Evolving applications of light therapy

Insomnia in Parkinson's Disease: Causes, Consequences, and Therapeutic Approaches

Sleep disorders represent prevalent non-motor symptoms in Parkinson's disease (PD), affecting over 90% of the PD population. Insomnia, characterized by difficulties in initiating and maintaining sleep, emerges as the most frequently reported sleep disorder in PD, with prevalence rates reported from 27 to 80% across studies. Insomnia not only significantly impacts the quality of life of PD patients but is also associated with cognitive impairment, motor disabilities, and emotional deterioration. This comprehensive review aims to delve into the mechanisms underlying insomnia in PD, including neurodegenerative changes, basal ganglia beta oscillations, and circadian rhythms, to gain insights into the neural pathways involved. Additionally, the review explores the risk factors and comorbidities associated with insomnia in PD, providing valuable insights into its management. Special attention is given to the challenges faced by healthcare providers in delivering care to PD patients and the impact of caregiving roles on patients' quality of life. Overall, this review provides a comprehensive understanding of insomnia in PD and highlights the importance of addressing this common sleep disorder in PD patients.

Advances in Vibrio-related infection management: an integrated technology approach for aquaculture and human health

Vibrio species pose significant threats worldwide, causing mortalities in aquaculture and infections in humans. Global warming and the emergence of worldwide strains of Vibrio diseases are increasing day by day. Control of Vibrio species requires effective monitoring, diagnosis, and treatment strategies at the global scale. Despite current efforts based on chemical, biological, and mechanical means, Vibrio control management faces limitations due to complicated implementation processes. This review explores the intricacies and challenges of Vibrio-related diseases, including accurate and cost-effective diagnosis and effective control. The global burden due to emerging Vibrio species further complicates management strategies. We propose an innovative integrated technology model that harnesses cutting-edge technologies to address these obstacles. The proposed model incorporates advanced tools, such as biosensing technologies, the Internet of Things (IoT), remote sensing devices, cloud computing, and machine learning. This model offers invaluable insights and supports better decision-making by integrating real-time ecological data and biological phenotype signatures. A major advantage of our approach lies in leveraging cloud-based analytics programs, efficiently extracting meaningful information from vast and complex datasets. Collaborating with data and clinical professionals ensures logical and customized solutions tailored to each unique situation. Aquaculture biotechnology that prioritizes sustainability may have a large impact on human health and the seafood industry. Our review underscores the importance of adopting this model, revolutionizing the prognosis and management of Vibrio-related infections, even under complex circumstances. Furthermore, this model has promising implications for aquaculture and public health, addressing the United Nations Sustainable Development Goals and their development agenda.

Identifying predictive factors for mood recurrence in early-onset major mood disorders: A 4-year, multicenter, prospective cohort study

We investigate the predictive factors of the mood recurrence in patients with early-onset major mood disorders from a prospective observational cohort study from July 2015 to December 2019. A total of 495 patients were classified into three groups according to recurrence during the cohort observation period: recurrence group with (hypo)manic or mixed features (MMR), recurrence group with only depressive features (ODR), and no recurrence group (NR). As a result, the baseline diagnosis of bipolar disorder type 1 (BDI) and bipolar disorder type 2 (BDII), along with a familial history of BD, are strong predictors of the MMR. The discrepancies in wake-up times between weekdays and weekends, along with disrupted circadian rhythms, are identified as a notable predictor of ODR. Our findings confirm that we need to be aware of different predictors for each form of mood recurrences in patients with early-onset mood disorders. In clinical practice, we expect that information obtained from the initial assessment of patients with mood disorders, such as mood disorder type, family history of BD, regularity of wake-up time, and disruption of circadian rhythms, can help predict the risk of recurrence for each patient, allowing for early detection and timely intervention.

Fine-tuning the circadian system with light treatment for Parkinson's disease: an in-depth, critical review

Late in the twentieth century, interest intensified regarding the involvement of the circadian system in the aetiology and treatment of Parkinson's disease (PD). It has been envisaged that this approach might provide relief beyond the limited benefits and severe side effects achieved by dopamine (DA) replacement. In the first clinical article, published in 1996, polychromatic light was used to shift the circadian clock as it is considered to be the most powerful zeitgeber (time keeper) that can be implemented to realign circadian phase. Since that time, 11 additional articles have implemented light treatment (LT) in various forms as an adjuvant to DA replacement. In spite of the growing interest in this area, the systematic exploration of LT in PD has been stymied by several methodological factors. Such factors include time of LT presentation, duration of studies undertaken, frequency of light employed, dose of light prescribed and relevance of experimental design to the prolonged course of the illness. On this basis, it is the purpose of this review to provide an in-depth examination of these papers, and the underlying preclinical work, to provide critique, thereby giving direction for future studies in therapeutic applications of LT for PD. Consideration of this collective work may serve to carve a path for future research and thereby improve the lives of those suffering from this debilitating disorder.

Current Considerations in the Diagnosis and Treatment of Circadian Rhythm Sleep-Wake Disorders in Children

Circadian Rhythm Sleep-Wake Disorders (CRSWDs) are important sleep disorders whose unifying feature is a mismatch between the preferred or required times for sleep and wakefulness and the endogenous circadian drives for these. Their etiology, presentation, and treatment can be different in pediatric patients as compared to adults. Evaluation of these disorders must be performed while viewed through the lens of a patient's comorbid conditions. Newer methods of assessment promise to provide greater diagnostic clarity and critical insights into how circadian physiology affects overall health and disease states. Effective clinical management of CRSWDs is multimodal, requiring an integrated approach across disciplines. Therapeutic success depends upon appropriately timed nonpharmacologic and pharmacologic interventions. A better understanding of the genetic predispositions for and causes of CRSWDs has led to novel clinical opportunities for diagnosis and improved therapeutics.

Functional connectivity of brain networks with three monochromatic wavelengths: a pilot study using resting-state functional magnetic resonance imaging

Exposure to certain monochromatic wavelengths can affect non-visual brain regions. Growing research indicates that exposure to light can have a positive impact on health-related problems such as spring asthenia, circadian rhythm disruption, and even bipolar disorders and Alzheimer’s. However, the extent and location of changes in brain areas caused by exposure to monochromatic light remain largely unknown. This pilot study (N = 7) using resting-state functional magnetic resonance shows light-dependent functional connectivity patterns on brain networks. We demonstrated that 1 min of blue, green, or red light exposure modifies the functional connectivity (FC) of a broad range of visual and non-visual brain regions. Largely, we observed: (i) a global decrease in FC in all the networks but the salience network after blue light exposure, (ii) a global increase in FC after green light exposure, particularly noticeable in the left hemisphere, and (iii) a decrease in FC on attentional networks coupled with a FC increase in the default mode network after red light exposure. Each one of the FC patterns appears to be best arranged to perform better on tasks associated with specific cognitive domains. Results can be relevant for future research on the impact of light stimulation on brain function and in a variety of health disciplines.

Morning blue light treatment improves sleep complaints, symptom severity, and retention of fear extinction memory in post-traumatic stress disorder

Disrupted sleep is a major feature in numerous clinical disorders and is related to decrements in affective memory processing. The prevalence of sleep disruption in post-traumatic stress disorder (PTSD) is suggested to be a key feature that exacerbates the impaired ability to recall extinction memories during experimental fear conditioning. We hypothesized that an intervention employing blue-wavelength light therapy (BLT) to regulate sleep and stabilize circadian rhythms in patients with PTSD (i.e., via regulated morning exposure) would be associated with PTSD symptom improvement, decreased sleep-related complaints, as well as improved consolidation and retention of extinction memories relative to a fear conditioning/extinction paradigm. Eighty-two individuals with PTSD underwent a well-validated fear conditioning/extinction protocol with subsequent assignment to receive morning BLUE (BLT) or placebo AMBER (ALT) light therapy daily for 30-min over 6-weeks. Participants returned after the intervention for post-treatment extinction recall, comprised of exposure to the previously conditioned stimuli, with the difference in skin conductance response between the "extinguished" and the "never-extinguished" stimuli at follow-up. Participants also viewed previously conditioned stimuli in a novel context during a functional magnetic resonance imaging (fMRI) scan. BLUE light therapy was associated with improvements relative to correlated decreases between PTSD symptoms and sleep-related complaints. Participants receiving BLT also sustained retention of the extinction memory, while those in the placebo amber light treatment group showed impairment, characterized by the restoration of the extinguished fear response after 6-weeks. Participants in the ALT also demonstrated greater reactivity in the left insula when viewing the previously extinguished fear-conditioned stimuli in a novel context. Daily BLUE-wavelength morning light exposure was associated with greater retention of extinction learning in patients with PTSD when compared to ALT, as supported by both autonomic and neurobiological reactivity. We speculate that improved sleep facilitated by a stabilized circadian rhythm, after fear-learning, led to greater consolidation of the fear extinction memory, decreased PTSD symptom presentation, and associated decreases in sleep-related complaints. Prominent exposure treatments for PTSD incorporate principles of fear extinction, and our findings suggest that blue light treatment may facilitate treatment gains by promoting the consolidation of extinction memories via improved sleep.

Effects of dynamic bedroom lighting on measures of sleep and circadian rest-activity rhythm in inpatients with major depressive disorder

Bright light therapy is an effective treatment option for seasonal and non-seasonal affective disorders. However up to now, no study has investigated effects of dynamic bedroom lighting in hospitalized patients with major depression. A bedroom lighting system, which automatically delivered artificial dawn and dusk and blue-depleted nighttime lighting (DD-N lighting) was installed in a psychiatric ward. Patients with moderate to severe depression were randomly assigned to stay in bedrooms with the new lighting or standard lighting system. Patients wore wrist actimeters during the first two treatment weeks. Additionally, hospitalization duration and daily psychotropic medication were retrieved from patients' medical charts. Data from thirty patients, recorded over a period of two weeks, were analyzed. Patients under DD-N lighting generally woke up earlier (+ 20 min), slept longer (week 1: + 11 min; week 2: + 27 min) and showed higher sleep efficiency (+ 2.4%) and shorter periods of nighttime awakenings (- 15 min). In the second treatment week, patients started sleep and the most active 10-h period earlier (- 33 min and - 64 min, respectively). This pilot study gives first evidence that depressed patients' sleep and circadian rest/activity system may benefit from bedroom lighting when starting inpatient treatment.

Multi-Level Processes and Retina-Brain Pathways of Photic Regulation of Mood

Light exerts powerful biological effects on mood regulation. Whereas the source of photic information affecting mood is well established at least via intrinsically photosensitive retinal ganglion cells (ipRGCs) secreting the melanopsin photopigment, the precise circuits that mediate the impact of light on depressive behaviors are not well understood. This review proposes two distinct retina–brain pathways of light effects on mood: (i) a suprachiasmatic nucleus (SCN)-dependent pathway with light effect on mood via the synchronization of biological rhythms, and (ii) a SCN-independent pathway with light effects on mood through modulation of the homeostatic process of sleep, alertness and emotion regulation: (1) light directly inhibits brain areas promoting sleep such as the ventrolateral preoptic nucleus (VLPO), and activates numerous brain areas involved in alertness such as, monoaminergic areas, thalamic regions and hypothalamic regions including orexin areas; (2) moreover, light seems to modulate mood through orexin-, serotonin- and dopamine-dependent pathways; (3) in addition, light activates brain emotional processing areas including the amygdala, the nucleus accumbens, the perihabenular nucleus, the left hippocampus and pathways such as the retina–ventral lateral geniculate nucleus and intergeniculate leaflet–lateral habenula pathway. This work synthetizes new insights into the neural basis required for light influence mood

[Positive effect of bright light therapy on mood and sleep quality in institutionalized older people]

INTRODUCTION

Bright light exposure during the day has a positive effect on health and its deficit can cause multiple physiological and cognitive disorders, including depression. The aim of this study was to evaluate the effect of bright light therapy (BLT) on the quality of sleep and mood emotional state; cognitive status, global deterioration and quality of life in institutionalized elderly.

MATERIAL AND METHODS

This is a study with repeated measures design. Thirty-seven older people admitted to a nursing home. The study lasted 3 weeks. The first week, the reference values were established with the Oviedo Sleep Questionnaire, Yesavage Depression Scale, Mini-Mental, Global Scale of Impairment and European Quality of Life Questionnaire. During the second week, they were exposed to BLT (7,000-10,000lx at eye level) between 9:30 a.m. and 11:00 a.m. During the third week, all the data were re-evaluated.

RESULTS

All variables improved significantly after the application of light therapy. Sleep (COS) pre-test 4.1±1.49, post-test 4.9±1.46, p: 0.01), mood (pre-test 3.65±2.78, post-test 2.65±2.9, p: 0.01), cognitive state (pre-test 22.72±6.53, post-test 24±5.92, p: 0.001), state of global deterioration (pre-test 3.10±1.26, post-test 2.72±5.92, p: 0.001) and health-related quality of life (pre-test 6.93±1.86, post-test 7.82±1.62, p: 0.001).

CONCLUSIONS

Sleep quality, mood, cognitive status, global deterioration status and quality of life significantly improved after the application of light bright therapy.

The effects of bright light therapy on depression and sleep disturbances in patients with Parkinson's disease: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Depression and sleep disturbance are well-recognized non-motor features in patients with Parkinson's disease (PD). This meta-analysis aimed to explore the potential role of bright light therapy (BLT) in depression and sleep disturbances in Parkinson's Disease (PD).

METHODS

Four databases were independently searched by two reviewers: PubMed, Cochrane, Web of Science and Embase until February 2021. We evaluated the following depression related scales: Beck's Depression Inventory (BDI); the Geriatric Depression Rating Scale, 30-item (GDS-30); the Hamilton Depression Rating Scale (HDRS); the Hospital Anxiety and Depression Scale (HADS); the Epworth sleepiness scale (ESS); the Fatigue Severity Scale (FSS); the Pittsburgh sleep quality index (PSQI); the Parkinson's disease sleep scale (PDSS); Scales for Outcomes in Parkinson's disease Sleep Scale (SCOPA) and the Insomnia severity index (ISI) to access the effects of bright light therapy on depression and sleep disturbances in patients with PD. Effect size (standardized mean deviation [SMD] and 95% confidence interval [CI]) were used to analyze the continuous results data of intervention group and control light group. Data from five randomized, controlled trials totaling 173 patients with PD was included.

RESULTS

BLT significantly improved depression symptoms (BDI, GDS-30, HDRS and HADS) of PD patients (0.34, 95% CI = 0.06-0.61). Insomnia symptoms (SCOPA and ISI) for patients with PD were significantly improved by BLT as well (1.15, 95% CI = 0.71-1.60). Whereas, no difference was observed in the control light group in improving the depression or insomnia symptoms of PD patients.

CONCLUSION

BLT is an effective intervention for improving depressive symptoms and sleep disturbances in patients with PD.

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.

Measuring circadian function in bipolar disorders: Empirical and conceptual review of physiological, actigraphic, and self-report approaches

BACKGROUND

Interest in biological clock pathways in bipolar disorders (BD) continues to grow, but there has yet to be an audit of circadian measurement tools for use in BD research and practice.

PROCEDURE

The International Society for Bipolar Disorders Chronobiology Task Force conducted a critical integrative review of circadian methods that have real-world applicability. Consensus discussion led to the selection of three domains to review-melatonin assessment, actigraphy, and self-report.

RESULTS

Measurement approaches used to quantify circadian function in BD are described in sufficient detail for researchers and clinicians to make pragmatic decisions about their use. A novel integration of the measurement literature is offered in the form of a provisional taxonomy distinguishing between circadian measures (the instruments and methods used to quantify circadian function, such as dim light melatonin onset) and circadian constructs (the biobehavioral processes to be measured, such as circadian phase).

CONCLUSIONS

Circadian variables are an important target of measurement in clinical practice and biomarker research. To improve reproducibility and clinical application of circadian constructs, an informed systematic approach to measurement is required. We trust that this review will decrease ambiguity in the literature and support theory-based consideration of measurement options.

Application of light therapy in older adults with cognitive impairment: A systematic review

This systematic review aims to assess the efficacy of light therapy on behavioural and psychological symptoms of dementia (BPSD), cognition, functional status, and quality of life in older adults with cognitive impairment; and secondarily, to identify the optimal characteristics of light therapy to establish an adequate protocol for its clinical application. We searched Web of Science and Medline databases through December 2019, resulting in 36 included articles: 3 evaluated the effects on BPSD, 25 on sleep, 12 on agitation, 10 on mood, 4 on neuropsychiatric symptoms, 4 on cognition, 2 on quality of life and 2 on functional status. Literature has shown potential evidence for positive effects of light therapy on managing sleep, behavioural and mood disturbances in people with cognitive impairment, but a limited effect on cognition, quality of life and functional status. This review provides guidelines for intervention protocols with light therapy in older people with cognitive impairment.

Delayed Bedtimes Are Associated With More Severe Obsessive-Compulsive Symptoms in Intensive Residential Treatment

Delays in behavioral and biological circadian rhythms (e.g., sleep timing, melatonin secretion) are found more frequently in individuals with severe and treatment-resistant obsessive-compulsive disorder (OCD). In recent years, it has been documented that these delays in behavioral and biological circadian rhythms are associated with more severe OCD symptoms and poorer response to some OCD treatments. This study examined self-reported sleep behaviors in individuals taking part in an intensive treatment for OCD and the relations between these and OCD symptoms (both at admission to and discharge from the treatment program). Replicating previous findings in less severe populations, delayed sleep phases were relatively common in this group and later bedtimes were associated with more severe OCD symptoms at admission. Sleep onset latency and sleep duration were not associated with OCD symptom severity at admission. Later bedtimes were not associated with self-reported depression or worry symptom severity. There was no evidence of sleep behaviors affecting change in OCD symptoms from admission to discharge from treatment-however, later bedtimes at admission were associated with more severe OCD symptoms at admission and discharge from treatment. There was no evidence of sleep onset latency or sleep duration having a similar predictive effect. More severe OCD symptoms at admission were also associated with later bedtimes at admission and discharge from treatment. These bidirectional predictive relations between late bedtimes and OCD symptoms were of small effect size but support the potential value of evaluating sleep timing in individuals with severe and/or treatment-resistant OCD.

Electrical stimulation of cranial nerves in cognition and disease

The cranial nerves are the pathways through which environmental information (sensation) is directly communicated to the brain, leading to perception, and giving rise to higher cognition. Because cranial nerves determine and modulate brain function, invasive and non-invasive cranial nerve electrical stimulation methods have applications in the clinical, behavioral, and cognitive domains. Among other neuromodulation approaches such as peripheral, transcranial and deep brain stimulation, cranial nerve stimulation is unique in allowing axon pathway-specific engagement of brain circuits, including thalamo-cortical networks. In this review we amalgamate relevant knowledge of 1) cranial nerve anatomy and biophysics; 2) evidence of the modulatory effects of cranial nerves on cognition; 3) clinical and behavioral outcomes of cranial nerve stimulation; and 4) biomarkers of nerve target engagement including physiology, electroencephalography, neuroimaging, and behavioral metrics. Existing non-invasive stimulation methods cannot feasibly activate the axons of only individual cranial nerves. Even with invasive stimulation methods, selective targeting of one nerve fiber type requires nuance since each nerve is composed of functionally distinct axon-types that differentially branch and can anastomose onto other nerves. None-the-less, precisely controlling stimulation parameters can aid in affecting distinct sets of axons, thus supporting specific actions on cognition and behavior. To this end, a rubric for reproducible dose-response stimulation parameters is defined here. Given that afferent cranial nerve axons project directly to the brain, targeting structures (e.g. thalamus, cortex) that are critical nodes in higher order brain networks, potent effects on cognition are plausible. We propose an intervention design framework based on driving cranial nerve pathways in targeted brain circuits, which are in turn linked to specific higher cognitive processes. State-of-the-art current flow models that are used to explain and design cranial-nerve-activating stimulation technology require multi-scale detail that includes: gross anatomy; skull foramina and superficial tissue layers; and precise nerve morphology. Detailed simulations also predict that some non-invasive electrical or magnetic stimulation approaches that do not intend to modulate cranial nerves per se, such as transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS), may also modulate activity of specific cranial nerves. Much prior cranial nerve stimulation work was conceptually limited to the production of sensory perception, with individual titration of intensity based on the level of perception and tolerability. However, disregarding sensory emulation allows consideration of temporal stimulation patterns (axon recruitment) that modulate the tone of cortical networks independent of sensory cortices, without necessarily titrating perception. For example, leveraging the role of the thalamus as a gatekeeper for information to the cerebral cortex, preventing or enhancing the passage of specific information depending on the behavioral state. We show that properly parameterized computational models at multiple scales are needed to rationally optimize neuromodulation that target sets of cranial nerves, determining which and how specific brain circuitries are modulated, which can in turn influence cognition in a designed manner.

Cross-sectional association between outdoor artificial light at night and sleep duration in middle-to-older aged adults: The NIH-AARP Diet and Health Study

INTRODUCTION

Artificial light at night (ALAN) can disrupt circadian rhythms and cause sleep disturbances. Several previous epidemiological studies have reported an association between higher levels of outdoor ALAN and shorter sleep duration. However, it remains unclear how this association may differ by individual- and neighborhood-level socioeconomic status, and whether ALAN may also be associated with longer sleep duration.

METHODS

We assessed the cross-sectional relationship between outdoor ALAN and self-reported sleep duration in 333,365 middle- to older-aged men and women in the NIH-AARP Diet and Health Study. Study participants reported baseline addresses, which were geocoded and linked with outdoor ALAN exposure measured by satellite imagery data obtained from the U.S. Defense Meteorological Satellite Program's Operational Linescan System. We used multinomial logistic regression to estimate the multinomial odds ratio (MOR) and 95% confidence intervals (CI) for the likelihood of reporting very short (<5 h), short (<7 h) and long (≥9 h) sleep relative to reporting 7-8 h of sleep across quintiles of LAN. We also conducted subgroup analyses by individual-level education and census tract-level poverty levels.

RESULTS

We found that higher levels of ALAN were associated with both very short and short sleep. When compared to the lowest quintile, the highest quintile of ALAN was associated with 16% and 25% increases in the likelihood of reporting short sleep in women (MORQ1 vs Q5, (95% CI), 1.16 (1.10, 1.22)) and men (1.25 (1.19, 1.31)), respectively. Moreover, we found that higher ALAN was associated with a decrease in the likelihood of reporting long sleep in men (0.79 (0.71, 0.89)). We also found that the associations between ALAN and short sleep were larger in neighborhoods with higher levels of poverty.

CONCLUSIONS

The burden of short sleep may be higher among residents in areas with higher levels of outdoor LAN, and this association is likely stronger in poorer neighborhoods. Future studies should investigate the potential benefits of reducing light intensity in high ALAN areas in improve sleep health.

Morningness-eveningness scores predict outcomes differentially for depressed patients attending morning vs. afternoon day treatment streams

At the Center for Addiction and Mental Health (CAMH) Integrated Day Treatment (IDT) program, each patient attends either a morning stream or an afternoon stream, but not both. We examined whether subjective chronotype, or the time of day an individual prefers to be most active and alert, predicted treatment outcomes differentially in depressed patients attending the morning vs. afternoon IDT streams. The Horne-Östberg Morningness-Eveningness Questionnaire (MEQ) was administered before IDT treatment to 203 consecutive patients experiencing a major depressive episode. Multiple regression was used to predict change in depression and quality of life scores based on treatment stream (morning or afternoon), baseline MEQ scores and the treatment stream by MEQ interaction. The treatment stream by MEQ interaction was a highly significant predictor of both depression and quality of life change scores. Post-hoc analyses based on established MEQ categories revealed that definite evening chronotypes had significantly better responses in the morning stream than did morning chronotypes, and significantly worse responses in the afternoon stream relative to moderate evening or neutral chronotypes. There were insufficient morning chronotypes in the afternoon stream to assess clinical responses for this subgroup. In the morning stream only, there was a significant positive correlation between the change in MEQ scores after four weeks of IDT treatment (i.e. a shift to greater morningness) and the decrease in depression scores (r = .36, p = .003), consistent with a therapeutic phase advance in circadian rhythms. In sum, these preliminary data suggest that definite evening chronotypes may have the greatest relative benefit from attending the morning vs. afternoon IDT stream. As patients currently select which IDT stream they will attend, future work based on randomized treatment assignment and using passive actigraphy to assess circadian phase is currently planned to extend these preliminary findings.

How Does Light Regulate Mood and Behavioral State?

The idea that light affects mood and behavioral state is not new. However, not much is known about the particular mechanisms and circuits involved. To fully understand these, we need to know what properties of light are important for mediating changes in mood as well as what photoreceptors and pathways are responsible. Increasing evidence from both human and animal studies imply that a specialized class of retinal ganglion cells, intrinsically photosensitive retinal ganglion cells (ipRGCs), plays an important role in the light-regulated effects on mood and behavioral state, which is in line with their well-established roles in other non-visual responses (pupillary light reflex and circadian photoentrainment). This paper reviews our current understanding on the mechanisms and paths by which the light information modulates behavioral state and mood.

Eveningness Is Associated With Greater Depressive Symptoms in Type 2 Diabetes Patients: A Study in Two Different Ethnic Cohorts

BACKGROUND

Eveningness is associated with greater depressive symptoms in the general population. Depression and type 2 diabetes (T2D) commonly coexist. We aimed to explore the association between morningness-eveningness and depressive symptoms in T2D patients in the United States and in Thailand.

PARTICIPANTS

T2D patients (n = 182) from an endocrinology clinic in Chicago, Illinois, and six hospitals in Thailand (n = 251) were enrolled.

METHODS

Diabetes history was collected. Depressive symptoms were assessed by the Center for Epidemiologic Studies Depression scale (CES-D). The Chicago cohort completed the Morningness-Eveningness Questionnaire (MEQ) and the Thai cohort completed the Composite Scale of Morningness (CSM). Sleep quality was assessed using the Pittsburg Sleep Quality Index (PSQI).

RESULTS

The mean (SD) CES-D score was 13.7 (9.1) in Chicago and 11.9 (6.4) in Thailand. In Chicago participants, after adjusting for age, sex, ethnicity, hemoglobin A1c, insulin use, and PSQI score, greater eveningness (lower MEQ scores) was associated with higher CESD scores (B = -0.117, p = 0.048). In Thai participants, after adjusting for age, sex, and PSQI score, eveningness (lower CSM score) was associated with higher CES-D score (B = -0.147, p = 0.016). In both cohorts, however, eveningness was not independently associated with the likelihood of being in the at-risk range for clinical depression (CES-D ≥ 16).

CONCLUSIONS

Eveningness is independently associated with greater depressive symptoms in T2D in two different ethnic cohorts. The results support the association between individual differences in circadian rhythms and psychological functioning in T2D.

Chronotherapies for Parkinson's disease

Parkinson's disease (PD) is the second-most common progressive neurodegenerative disorder. Although the clinical diagnosis of PD is still based on its cardinal motor dysfunctions, several non-motor symptoms (NMS) have been established as integral part of the disease. Unlike motor disorders, development of therapies against NMS are still challenging and remain a critical unmet clinical need. During the last decade, several studies have characterised the molecular, physiological and behavioural alterations of the circadian system in PD patients. As a consequence, and given the ubiquitous nature of circadian rhythms in the entire organism, the biological clock has emerged as a potential therapeutic target to ease suffering from both motor and NMS in PD patients. Here we discuss the emerging field of using bright light, physical exercise and melatonin as chronotherapeutic tools to alleviate motor disorders, sleep/wake alterations, anxiety and depression in PD patients. We also highlight the potential of these readily available therapies to improve the general quality of life and wellbeing of PD patients. Finally, we provide specific data- and mechanisms-driven recommendations that might help improve the therapeutic benefit of light and physical exercise in PD patients.

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.

Light exposure via a head-mounted device suppresses melatonin and improves vigilant attention without affecting cortisol and comfort

We aimed at assessing whether a head-mounted light therapy device, enriched in blue wavelengths, suppresses melatonin secretion and improves vigilant attention in the late evening hours. We also assessed whether using such light device is associated with discomfort and physiological stress. Seventeen healthy young participants (eight females) participated in a counterbalanced within-subject design during which they were exposed for 2 hr before habitual sleep time to a blue-enriched light (1500 lx) or to a lower intensity red-light (150 lx) control condition, using a new-generation light emitting diode (LED) head-mounted device. Compared to the red light control condition, blue-enriched light significantly reduced melatonin secretion and reaction times during a psychomotor vigilance task while no significant differences were detected in discomfort and cortisol levels. These results suggest that, compared to a control condition, blue-enriched light, delivered by a new-generation head-mounted device, elicits typical non-visual responses to light without detectable discomfort and physiological stress. They suggest that such devices might constitute an effective alternative to standard light boxes.

The Antidepressant Effect of Light Therapy from Retinal Projections

Observations from clinical trials have frequently demonstrated that light therapy can be an effective therapy for seasonal and non-seasonal major depression. Despite the fact that light therapy is known to have several advantages over antidepressant drugs like a low cost, minimal side-effects, and fast onset of therapeutic effect, the mechanism underlying light therapy remains unclear. So far, it is known that light therapy modulates mood states and cognitive functions, involving circadian and non-circadian pathways from retinas into brain. In this review, we discuss the therapeutic effect of light on major depression and its relationship to direct retinal projections in the brain. We finally emphasize the function of the retino-raphe projection in modulating serotonin activity, which probably underlies the antidepressant effect of light therapy for depression.

The potential influence of LED lighting on mental illness

OBJECTIVES

Two recent scientific breakthroughs may alter the treatment of mental illness, as discussed in this narrative review. The first was the invention of white light-emitting diodes (LEDs), which enabled an ongoing, rapid transition to energy-efficient LEDs for lighting, and the use of LEDs to backlight digital devices. The second was the discovery of melanopsin-expressing photosensitive retinal ganglion cells, which detect environmental irradiance and mediate non-image forming (NIF) functions including circadian entrainment, melatonin secretion, alertness, sleep regulation and the pupillary light reflex. These two breakthroughs are interrelated because unlike conventional lighting, white LEDs have a dominant spectral wavelength in the blue light range, near the peak sensitivity for the melanopsin system.

METHODS

Pertinent articles were identified.

RESULTS

Blue light exposure may suppress melatonin, increase alertness, and interfere with sleep in young, healthy volunteers and in animals. Areas of concern in mental illness include the influence of blue light on sleep, other circadian-mediated symptoms, prescribed treatments that target the circadian system, measurement using digital apps and devices, and adolescent sensitivity to blue light.

CONCLUSIONS

While knowledge in both fields is expanding rapidly, future developments must address the potential impact of blue light on NIF functions for healthy individuals and those with mental illness.

Clinical efficacy, onset time and safety of bright light therapy in acute bipolar depression as an adjunctive therapy: A randomized controlled trial

BACKGROUND

Bright light therapy (BLT) is an effective treatment for seasonal affective disorder and non- seasonal depression. The efficacy of BLT in treating patients with bipolar disorder is still unknown.

AIMS

The aim of this study is to examine the efficacy, onset time and clinical safety of BLT in treating patients with acute bipolar depression as an adjunctive therapy (trial registration at ClinicalTrials.gov: NCT02009371).

METHODS

This was a multi-center, single blind, randomized clinical trial. Seventy-four participants were randomized in one of two treatment conditions: BLT and control (dim red light therapy, dRLT). Sixty-three participants completed the study (33 BLT, 30 dRLT). Light therapy lasted for two weeks, one hour every morning. All participants were required to complete several scales assessments at baseline, and at the end of weeks 1 and 2. The primary outcome measures were the clinical efficacy of BLT which was assessed by the reduction rate of HAMD-17 scores, and the onset time of BLT which was assessed by the reduction rate of QIDS-SR16 scores. The secondary outcome measures were rates of switch into hypomania or mania and adverse events.

RESULTS

1) Clinical efficacy: BLT showed a greater ameliorative effect on bipolar depression than the control, with response rates of 78.19% vs. 43.33% respectively (p < 0.01). 2) Onset day: Median onset day was 4.33 days in BLT group. 3) BLT-emergent hypomania: No participants experienced symptoms of hypomania. 4) Side effects: No serious adverse events were reported.

CONCLUSION

BLT can be considered as an effective and safe adjunctive treatment for patients with acute bipolar depression.

The effect of light exposure on insomnia and nocturnal movement in Parkinson's disease: an open label, retrospective, longitudinal study

Insomnia, hypersomnia and REM Sleep Behavior Disorder (RSBD) during sleep are major problems for patients suffering from Parkinson's disease (PD) but they are also used to predict its onset. While these secondary symptoms detract from the quality of life in PD patients, few treatment options are available due to limited efficacy or risk of complicating the treatment regimen. Light therapy (LT) has been suggested as a strategy for sleep disorders but it has only been implemented recently for use in PD. An open label, retrospective study was undertaken where PD patients had been undergoing LT, using polychromatic light, for four months to 15 years prior. It was found that 1 h exposure to light, just prior to retiring, significantly improved insomnia and reduced RSBD in as little as one month after commencing LT. In addition, the improvement was maintained as long as LT was continued over a four to six year period. The efficacy of LT in alleviating these sleep related conditions was not compromised by time since diagnosis or age of the patient. These results intimate the value of long term application of non-invasive techniques such as LT for treating sleep disorders in PD and justify further controlled trials on the long term efficacy of LT.

Precision Light for the Treatment of Psychiatric Disorders

Circadian timekeeping can be reset by brief flashes of light using stimulation protocols thousands of times shorter than those previously assumed to be necessary for traditional phototherapy. These observations point to a future where flexible architectures of nanosecond-, microsecond-, and millisecond-scale light pulses are compiled to reprogram the brain's internal clock when it has been altered by psychiatric illness or advanced age. In the current review, we present a chronology of seminal experiments that established the synchronizing influence of light on the human circadian system and the efficacy of prolonged bright-light exposure for reducing symptoms associated with seasonal affective disorder. We conclude with a discussion of the different ways that precision flashes could be parlayed during sleep to effect neuroadaptive changes in brain function. This article is a contribution to a special issue on Circadian Rhythms in Regulation of Brain Processes and Role in Psychiatric Disorders curated by editors Shimon Amir, Karen Gamble, Oliver Stork, and Harry Pantazopoulos.

Efficacy of light therapy on nonseasonal depression among elderly adults: a systematic review and meta-analysis

OBJECTIVE

The aim of this study was to examine the effectiveness of light therapy in the treatment of geriatric depression.

METHODS

A systematic review and meta-analysis were carried out. Data sources for the literature search were PubMed, Cochrane Collaboration's Central Register of Controlled Clinical Trials, Cochrane Systematic Reviews, and ClinicalTrials.gov. Controlled trials of light therapy on older patients with nonseasonal depression and depression rating scales were eligible. Studies were pooled using a random-effect model for comparisons with light therapy. We used effect size (ES), which expresses changes in depression severity, in each selected meta-analysis to calculate the standardized mean difference on the basis of Hedges' adjusted g; positive values indicated that the depression severity improved after light therapy. All results were presented with 95% CIs. Statistical heterogeneity was explored through visual inspection of funnel plots and the I2 statistic. Moderators of effects were explored using meta-regression.

RESULTS

We identified eight trials involving 395 participants that met the inclusion criteria. Light therapy was significantly more effective than comparative treatments, including placebo or dim light, with an ES of 0.422 (95% CI: 0.174-0.709, P=0.001). In addition, six of the eight trials used bright (white) light, resulting in significantly reduced severity of geriatric depression (N=273, ES: 0.460, 95% CI: 0.085-0.836, P=0.016). Furthermore, pale blue light therapy reduced the severity of geriatric depression (N=89, ES: 0.464, 95% CI: 0.046-0.882, P=0.030).

CONCLUSION

Our results highlighted the significant efficacy of light therapy in the treatment of geriatric depression. Additional well-designed, controlled studies are necessary to adopt standard parameters, adequate group sizes, and randomized assignment to evaluate more thoroughly the efficacy of light therapy for treating geriatric depression.

The effect of directed photic stimulation of the pineal on experimental Parkinson's disease

The role of the circadian system in Parkinson's disease (PD) is a topic of increasing scientific interest. This has emerged from recent studies demonstrating an altered response of PD patients to treatment in relation to the phase of the light/dark cycle and from other work defining the functional significance of melanocytes in PD: a cell type that the nigro-striatal dopamine (NSD) system and circadian system both contain. The present study was undertaken to determine the sensitivity of the pineal, as the final common pathway of the circadian system, to light delivered directly to the pineal via surgical implantation of LEDs. Direct photic stimulation of the pineal altered the course of experimental PD while anatomical controls receiving stimulation of the frontal cortex exhibited a negative impact on the course of recovery of these animals. These effects were closely linked to the phase of the light/dark cycle. The present results suggest that while pineal photoreceptors are regarded as vestigial, functional photo-reactivity of the pineal remains. It is inferred that melanocytes are the active cells responsible for the observed effect since they remain functionally intact in mammalian pineal even though pineal photoreceptors are functionally inert. Although the stimuli applied in the present study may be regarded as artificial this study demonstrates that brain parenchyma remains differentially reactive to direct light exposure and presents a novel mechanism in circadian structures that needs to be explored.

Emerging preclinical interest concerning the role of circadian function in Parkinson's disease

The importance of circadian function in the aetiology, progression and treatment of Parkinson's disease is a topic of increasing interest to the scientific and clinical community. While clinical studies on this theme are relatively new and limited in number there are many preclinical studies which explore possible circadian involvement in Parkinson's disease and speculate as to the mechanism by which clinical benefit can be derived by manipulating the circadian system. The present review explores the sequelae of circadian related studies from a historical perspective and reveals mechanisms that may be involved in the aetiology and progression of the disease. A systematic review of these studies also sets the stage for understanding the basic neuroscientific approaches which have been applied and provides new direction from which circadian function can be explored.

The applicability of bright light therapy in adults with moderate, severe or profound intellectual disabilities: a brief report

BACKGROUND

Bright light therapy (BLT) is effective in the treatment of depression in the general population. It may be a good treatment option for adults with intellectual disabilities (ID) too. However, its applicability and effectiveness are not studied in groups of adults with ID, yet. Our aim was to study the applicability of BLT in adults with ID.

METHODS

Bright light therapy was offered for 2 weeks, using a 10 000 lux light box, to 14 adults with moderate, severe or profound ID. Applicability of BLT and change in depressive symptoms were studied with questionnaires.

RESULTS

Bright light therapy was successfully applied for ≥10 days in 10 participants. It was also applicable in participants with rather severe challenging behaviour. Before BLT, nine participants scored above the cut-off score of the ADAMS' depressive mood subscale. After BLT, six of them scored below cut-off.

CONCLUSIONS

Bright light therapy is applicable in adults with moderate, severe of profound ID. Its effectiveness as a treatment for depression in adults with ID should be further studied.

Seasonality of blood neopterin levels in the Old Order Amish

Seasonal changes in non-human animals and seasonal affective disorder (SAD) in humans are associated with immune activation in winter relative to summer. We intended to measure seasonal variation in neopterin, a marker of cellular immunity, and its interactions with gender and seasonality of mood. We studied 320 Amish from Lancaster, PA, USA (men = 128; 40%) with an average age [Standard deviation (SD)] of 56.7 (13.9) years. Blood neopterin level was measured with enzyme-linked immunosorbent assay (ELISA). Seasonality was measured with Seasonal Pattern Assessment Questionnaire (SPAQ). Statistical analysis included analysis of covariance (ANCOVAs) and multivariate linear regression. We also investigated interactions of seasonal differences in neopterin with gender, seasonality scores and estimation of SAD diagnosis. We found a significantly higher neopterin level in winter than in summer (p = 0.006). There were no significant gender or seasonality interactions. Our study confirmed the hypothesized higher neopterin level in winter. A cross sectional design was our major limitation. If this finding will be replicated by longitudinal studies in multiple groups, neopterin could be used to monitor immune status across seasons in demographically diverse samples, even if heterogeneous in gender distribution, and degree of seasonality of mood.

Effect of color temperature on melatonin production for illumination of working environments

We studied the influence of correlated color temperature (CCT) of 7 polychromatic white light illuminations (1600 K-14,000 K, 200 lx) in two experiments. Visual performance was tested in 17 students (8 men) during daytime. Visual acuity, contrast sensitivity and sleepiness did not vary with illuminations but polychromatic white light of <2000 K impaired color discrimination. Melatonin synthesis was tested with weekly intervals in 8 trials from 10pm to 2am (7 polychromatic illuminations and a dim light reference (<0.1 lx)) in 16 students (9 men, semi-recumbent position). Melatonin suppression was almost negligible for CCT <2000 K but increased with increasing CCT.

CONCLUSIONS

CCTs <2000 K are not suitable for work places. Polychromatic white light with higher CCTs and significant melatonin suppression is expected to shift the circadian rhythm and to accelerate the adaptation to night work. This effect should be enhanced with elevation of luminance.

A New Perspective for Parkinson's Disease: Circadian Rhythm

Circadian rhythm is manifested by the behavioral and physiological changes from day to night, which is controlled by the pacemaker and its regulator. The former is located at the suprachiasmatic nuclei (SCN) in the anterior hypothalamus, while the latter is composed of clock genes present in all tissues. Circadian desynchronization influences normal patterns of day-night rhythms such as sleep and alertness cycles, rest and activity cycles. Parkinson's disease (PD) exhibits diurnal fluctuations. Circadian dysfunction has been observed in PD patients and animal models, which may result in negative consequences to the homeostasis and even exacerbate the disease progression. Therefore, circadian therapies, including light stimulation, physical activity, dietary and social schedules, may be helpful for PD patients. However, the cellular and molecular mechanisms that underlie the circadian dysfunction in PD remain elusive. Further research on circadian patterns is needed. This article summarizes the existing research on the circadian rhythms in PD, focusing on the clinical symptom variations, molecular changes, as well as the available treatment options.

Treatment of depression with low-strength transcranial pulsed electromagnetic fields: A mechanistic point of view

BACKGROUND

Mood disorders constitute a high burden for both patients and society. Notwithstanding the large arsenal of available treatment options, a considerable group of patients does not remit on current antidepressant treatment. There is an urgent need to develop alternative treatment strategies. Recently, low-strength transcranial pulsed electromagnetic field (tPEMF) stimulation has been purported as a promising strategy for such treatment-resistant depression (TRD). The mode of action of this new technique is however largely unknown.

METHODS

We searched PubMed for literature reports on the effects of tPEMF and for information regarding its working mechanism and biological substrate.

RESULTS

Most studies more or less connect with the major hypotheses of depression and concern the effects of tPEMF on brain metabolism, neuronal connectivity, brain plasticity, and the immune system. Relatively few studies paid attention to the possible chronobiologic effects of electromagnetic fields.

LIMITATIONS

We reviewed the literature of a new and still developing field. Some of the reports involved translational studies, which inevitably limits the reach of the conclusions.

CONCLUSION

Weak magnetic fields influence divergent neurobiological processes. The antidepressant effect of tPEMF may be specifically attributable to its effects on local brain activity and connectivity.

Antidepressant chronotherapeutics in a group of drug free outpatients

The combination of Total Sleep Deprivation (TSD) and Light Therapy (LT) has been shown to prevent the early relapses characterizing response to TSD. Despite their proved efficacy, TSD and LT are still far from being considered standard therapy in the inpatient units and no study has assessed their efficacy and feasibility in outpatient settings. We studied 27 drug-free out-patients affected by Major Depression, divided in 7 groups according to the date of the wake night. Patients were administered one night of TSD and received LT during consecutive mornings following a predictive algorithm based on Morningness-Eveningness Questionnaire scores. Severity of depression was rated on Back Depression Inventory Scale (BDI) at baseline, one week and three months after the end of treatment. BDI scores significantly decreased during treatment with no difference between the seven consecutively treated groups of patients. Significant differences in BDI scores were confirmed between the baseline and both one week and three months after the end of treatment. TSD and LT caused a significant amelioration of depressive symptoms in an outpatient setting. Similar effects were observed in seven independent groups, suggesting that there is repeatability in findings. Chronotherapeutics confirmed their efficacy in the treatment of depression.

Light therapy in the treatment of patients with bipolar depression: A meta-analytic study

Light therapy (LT) has been widely used in the treatment of seasonal affective disorder. Recently some evidence indicated that LT may play a role in bipolar depression, either as monotherapy or in combination with total sleep deprivation (TSD). However, the studies examining the treatment effect of LT in bipolar depression resulted in inconsistent findings. To clarify the role of LT in the disorder, we conducted a meta-analysis to compare the efficacy of LT in the treatment of bipolar depression. The results of individual studies were synthesized by a random effects model. Nine studies including 489 patients with bipolar depression were included in this current meta-analysis. We found that disease severity was significantly decreased after LT, in both with and without TSD, and with concomitant medication (p<0.001). Augmentation treatment with LT significantly decreased disease severity compared to treatment without LT (p=0.024). Our results highlight the significant efficacy of LT, either as monotherapy or in combination with TSD, in the treatment of bipolar depression. However, the detailed mechanism of LT still remains elusive. Further well-designed controlled trials are required to investigate the optimal intensity and frequency of LT in the treatment of bipolar depression.

Pilot trial of light therapy for depression in hospitalized patients with cystic fibrosis

BACKGROUND

Depression is common in cystic fibrosis (CF) and linked with worse outcomes during hospitalization. Bright-light therapy during hospitalizations augments antidepressant regimens and reduces length of stay (LOS) in depressed non-CF patients, but has not been examined in CF METHODS: Thirty subjects used a light box emitting 10,000lx for 30min each day for 7 straight days following hospital admission for pulmonary exacerbation. Depressive symptom severity (QIDS-C) and quality of life factors (CFQ-R) were recorded pre/post light therapy.

RESULTS

Eighty percent of subjects had at least mild depressive symptoms upon admission. Hospitalized CF patients had a significantly lower mean LOS of 11.0±3.6 days compared to a historical cohort from the year prior (13.3±4.4 days, p value=0.038). There was a significant decrease in depressive symptoms for all subjects receiving light therapy (p value<0.0001). There was no relation between depressive symptoms and lung function or vitamin D. Six out of twelve quality of life indicators improved with light therapy including the domains of vitality, emotion, and health perceptions. There were no adverse events reported.

LIMITATIONS

As a pilot study, the design was limited by a lack of a control group and possible confounding effects of hospitalization treatment on systemic symptoms.

CONCLUSIONS

Light therapy was well tolerated by hospitalized CF patients and resulted in improved depressive symptoms and quality of life. Light therapy was associated with a reduced length of stay. Large, randomized trials of light therapy may be indicated for hospitalized CF patients.

Chronobiological Therapy for Mood Disorders

Chronobiological therapies for mood disorders include manipulations of the sleep-wake cycle such as sleep deprivation and sleep phase advance and the controlled exposure to light and darkness. Their antidepressant efficacy can overcome drug resistance and targets the core depressive symptoms including suicide, thus making them treatment options to be tried either alone or as adjunctive treatments combined with common psychopharmacological interventions. The specific pattern of mood change observed with chronobiological therapies is characterized by rapid and sustained effects, when used among themselves or combined with drugs. Effects sizes are the same reported for the most effective psychiatric treatments, but side effects are usually marginal or absent. New treatment protocols are developed to adapt them in different clinical settings. This review deals with the general principles of clinical chronobiology and the latest findings in this rapidly developing field.

Bright white light therapy in depression: A critical review of the evidence

BACKGROUND

Light therapy is an accepted treatment option, at least for seasonal affective disorder (SAD). Our aim was to critically evaluate treatment effects of bright white light (BWL) on the depressive symptoms in both SAD and non-seasonal depression.

METHODS

The systematic review was performed according to the PRISMA guidelines. PubMed, Embase, and PsycINFO were searched (December 1974 through June 2014) for randomized controlled trials published in peer-reviewed journals. Study quality was assessed with a checklist developed by the Swedish Council on Technology Assessment in Health Care. Only studies with high or medium quality were used in the meta-analyses.

RESULTS

Eight studies of SAD and two studies of non-seasonal depression met inclusion and quality criteria. Effects on SAD were estimated in two meta-analyses. In the first, week by week, BWL reached statistical significance only at two and three weeks of treatment (Standardized Mean Difference, SMD: -0.50 (-CI 0.94, -0.05); -0.31 (-0.59, -0.03) respectively). The second meta-analysis, of endpoint data only, showed a SMD of -0.54 (CI: -0.95, -0.13), which indicates an advantage for BWL. No meta-analysis was performed for non-seasonal depression due to heterogeneity between studies.

LIMITATIONS

This analysis is restricted to short-term effects of BWL measured as mean changes in scores derived from SIGH-SAD, SIGH-SAD self-report, or HDRS rating scales.

CONCLUSIONS

Most studies of BWL have considerable methodological problems, and the results of published meta-analyses are highly dependent on the study selection. Even though quality criteria are introduced in the selection procedures of studies, when the results are carefully scrutinized, the evidence is not unequivocal.

Chronobiology of bipolar disorder: therapeutic implication

Multiple lines of evidence suggest that psychopathological symptoms of bipolar disorder arise in part from a malfunction of the circadian system, linking the disease with an abnormal internal timing. Alterations in circadian rhythms and sleep are core elements in the disorders, characterizing both mania and depression and having recently been shown during euthymia. Several human genetic studies have implicated specific genes that make up the genesis of circadian rhythms in the manifestation of mood disorders with polymorphisms in molecular clock genes not only showing an association with the disorder but having also been linked to its phenotypic particularities. Many medications used to treat the disorder, such as antidepressant and mood stabilizers, affect the circadian clock. Finally, circadian rhythms and sleep researches have been the starting point of the developing of chronobiological therapies. These interventions are safe, rapid and effective and they should be considered first-line strategies for bipolar depression.

The psychiatry of light

Bright light therapy and the broader realm of chronotherapy remain underappreciated and underutilized, despite their empirical support. Efficacy extends beyond seasonal affective disorder and includes nonseasonal depression and sleep disorders, with emerging evidence for a role in treating attention-deficit/hyperactivity disorder, delirium, and dementia. A practical overview is offered, including key aspects of underlying biology, indications for treatment, parameters of treatment, adverse effects, and transformation of our relationship to light and darkness in contemporary life.

Lighting the darkness of addiction: can phototherapy enhance contingency-management-based treatment of substance-related and addictive disorders?

Maladaptive patterns of substance use are serious social problems. Both pharmacological and nonpharmacological treatments are available, but nondrug options may be preferable because they avoid the expense and adverse side effects of psychotropic medication. Contingency management (CM) and nondrug social and recreational activities (NDSRAs) are based on operant conditioning principles and seek to decrease substance use by means of nondrug rewards. However, their efficacy may be hindered where brain reward circuitry is dysfunctional. Research shows that substance abuse biases neural reward systems in favor of drug-induced highs, while disrupting circadian-based rhythms. Circadian systems also have been found to influence human reward pathways. Possibly, a bidirectional relationship exists between circadian disturbance and substance abuse effects. If so, repair of abnormal circadian rhythms might help normalize reward response in substance abusers, with positive effects on CM or NDSRA treatment outcomes. Phototherapy has been effective in repairing circadian rhythms in persons with seasonal affective disorder and other chronobiological conditions. This article proposes that it similarly may repair circadian response in substance abusers, thereby normalizing brain reward systems. By doing so, it would enhance the efficacy of CM and NDSRA therapies and may also help prevent relapse. Given its low cost and ease of administration, phototherapy seems a promising avenue to pursue.