the end of week 3 | 
| adverse effects - short-term | astenopic complaints measured with 12 items; scale: sum score; range: 10 - 60; higher sum score means more astenopic complaints | day 5 | 
| adverse effects - long-term | astenopic complaints scale measured with 12 items: sum score; range: 10 - 60; higher sum score means more astenopic complaints | day 15 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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stress, light therapy