Background

Depression is a common mental disorder. The World Health Organization1 has indicated that depression is among the 10 leading causes of disability-adjusted life years (DALYs) lost globally and regionally. In the year 2030, depression is projected to reach the third place in the ranking of DALY calculated for all ages.1

Depression is characterized by low energy, sadness, loss of interest or pleasure, feelings of guilt or low self-worth, disturbed sleep or appetite and poor concentration.1 It is also associated with increased risk of morbidity, increased risk of suicide, decreased physical, cognitive and social functioning, and greater self-neglect, all of which are in turn associated with increased mortality.2,3 Studies have found that approximately 4.6-12.5% of people suffer from a current major depressive disorder.4-6 Moreover, the prevalence of depression is 10-25% in older adults in community settings7,8 and up to 48-50% in nursing homes and medical settings.9,10 Depression is the most prevalent mood disorder, and it becomes a chronic or recurrent problem for many older adults.11

Many older adults experience symptoms that do not meet the criteria for major depressive disorder but are thought to significantly affect their lives.12 Depression has a large impact in older adults, and it has consistently been found to be a significant risk factor contributing to death, particularly in those with poor physical health.13 Depressive symptoms are frequently experienced with medical illnesses and associated with higher levels of functional disability and pain in older adults.14 People with depression aged over 65 years commit suicide more than any other age group4,15 Older adults who attempt suicide are more likely to die than younger people, whereas in those who survive, the prognosis is worse in older adults.16 Despite its clinical significance, depression remains underdiagnosed and inadequately treated in older patients in the clinical settings.17-19

Depression in older adults can be treated by psychotherapy and/or antidepressants. Antidepressants are reasonably effective in older adults; however, because of the changes in the efficiency of hepatic, renal and gastrointestinal function with aging, older adults may be exposed to a higher risk of side effects at a given dose of antidepressants compared with younger patients.20 Older adults seem more susceptible to common antidepressant side effects such as sedation, anti-cholinergic effects, extrapyramidal effects and orthostatic hypertension, and these side effects can occur even at the modest plasma drug levels.21,22 Although antidepressants are the first-line treatment for moderate and severe depression, only 9% of depressed primary care patients receive adequate treatment, and only 6% reach remission.22 The National Institute for Health and Clinical Excellence23 recommends that patients with severe, treatment-resistant or recurrent depression should receive a combination of antidepressants and other non-pharmacological strategies, such as psychotherapy. In addition, sedatives and hypnotics are commonly used to manage sleep problems for older adults. However, the adverse events, such as ataxia or memory impairment, are thought to be particularly detrimental for older adults.24 In particular, sedation from these medications is concerning in older adults because of falls, which can cause fractures, other physical injury or even death.25 Tindle et al.26 reported that complementary and alternative medicine (CAM) treatments (for example, light therapy, acupuncture, yoga) are commonly used by people with depression and other psychiatric conditions. Light therapy, considered as one approach of CAM, has been increasingly applied in a variety of psychiatric conditions including circadian rhythm sleep disorders,27 seasonal affective disorder (SAD),27-29 non-SAD29,30 and dementia.31

In the early 1980s, the observation that light is able to shift the circadian phase and seasonal rhythms in animals and the concept of extending daylight during winter months to interfere with these rhythms resulted in the first trial of bright light therapy (BLT) in SAD.32 Nowadays, light therapy represents a potent, non-pharmacological treatment modality whose efficacy and tolerability have been a matter of extensive research.33-35 Labbate et al.36 noted that the side effects of light therapy are rare; however, headache, eyestrain, nausea and agitation have been reported but tend to remit spontaneously or after dose reduction.

Light therapy has become a standard treatment for SAD, as researchers have demonstrated the efficacy of BLT as a first-line treatment in SAD,37-40 and some evidence supports its use as an adjunctive treatment in mild-to-moderate non-seasonal major depressive disorder, and thus, is recommended as a second-line treatment.38 Light therapy is also suggested to have positive impact on sleep quality. Bright light therapy might be used to reduce unwanted behavioral and cognitive symptoms associated with dementia and depression in older adults41 and has also been found to have effects on decreasing depressive symptoms and improving sleep in elderly patients with non-seasonal major depressive disorder.42

Several scales were designed to measure depressive symptoms, such as Hamilton Rating Scale for Depression, Montgomery-Asberg Depression Rating Scale (MADRS), Beck Depression Inventory-II (BDI-II) or Geriatric Depression Scale (GDS). The items of each scale are symptoms associated with depression which have been tested with high internal consistency and adequate test-retest repeatability, also have good validity and reliability.43-45

A preliminary search of the JBI Database of Systematic Reviews and Implementation Reports, Cochrane library, PubMed and CINAHL has shown that there is no systematic review assessing the effectiveness of BLT on depression for older adults with non-seasonal depression. In this review, we will systematically review the literature to determine the effectiveness of BLT in older adults with non-seasonal depression and will include published studies written in English or Chinese.

Inclusion criteria

Types of participants

The current review will consider studies that include adults aged 60 years or older diagnosed with a major depression disorder or non-seasonal depression (such as GDS score [greater than over equal to]10 or Hamilton Depression Rating Scale [HDRS] [greater than over equal to]8) residing in community or long-term care facility. Studies in which participants had significant psychiatric disorders, medical comorbidities or SADs will be excluded.

Types of intervention(s)

The current review will consider studies that evaluate the effects of BLT with all types of intensity and duration. Bright light therapy delivered both individually or in a group setting will be included.

Types of comparator(s)

The intervention will be compared with standard care or use of other types of light therapy, such as dim red light, green light or different intensities of BLT. Standard care is defined as no BLT with a normal level of psychiatric routine care, which includes medication treatment, individual or group counseling.

Outcomes

The current review will consider studies that include the following outcomes measures: depressive symptoms as measured by GDS, HDRS, MADRS, BDI-II or Hospital Anxiety and Depression Scale.

Types of studies

The quantitative component of this review will consider both experimental and epidemiological study designs including randomized controlled trials, non-randomized controlled trials, quasi-experimental studies, before and after studies, prospective and retrospective cohort studies, case-control studies and analytical cross-sectional studies for inclusion.

Search strategy

The search strategy aims to find both published and unpublished studies. A three-step search strategy will be utilized in this review. An initial limited search of MEDLINE and CINAHL will be undertaken followed by an analysis of the text words contained in the title and abstract, and of the index terms used to describe the article. A second search, using all identified keywords and index terms, will then be undertaken across all included databases. Third, the reference list of all identified reports and articles will be searched for additional studies. Studies published in English or Chinese will be considered for inclusion in this review. Studies published up to 2015 will be considered for inclusion in this review.

The databases to be searched include: PubMed, CINAHL, EMBASE, PsychInfo, Cochrane Central Trials, clinical trials.gov and current controlled trials as well as Chinese publication databases. The Chinese databases will include:

* http://http://www.ceps.com.tw (Chinese Electronic Periodical Services)

* http://http://www.cetd.com.tw (Chinese Electronic Theses and Dissertations Service)

* http://http://www.ncl.edu.tw/journal/journal_docu01.htm (National Central Library)

Initial keywords to be used will be: light therapy, bright light therapy, photo therapy, depress^*, non-seasonal depression, depressive disorder, sleep problem, sleep disruption, older people, older adult, elderly patient, elders

Assessment of methodological quality

Papers selected for retrieval will be assessed by two independent reviewers for methodological validity prior to inclusion in the review using standardized critical appraisal instruments from the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI) (Appendix I). Any disagreements that arise between the reviewers will be resolved through discussion or with a third reviewer.

Data extraction

Quantitative data will be extracted from papers included in the review using the standardized data extraction tool from JBI-MAStARI (Appendix II). The data extracted will include specific details about the interventions, populations, study methods and outcomes of significance to the review question and specific objectives.

Data synthesis

Quantitative data will, where possible, be pooled in statistical meta-analysis using JBI-MAStARI. All results will be subject to double data entry. Effect sizes expressed as weighted mean differences (for continuous data) and their 95% confidence intervals will be calculated for analysis. Heterogeneity will be assessed statistically using the standard chi-square test and also explored using subgroup analyses based on the different study designs included in this review. Where statistical pooling is not possible, the findings will be presented in narrative form including tables and figures to aid in data presentation where appropriate.

Appendix I: Appraisal instruments

MAStARI appraisal instrument

Appendix II: Data extraction instruments

MAStARI data extraction instrument

References