Rate of switch from bipolar depression into mania after morning light therapy: A historical review

Treatment measures for seasonal affective disorder: A network meta-analysis

OBJECTIVE

The purpose of this study was to assess the potential effectiveness of several mainstream therapies, including phototherapy, antidepressants, cognitive-behavioral therapy, and negative ion generators, in the treatment of Seasonal Affective Disorder (SAD).

METHODS

A systematic search of PubMed, Embase, Cochrane, and WOS databases was conducted from January 1975 to December 3, 2022. Randomized controlled trials meeting predefined selection criteria for the treatment of SAD using mainstream therapeutic approaches were identified. After reviewing abstracts, data were synthesized and categorized based on the type of intervention and the targeted disorder.

RESULTS

A total of 21 randomized controlled trials, involving 1037 participants, were included. The standardized mean difference of depression scores and corresponding 95 % confidence intervals were calculated to assess the efficacy of phototherapy for Seasonal Affective Disorder. The meta-analysis revealed that phototherapy was significantly more effective than other intervention groups or control therapies, with an effect size of 4.64(2.38,7.03). Subgroup analysis demonstrated that no factors could explain the significant heterogeneity observed. Phototherapy exhibited statistically significant mild to moderate therapeutic effects in alleviating depressive symptoms and can be considered as a clinical therapy for treating Seasonal Affective Disorder. However, the quality of evidence remains low, and further well-designed, larger sample size, and high-quality studies are needed to confirm the efficacy of phototherapy in treating Seasonal Affective Disorder.

CONCLUSION

In conclusion, our systematic review and meta-analysis indicate that bright light therapy is a promising first-line non-pharmacological treatment for Seasonal Affective Disorder (SAD), showing significant improvement in mood symptoms compared to placebo. The findings support the use of bright light therapy as an effective and well-tolerated intervention for SAD. However, further large-scale, multicenter randomized controlled trials with long-term follow-up are needed to assess the long-term efficacy and safety of different treatment approaches for SAD.

Delivery of bright light therapy within the Veterans Health Administration

BACKGROUND

Bright light therapy (BLT) is efficacious for seasonal and non-seasonal depression. However, the current state of BLT use in practice is unknown, impeding efforts to identify and address utilization gaps. This study's objective was to investigate BLT delivery in a nationwide U.S. healthcare system.

METHODS

This was a retrospective observational study of electronic medical records from all veterans who received outpatient mood disorder-related care in the Veterans Health Administration (VHA) from October 2008 through September 2020. BLT delivery was measured through the placement of light box consults.

RESULTS

Of the 3,442,826 veterans who received outpatient mood disorder care, only 57,908 (1.68 %) received a light box consult. Consults increased by 548.44 % (99.9 % credible interval: 467.36 %, 638.74 %) over the timeframe and displayed a robust yearly cycle that peaked on either December 21st or December 22nd. Past mental health treatment for a mood disorder was associated with a higher probability of a consult (relative risk = 4.79, 99.9 % CI: 4.21, 5.60). There was low representation related to veteran age, gender, race, and ethnicity.

LIMITATIONS

No information on patients who declined light boxes or actual light box use following consult placement.

CONCLUSIONS

Outpatient BLT delivery for mood disorders in the VHA remains low, despite significant growth over the past decade. It also displays a strong seasonal rhythm that peaks on the winter solstice, suggesting a limited focus on seasonal depression and a suboptimal reactive approach to changing sunlight. Overall, there exists ample opportunity for novel implementation efforts aimed at increasing utilization of BLT.

Longitude-based time zone partitions and rates of suicide

BACKGROUND

Increasing evidence suggests that conditions with decreased morning and increased evening light exposure, including shift work, daylight-saving time, and eveningness, are associated with elevated mortality and suicide risk. Given that the alignment between the astronomical, biological, and social time varies across a time zone, with later-shifted daylight exposure in the western partition, we hypothesized that western time zone partitions would have higher suicide rates than eastern partitions.

METHODS

United States (U.S.) county-level suicide and demographic data, from 2010 to 2018, were obtained from a Centers for Disease Control database. Using longitude and latitude, counties were sorted into the western, middle, or eastern partition of their respective time zones, as well as the northern and southern halves of the U.S. Linear regressions were used to estimate the associations between suicide rates and time zone partitions, adjusting for gender, race, ethnicity, age group, and unemployment rates.

RESULTS

Data were available for 2872 counties. Across the U.S., western partitions had statistically significantly higher rates of suicide compared to eastern partitions and averaged up to two additional yearly deaths per 100,000 people (p < .001).

LIMITATIONS

Ecological design and limited adjustment for socioeconomic factors.

CONCLUSIONS

To our knowledge, this is the first study of the relationship between longitude-based time zone partitions and suicide. The results were consistent with the hypothesized elevated suicide rates in the western partitions, and concordant with previous reports on cancer mortality and transportation fatalities. The next step is to retest the hypothesis with individual-level data, accounting for latitude, photoperiodic changes, daylight-saving time, geoclimatic variables, physical and mental health indicators, as well as socioeconomic adversity and protection.

Role of adjunctive nonpharmacological strategies for treatment of rapid-cycling bipolar disorder

Rapid-cycling bipolar disorder (RCBD) is a phase of bipolar disorder defined by the presence of ≥ 4 mood episodes in a year. It is a common phenomenon characterized by greater severity, a predominance of depression, higher levels of disability, and poorer overall outcomes. It is resistant to treatment by conventional pharmacotherapy. The existing literature underlines the scarcity of evi-dence and the gaps in knowledge about the optimal treatment strategies for RCBD. However, most reviews have considered only pharmacological treatment options for RCBD. Given the treatment-refractory nature of RCBD, nonpharmacological interventions could augment medications but have not been adequately examined. This review carried out an updated and comprehensive search for evidence regarding the role of nonpharmacological therapies as adjuncts to medications in RCBD. We identified 83 reviews and meta-analyses concerning the treatment of RCBD. Additionally, we found 42 reports on adjunctive nonpharmacological treatments in RCBD. Most of the evidence favoured concomitant electroconvulsive therapy as an acute and maintenance treatment. There was pre-liminary evidence to suggest that chronotherapeutic treatments can provide better outcomes when combined with medications. The research on adjunctive psychotherapy was particularly scarce but suggested that psychoeducation, cognitive behavioural therapy, family interventions, and supportive psychotherapy may be helpful. The overall quality of evidence was poor and suffered from several methodological shortcomings. There is a need for more methodologically sound research in this area, although clinicians can use the existing evidence to select and individualize nonpharmacological treatment options for better management of RCBD. Patient summaries are included to highlight some of the issues concerning the implementation of adjunctive nonpharmacological treatments.

Illuminating the way: the role of bright light therapy in the treatment of depression

INTRODUCTION

Despite the growing number of different therapeutic options, treatment of depression is still a challenge. A broader perspective reveals the benefits of bright light therapy (BLT). It stimulates intrinsically photosensitive retinal ganglion cells, which induces a complex cascade of events, including alterations in melatonergic, neurotrophic, GABAergic, glutamatergic, noradrenergic, serotonergic systems, and HPA axis, suggesting that BLT effects expand beyond the circadian pacemaker.

AREAS COVERED

In this review, the authors present and discuss recent data of BLT in major depressive disorder, non-seasonal depression, bipolar depression or depressive phase of bipolar disorder, and seasonal affective disorder, as well as in treatment-resistant depression (TRD). The authors further highlight BLT effects in various depressive disorders compared to placebo and report data from several studies suggesting a response to BLT in TRD. Also, the authors report data showing that BLT can be used both as a monotherapy or in combination with other pharmacological treatments.

EXPERT OPINION

BLT is an easy-to-use and low-budget therapy with good tolerability. Future studies should focus on clinical and biological predictors of response to BLT, on defining specific populations which may benefit from BLT and establishing treatment protocols regarding timing, frequency, and duration of BLT.

When is pharmacotherapy necessary for the treatment of seasonal affective disorder?

No abstract is required for the editorial.

Molecular Link between Circadian Rhythmicity and Mood Disorders

BACKGROUND

The internal clock is driven by circadian genes [e.g., Clock, Bmal1, Per1-3, Cry1-2], hormones [e.g., melatonin, cortisol], as well as zeitgeber ['synchronisers']. Chronic disturbances in the circadian rhythm in patients diagnosed with mood disorders have been recognised for more than 50 years.

OBJECTIVES

The aim of this review is to summarise the current knowledge and literature regarding circadian rhythms in the context of mood disorders, focussing on the role of circadian genes, hormones, and neurotransmitters.

METHOD

The review presents the current knowledge and literature regarding circadian rhythms in mood disorders using the Pubmed database. Articles with a focus on circadian rhythms and mood disorders [n=123], particularly from 1973 to 2020, were included.

RESULTS

The article suggests a molecular link between disruptions in the circadian rhythm and mood disorders. Circadian disturbances, caused by the dysregulation of circadian genes, hormones, and neurotransmitters, often result in a clinical picture resembling depression.

CONCLUSION

Circadian rhythms are intrinsically linked to affective disorders, such as unipolar depression and bipolar disorder.

Sleep Disorders and Mood, Anxiety, and Post-Traumatic Stress Disorders: Overview of Clinical Treatments in the Context of Sleep Disturbances

Sleep disruptions are frequently reported by persons with mood, anxiety, and post-traumatic stress disorders, and co-occur with psychiatric disorders. There is evidence that sleep disorders can predict the likelihood of developing a future psychiatric disorder and exacerbate existing symptoms. Understanding the inter-relationships between sleep and psychiatric disorders is important. The primary goals of this article are to describe the interactions between psychiatric and sleep disorders in the context of sleep disturbances, underscore the bidirectional effects of mental health treatments on sleep disorder outcomes, and provide general recommendations to optimize treatment in the context of sleep disturbances.

Preventive effect of morning light exposure on relapse into depressive episode in bipolar disorder

OBJECTIVE

Light therapy has been suggested to have a curative effect on bipolar depression; however, preventive effects of light exposure on depressive episodes remain unclear. This study evaluated whether daytime light exposure in real-life situations was associated with a preventive effect on relapse into depressive episodes in patients with bipolar disorder.

METHODS

This prospective, naturalistic, observational study was conducted in Japan between August 2017 and June 2020. Outpatients with bipolar disorder were objectively evaluated for daytime light exposure over 7 consecutive days using an actigraph that could measure ambient light at baseline assessment and then assessed at 12-month follow-up for relapse into mood episodes.

RESULTS

Of 202 participants, 198 (98%) completed follow-up at 12 months and 78 (38%) experienced relapse into depressive episodes during follow-up. In a Cox proportional hazards model adjusting for potential confounders, a longer time above 1000 lux at daytime was significantly associated with decrease in relapse into depressive episodes (per log min; hazard ratio, 0.66; 95% confidence interval, 0.50-0.91). In addition, a higher average illuminance and longer time above 1000 lux in the morning exhibited a significant decrease in relapse into depressive episodes (per log lux and per log min; hazard ratio, 0.65 and 0.61; 95% confidence interval, 0.49-0.86 and 0.47-0.78, respectively). The association between daytime light exposure and relapse into manic/hypomanic/mixed episodes was not significantly different.

CONCLUSION

A significant association was observed between increased daytime light exposure, mainly in the morning, and decreased relapse into depressive episodes.

Biological rhythms and chronotherapeutics in depression

Depressive syndromes are frequent and heterogeneous brain conditions with more than 90% of patients suffering from sleep complaints. Better characterizing this "sleep" domain may allow to both better treat acute episodes with existing chronotherapeutics, but also to prevent the manifestation or recurrences of mood disorders. This work aims to i) review theoretical and fundamental data of chronotherapeutics, and ii) provide practical recommendations. Light therapy (LT) can be used as a first-line monotherapy of moderate to severe depression of all subtypes. LT can be also used as a combination with antidepressant to maximize patients' response rates, which has a clear superiority to antidepressant alone. Sleep deprivation (SD) is a rapid and powerful chronotherapeutic with antidepressant responses within hours in 45-60% of patients with unipolar or bipolar depression. Different strategies should be combined to stabilize the SD antidepressant effect, including concomitant medications, repeated SD, combination with sleep phase advance and/or LT (triple chronotherapy). Melatonin treatment is of interest in remitted patients with mood disorder to prevent relapses or recurrences, if a complaint of insomnia, poor sleep quality or phase delay syndrome is associated. During the acute phase, melatonin could be used as an adjuvant treatment for symptoms of insomnia associated with depression. The cognitive behavioral therapy for insomnia (CBT-I) can be recommend to treat insomnia during euthymic phases. The Interpersonal and social rhythm therapy (IPSRT) is indicated for the acute treatment of bipolar depression and for the prevention of mood episodes. Chronotherapeutics should always be associated with behavioral measures for healthy sleep.

Sleep deprivation as treatment for depression: Systematic review and meta-analysis

OBJECTIVE

To systematically review evidence on the efficacy and safety of sleep deprivation (SD) as a treatment option for patients with unipolar or bipolar depression.

METHODS

A systematic review according to PRISMA guidelines was conducted. The certainty of evidence was assessed using the GRADE approach. Controlled trials were included in efficacy analysis, case series for evaluating complications and qualitative studies for patients' experiences.

RESULTS

Eight controlled studies (368 patients), one qualitative study and seven case series (825 patients) were included. One week after treatment start, SD combined with standard treatment did not reduce depressive symptoms compared with standard treatment (standardized mean difference, SMD = -0.29, [95% confidence interval, CI: -0.84 to 0.25], p = 0.29). When excluding a study in elderly patients in a post hoc analysis, the difference was statistically significant (SMD = -0.54 ([95% CI: -0.86 to -0.22], p < 0.001)) but it diminished two weeks after treatment start. No superiority of SD was found compared with antidepressants, but SD may be superior to exercise in certain settings. It is uncertain whether SD affects quality of sleep, quality of life, everyday functioning or length of stay. Apart from switch to mania (ranging between 2.7% and 10.7%), no other serious complications were reported.

CONCLUSION

Sleep deprivation has been studied in a wide range of settings resulting in divergent results for the short-term efficacy on depressive symptoms. Post hoc analyses indicated that there may be a significant but transient effect in certain populations. Further studies should focus on identifying subgroups of responders as well as examining feasibility in routine clinical care.

Light therapy for mood disorders

In this chapter, light therapy for mood disorders is discussed, including mood disorders during and after pregnancy. In the introduction, we discuss the symptomatology, etiology, and treatment of a specific type of mood disorder, seasonal affective disorder, since it kick-started the first clinical trials with light therapy. Second, we elaborate on the pathophysiology of mood disorders, in particular in the peripartum period. Next, we present an overview of the proposed working mechanisms of light therapy, followed by a discussion of the clinical trials that have followed after the initial research in seasonal affective disorder. Finally, we also focus on the limitations of these trials, such as considerable heterogeneity among studies and many methodological shortcomings. This is complemented by a number of suggestions for future research. Further studies are needed, which stems from the fact that the results have not always been consistent. Despite this, light therapy may be a promising treatment option for various types of mood disorders, since it shows a significant reduction in symptoms in many patients with few adverse effects.

Adjunctive bright light therapy for treating bipolar depression: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

Bright light therapy (BLT) was reported as an effective adjunctive treatment option for bipolar disorder. Previous meta-analytic study showed that augmentation treatment with light therapy significantly decreased the severity of bipolar depression. However, most of included studies were case-control studies and several of them focused on BLT that was provided in combination with sleep deprivation therapy.

METHODS

In this meta-analysis, we used several electronic databases to search the studies and included only randomized controlled trial (RCT) studies to compare BLT with control experimental groups for treating bipolar depression with pharmacological treatment to clarify the adjunctive efficacy of BLT. We searched the databases of EMBASE, MEDLINE, Scopus, The Cochrane Central Register of Controlled Trials, the Cumulative Index to Nursing and Allied Health Literature, and Clinicaltrials.gov for studies published in English until September 19, 2019. Two researchers conducted the literature screening, data extraction, and methodological quality assessment independently. The main outcome was the response rate and remission rate. We used the Review Manager 5.3 Software for the meta-analysis.

RESULTS

Four trials with a total of 190 participants (intervention: 94, control: 96) with bipolar depression were evaluated to gauge the effects of light therapy. The meta-analysis showed risk ratios of 1.78 (95% CI 1.24-2.56, p = .002; I2  = 17%) demonstrating a significant effect of light therapy in the response rate of bipolar disorder. The meta-analysis shows risk ratios of 2.03 (95% CI 0.48-8.59, p = .34; I2  = 67%) demonstrating no significant effect of light therapy in the remission rate of patients with bipolar disorder. None of the articles reported any serious adverse effects. Manic switch rate was 1.1% in the light therapy group and 1.2% in the control group.

CONCLUSIONS

Bright light therapy is an effective treatment for reducing depression symptoms among patients with bipolar depression.

Treating winter depressive episodes in bipolar disorder: an open trial of light therapy

BACKGROUND

Light therapy has been used to treat winter depression in bipolar disorder, although the dose, duration, and timing of treatment have differed. The present study is an open trial of light therapy for depressive episodes in autumn/winter using a Dutch protocol specific for patients with a bipolar disorder.

METHODS

Data were collected for the seasons September-April 2017-2018 and September-April 2018-2019. In total, 58 patients received light therapy for a minimum of 7 days and a maximum of 21 days; there was a follow-up measurement after two weeks. Outcomes were quick inventory of depressive symptomatology (QIDS) scores and side effects.

RESULTS

QIDS scores were significantly lower at the last day of therapy (B = - 6.00, p < 0.001) and 2 weeks after the end of treatment (B = - 6.55, p < 0.001) compared with pre-intervention. Remission (QIDS ≤ 5) was reached in 55% of the treatments and response (50% symptom reduction) in 57% of the treatments. Side effects were mild; two hypomanic periods occurred.

CONCLUSIONS

The Dutch light therapy protocol for patients with a bipolar disorder may be effective in treating a seasonal depression and side effects are mild. Light therapy deserves a prominent place in the treatment because effects may be large and quick.

Light Therapy for Patients With Bipolar Depression: Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

Bipolar disorder (BD) is challenging to treat, and fewer treatments are available for depressive episodes compared to mania. Light therapy is an evidence-based nonpharmacological treatment for seasonal and nonseasonal major depression, but fewer studies have examined its efficacy for patients with BD. Hence, we reviewed the evidence for adjunctive light therapy as a treatment for bipolar depression.

METHODS

We conducted a systematic review of databases from inception to June 30, 2019, for randomized, double-blind, placebo-controlled trials of light therapy in patients with BD (CRD42019128996). The primary outcome was change in clinician-rated depressive symptom score; secondary outcomes included clinical response, remission, acceptability, and treatment-emergent mood switches. We quantitatively pooled outcomes using meta-analysis with random-effects models.

RESULTS

We identified seven trials representing 259 patients with BD. Light therapy was associated with a significant improvement in Hamilton Depression Rating Scale score (standardized mean difference = 0.43, 95% confidence interval [CI], 0.04 to 0.82, P = 0.03). There was also a significant difference in favor of light therapy for clinical response (odds ratio [OR] = 2.32; 95% CI, 1.12 to 4.81; P = 0.024) but not for remission. There was no difference in affective switches between active light and control conditions (OR = 1.30; 95% CI, 0.38 to 4.44; P = 0.67). Study limitations included different light treatment parameters, small sample sizes, short treatment durations, and variable quality across trials.

CONCLUSION

There is positive but nonconclusive evidence that adjunctive light therapy reduces symptoms of bipolar depression and increases clinical response. Light therapy is well tolerated with no increased risk of affective switch.

Efficacy and safety of bright light therapy for manic and depressive symptoms in patients with bipolar disorder: A systematic review and meta-analysis

AIM

This systematic review and meta-analysis evaluated whether bright light therapy (BLT) is an effective and safe treatment for manic/depressive symptoms and a preventive measure for recurrent mood episodes in patients with bipolar disorder.

METHODS

A literature search of major electronic databases was conducted in June 2019, including all published articles up to that date. Two researchers independently selected relevant publications, extracted data, and evaluated methodological quality according to the Cochrane criteria.

RESULTS

Six randomized controlled trials (RCT) evaluated the efficacy of BLT for bipolar depression. A meta-analysis found no significant differences between BLT and placebo for the following outcomes: (i) rates of remission from depressive episodes (risk ratio [RR]: 1.81, 95% confidence interval [CI]: 0.43 to 7.64, P = 0.42); (ii) depressive symptom scores (standardized mean difference: -0.25, 95%CI: -0.74 to 0.23, P = 0.30); and (iii) rates of manic switching (RR: 1.00, 95%CI: 0.28 to 3.59, P = 0.26). The sensitivity analysis for studies with low overall indirectness did show a significant antidepressant effect for BLT (RR: 3.09, 95%CI: 1.62 to 5.90, P = 0.006). No RCT investigated the effect of BLT in preventing the recurrence of mood episodes in the euthymic state or in improving manic symptoms in the manic state. No severe adverse events were reported.

CONCLUSION

While a meta-analysis was unable to demonstrate the efficacy of BLT for bipolar depression, a sensitivity analysis did show a significant effect. Further well-designed studies are needed to clarify the effectiveness of BLT, not only for the depressive state but also for other states, in the treatment of bipolar disorder.

Sleep and sleep treatments in bipolar disorder

Sleep and circadian disturbances in bipolar disorder are common and persistent within and between illness episodes. Insomnia, hypersomnia, reduced need for sleep, sleep schedule variability and circadian rhythm disorders are frequently observed. In this article, recent research is reviewed suggesting that the presence of sleep disturbance is associated with functional impairment, interacts with other physical and environmental systems (e.g. physical activity, light exposure), and may attenuate response to treatment. Established and emerging treatments for various sleep disturbances are reviewed, with emphasis on applications for light therapy and adapted cognitive behavioral therapy. There remains a critical need to understand the co-occurrence of various sleep disturbances, develop, and refine treatment approaches (especially for hypersomnia/long sleep duration) and adapt wearable and smartphone technologies to aid assessment and intervention.

Dynamic LED-light versus static LED-light for depressed inpatients: study protocol for a randomised clinical study

INTRODUCTION

Retrospective studies conducted in psychiatric inpatient wards have shown a relation between the intensity of daylight in patient rooms and the length of stay, pointing to an antidepressant effect of ambient lighting conditions. Light therapy has shown a promising antidepressant effect when administered from a light box. The emergence of light-emitting diode (LED) technology has made it possible to build luminaires into rooms and to dynamically mimic the spectral and temporal distribution of daylight. The objective of this study is to investigate the antidepressant efficacy of a newly developed dynamic LED-lighting system installed in an inpatient ward.

METHODS AND ANALYSIS

In all, 150 inpatients with a major depressive episode, as part of either a major depressive disorder or as part of a bipolar disorder, will be included. The design is a two-arm 1:1 randomised study with a dynamic LED-lighting arm and a static LED-lighting arm, both as add-on to usual treatment in an inpatient psychiatric ward. The primary outcome is the baseline adjusted score on the 6-item Hamilton Depression Rating Scale at week 3. The secondary outcomes are the mean score on the Suicidal Ideation Attributes Scale at week 3, the mean score on the 17-item Hamilton Depression Rating Scale at week 3 and the mean score on the World Health Organisation Quality of Life-BREF (WHOQOL-BREF) at week 3. The spectral distribution of daylight and LED-light, with a specific focus on light mediated through the intrinsically photosensitive retinal ganglion cells, will be measured. Use of light luminaires will be logged. Assessors of Hamilton Depression Rating Scale scores and data analysts will be blinded for treatment allocation. The study was initiated in May 2019 and will end in December 2021.

ETHICS AND DISSEMINATION

No ethical issues are expected. Results will be published in peer-reviewed journals, disseminated electronically and in print and presented at symposia.

TRIAL REGISTRATION NUMBER

NCT03821506; Pre-results.

Sleep and Circadian Rhythm Disorder in Bipolar Affective Disorder

Symptoms of affective disorders encompass a range of changes to biological processes such as sleep and appetite. These processes are regulated over a 24-h cycle known as the circadian rhythm. Sleep is a particularly useful marker of this rhythm as it is readily measurable and functionally significant. Sleep disturbance is common in bipolar affective disorder and may act as a marker, and precipitant, of relapse. Circadian rhythms are modulated by environmental and social cues and have been shown to be influenced by treatment in BPAD. As such understanding of circadian rhythms may lead to a better understanding of the pathophysiology of BPAD and its treatment. This chapter will explore the neurobiology of the circadian clock and the putative role of circadian rhythm dysregulation in the pathophysiology and treatment of bipolar affective disorder (BPAD).

Perspectives in affective disorders: Clocks and sleep

Mood disorders are often characterised by alterations in circadian rhythms, sleep disturbances and seasonal exacerbation. Conversely, chronobiological treatments utilise zeitgebers for circadian rhythms such as light to improve mood and stabilise sleep, and manipulations of sleep timing and duration as rapid antidepressant modalities. Although sleep deprivation ("wake therapy") can act within hours, and its mood-elevating effects be maintained by regular morning light administration/medication/earlier sleep, it has not entered the regular guidelines for treating affective disorders as a first-line treatment. The hindrances to using chronotherapeutics may lie in their lack of patentability, few sponsors to carry out large multi-centre trials, non-reimbursement by medical insurance and their perceived difficulty or exotic "alternative" nature. Future use can be promoted by new technology (single-sample phase measurements, phone apps, movement and sleep trackers) that provides ambulatory documentation over long periods and feedback to therapist and patient. Light combinations with cognitive behavioural therapy and sleep hygiene practice may speed up and also maintain response. The urgent need for new antidepressants should hopefully lead to reconsideration and implementation of these non-pharmacological methods, as well as further clinical trials. We review the putative neurochemical mechanisms underlying the antidepressant effect of sleep deprivation and light therapy, and current knowledge linking clocks and sleep with affective disorders: neurotransmitter switching, stress and cortico-limbic reactivity, clock genes, cortical neuroplasticity, connectomics and neuroinflammation. Despite the complexity of multi-system mechanisms, more insight will lead to fine tuning and better application of circadian and sleep-related treatments of depression.

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.

Prospects for circadian treatment of mood disorders

Disruption of circadian clocks is strongly associated with mood disorders. Chronotherapies targeting circadian rhythms have been shown to be very effective treatments of mood disorders, but still are not widely used in clinical practice. The mechanisms by which circadian disruption leads to mood disorders are poorly characterized and, therefore, may not convince clinicians to apply chronotherapies. Hence, in this review, we describe specific potential mechanisms, in order to make this connection more credible to clinicians. We believe that four major features of disrupted clocks may contribute to the development of mood disorders: (1) loss of synchronization to environmental 24-h rhythms, (2) internal desynchronization among body clocks, (3) low rhythm amplitude, and (4) changes in sleep architecture. Discussing these attributes and giving plausible examples, we will discuss prospects for relatively simple chronotherapies addressing these features that are easy to implement in clinical practice. Key messages In this review, we describe specific potential mechanisms by which disrupted clocks may contribute to the development of mood disorders: (1) loss of synchronization to environmental 24-h rhythms, (2) internal desynchronization among body clocks, (3) low rhythm amplitude, and (4) changes in sleep architecture. We provide prospects for relatively simple chronotherapies addressing these features that are easy to implement in clinical practice.

Bright Light Therapy in the Morning or at Mid-Day in the Treatment of Non-Seasonal Bipolar Depressive Episodes (LuBi): Study Protocol for a Dose Research Phase I / II Trial

Objective This study protocol aims to determine, using a rigorous approach in patients with bipolar disorder (BD) and non-seasonal major depressive episode (MDE), the characteristics of bright light therapy (BLT) administration (duration, escalation, morning and mid-day exposures) depending on the tolerance (hypomanic symptoms). Methods Patients with BD I or II and treated by a mood stabilizer are eligible. After 1 week of placebo, patients are randomized between either morning or mid-day exposure for 10 weeks of active BLT with glasses using a dose escalation at 7.5, 10, 15, 30 and 45 minutes/day. A further follow-up visit is planned 6 months after inclusion. Patients will be included by cohorts of 3, with at least 3 days of delay between them, and 1 week between cohorts. If none meet a dose limiting toxicity (DLT; i.e hypomanic symptoms), the initiation dose of the next cohort will be increased. If one patient meet a DLT, an additionnal cohort will start at the same dose. If 2 or 3 patients meet a DLT, from the same cohort or from two cohorts at the same dose initiation, the maximum tolerated dose is defined. This dose escalation will also take into account DLTs observed during the intra-subject escalation on previous cohorts, with a "Target Ceiling Dose" defined if 2 DLTs occured at a dose. Discussion Using an innovative and more ergonomic device in the form of glasses, this study aims to better codify the use of BLT in BD to ensure a good initiation and tolerance. Trial registrationaaClinicalTrials.gov Identifier: NCT03396744.