Overall , both forms of preventive light therapy reduced the incidence of SAD numerically compared with no light therapy .
BACKGROUND Seasonal affective disorder ( SAD ) is a seasonal pattern of recurrent major depressive episodes that most commonly occurs during autumn or winter and remits in spring .
The prevalence of SAD ranges from 1.5 % to 9 % , depending on latitude .
The predictable seasonal aspect of SAD provides a promising opportunity for prevention .
This review - one of four review s on efficacy and safety of interventions to prevent SAD - focuses on light therapy as a preventive intervention .
Light therapy is a non-pharmacological treatment that exposes people to artificial light .
Mode of delivery ( e.g. visors , light boxes ) and form of light ( e.g. bright white light ) vary .
OBJECTIVES To assess the efficacy and safety of light therapy ( in comparison with no treatment , other types of light therapy , second-generation antidepressants , melatonin , agomelatine , psychological therapies , lifestyle interventions and negative ion generators ) in preventing SAD and improving patient-centred outcomes  among adults with a history of SAD .
Prevention of depression and sleep disturbances in elderly with memory-problems by activation of the biological clock with light - a randomized clinical trial
Background  Depression  frequently occurs in the elderly and in patients suffering from dementia . Its cause is largely unknown , but several studies point to a possible contribution of circadian rhythm disturbances . Post-mortem studies on aging , dementia and depression show impaired functioning of the suprachiasmatic nucleus ( SCN ) which is thought to be involved in the increased prevalence of day-night rhythm perturbations in these conditions . Bright light enhances neuronal activity in the SCN . Bright light therapy has beneficial effects on rhythms and mood in institutionalized moderate to advanced demented elderly . In spite of the fact that this is a potentially safe and inexpensive treatment option , no previous clinical trial evaluated the use of long-term daily light therapy to prevent worsening of sleep-wake rhythms and depressive symptoms in early to moderately demented home-dwelling elderly . Methods / Design This study investigates whether long-term daily bright light prevents worsening of sleep-wake rhythms and depressive symptoms in elderly people with memory complaints . Patients with early Alzheimer 's Disease ( AD ) , Mild Cognitive Impairment ( MCI ) and Subjective Memory Complaints ( SMC ) , between the ages of 50 and 75 , are included in a r and omized double-blind placebo-controlled trial . For the duration of two years , patients are exposed to ~10,000 lux in the active condition or ~300 lux in the placebo condition , daily , for two half-hour sessions at fixed times in the morning and evening . Neuropsychological , behavioral , physiological and endocrine measures are assessed at baseline and follow-up every five to six months . Discussion If bright light therapy attenuates the worsening of sleep-wake rhythms and depressive symptoms , it will provide a measure that is easy to implement in the homes of elderly people with memory complaints , to complement treatments with cholinesterase inhibitors , sleep medication or anti-depressants or as a st and -alone treatment . Trial registration IS RCT
Overall , both forms of preventive light therapy reduced the incidence of SAD numerically compared with no light therapy .
BACKGROUND Seasonal affective disorder ( SAD ) is a seasonal pattern of recurrent major depressive episodes that most commonly occurs during autumn or winter and remits in spring .
The prevalence of SAD ranges from 1.5 % to 9 % , depending on latitude .
The predictable seasonal aspect of SAD provides a promising opportunity for prevention .
This review - one of four review s on efficacy and safety of interventions to prevent SAD - focuses on light therapy as a preventive intervention .
Light therapy is a non-pharmacological treatment that exposes people to artificial light .
Mode of delivery ( e.g. visors , light boxes ) and form of light ( e.g. bright white light ) vary .
OBJECTIVES To assess the efficacy and safety of light therapy ( in comparison with no treatment , other types of light therapy , second-generation antidepressants , melatonin , agomelatine , psychological therapies , lifestyle interventions and negative ion generators ) in preventing SAD and improving patient-centred outcomes  among adults with a history of SAD .