Bright Light Therapy to Treat Depression in Individuals with Mild/Moderate or Severe Dementia

Photobiomodulation therapy mitigates depressive-like behaviors by remodeling synaptic links and mitochondrial function

Depression, a multifactorial mental disorder, characterized by cognitive slowing, anxiety, and impaired cognitive function, imposes a significant burden on public health. Photobiomodulation (PBM), involving exposure to sunlight or artificial light at a specific intensity and wavelength for a determined duration, influences brain activity, functional connectivity, and plasticity. It is recognized for its therapeutic efficacy in treating depression, yet its molecular and cellular underpinnings remain obscure. Here, we investigated the impact of PBM with 468 nm light on depression-like behavior and neuronal damage in the chronic unpredictable mild stress (CUMS) murine model, a commonly employed animal model for studying depression. Our results demonstrate that PBM treatment ameliorated behavioral deficits, inhibited neuroinflammation and apoptosis, and notably rejuvenates the hippocampal synaptic function in depressed mice, which may be mainly attributed to the up-regulation of brain-derived neurotrophic factor signaling pathways. In addition, in vitro experiments with a corticosterone-induced hippocampal neuron injury model demonstrate reduced oxidative stress and improved mitochondrial function, further validating the therapeutic potential of PBM. In summary, these findings suggest PBM as a promising, non-invasive treatment for depression, offering insights into its biological mechanisms and potential for clinical application.

The Effects of Light Therapy on Sleep, Depression, Neuropsychiatric Behaviors, and Cognition Among People Living With Dementia: A Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

Alterations in the suprachiasmatic nucleus due to underlying pathologies disrupt the circadian rhythms in people living with dementia (PLWD). Circadian rhythms significantly impact sleep, emotional, and cognitive functions, with its synchronization depending on light exposure. We performed a meta-analysis to evaluate the effects of light therapy on sleep, depression, neuropsychiatric behaviors, and cognition among PLWD.

METHODS

A systematic search was conducted in Cochrane, ClinicalTrials.gov, Embase, EBSCOhost, Ovid-MEDLINE, PubMed, Scopus, Web of Science, and CINAHL databases. The pooled effect size was calculated using the Hedges' g with random-effects model adopted in comprehensive meta-analysis software. The Cochrane risk of bias (RoB 2.0) tool evaluated the quality of studies, while Cochrane's Q and I² tests assessed heterogeneity.

RESULTS

A total of 24 studies with 1,074 participants were included. Light therapy demonstrated small-to-medium effects on improving sleep parameters: total sleep time (Hedges' g = 0.19), wake after sleep onset (Hedges' g = 0.24), sleep efficiency (Hedges' g = 0.31), sleep latency (Hedges' g = 0.35), circadian rhythm (acrophase: Hedges' g = 0.36; amplitude: Hedges' g = 0.43), number of night awakenings (Hedges' g = 0.37), sleep disturbance (Hedges'g = 0.45), and sleep quality (Hedges' g = 0.60). Light therapy showed small-to-medium effect on reducing depression (Hedges' g = -0.46) with medium-to-large effect on cyclical function (Hedges' g = -0.68) and mood-related signs and symptoms (Hedges' g = -0.84) subscales. Light therapy also demonstrated small effect on reducing neuropsychiatric behaviors (Hedges' g = -0.34) with medium-to-large effect on agitation (Hedges' g = -0.65), affective symptom (Hedges' g = -0.70), psychosis (Hedges' g = -0.72), and melancholic behavior (Hedges' g = -0.91) subscales. Additionally, light therapy also improved cognition (Hedges' g = 0.39).

CONCLUSION

Light therapy could be used as a supportive therapy to improve sleep, depression, cognition, and neuropsychiatric behaviors among PLWD.

The Effects of Light Therapy on Sleep, Agitation and Depression in People With Dementia: A Systematic Review and Meta-analysis of Randomized Controlled Trials

OBJECTIVE

To evaluate the effects of light therapy on the alleviation of sleep disturbances, agitation and depression in people with dementia.

METHODS

A search was performed in PubMed, Medline, SCOPUS, Web of Science, EMBASE, CINAHL, Cochrane Library, for studies published between 2000 and 2021.

RESULTS

A total of 4315 articles were screened. Sixteen articles were eligible for this review and 11 randomized controlled studies were included in the meta-analysis. Light therapy had a significant effect on reducing the number of awakenings in sleep (n = 4; 95% CI = -.56, -.05; I2 = 0%; SMD = -.31) but was not significant in reducing the wake after sleep onset (n = 3; 95% CI = -.14, .59; I2 = 0%; SMD = .23), agitation (n = 4; 95% CI = -1.02, .45; I2 = 87%; SMD = -.28) and depression (n = 6; 95% CI = -.80, .40, I2 = 85%; SMD = -.20).

CONCLUSION

Light therapy appeared to be more effective in terms of alleviating sleep disturbances, rather than reducing agitation and depression, but its long-term effects remain unclear.

Development of a Home-Based Stress Management Toolkit for Dementia Caring Dyads: Protocol for a Pilot Intervention Development and Feasibility Study

BACKGROUND

People living with dementia (PLWD) and their care partners (dementia caring dyads) are at a heightened risk of experiencing stress-related symptoms and conditions. Yet, many dyadic stress management interventions have had limited uptake by health care systems and in the community. An intervention that combines simple, safe, easy-to-use, nonpharmacologic tools (eg, animatronic social pets, weighted blankets and garments, aromatherapy and bright light therapy devices, acupressure, and massage tools) that can be used in the home may be a promising approach to promote stress management among dementia caring dyads.

OBJECTIVE

The proposed study aims to develop and user test a dyadic toolkit intervention composed of simple, tangible stress management tools for community-dwelling PLWD and their care partners. This study will also explore the feasibility of collecting several stress-related outcome measures to inform measurement selection for future studies.

METHODS

A human-centered design (HCD) approach will be used to increase the likelihood of developing an intervention that will be translatable to real-world settings. This study consists of 2 phases. The first phase will address the discover, define, and design stages of HCD using qualitative focus groups with dementia caring dyads (N=12-16 dyads). Dyadic focus groups (3-4 groups anticipated) will be convened to understand participants' stress experiences and to co-design a stress management toolkit prototype. Rapid qualitative analysis will be used to analyze focus group data. In phase 2, the toolkit prototype will be user tested for 2 weeks in a new sample to address the validation step of HCD. A within-subjects (n=10 dyads), pre-post design will be used with measures of usability (frequency of toolkit use), feasibility (enrollment and withdrawal rates, adverse events/injuries), and acceptability (satisfaction, benefit) collected via questionnaires (at the end of weeks 1 and 2 of user testing) and focus groups (n=3-4 dyads/group at the end of week 2). The feasibility of collecting participant-reported, stress-related outcomes (neuropsychiatric symptoms of dementia, caregiver stress, dyadic relationship strain) and salivary cortisol as a physiologic measure of stress will be assessed at baseline and after user testing.

RESULTS

This study will yield a working prototype of a stress management toolkit for dementia caring dyads, as well as preliminary data to support the feasibility and acceptability of the intervention. User testing will elucidate areas to refine the prototype and provide data to inform preliminary testing of the intervention. As of September 2022, this study has received institutional ethics board approval with phase 1 recruitment anticipated to begin January 2023.

CONCLUSIONS

Few interventions have focused on combining simple, safe, low burden tools to promote stress management among community-dwelling dementia caring dyads. By involving families and exploring feasibility and acceptability at the onset of development, this intervention will have greater potential to be implemented and sustained in the future.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05465551; https://clinicaltrials.gov/ct2/show/NCT05465551.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/43098.

When Lights Can Breathe: Investigating the Influences of Breathing Lights on Users' Emotion

Light can significantly influence users' physiological and behavioural performance. However, how light breathing influences users' mood regulation remains unknown. To fill this gap, this study conducted a 2-by-2 experiment (N = 20) with light breathing as the between-subject factor and light condition as the within-subject factor. Both physiological indicators and subjective indicators are measured to reflect mood regulation. The data were analysed using a generalised linear mixed model. The results showed that breathing lights are effective in regulating users' moods. More specifically, breathing lights help users lower their electrodermal values and heart rates. Users did not report any significant difference in terms of subjective measures, which suggest that the influence of a breathing light happens unconsciously. Furthermore, this effect is significant for both cold and warm colour temperatures. Designers and engineers can use the research findings to manage user emotion when necessary.

The efficacy of complementary and traditional practice on psychiatric patients with depression symptoms: A meta- analysis study

PURPOSE

This study examined the effect sizes of the complementary and traditional practices on the depressive symptom levels in psychiatric patients DESIGN AND METHODS: The "Health Evidence™ Quality Assessment Tool" and "Comprehensive Meta-Analysis 3" program was used.

FINDINGS

A total of 81 studies with 5934 patients were included. The effect size of the complementary and traditional methods applied to psychiatric patient on depressive symptoms was calculated as d = 0.718 (p = 0.000). According to Cohen, studies have moderate effect size.

PRACTICE IMPLICATIONS

Complementary and traditional practices were found to be significant and effective on depressive symptoms in psychiatric patients.

Ambient bright lighting in the morning improves sleep disturbances of older adults with dementia

BACKGROUND

Ambient light therapies are potentially effective in improving sleep disturbances and circadian rhythms. This study created a new lighting intervention model for elderly patients with dementia. It is hypothesized that exposure to bright ambient light in the morning is more effective than general lighting in improving sleep disturbances and circadian rhythms.

METHODS

A single-blind longitudinal-group experimental design was employed. The dementia participants came from the community and nursing homes. Those in the experimental group were exposed to ambient light at 2500 lux, and those in the comparison group were exposed to 114-307 lux. The corresponding sleep disturbances and circadian rhythms were determined using an accelerometer (XA-5). A longitudinal experimental design was adopted to observe the time to an effective response.

RESULTS

The covariates of benzodiazepine use and total activity during the day were analyzed using generalized estimating equations. The experimental group showed significant sleep efficiency improvement, with mean increases of 41.9% (P < 0.001) and 31.7% (P = 0.002), sleep time increases of 141 min (P = 0.001) and 135 min (P = 0.008), awakening time decreases of 116 min (P = 0.001) and 108 min (P = 0.002), and sleep onset advancements of 60-84 min/sleep offset delays of 57-79 min upon the fifth and ninth week, respectively. A 4-week bright ambient light intervention was the most effective.

CONCLUSIONS

This study found that bright ambient light in the morning is beneficial for improving sleep disturbances and was driven by stabilizing circadian rhythms.

Bright Light Therapy in Older Adults with Moderate to Very Severe Dementia: Immediate Effects on Behavior, Mood, and Physiological Parameters

Bright light therapy (BLT) has demonstrated positive short- and long-term effects in people with cognitive impairment or dementia; however, the immediate impact of BLT sessions has been scarcely investigated. In this study, we aimed to explore the immediate effects of BLT on behavior, mood, and physiological parameters (oxygen saturation/heart rate) in a sample of institutionalized older adults with moderate to very severe dementia, with a median age of 85.0 (interquartile range, IQR, 82.0–90.0), being higher in men (87.0 years, IQR 80.0–94.0) than in women (84.5 years, IQR 82.0–89.5). The BLT protocol consisted of 30-min morning sessions of 10,000 lux, Monday through Friday, for 4 weeks. The physiological parameters were recorded immediately before and after each session by pulse oximetry. Mood and behavior were assessed before, after, and during the sessions using the Interact scale. Post-session Interact scores showed a significant decrease in the items Tearful/sad and Talked spontaneously, and a significant increase in the items Enjoying self, active or alert, and Relaxed, content or sleeping appropriately. Interact scores during the sessions reflected a significant decrease in the speech-related items. Both physiological parameters changed positively from before to after sessions. Our results suggest that BLT provides immediate positive effects on mood, stimulation level, and physiological parameters, as well as a trend toward decreased speech. More robust research is needed to further explore the immediate impact of BLT. This study is registered with Clinicaltrials.gov (NCT04949984).

The effects of bright light treatment on affective symptoms in people with dementia: a 24-week cluster randomized controlled trial

BACKGROUND

The majority of people with dementia have behavioral and psychological symptoms of dementia (BPSD), including depression, anxiety and agitation. These may be elicited or aggravated by disrupted circadian rhythms. Bright light treatment (BLT) is a promising non-pharmacological approach to the management of BPSD, but previous research has yielded mixed results.

METHODS

Eight nursing home dementia units (1 unit = 1 cluster) with 78 patients were invited to participate in a cluster randomized controlled trial from September 2017 to April 2018 investigating the effects of BLT on sleep and circadian rhythms (primary outcome) and BPSD (secondary outcome). Ceiling mounted LED-panels were installed in the intervention group (four units), providing light at 1000 lx and 6000 K (vertically at 1.2 m) between 10 a.m. and 3 p.m., with lower values in the mornings and evenings. Standard indoor light was used in the control group (four units). BPSD were assessed with The Cornell Scale for Depression in Dementia (CSDD) and the Neuropsychiatric Inventory Nursing Home Version (NPI-NH). Data collection took place at baseline and after 8, 16 and 24 weeks. Multilevel regression models with and without false discovery rate correction were used for the analysis, with baseline values and dementia stage entered as covariates.

RESULTS

Sixty-nine patients were included in the study at baseline. Compared to the control group, the intervention group had a larger reduction on the composite scores of both the CSDD (95% CI = - 6.0 - - 0.3) and the NPI-NH (95% CI = - 2.2 - - 0.1), as well as on the NPI-NH Affect sub-syndrome, and the CSDD Mood related signs sub-scale at follow-up after 16 weeks. With FDR correction, the group difference was significant on the CSDD Mood related signs sub-scale (95% CI = - 2.7 - - 0.8) and the NPI-NH Affect sub-syndrome (95% CI = - 1.6 - - 0.2). No differences were found between conditions at weeks 8 or 24.

CONCLUSION

Compared to the control condition, affective symptoms were reduced after 16 weeks in the group receiving BLT, suggesting BLT may be beneficial for nursing home patients with dementia.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03357328 . Retrospectively registered on November 29, 2017.

Sensory Stimulation for Nursing-Home Residents: Systematic Review and Meta-Analysis of Its Effects on Sleep Quality and Rest-Activity Rhythm in Dementia

INTRODUCTION

Disrupted sleep-wake cycles might be associated with an exacerbation of behavioural disturbances and accelerate disease progression in dementia. The effect of sensory stimulation for improving sleep quality is unclear.

METHODS

A systematic literature search was performed and all studies examining the effects of a sensory stimulation intervention (i.e. bright light, massage, acupuncture, animal-assisted interventions) on rest-activity rhythm (RAR) and/or nocturnal restlessness in nursing-home residents with dementia were included.

RESULTS

Sensory stimulation was shown to improve nocturnal behavioural restlessness as well as sleep duration and continuation, but the effect on the number of awakenings, RAR, and daytime sleep was negligible. Notable was the high heterogeneity between studies regarding treatments and patients' characteristics and sleep parameters.

CONCLUSION

Sleep quality and nocturnal restlessness in nursing-home residents with dementia may benefit from sensory stimulation. An environment with sensory stimulation may prevent or improve sleep disturbances in nursing homes, and thereby contribute to a better quality of life for their patients.

Dementia Enlightened?! A Systematic Literature Review of the Influence of Indoor Environmental Light on the Health of Older Persons with Dementia in Long-Term Care Facilities

Light therapy for older persons with dementia is often administered with light boxes, even though indoor ambient light may more comfortably support the diverse lighting needs of this population. Our objective is to investigate the influence of indoor daylight and lighting on the health of older adults with dementia living in long-term care facilities. A systematic literature search was performed within PubMed, CINAHL, PsycINFO, Web of Science and Scopus databases. The included articles (n=37) were published from 1991 to 2020. These articles researched the influence of existing and changed indoor light conditions on health and resulted in seven categories of health outcomes. Although no conclusive evidence was found to support the ability of indoor light to decrease challenging behaviors or improve circadian rhythms, findings of two studies indicate that exposure to (very) cool light of moderate intensity diminished agitation. Promising effects of indoor light were to reduce depressive symptoms and facilitate spatial orientation. Furthermore, there were indications that indoor light improved one’s quality of life. Despite interventions with dynamic lighting having yielded little evidence of its efficacy, its potential has been insufficiently researched among this study population. This review provides a clear and comprehensive description of the impact of diverse indoor light conditions on the health of older adults with dementia living in long-term care facilities. Variation was seen in terms of research methods, (the description of) light conditions, and participants’ characteristics (types and severity of dementia), thus confounding the reliability of the findings. The authors recommend further research to corroborate the beneficial effects of indoor light on depression and to clarify its role in supporting everyday activities of this population. An implication for practice in long-term care facilities is raising the awareness of the increased lighting needs of aged residents.

The therapeutic effects and safety of bright light therapy combined with escitalopram oxalate on insomnia in patients with poststroke depression

INTRODUCTION

Bright light therapy (BLT) is known to treat depression and sleep disorders in clinical practice, but its efficacy on poststroke depression (PSD) has not been studied.

OBJECTIVE

To investigate the therapeutic effects and safety of BLT combined with escitalopram oxalate (ESC) on insomnia in patients with PSD.

METHODS

Ischemic stroke patients with depressive symptoms and a score of ≥8 on the Hamilton Depression Scale (HAMD-17) while meeting DSM-IV criteria were diagnosed as having PSD. A total of 112 PSD patients with symptoms of insomnia were randomly assigned to polytherapy (BLT plus ESC) and monotherapy (ESC only) groups. Each regimen continued for 6 weeks. The primary outcomes were a change in scores on the Pittsburgh Sleep Quality Index (PSQI) and a remission rate (PSQI ≤7 at the endpoint). The secondary outcomes included changes in the HAMD-17 and Barthel Index (BI) scores. Adverse effects were assessed by the Adverse Events Scale.

RESULTS

The endpoint assessment included 106 patients (monotherapy, 54; polytherapy, 52). The mean changes in the PSQI scores for the monotherapy and polytherapy groups were 4.85 (1.47) and 5.87 (1.72) (P = 0.001), respectively. Compared to monotherapy, polytherapy improved PSQI remission rate (71.4% vs 50.0%; χ2 = 5.390; P = 0.020), and HAMD-17 score (6.70 [2.12] vs 4.75 [1.98]; P < 0.001). Both treatments improved BI score, with no statistical difference, and were well tolerated, with few significant differences in treatment-associated adverse events.

CONCLUSION

BLT combined with ESC is effective and well tolerated for the treatment of PSD-associated insomnia.

Fiat Lux: The Light Became Therapy. An Overview on the Bright Light Therapy in Alzheimer's Disease Sleep Disorders

BACKGROUND

A system of photosensitive retinal ganglion cells provides 'non-visual' information on the circadian sequences of light to the suprachiasmatic nucleus (SCN), which, as the 'master clock', synchronizes the chronobiological mechanisms of all the biological clocks. Damage to SCN structure alters circadian behavioral and hormonal rhythms and interferes with a regular sleep-wake pattern. Several studies have shown that, in aging and in Alzheimer's disease (AD), circadian rhythms change their synchronization with the environment and behavior loses sync with light.

OBJECTIVE

The current overview aims to examine research studies showing the effect of bright light therapy (BLT) on sleep disorders and sleep-wake patterns in AD.

METHODS

A literature search was conducted, taking into consideration the relevant studies over the last 20 years. Fifteen studies have been thorough: seven followed an environmental-architectural approach and eight followed a treatment devices approach.

RESULTS

Studies agree in considering BLT as a promising non-pharmacological intervention to compensate for circadian rhythm alterations and they support the need for standardized protocols that allow a comparison between multicenter studies.

CONCLUSION

Interestingly, in an attempt to contain the spread of the COVID-19 pandemic, health authorities have forced the population to stay home. Therefore, AD people are not currently able to enjoy exposure to sunlight. It is predictable that they may experience an exacerbation of circadian disturbances and that the BLT can be an effective response to prevent such exacerbation.

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.

Light interventions and sleep, circadian, behavioral, and psychological disturbances in dementia: A systematic review of methods and outcomes

Dementia is a devastating disease with a global impact, and there is an urgent need for effective interventions to alleviate the accompanying disturbances in behavior, mood, sleep, and circadian rhythms. Bright light treatment (BLT) is a promising non-pharmacological intervention; however, studies have yielded conflicting results. This systematic review provides a comprehensive overview of the effect of BLT in dementia, with a specific focus on how study characteristics might have affected the available results. The included studies were small and comprised time-limited interventions and follow-ups. Light values, adherence to treatment, and time of year were not consistently reported. Varying designs, methods, and population characteristics such as age, gender, dementia diagnosis, circadian phase, and baseline symptoms may have moderated the outcomes and affected review results. The use of crossover designs and too high illumination as placebo lights might have nullified positive effects of BLT. Because some studies had negative outcomes after ambient BLT with high amounts of short wavelengths, more modest light levels should be further investigated. Employing rigorous designs and detailed reporting of intervention characteristics, i.e., the illumination, correlated color temperature, timing, and duration of light utilized, are of utmost importance to establish the optimal treatment approach in this population. Systematic review registration number: PROSPERO CRD42017051004.

Resetting the Aging Clock: Implications for Managing Age-Related Diseases

Worldwide, individuals are living longer due to medical and scientific advances, increased availability of medical care and changes in public health policies. Consequently, increasing attention has been focused on managing chronic conditions and age-related diseases to ensure healthy aging. The endogenous circadian system regulates molecular, physiological and behavioral rhythms orchestrating functional coordination and processes across tissues and organs. Circadian disruption or desynchronization of circadian oscillators increases disease risk and appears to accelerate aging. Reciprocally, aging weakens circadian function aggravating age-related diseases and pathologies. In this review, we summarize the molecular composition and structural organization of the circadian system in mammals and humans, and evaluate the technological and societal factors contributing to the increasing incidence of circadian disorders. Furthermore, we discuss the adverse effects of circadian dysfunction on aging and longevity and the bidirectional interactions through which aging affects circadian function using examples from mammalian research models and humans. Additionally, we review promising methods for managing healthy aging through behavioral and pharmacological reinforcement of the circadian system. Understanding age-related changes in the circadian clock and minimizing circadian dysfunction may be crucial components to promote healthy aging.

What is the evidence for the activities of Namaste Care? A rapid assessment review

Objectives

To assess the quality of research evidence for the different activity components for the psycho-social Namaste Care intervention for care home residents with advanced dementia.

Design

Namaste Care is a multi-component intervention delivered on a daily basis to people living with advanced dementia or people at end of life with dementia. A significant part of its operationalisation within care homes is the delivery of a number of activities delivered by trained in-house Namaste Care workers to a group of residents with similar high dependency needs. The Namaste Care workers focus on touch, music, nature, sensory experience, aromas and interactions with objects delivered in a way to enhance feelings of enjoyment and wellbeing. This review evaluated the evidence for using these activities with people living with advanced dementia. A systematic search of peer-reviewed research articles was conducted between November 2016 and September 2018 using search terms of activities used in Namaste Care. The quality of each accepted article was rated using the Rapid Evidence Assessment scale.

Results

The initial literature search returned 1341 results: 127 articles including 42 reviews were included. The majority of activity interventions yielded between 10 and 20 peer-reviewed papers. The use of smells and aromas, interacting with animals and dolls, the use of various forms of music (e.g. background music, singing, personalised music), nature, lighting, various forms of touch/massage and sensory interventions (including Snoezelen) all appear to have proven efficacy with people living with advanced dementia.

Conclusions

There is generally a limited number of research papers and reviews in this area, but overall there is a good evidence base for including these activities within Namaste Care for people living with advanced dementia.

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.