Prophylactic treatment of seasonal affective disorder (SAD) by using light visors: bright white or infrared light?

35 years of light treatment for mental disorders in the Netherlands

BACKGROUND

Light therapy (LT) for Seasonal Affective Disorders (SAD) has been a well-known and effective treatment for 40 years. The psychiatric university clinic of Groningen, the Netherlands was an early adopter and started research and treatment of SAD in 1987. Research projects on mechanisms, the role of the circadian system, treatment optimization, and investigating new areas for the effects of light treatment have been carried out ever since, leading to a widespread interest across the country.

OBJECTIVE

To provide an overview and description of the historical development of LT for mental disorders in the Netherlands.

METHODS

A non-systematic, review of research on light treatment for mental problems in the Netherlands, published since 1987 was conducted.

RESULTS

The fields of LT and chronotherapy are strongly based in the scientific interests of both chrono-biologists and therapists in the Netherlands. LT has shown effectiveness in treating mood disorders. Likewise, results for other mental disorders have shown some promise, but so far, the outcomes are not always unequivocal and have not always been based on robust data. Ongoing research is discussed.

CONCLUSIONS

LT, and in addition exposure to the right light at the right time is an important issue in mental health. Over the past 3 decades research on light and LT in the Netherlands has become well established and is still growing.

"Shedding Light on Light": A Review on the Effects on Mental Health of Exposure to Optical Radiation

In relation to human health and functioning, light, or more specifically optical radiation, plays many roles, beyond allowing vision. These may be summarized as: regulation of circadian rhythms; consequences of direct exposure to the skin; and more indirect effects on well-being and functioning, also related to lifestyle and contact with natural and urban environments. Impact on mental health is relevant for any of these specifications and supports a clinical use of this knowledge for the treatment of psychiatric conditions, such as depression or anxiety, somatic symptom disorder, and others, with reference to light therapy in particular. The scope of this narrative review is to provide a summary of recent findings and evidence on the regulating functions of light on human beings’ biology, with a specific focus on mental health, its prevention and care.

Melatonin and agomelatine for preventing seasonal affective disorder

BACKGROUND

Seasonal affective disorder (SAD) is a seasonal pattern of recurrent major depressive episodes that most commonly starts in autumn or winter and remits in spring. The prevalence of SAD depends on latitude and ranges from 1.5% to 9%. The predictable seasonal aspect of SAD provides a promising opportunity for prevention in people who have a history of SAD. This is one of four reviews on the efficacy and safety of interventions to prevent SAD; we focus on agomelatine and melatonin as preventive interventions.

OBJECTIVES

To assess the efficacy and safety of agomelatine and melatonin (in comparison with each other, placebo, second-generation antidepressants, light therapy, psychological therapy or lifestyle interventions) in preventing SAD and improving person-centred outcomes among adults with a history of SAD.

SEARCH METHODS

We searched Ovid MEDLINE (1950- ), Embase (1974- ), PsycINFO (1967- ) and the Cochrane Central Register of Controlled Trials (CENTRAL) to 19 June 2018. An earlier search of these databases was conducted via the Cochrane Common Mental Disorders Controlled Trial Register (CCMD-CTR) (all years to 11 August 2015). Furthermore, we searched the Cumulative Index to Nursing and Allied Health Literature, Web of Science, the Cochrane Library, the Allied and Complementary Medicine Database and international trial registers (to 19 June 2018). We also conducted a grey literature search and handsearched the reference lists of included studies and pertinent review articles.

SELECTION CRITERIA

To examine efficacy, we included randomised controlled trials (RCTs) on adults with a history of winter-type SAD who were free of symptoms at the beginning of the study. For adverse events, we intended also to include non-randomised studies. We planned to include studies that compared agomelatine versus melatonin, or agomelatine or melatonin versus placebo, any second-generation antidepressant, light therapy, psychological therapies or lifestyle changes. We also intended to compare melatonin or agomelatine in combination with any of the comparator interventions mentioned above versus the same comparator intervention as monotherapy.

DATA COLLECTION AND ANALYSIS

Two review authors screened abstracts and full-text publications, abstracted data and assessed risk of bias of included studies independently. We intended to pool data in a meta-analysis using a random-effects model, but included only one study.

MAIN RESULTS

We identified 3745 citations through electronic searches and reviews of reference lists after deduplication of search results. We excluded 3619 records during title and abstract review and assessed 126 full-text papers for inclusion in the review. Only one study, providing data of 225 participants, met our eligibility criteria and compared agomelatine (25 mg/day) with placebo. We rated it as having high risk of attrition bias because nearly half of the participants left the study before completion. We rated the certainty of the evidence as very low for all outcomes, because of high risk of bias, indirectness, and imprecision.The main analysis based on data of 199 participants rendered an indeterminate result with wide confidence intervals (CIs) that may encompass both a relevant reduction as well as a relevant increase of SAD incidence by agomelatine (risk ratio (RR) 0.83, 95% CI 0.51 to 1.34; 199 participants; very low-certainty evidence). Also the severity of SAD may be similar in both groups at the end of the study with a mean SIGH-SAD (Structured Interview Guide for the Hamilton Depression Rating Scale, Seasonal Affective Disorders) score of 8.3 (standard deviation (SD) 9.4) in the agomelatine group and 10.1 (SD 10.6) in the placebo group (mean difference (MD) -1.80, 95% CI -4.58 to 0.98; 199 participants; very low-certainty evidence). The incidence of adverse events and serious adverse events may be similar in both groups. In the agomelatine group, 64 out of 112 participants experienced at least one adverse event, while 61 out of 113 did in the placebo group (RR 1.06, 95% CI 0.84 to 1.34; 225 participants; very low-certainty evidence). Three out of 112 patients experienced serious adverse events in the agomelatine group, compared to 4 out of 113 in the placebo group (RR 0.76, 95% CI 0.17 to 3.30; 225 participants; very low-certainty evidence).No data on quality of life or interpersonal functioning were reported. We did not identify any studies on melatonin.

AUTHORS' CONCLUSIONS

Given the uncertain evidence on agomelatine and the absence of studies on melatonin, no conclusion about efficacy and safety of agomelatine and melatonin for prevention of SAD can currently be drawn. The decision for or against initiating preventive treatment of SAD and the treatment selected should consider patient preferences and reflect on the evidence base of all available treatment options.

Psychological therapies for preventing seasonal affective disorder

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 is one of four reviews on the efficacy and safety of interventions to prevent SAD; we focus on psychological therapies as preventive interventions.

OBJECTIVES

To assess the efficacy and safety of psychological therapies (in comparison with no treatment, other types of psychological therapy, second-generation antidepressants, light therapy, melatonin or agomelatine or lifestyle interventions) in preventing SAD and improving person-centred outcomes among adults with a history of SAD.

SEARCH METHODS

We searched Ovid MEDLINE (1950- ), Embase (1974- ), PsycINFO (1967- ) and the Cochrane Central Register of Controlled Trials (CENTRAL) to 19 June 2018. An earlier search of these databases was conducted via the Cochrane Common Mental Disorders Controlled Trial Register (CCMD-CTR) (all years to 11 August 2015). Furthermore, we searched the Cumulative Index to Nursing and Allied Health Literature, Web of Science, the Cochrane Library, the Allied and Complementary Medicine Database and international trial registers (to 19 June 2018). We also conducted a grey literature search and handsearched the reference lists of included studies and pertinent review articles.

SELECTION CRITERIA

To examine efficacy, we included randomised controlled trials (RCTs) on adults with a history of winter-type SAD who were free of symptoms at the beginning of the study. To examine adverse events, we intended to include non-randomised studies. We planned to include studies that compared psychological therapy versus no treatment, or any other type of psychological therapy, light therapy, second-generation antidepressants, melatonin, agomelatine or lifestyle changes. We also planned to compare psychological therapy in combination with any of the comparator interventions listed above versus no treatment or the same comparator intervention as monotherapy.

DATA COLLECTION AND ANALYSIS

Two review authors screened abstracts and full-text publications against the inclusion criteria, independently extracted data, assessed risk of bias, and graded the certainty of evidence.

MAIN RESULTS

We identified 3745 citations through electronic searches and reviews of reference lists after deduplication of search results. We excluded 3619 records during title and abstract review and assessed 126 articles at full-text review for eligibility. We included one controlled study enrolling 46 participants. We rated this RCT at high risk for performance and detection bias due to a lack of blinding.The included RCT compared preventive use of mindfulness-based cognitive therapy (MBCT) with treatment as usual (TAU) in participants with a history of SAD. MBCT was administered in spring in eight weekly individual 45- to 60-minute sessions. In the TAU group participants did not receive any preventive treatment but were invited to start light therapy as first depressive symptoms occurred. Both groups were assessed weekly for occurrence of a new depressive episode measured with the Inventory of Depressive Syptomatology-Self-Report (IDS-SR, range 0-90) from September 2011 to mid-April 2012. The incidence of a new depressive episode in the upcoming winter was similar in both groups. In the MBCT group 65% of 23 participants developed depression (IDS-SR ≥ 20), compared to 74% of 23 people in the TAU group (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.60 to 1.30; 46 participants; very low quality-evidence).For participants with depressive episodes, severity of depression was comparable between groups. Participants in the MBCT group had a mean score of 26.5 (SD 7.0) on the IDS-SR, and TAU participants a mean score of 25.3 (SD 6.3) (mean difference (MD) 1.20, 95% CI -3.44 to 5.84; 32 participants; very low quality-evidence).The overall discontinuation rate was similar too, with 17% discontinuing in the MBCT group and 13% in the TAU group (RR 1.33, 95% CI 0.34 to 5.30; 46 participants; very low quality-evidence).Reasons for downgrading the quality of evidence included high risk of bias of the included study and imprecision.Investigators provided no information on adverse events. We could not find any studies that compared psychological therapy with other interventions of interest such as second-generation antidepressants, light therapy, melatonin or agomelatine.

AUTHORS' CONCLUSIONS

The evidence on psychological therapies to prevent the onset of a new depressive episode in people with a history of SAD is inconclusive. We identified only one study including 46 participants focusing on one type of psychological therapy. Methodological limitations and the small sample size preclude us from drawing a conclusion on benefits and harms of MBCT as a preventive intervention for SAD. Given that there is no comparative evidence for psychological therapy versus other preventive options, the decision for or against initiating preventive treatment of SAD and the treatment selected should be strongly based on patient preferences and other preventive interventions that are supported by evidence.

Light therapy for preventing seasonal affective disorder

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 reviews 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 and form of 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.

SEARCH METHODS

We searched Ovid MEDLINE (1950- ), Embase (1974- ), PsycINFO (1967- ) and the Cochrane Central Register of Controlled Trials (CENTRAL) to 19 June 2018. An earlier search of these databases was conducted via the Cochrane Common Mental Disorders Controlled Trial Register (CCMD-CTR) (all years to 11 August 2015). Furthermore, we searched the Cumulative Index to Nursing and Allied Health Literature, Web of Science, the Cochrane Library, the Allied and Complementary Medicine Database and international trial registers (to 19 June 2018). We also conducted a grey literature search and handsearched the reference lists of included studies and pertinent review articles.

SELECTION CRITERIA

For efficacy, we included randomised controlled trials (RCTs) on adults with a history of winter-type SAD who were free of symptoms at the beginning of the study. For adverse events, we also intended to include non-randomised studies. We intended to include studies that compared any type of light therapy (e.g. bright white light, administered by visors or light boxes, infrared light, dawn stimulation) versus no treatment/placebo, second-generation antidepressants, psychological therapies, melatonin, agomelatine, lifestyle changes, negative ion generators or another of the aforementioned light therapies. We also planned to include studies that looked at light therapy in combination with any comparator intervention.

DATA COLLECTION AND ANALYSIS

Two review authors screened abstracts and full-text publications, independently abstracted data and assessed risk of bias of included studies.

MAIN RESULTS

We identified 3745 citations after de-duplication of search results. We excluded 3619 records during title and abstract review. We assessed 126 full-text papers for inclusion in the review, but only one study providing data from 46 people met our eligibility criteria. The included RCT had methodological limitations. We rated it as having high risk of performance and detection bias because of lack of blinding, and as having high risk of attrition bias because study authors did not report reasons for dropouts and did not integrate data from dropouts into the analysis.The included RCT compared preventive use of bright white light (2500 lux via visors), infrared light (0.18 lux via visors) and no light treatment. Overall, white light and infrared light therapy reduced the incidence of SAD numerically compared with no light therapy. In all, 43% (6/14) of participants in the bright light group developed SAD, as well as 33% (5/15) in the infrared light group and 67% (6/9) in the non-treatment group. Bright light therapy reduced the risk of SAD incidence by 36%; however, the 95% confidence interval (CI) was very broad and included both possible effect sizes in favour of bright light therapy and those in favour of no light therapy (risk ratio (RR) 0.64, 95% CI 0.30 to 1.38; 23 participants, very low-quality evidence). Infrared light reduced the risk of SAD by 50% compared with no light therapy, but the CI was also too broad to allow precise estimations of effect size (RR 0.50, 95% CI 0.21 to 1.17; 24 participants, very low-quality evidence). Comparison of both forms of preventive light therapy versus each other yielded similar rates of incidence of depressive episodes in both groups (RR 1.29, 95% CI 0.50 to 3.28; 29 participants, very low-quality evidence). Reasons for downgrading evidence quality included high risk of bias of the included study, imprecision and other limitations, such as self-rating of outcomes, lack of checking of compliance throughout the study duration and insufficient reporting of participant characteristics.Investigators provided no information on adverse events. We could find no studies that compared light therapy versus other interventions of interest such as second-generation antidepressants, psychological therapies, melatonin or agomelatine.

AUTHORS' CONCLUSIONS

Evidence on light therapy as preventive treatment for people with a history of SAD is limited. Methodological limitations and the small sample size of the only available study have precluded review author conclusions on effects of light therapy for SAD. Given that comparative evidence for light therapy versus other preventive options is limited, the decision for or against initiating preventive treatment of SAD and the treatment selected should be strongly based on patient preferences.

Second-generation antidepressants for preventing seasonal affective disorder in adults

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 reviews on efficacy and safety of interventions to prevent SAD - focuses on second-generation antidepressants (SGAs).

OBJECTIVES

To assess the efficacy and safety of SGAs (in comparison with other SGAs, placebo, light therapy, melatonin or agomelatine, psychological therapies or lifestyle interventions) in preventing SAD and improving patient-centred outcomes among adults with a history of SAD.

SEARCH METHODS

We searched Ovid MEDLINE (1950- ), Embase (1974- ), PsycINFO (1967- ) and the Cochrane Central Register of Controlled Trials (CENTRAL) to 19 June 2018. An earlier search of these databases was conducted via the Cochrane Common Mental Disorders Controlled Trial Register (CCMD-CTR) (all years to 11 August 2015). Furthermore, we searched the Cumulative Index to Nursing and Allied Health Literature, Web of Science, the Cochrane Library, the Allied and Complementary Medicine Database and international trial registers (to 19 June 2018). We also conducted a grey literature search and handsearched the reference lists of included studies and pertinent review articles.

SELECTION CRITERIA

For efficacy, we included randomised controlled trials (RCTs) on adults with a history of winter-type SAD who were free of symptoms at the beginning of the study. For adverse events, we planned to include non-randomised studies. Eligible studies compared a SGA versus another SGA, placebo, light therapy, psychological therapy, melatonin, agomelatine or lifestyle changes. We also intended to compare SGAs in combination with any of the comparator interventions versus placebo or the same comparator intervention as monotherapy.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened abstracts and full-text publications, extracted data and assessed risk of bias of included studies. When data were sufficient, we conducted random-effects (Mantel-Haenszel) meta-analyses. We assessed statistical heterogeneity by calculating the Chi2 statistic and the Cochran Q. We used the I2 statistic to estimate the magnitude of heterogeneity. We assessed publication bias by using funnel plots.We rated the strength of the evidence using the system developed by the GRADE Working Group.

MAIN RESULTS

We identified 3745 citations after de-duplication of search results and excluded 3619 records during title and abstract reviews. We assessed 126 full-text papers for inclusion in the review, of which four publications (on three RCTs) providing data from 1100 people met eligibility criteria for this review. All three RCTs had methodological limitations due to high attrition rates.Overall, moderate-quality evidence indicates that bupropion XL is an efficacious intervention for prevention of recurrence of depressive episodes in people with a history of SAD (risk ratio (RR) 0.56, 95% confidence interval (CI) 0.44 to 0.72; 3 RCTs, 1100 participants). However, bupropion XL leads to greater risk of headaches (moderate-quality evidence), insomnia and nausea (both low-quality evidence) when compared with placebo. Numbers needed to treat for additional beneficial outcomes (NNTBs) vary by baseline risks. For a population with a yearly recurrence rate of 30%, the NNTB is 8 (95% CI 6 to 12). For populations with yearly recurrence rates of 50% and 60%, NNTBs are 5 (95% CI 4 to 7) and 4 (95% CI 3 to 6), respectively.We could find no studies on other SGAs and no studies comparing SGAs with other interventions of interest, such as light therapy, psychological therapies, melatonin or agomelatine.

AUTHORS' CONCLUSIONS

Available evidence indicates that bupropion XL is an effective intervention for prevention of recurrence of SAD. Nevertheless, even in a high-risk population, three out of four people will not benefit from preventive treatment with bupropion XL and will be at risk for harm. Clinicians need to discuss with patients advantages and disadvantages of preventive SGA treatment, and might want to consider offering other potentially efficacious interventions, which might confer a lower risk of adverse events. Given the lack of comparative evidence, the decision for or against initiating preventive treatment of SAD and the treatment selected should be strongly based on patient preferences.Future researchers need to assess the effectiveness and risk of harms of SGAs other than bupropion for prevention of SAD. Investigators also need to compare benefits and harms of pharmacological and non-pharmacological interventions.

Bright Light as a Personalized Precision Treatment of Mood Disorders

Background: The use of light for its antidepressant action dates back to the beginnings of civilization. Three decades ago, the use of bright-light therapy (BLT) for treating Seasonal Affective Disorder (SAD) was officially proposed. Since then, a growing scientific literature reports its antidepressant efficacy in both unipolar and bipolar disorders (BD), with or without seasonal patterns. This review aims to examine the management of BLT as a personalized and precision treatment in SAD, unipolar, and BD. Methods: We conducted a narrative review using Medline and Google Scholar databases up to June 2018. Results: BLT has physiological effects by resynchronizing the biological clock (circadian system), enhancing alertness, increasing sleep pressure (homeostatic system), and acting on serotonin, and other monoaminergic pathways. Effects of BLT on mood depend on several factors such as light intensity, wavelength spectrum, illumination duration, time of the day, and individual circadian rhythms. A growing body of evidence has been generated over the last decade about BLT evolving as an effective depression treatment not only to be used in SAD, but also in non-seasonal depression, with efficiency comparable to fluoxetine, and possibly more robust in patients with BD. The antidepressant action of BLT is fast (within 1-week) and safe, with the need in BD to protect against manic switch with mood stabilizers. Side effects might be nausea, diarrhea, headache, and eye irritation, and are generally mild and rare. This good safety profile may be of particular interest, especially in women during the perinatal period or for the elderly. The management of BLT needs to be clarified across mood disorders and future studies are expected to compare different dose-titration protocols, to validate its use as a maintenance treatment, and also to identify predictive biomarkers of response and tolerability. We propose clinical guidelines for BLT use in SAD, non-seasonal depression, and BD. Conclusions : BLT is an efficient antidepressant strategy in mono- or adjunct-therapy, that should be personalized according the unipolar or bipolar subtype, the presence or absence of seasonal patterns, and also regarding its efficacy and tolerability.

ATR-IR study of skin components: Lipids, proteins and water. Part II: Near infrared radiation effect

Near infrared (NIR) radiation has been widely used in medicine and biomedical engineering. In spite of numerous studies the molecular mechanism of NIR radiation on biological systems has not been established as yet. The objective of this work was examination of the effect of NIR irradiation on the skin components. Modifications of lipid organization after NIR exposure vs. temperature (from 20 to 90 °C) have been investigated using Attenuated Total Reflectance Infrared (ATR-IR) spectroscopy. This work is a continuation of our previous studies on the temperature effect on skin components [1]. After NIR exposure a temperature shift of the phase transition from the orthorhombic to hexagonal packing (≈40 °C) has been observed. In contrast, the second phase transition temperature (≈70 °C) is almost invariable. The phase transitions in lipids were correlated with modifications of the structure of water and proteins. To our knowledge, for the first time the temperatures of the phase transitions after NIR exposure were investigated.

Pharmacotherapy and nutritional supplements for seasonal affective disorders: a systematic review

INTRODUCTION

A seasonal affective disorder (SAD) is a subtype of unipolar and bipolar major depressive disorders. It is characterized by its annual recurrence of depressive episodes at a particular season, mostly seen in winter and is responsible for 10-20% of the prevalence of major depressive disorders. Some pathophysiological hypotheses, such as the phase delay and the monoamine depletion hypotheses, have been postulated but the exact cause has not been fully unraveled yet. Studies on treatment for SAD in the last decade are lacking. To tackle this chronic disease, attention needs to be drawn to the gaps in this research field.

AREAS COVERED

In this systematic review, the authors give a broad overview of the pharmacological therapy available for SAD. Also, nutritional substances fitting well with the postulated hypotheses are reviewed for the treatment and prevention of SAD. There is a specific focus on the quality of the currently performed studies.

EXPERT OPINION

Light therapy and fluoxetine are the only proven and effective acute treatment options for SAD, while bupropion is the only registered drug for prevention of SAD. This area of research is in dire need of valid large-scale and sufficiently reproducible randomized control trials.

Seasonal affective disorder, winter type: current insights and treatment options

Seasonal affective disorder (SAD), winter type, is a seasonal pattern of recurrent major depressive episodes most commonly occurring in autumn or winter and remitting in spring/summer. The syndrome has been well-known for more than three decades, with light treatment being the treatment of first choice. In this paper, an overview is presented of the present insights in SAD. Description of the syndrome, etiology, and treatment options are mentioned. Apart from light treatment, medication and psychotherapy are other treatment options. The predictable, repetitive nature of the syndrome makes it possible to discuss preventive treatment options. Furthermore, critical views on the concept of SAD as a distinct diagnosis are discussed.

Melatonin and agomelatine for preventing seasonal affective disorder

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 in the United States ranges from 1.5% to 9%, depending on latitude. The predictable seasonal aspect of SAD provides a promising opportunity for prevention. This is one of four reviews on the efficacy and safety of interventions to prevent SAD; we focus on agomelatine and melatonin as preventive interventions.

OBJECTIVES

To assess the efficacy and safety of agomelatine and melatonin (in comparison with each other, placebo, second-generation antidepressants, light therapy, psychological therapy or lifestyle interventions) in preventing SAD and improving patient-centred outcomes among adults with a history of SAD.

SEARCH METHODS

We conducted a search of the Specialised Register of the Cochrane Depression, Anxiety and Neurosis Review Group (CCDANCTR) to 11 August 2015. The CCDANCTR contains reports of relevant randomised controlled trials from EMBASE (1974 to date), MEDLINE (1950 to date), PsycINFO (1967 to date) and the Cochrane Central Register of Controlled Trials (CENTRAL). Furthermore, we searched the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Knowledge, The Cochrane Library and the Allied and Complementary Medicine Database (AMED) (to 26 May 2014). We conducted a grey literature search (e.g. in clinical trial registries) and handsearched the reference lists of all included studies and pertinent review articles.

SELECTION CRITERIA

To examine efficacy, we planned to include randomised controlled trials (RCTs) on adults with a history of winter-type SAD who were free of symptoms at the beginning of the study. To examine adverse events, we intended to include non-randomised studies. We planned to include studies that compared agomelatine versus melatonin, or agomelatine or melatonin versus placebo, any second-generation antidepressant (SGA), light therapy, psychological therapies or lifestyle changes. We also intended to compare melatonin or agomelatine in combination with any of the comparator interventions listed above versus the same comparator intervention as monotherapy.

DATA COLLECTION AND ANALYSIS

Two review authors screened abstracts and full-text publications against the inclusion criteria. Two review authors planned to independently extract data and assess risk of bias of included studies. We planned to pool data for meta-analysis when participant groups were similar and when studies assessed the same treatments by using the same comparator and presented similar definitions of outcome measures over a similar duration of treatment; however, we identified no studies for inclusion.

MAIN RESULTS

We identified 2986 citations through electronic searches and reviews of reference lists after de-duplication of search results. We excluded 2895 records during title and abstract review and assessed 91 articles at full-text level for eligibility. We identified no controlled studies on use of melatonin and agomelatine to prevent SAD and to improve patient-centred outcomes among adults with a history of SAD.

AUTHORS' CONCLUSIONS

No available methodologically sound evidence indicates that melatonin or agomelatine is or is not an effective intervention for prevention of SAD and improvement of patient-centred outcomes among adults with a history of SAD. Lack of evidence clearly shows the need for well-conducted, controlled studies on this topic. A well-conducted RCT of melatonin or agomelatine for prevention of SAD would assess the comparative benefits and risks of these interventions against others currently used to treat the disorder.

Psychological therapies for preventing seasonal affective disorder

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 is one of four reviews on the efficacy and safety of interventions to prevent SAD; we focus on psychological therapies as preventive interventions.

OBJECTIVES

To assess the efficacy and safety of psychological therapies (in comparison with no treatment, other types of psychological therapy, second-generation antidepressants (SGAs), light therapy, melatonin or agomelatine or lifestyle interventions) in preventing SAD and improving patient-centred outcomes among adults with a history of SAD.

SEARCH METHODS

We conducted a search of the Cochrane Depression, Anxiety and Neurosis Review Group Specialised Register (CCDANCTR) to 11 August 2015. The CCDANCTR contains reports of relevant randomised controlled trials from EMBASE (1974 to date), MEDLINE (1950 to date), PsycINFO (1967 to date) and the Cochrane Central Register of Controlled Trials (CENTRAL). Furthermore, we searched the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Knowledge, The Cochrane Library and the Allied and Complementary Medicine Database (AMED) (to 26 May 2014). We conducted a grey literature search (e.g. in clinical trial registries) and handsearched the reference lists of all included studies and pertinent review articles.

SELECTION CRITERIA

To examine efficacy, we planned to include randomised controlled trials on adults with a history of winter-type SAD who were free of symptoms at the beginning of the study. To examine adverse events, we intended to include non-randomised studies. We planned to include studies that compared psychological therapy versus any other type of psychological therapy, placebo, light therapy, SGAs, melatonin, agomelatine or lifestyle changes. We also intended to compare psychological therapy in combination with any of the comparator interventions listed above versus the same comparator intervention as monotherapy.

DATA COLLECTION AND ANALYSIS

Two review authors screened abstracts and full-text publications against the inclusion criteria. Two review authors planned to independently extract data and assess risk of bias. We planned to pool data for meta-analysis when participant groups were similar and when studies assessed the same treatments versus the same comparator and provided similar definitions of outcome measures over a similar duration of treatment; however, we included no studies.

MAIN RESULTS

We identified 2986 citations through electronic searches and reviews of reference lists after de-duplication of search results. We excluded 2895 records during title and abstract review and assessed 91 articles at full-text review for eligibility. We found no controlled studies on use of psychological therapy to prevent SAD and improve patient-centred outcomes in adults with a history of SAD.

AUTHORS' CONCLUSIONS

Presently, there is no methodologically sound evidence available to indicate whether psychological therapy is or is not an effective intervention for prevention of SAD and improvement of patient-centred outcomes among adults with a history of SAD. Randomised controlled trials are needed to compare different types of psychological therapies and to compare psychological therapies versus placebo, light therapy, SGAs, melatonin, agomelatine or lifestyle changes for prevention of new depressive episodes in patients with a history of winter-type SAD.

Second-generation antidepressants for preventing seasonal affective disorder in adults

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 reviews on efficacy and safety of interventions to prevent SAD - focuses on second-generation antidepressants (SGAs).

OBJECTIVES

To assess the efficacy and safety of second-generation antidepressants (in comparison with other SGAs, placebo, light therapy, melatonin or agomelatine, psychological therapies or lifestyle interventions) in preventing SAD and improving patient-centred outcomes among adults with a history of SAD.

SEARCH METHODS

A search of the Specialised Register of the Cochrane Depression, Anxiety and Neuorosis Review Group (CCDANCTR) included all years to 11 August 2015. The CCDANCTR contains reports of randomised controlled trials derived from EMBASE (1974 to date), MEDLINE (1950 to date), PsycINFO (1967 to date) and the Cochrane Central Register of Controlled Trials (CENTRAL). Furthermore, we searched the Cumulative Index to Nursing and Allied Health Literature, Web of Knowledge, The Cochrane Library and the Allied and Complementary Medicine Database (to 26 May 2014). We also conducted a grey literature search and handsearched the reference lists of included studies and pertinent review articles.

SELECTION CRITERIA

For efficacy, we included randomised controlled trials on adults with a history of winter-type SAD who were free of symptoms at the beginning of the study. For adverse events, we planned to include non-randomised studies. Eligible studies compared an SGA versus another SGA, placebo, light therapy, psychological therapy, melatonin, agomelatine or lifestyle changes. We also intended to compare SGAs in combination with any of the comparator interventions versus the same comparator intervention as monotherapy.

DATA COLLECTION AND ANALYSIS

Two review authors screened abstracts and full-text publications and assigned risk of bias ratings based on the Cochrane 'Risk of bias' tool. We resolved disagreements by consensus or by consultation with a third party. Two review authors independently extracted data and assessed risk of bias of included studies. When data were sufficient, we conducted random-effects (Mantel-Haenszel) meta-analyses. We assessed statistical heterogeneity by calculating the Chi(2) statistic and the Cochran Q. We used the I(2) statistic to estimate the magnitude of heterogeneity and examined potential sources of heterogeneity using sensitivity analysis or analysis of subgroups. We assessed publication bias by using funnel plots. However, given the small number of component studies in our meta-analyses, these tests have low sensitivity to detect publication bias. We rated the strength of the evidence using the system developed by the GRADE (Grading of Recommendations Assessment, Development and Evaluation) Working Group.

MAIN RESULTS

We identified 2986 citations after de-duplication of search results and excluded 2895 records during title and abstract reviews. We assessed 91 full-text papers for inclusion in the review, of which four publications (on three RCTs) providing data from 1100 people met eligibility criteria for this review. All three RCTs had methodological limitations due to high attrition rates.Overall moderate-quality evidence indicates that bupropion XL is an efficacious intervention for prevention of recurrence of depressive episodes in patients with a history of SAD (risk ratio (RR) 0.56, 95% confidence interval (CI) 0.44 to 0.72; three RCTs, 1100 participants). However, bupropion XL leads to greater risk of headaches (moderate-quality evidence), insomnia and nausea (both low-quality evidence) when compared with placebo. Numbers needed to treat for additional beneficial outcomes (NNTBs) vary by baseline risks. For a population with a yearly recurrence rate of 30%, the NNTB is 8 (95% CI 6 to 12). For populations with yearly recurrence rates of 40% and 50%, NNTBs are 6 (95% CI 5 to 9) and 5 (95% CI 4 to 7), respectively.We could find no studies on other SGAs and no studies comparing SGAs with other interventions of interest such as light therapy, psychological therapies, melatonin or agomelatine.

AUTHORS' CONCLUSIONS

Available evidence indicates that bupropion XL is an effective intervention for prevention of recurrence of SAD. Nevertheless, even in a high-risk population, four of five patients will not benefit from preventive treatment with bupropion XL and will be at risk for harm. Clinicians need to discuss with patients advantages and disadvantages of preventive SGA treatment and might want to consider offering other potentially efficacious interventions, which might confer lower risk of adverse events. Given the lack of comparative evidence, the decision for or against initiating preventive treatment of SAD and the treatment selected should be strongly based on patient preferences.Future researchers need to assess the effectiveness and risk of harms of SGAs other than bupropion for prevention of SAD. Investigators also need to compare benefits and harms of pharmacological and non-pharmacological interventions.

Light therapy for preventing seasonal affective disorder

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 reviews 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.

SEARCH METHODS

A search of the Specialised Register of the Cochrane Depression, Anxiety and Neuorosis Review Group (CCDANCTR) included all years to 11 August 2015. The CCDANCTR contains reports of relevant randomised controlled trials derived from EMBASE (1974 to date), MEDLINE (1950 to date), PsycINFO (1967 to date) and the Cochrane Central Register of Controlled Trails (CENTRAL). Furthermore, we searched the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Knowledge, The Cochrane Library and the Allied and Complementary Medicine Database (AMED) (to 26 May 2014). We also conducted a grey literature search and handsearched the reference lists of all included studies and pertinent review articles.

SELECTION CRITERIA

For efficacy, we included randomised controlled trials on adults with a history of winter-type SAD who were free of symptoms at the beginning of the study. For adverse events, we also intended to include non-randomised studies. We intended to include studies that compared any type of light therapy (e.g. bright white light, administered by visors or light boxes, infrared light, dawn stimulation) versus no treatment/placebo, second-generation antidepressants (SGAs), psychological therapies, melatonin, agomelatine, lifestyle changes, negative ion generators or another of the aforementioned light therapies. We also planned to include studies that looked at light therapy in combination with any comparator intervention and compared this with the same comparator intervention as monotherapy.

DATA COLLECTION AND ANALYSIS

Two review authors screened abstracts and full-text publications against the inclusion criteria. Two review authors independently abstracted data and assessed risk of bias of included studies.

MAIN RESULTS

We identified 2986 citations after de-duplication of search results. We excluded 2895 records during title and abstract review. We assessed 91 full-text papers for inclusion in the review, but only one study providing data from 46 people met our eligibility criteria. The included randomised controlled trial (RCT) had methodological limitations. We rated it as having high risk of performance and detection bias because of lack of blinding, and as having high risk of attrition bias because study authors did not report reasons for dropouts and did not integrate data from dropouts into the analysis.The included RCT compared preventive use of bright white light (2500 lux via visors), infrared light (0.18 lux via visors) and no light treatment. Overall, both forms of preventive light therapy reduced the incidence of SAD numerically compared with no light therapy. In all, 43% (6/14) of participants in the bright light group developed SAD, as well as 33% (5/15) in the infrared light group and 67% (6/9) in the non-treatment group. Bright light therapy reduced the risk of SAD incidence by 36%; however, the 95% confidence interval (CI) was very broad and included both possible effect sizes in favour of bright light therapy and those in favour of no light therapy (risk ratio (RR) 0.64, 95% CI 0.30 to 1.38). Infrared light reduced the risk of SAD by 50% compared with no light therapy, but in this case also the CI was too broad to allow precise estimations of effect size (RR 0.50, 95% CI 0.21 to 1.17). Comparison of both forms of preventive light therapy versus each other yielded similar rates of incidence of depressive episodes in both groups (RR 1.29, 95% CI 0.50 to 3.28). The quality of evidence for all outcomes was very low. Reasons for downgrading evidence quality included high risk of bias of the included study, imprecision and other limitations, such as self rating of outcomes, lack of checking of compliance throughout the study duration and insufficient reporting of participant characteristics.Investigators provided no information on adverse events. We could find no studies that compared light therapy versus other interventions of interest such as SGA, psychological therapies, melatonin or agomelatine.

AUTHORS' CONCLUSIONS

Evidence on light therapy as preventive treatment for patients with a history of SAD is limited. Methodological limitations and the small sample size of the only available study have precluded review author conclusions on effects of light therapy for SAD. Given that comparative evidence for light therapy versus other preventive options is limited, the decision for or against initiating preventive treatment of SAD and the treatment selected should be strongly based on patient preferences.

Seasonal affective disorder: is there light at the end of the tunnel?

Seasonal affective disorder, which is underdiagnosed in the primary care setting, is a mood disorder subtype characterized by episodic major depression that typically develops in winter when daylight hours are short. Patients with SAD experience increased morbidity and decreased quality of life. This article focuses on recognition and management of this condition. Light therapy is the preferred treatment for SAD because it is safe and easy to administer; light therapy may be combined with pharmacologic therapy. Cognitive behavioral therapy (CBT) also has a positive therapeutic effect when combined with light therapy and may help prevent SAD in subsequent seasons.

Bright-light therapy in the treatment of mood disorders

Bright-light therapy (BLT) is established as the treatment of choice for seasonal affective disorder/winter type (SAD). In the last two decades, the use of BLT has expanded beyond SAD: there is evidence for efficacy in chronic depression, antepartum depression, premenstrual depression, bipolar depression and disturbances of the sleep-wake cycle. Data on the usefulness of BLT in non-seasonal depression are promising; however, further systematic studies are still warranted. In this review, the authors present a comprehensive overview of the literature on BLT in mood disorders. The first part elucidates the neurobiology of circadian and seasonal adaptive mechanisms focusing on the suprachiasmatic nucleus (SCN), the indolamines melatonin and serotonin, and the chronobiology of mood disorders. The SCN is the primary oscillator in humans. Indolamines are known to transduce light signals into cells and organisms since early in evolution, and their role in signalling change of season is still preserved in humans: melatonin is synthesized primarily in the pineal gland and is the central hormone for internal clock circuitries. The melatonin precursor serotonin is known to modulate many behaviours that vary with season. The second part discusses the pathophysiology and clinical specifiers of SAD, which can be seen as a model disorder for chronobiological disturbances and the mechanism of action of BLT. In the third part, the mode of action, application, efficacy, tolerability and safety of BLT in SAD and other mood disorders are explored.

Infrared radiation has potential antidepressant and anxiolytic effects in animal model of depression and anxiety

BACKGROUND

Bright light therapy has been shown to have antidepressant and anxiolytic effects in humans.

OBJECTIVE

The antidepressant and anxiolytic effects of infrared radiation were evaluated using an experimental animal model.

METHODS

Rats were randomly assigned to either an acutely or chronically exposed infrared radiation group or to a nonexposed control group. Acutely exposed rats were treated with an infrared radiation machine for one session, whereas chronically exposed animals were treated with an infrared radiation for 10 sessions. Control group rats were exposed to the sound of the infrared radiation machine as a sham treatment. After infrared radiation or control exposure, rats underwent behavioral evaluation, including elevated plus maze test, light/dark box, and forced swim test.

RESULTS

Chronic infrared radiation exposure decreased indicators of depression- and anxiety-like behavior. No significant effect on general locomotor activity was observed. The number of BrdU-positive cells in CA1 of the hippocampus was significantly increased in both acutely and chronically exposed infrared radiation groups compared with the control group.

CONCLUSIONS

These results indicate that chronic infrared radiation might produce antidepressant- and anxiolytic-like effects.

Potential antidepressant effect of infrared irradiation has seasonality

OBJECTIVE

This study aimed to explore the seasonality of the antidepressant effect of infrared ray (IR) irradiation.

BACKGROUND

IR has been found to reduce immobility in the forced swimming test (FST) in mice in the winter, suggesting an antidepressant effect. However, whether IR also possesses antidepressant effects in the summer remains questionable.

METHODS

Fourteen mice were randomly assigned to the exposure group (n=7) and the control group (n=7). The mice in the exposure group received IR irradiation 60 minutes daily for six weeks in the summer. FSTs and tail suspension tests (TSTs) were administered to the two groups weekly. The mean immobility times in both tests were compared between and within groups.

RESULTS

In both FST and TST, there were no significant differences among the mean immobility times overall. (Repeated measures two-way ANOVA: p=0.648, 0.574, respectively). Weekly comparison between groups revealed no significant differences at baseline (two-sample t-test: t12=-0.743, 0.341, respectively) or at the end of the study (p=0.924, 0.925, respectively). A repeated measures ANOVA showed no significant differences within the exposure group during the study period (p=0.602, 0.465, respectively).

CONCLUSIONS

Taken together with the results of the previous study, the present results indicate that the antidepressant effect of IR irradiation has seasonality.

Long-term and preventative treatment for seasonal affective disorder

Recurrent major depressive disorder with regular seasonal patterns, commonly known as seasonal affective disorder (SAD), has evoked substantial research in the last two decades. It is now recognised that SAD is a common condition with prevalence rates between 0.4% and 2.9% of the general population, and that patients with SAD experience significant morbidity and impairment in psychosocial function. There is good evidence that bright light therapy and antidepressant medications are effective for the short-term treatment of SAD; however, given that SAD is characterised by recurrent major depressive episodes, long-term and maintenance treatment must be considered. Unfortunately, there are few studies of longer term (>8 weeks) and maintenance (preventative) treatments for SAD. The weight of evidence suggests that light therapy usually needs to be continued daily throughout the winter season because of rapid relapse when light is stopped too early in the treatment period. However, some studies support the use of antidepressants to continue the response from a brief (1-2 weeks) course of light therapy early in the depressive episode, as soon as the first symptoms emerge in autumn. Only small studies have examined preventative treatment (before onset of symptoms) with light therapy, all of which have methodological limitations. The best evidence for preventative treatment in SAD comes from antidepressant studies. Three large, randomised, placebo-controlled studies have shown that preventative treatment with bupropion XL reduces the recurrence rate of depressive episodes in patients with SAD. Given the limitations in the evidence base and the inconsistent recurrence rate of winter depressive episodes, clinical recommendations for long-term and preventative treatment must individualise treatment choices and weigh potential benefits against possible adverse effects.

Infrared irradiation has potential antidepressant effect

PURPOSE

Light therapy was only partially effective in treatment of depression when compared with summer's sunlight. The antidepressant effect of infrared irradiation was evaluated using an experimental animal model.

METHODS

Seventeen mice were randomly assigned to the exposure group (n = 9) and the control group (n = 8). The mice in the exposure group received infrared irradiation for 60 min daily during the study period of 4 weeks. The two groups were given forced swim test once a week to evaluate depression with the measurement of the immobility time.

RESULTS

We found that the exposure group showed a tendency of less immobility time by the end of the 3rd week when compared with the control group, and at the end of 4th week the difference reached a statistical significance (t(15) = 2.873; p = 0.012).

CONCLUSIONS

The result indicates that the immobility time in forced swim test, the sign of depression, can be reduced after prolonged (4 weeks) exposure to infrared irradiation in the animal model. The result suggests that a continuous application of infrared irradiation has antidepressant effect.

Influence of near-infrared radiation on the pKa values of L-phenylalanine

The effect of pH on L-phenylalanine (L-phe) before and after exposure to near-infrared (NIR) radiation (15 min, 700-2000 nm) was investigated by attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. Characteristic bands of L-phe were described and the pK(a) values were retrieved from IR spectra by using an intensity ratio method according to our recent paper (Olsztynska et al., Appl. Spectrosc. 55, 901 (2001)). It has been found that the irradiation process modifies pK(a) values of L-phe. The spectroscopic study clearly shows the shift of acid-base equilibrium after exposure to NIR radiation. The phenomenon is due to modification of the water structure. Intra- and intermolecular hydrogen bonds weaken, which could induce conformational changes of the phe molecule. Subsequently, hydrophobic interactions strongly increase. These processes favor aggregation of phe molecules, which leads to deprotonation of the -NH(3)(+) to -NH(2) group and protonation of the -COO(-) to -COOH group, changing the pK(a) values.

Seasonal affective disorder: an overview

Seasonal Affective Disorder (SAD) is a condition of regularly occurring depressions in winter with a remission the following spring or summer. In addition to depressed mood, the patients tend to experience increased appetite and an increased duration of sleep during the winter. SAD is a relatively common condition, affecting 1-3% of adults in temperate climates, and it is more prevalent in women. The pathological mechanisms underlying SAD are incompletely understood. Certain neurotransmitters have been implicated; a dysfunction in the serotonin system in particular has been demonstrated by a variety of approaches. The role of circadian rhythms in SAD needs to be clarified. The phase-delay hypothesis holds that SAD patients' circadian rhythms are delayed relative to the sleep/wake or rest/activity cycle. This hypothesis predicts that the symptoms of SAD will improve if the circadian rhythms can be phase-advanced. There is some experimental support for this. SAD can be treated successfully with light therapy. In classical light therapy, the SAD sufferer sits in front of a light box, exposed to 2000-10,000 lux for 30-120 min daily during the winter. Other forms of light treatments, pharmacotherapy, and other therapies are currently being tested for SAD.

Erythrocyte response to near-infrared radiation

The effects of NIR (near-infrared radiation 700-2,000 nm) on bovine erythrocytes in plasma was studied as a continuation of earlier studies. Cell shape was observed and the changes of ratio of hemolysis and electrokinetic potential measured as a function of irradiation time. After 10 min of irradiation, the shape of erythrocyte cells was mainly echinocytic. When these cells were incubated at 311 K for 24 h they regained their initial shape, but fresh erythrocytes that were irradiated for 30 min and aged in vitro did not. These phenomena are due to: (1) the absorption of NIR excitation by hemoglobin; the primary photochemical process being the photo-dissociation of oxyhemoglobin to deoxyhemoglobin. Resulting shape and ratio of hemolysis, structural changes and oxidative stress follow higher deoxyhemoglobin concentration. (2) The absorption of the NIR excitation by proteins, water and lipids. After NIR absorption the membrane surface dehydrates, leading to enhanced protonation and dissociation of hydrogen-bonded complexes. This in turn leads to a change in electrokinetic potential.

Sleep fragmentation in mentally retarded people decreases with increasing daylength in spring

We studied the sleep-wake behavior of mentally retarded people from late winter to early summer at 60 degrees N. During this time the daylength increased 8 h 51 min. The data were collected by observing the sleep-wake status of 293 subjects at 20-min intervals for five randomized 24h periods (= recording days). The intervals during which the individual recording days of the same order (1st, 2nd, etc.) were carried out, were called recording periods. Consequently, there were five recording periods, each containing 293 individual recording days. Even though there was overlap among the recording periods, the median daylength from one period to another increased approximately by 100 min. In the initial statistical analysis, the number of wake-sleep transitions was found to differ significantly among the five recording periods (Friedman test, p < 0.001). The mean ranks in the Friedman test suggested that the number of wake-sleep transitions was highest during the 1st and lowest during the 5th recording period. In further statistical analyses using a program for mixed effects regression analysis (MIXOR 2.0) it was found that the increase in daylength during the study period was associated with a simultaneous decrease of approximately 0.5 wake-sleep transitions in the whole study population (p < 0.001). The decrease in the number of wake-sleep transitions was significant only in the subgroups of subjects with a daylength change of more than 350 min between the 1st and 5th recording days (Wilcoxon tests, p < 0.005). This suggests that after a marked prolongation of the natural photoperiod, the reduction in sleep episodes was more probable than after smaller changes in daylength. It is concluded that the sleep of mentally retarded people living in a rehabilitation center at a northern latitude is more fragmented in winter than in early summer and that the change is related probably to the simultaneous increase in the length of the natural photoperiod. The sleep quality of persons living in institutional settings might be improved by increasing the intensity and/or duration of daily artificial light exposure during the darker seasons.

Light therapy for seasonal affective disorder in primary care: randomised controlled trial

BACKGROUND

Studies of light therapy have not been conducted previously in primary care.

AIMS

To evaluate light therapy in primary care.

METHOD

Fifty-seven participants with seasonal affective disorder were randomly allocated to 4 weeks of bright white or dim red light. Baseline expectations for treatment were assessed. Outcome was assessed with the Structured Interview Guide for the Hamilton Depression Scale, Seasonal Affective Disorder Version.

RESULTS

Both groups showed decreases in symptom scores of more than 40%. There were no differences in proportions of responders in either group, regardless of the remission criteria applied, with around 60% (74% white light, 57% red light) meeting broad criteria for response and 31% (30% white light, 33% red light) meeting strict criteria. There were no differences in treatment expectations.

CONCLUSIONS

Primary care patients with seasonal affective disorder improve after light therapy, but bright white light is not associated with greater improvements.