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 .
Cognitive-behavioral therapy vs. light therapy for preventing winter depression recurrence: study protocol for a randomized controlled trial
Background Seasonal affective disorder ( SAD ) is a subtype of recurrent depression involving major depressive episodes during the fall and /or winter months that remit in the spring . The central public health challenge in the management of SAD is prevention of winter depression recurrence .  Light therapy ( LT ) is the established and best available acute SAD treatment . However , long-term compliance with daily LT from first symptom through spontaneous springtime remission every fall/winter season is poor . Time-limited alternative treatments with effects that endure beyond the cessation of acute treatment are needed to prevent the annual recurrence of SAD . Methods / design This is an NIMH-funded R01-level r and omized clinical trial to test the efficacy of a novel , SAD-tailored cognitive-behavioral group therapy ( CBT ) against LT in a head-to-head comparison on next winter outcomes . This project is design ed to test for a clinical ly meaningful difference between  CBT and LT on depression recurrence in the next winter ( the primary outcome ) . This is a concurrent two-arm study that will r and omize 160 currently symptomatic community adults with major depression , recurrent with seasonal pattern , to CBT or LT .  After 6 weeks of treatment in the initial winter , participants are followed in the subsequent summer , the next winter , and two winters later . Key method ological issues surround timing study procedures for a predictably recurrent and time-limited disorder with a focus on long-term outcomes . Discussion The chosen design answers the primary question of whether prior exposure to CBT is associated with a substantially lower likelihood of depression recurrence the next winter than LT . This design does not test the relative contributions of the cognitive-behavioral treatment components vs. nonspecific factors to CBT ’s outcomes and is not adequately powered to test for differences or equivalence between cells at treatment endpoint . Alternative design s addressing these limitations would have required more patients , increased costs , and reduced power to detect a difference in the primary outcome .Trial registration Clinical trials.gov identifier
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 .