Light Therapy in Sleep Disorders 2014 Andrew G Veale
Light and Health Effects through the eye Effects through the skin Positive effects Mood Vitality Alertess Light on skin Vitamin D production light therapy through the skin Negative effects Seasonal affective disorder Light at Night Shift work Disturbance to Sleep-wake cycle Light and cancer Light at night may lead to breast cancer blue-light hazard UV radiation to eye --> cell deaths in the eye Light on skin skin cancer
Biological effects of light Light is not just for vision any more All non-visual effects of light Biological clock Surrounding world have external rhythms, where people have to adapt. Organisms have built an internal clock, which can react to external cues
Biological effects of light Biological clock External cues / stimulation Light Auditive stimulants Physical exercise Drugs Eating habits Social stimulus temperature
Structure of biological clock Non visual photoreceptor in retina Retinohypothalamic track (RHT) Suprachiasmatic nuclei (SCN) In hypothalamus Master clock of biological rhythms Pineal gland Melatonin secretion
Circadian rhythms Circa dies = day Biological rhythms: cycles around 24 h Well-known circadian cycles Sleep-wake cycle Hormonal endocrine secretion Melatonin, cortisol Blood pressure cycle Body temperature Alertness Light is the strongest syncroniser
Circadian rhythms
CIRCADIAN RHYTHMS Melatonin Night hormone, secretion from pineal gland Strongest regulator is light Melatonin, CBTemp, cortisol and sleep-wake cycles are in strong correlation
CIRCADIAN RHYTHMS Sleep-wake cycle What happens without external cues? What happens without sleep?
Other biological cycles and correlation between them
Biological effects of light Important dates Light is shown to influence plants 24 h cycle (Bunning 1936) Light on melatonin suppression (Alfred J. Lewy 1980) Light is shown to impact human circadian system (Czeisler 1981) Light alleviates depressive symptoms (Alfred J. Lewy 1982) Seasonal Affective disorder discription of the syndrome was presented (Rosenthal 1984) New light sensitive photoreceptor in human retina detected (David Berson 2002)
Light can affect More alert on night (Cajochen 2000) and daytime (Phipps-Nelson 2003) More productivity in office environment (Mills 2007) more alert, less daytime sleepiness, more vitality Cognitive performance (Lehrl 2007) alerness, speed of information processing
Seasonal affective disorder Depressive symptoms Lack of energy 96% Sadness 96% Social withdrawal 92% Irritation 86% Daytime tiredness 81% Seasonal symptoms Prolonged sleep 76% Weight gain 74% Carbohydrate craving 70%
Seasonal affective disorder Why we have this? Short light period is the strongest trigger of SAD Circadian rhythm phase delay Genes Treatment Bright light therapy 2500-10000 lux Dawn simulation 250 lux Fitness training In combination with light exposure
Subsyndromal SAD similar to SAD, but patients don t fill definition of major depressive disorder More common (Finland 27%) Symptoms as: craving to food and carbohydrate, difficult awakening and hypersomnia and exhaustion and daytime sleepiness similar to SAD
Bright light therapy 2500 10000 lux 30 min 2 h per day 4000 Kelvin History of research and treatment to SAD 25 years Best result after awakening Effect mechanism Synchronize circadian rhythms and sleep-wake cycle
Bright light therapy Applications SAD Response 60-90 % to alleviating depressive symptoms (Lam RW, Levitt AJ. 1999. Canadian Consensus Guidelines for the Treatment of Seasonal Affective Disorder) Subsyndromal SAD Non-seasonal depression 12-35% alleviating depressive symptoms, equal to traditional pharmaceutigal drug (Kripke 1998) Meta-analysis: light therapy offers modest though promising antidepressive efficacy (Tuunainen 2004) Light therapy: effective adjuvant therapy to antidepressant medication (Even 2007, Martiny 2004) Jet lag
Bright light beyond SAD illumination and seasonal changes in mood and behavior are associated with the health-related quality of life (Partonen 2008) Seasonal changes in mood and behavior are common in a general population (Partonen 2008). Disfunction of biological clock may lead to insomnia and metabolical disturbances (Partonen 2008).
Bright light beyond SAD Office environment Bright light alleviate sub-sad symptoms, improve the mood, vitality, alertness and productivity (Avery 2001) Improved vitality and mood people with or without sub-sad (Partonen 2000) Continous exposure to bright light may improve quality of life, because it will improve the vitality (Partonen 2000)
Bright light therapy and physical exercise 4 study by National Public Health Institute (Leppämäki, Partonen 1998-2004) Combination: bigger alleviation of typical depressive symptoms and more vitality than exercise alone Carbohydrate craving, prolonged sleep, weight gain Effective combination to improve mood and certain components of health related quality of life in wintertime Social activity, overall mental heath Affect also to healthy people
The effect of exercise and light on mood (2006) Depressive symptoms alleviated 40-66% and atypical depressive symptoms alleviated 45-88% Bright light alone is more effective on atypical depressive symptoms than physical exercise alone Bright light dosing two times a week (with or without exercise) is effective to alleviate atypical depressive symtoms, which are associated with wintertime depression
New applications of bright light therapy Strong seasonality Adult with attention-deficit disorder Bulimia Circadian system disorders Bright light and elderly, Phase Advance Alzheimer disease and dementia, Parkinson disease Phase delay Syndrome When medication is unwanted Depression during pregnancy/ postpartum depression
Bright light and bulimia Bulimia is mainly eating disorder, but atypical depressive symptoms are prevalent Binge eating problems are strongly depentent on season Morning bright light significantly alleviated bulimia symptoms (Lam RW, Am J Psychiatry. 1994) Significant improvement in eating disorders during bright light treatment (Braun DL, Compr Psychiatry. 1999)
Bright light and weight control Seasonal symptoms Carbohydrate craving 70% Weight gain 74% Seasonal affective disorder and metabolic syndrome are strongly related (Partonen 2008) Obesity, high blood sugar level, high blood pressure
Dawn simulation Research subjects SAD, sub-sad hypersomnia, difficult awakening, quality of sleep and morning-time alertness synchronisation of delayed sleep-wake cycle Treatment parameters Illuminance 150-300 lux Time 15 min to 60 min
Dawn simulation Effect mechanism Same as in bright light therapy Synchronisation of circadian cycles Effect size almost same as in bright light therapy on SAD (Golden 2005) Dawn simulation is more user-friendly, because treatment happens at the time when subject is waking from sleep
Dawn simulation Effect mechanism Same as in bright light therapy Synchronisation of circadian cycles hypersomnia, difficult awakening, quality of sleep and morning-time alertness Dawn simulation is more user-friendly, because treatment happens on time when subject is waking
We live in a light-deprived world...
Why we are light deprived Work indoors Play indoors Travel indoors Many now believe that sunlight = bad ozone layer depletion = > UV radiation > risk of skin cancer Avg. exposure 57 mins/day in sunny San Diego
Other Indications for Light Therapy: Shift-work Jet lag Sleep Disorders Delayed Phase Sleep Disorder (DPSD) Advanced Phase Sleep Disorder (APSD) Fatigue Management (CFS, MS, Chemo pts.) Performance enhancement athletes, execs Baby Blues & Post-partum depression
Melatonin Suppression Curve Primary = 464nm (blue) Secondary = 550nm (green)
Traditional Light therapy Litebook Knock-offs
Litebook Usage: