People suffering from non-seasonal depression had been shown in some previous studies to respond to BLT, and their depressive symptoms often include sleep disturbances. These symptoms are thought to involve a major pathway of the nervous system (the retinohypothalamic tract) that relays signals from the eyes to the brain, particularly to the area (the suprachiasmatic nucleus) that manages the sleep/wake cycle . Since the retinohypothalamic tract is also thought to be implicated in SAD, this clinical study tested whether BLT (10 000 LUX, for 30 min every morning using our SADelite) could alleviate symptoms in patients with non-seasonal depression, either on its own, or in addition to antidepressant treatment. Overall, the study found that both light therapy and antidepressants were about equally effective in treating depression, but that there was no added benefit of combining the two.
Besides SAD, BLT is also an effective treatment for depressive symptoms—commonplace, in fact, among breast cancer patients. Previous studies had found similar benefits using cognitive behavioral therapy instead of SAD, so this study was designed to test whether there were any characteristics of individual patients that would make one or the other treatment more effective. Using the Hospital Anxiety and Depression Scale (HADS-D), they found that those without histories of major depression benefited more from BLT. And, so did those who had higher baseline levels of anxiety/depression on the HADS-D.
A number of previous studies had shown that cardiac patients commonly suffer from depressive symptoms, and these can lead to worse cardiovascular outcomes. And, since BLT can be an effective treatment for symptoms of depression, the researchers wanted to test whether it could be effective for these patients. Unfortunately, their pilot study could not recruit enough patients to provide conclusive evidence for BLT’s effectiveness. Primarily, they surmise, this was because patient eligibility for inclusion in the study was too restrictive. But, among those patients who were eventually enrolled, the researchers found promising adherence to treatment, all the way until follow-up.
It may seem on the surface that insomnia is better understood than SAD. But, counterintuitively, scientists actually have a better understanding of SAD’s underlying neurobiology than insomnia’s. Since sleep disturbances are a common feature of SAD, this group of researchers wanted to see if light therapy (either bright or dim) would alleviate insomnia symptoms, and potentially shed some light on its underlying neurobiology. The light therapy regimens both (bright and dim) shifted circadian rhythms as would be expected, but didn’t change participants’ sleep quality. Even if light therapy was ineffective as an insomnia treatment, participants’ circadian systems still seemed to respond to it normally. Overall, this study at least found that insomnia’s neurobiological roots differ from SAD’s.
Fascinatingly, we can begin to measure the effects of bright light therapy even in the retina. A group of retinal cells called ipRGCs (intrinsically photosensitive retinal ganglion cells) resets circadian rhythms in response to the overall illumination in our surroundings. But at what levels of ‘brightness’ (measured in units called lux) would these cells begin to respond to light? Is this different amongst SAD patients, and is it only during winter months? To answer the question, this group of researchers recorded the electrical activity from the retinas (using a technique called ERG) of SAD patients and controls in both winter and summer after they were given 1h of light therapy at different levels of brightness. They observed for the first time that SAD patients’ retinas responded differently from controls’, both in winter and in summer, even when they weren’t in a depressive episode.
SAD tends to occur during fall and winter months, during which less sunlight is available—particularly during mornings. Morning sunlight, like any other kind, is made up of different wavelengths that, when combined, look relatively white. However, while researchers knew of the group of light-sensitive cells in the retina (the IPRGCs) that regulate the body’s biological clock, they still did not know which parts of the light’s spectrum were essential in preventing SAD. So, they randomly assigned two groups of participants to receive light therapy with either blue light or red light. They found that even after just a single light-therapy session, blue light changed people’s retinal response far more than red—patients and controls alike. So, even among healthy individuals, light therapy still does the job of driving the retina’s response to early morning bright light. While they didn’t directly test for it, this could be taken as evidence that light therapy including blue wavelengths could protect against SAD.
OBJECTIVE Bright light therapy is effective and well tolerated in seasonal affective disorder and some studies reported an antidepressant effect of bright light also in non-seasonal depression. On the other hand, total sleep deprivation leads to a rapid and marked improvement of mood in 60% of depressed patients. Combinations of antidepressant medication with those somatic therapies are generally indicated. The aim of this study was to compare the efficacy of the combination of sertraline and partial sleep deprivation or light therapy with sertraline monotherapy in the treatment of major depression.
METHOD Thirty-seven patients with major depressive disorder were randomly allocated into 3 treatment groups. Thirteen were treated with sertraline and late partial sleep deprivation, 13 with sertraline and bright light therapy and 11 sertaline monotherapy as a control group. Outcome measures included daily (first 15 days) and weekly Hamilton Rating Scale for Depression and biweekly Hamilton Anxiety Rating Scale.
RESULTS Partial sleep deprivation group improved significantly and more rapidly. Accelerated treatment response was shown in sleep deprivation group that improvement was observed after the third day. Bright light and sleep deprivation combinations with sertraline were more effective than sertraline monotherapy for accompanied anxiety in depression.
CONCLUSION Late partial sleep deprivation in combination with sertraline can accelerate and increase the treatment response in non-seasonal major depressive disorder.
PURPOSE Seasonal affective disorder (SAD) is a syndrome characterized by the apparition of depressive symptoms in Autumn/Winter with remission in Spring/Summer. For most patients, light therapy is an effective treatment. The origin of the syndrome is unknown as well as the mechanism underlying the therapeutics of light, although retinal sensitivity anomalies have been reported by our group using the ERG. Our goal was to investigate for the first time the impact of seasons (autumn versus summer) and light therapy on ERG cone and rod functions in patients affected with seasonal affective disorder (SAD).
METHOD This study was composed on 22 patients with SAD symptoms and 16 normal controls, sex and age matched as much as possible. Patients’ cone and rod ERG luminance responses were obtained in autumn before and after 2 and 4 weeks of daily light therapy (30 min at 5000 lux SADelite lamp, Northern Light Technologies) as well as during natural remission in summer. Normal controls were evaluated once in autumn and once in summer.
RESULTS Cone Vmax b-wave amplitudes were on average 17% lower in SAD patients when compared to controls (P=0.01). Rod retinal sensitivity (log K value) was 0.13 log units lower in SAD patients (P=0.01). After 4 weeks of light therapy (but not after 2), both cone (Vmax) and rod (log K) parameters were not significantly different than the controls (P>0.05). In summer, both parameters were not significantly different between patients and controls (P>0.05) and normal controls did not demonstrate any seasonal change in retina function (P>0.05).
CONCLUSION This is the first objective evidence of cone and rod function anomalies in SAD patients occurring during the depressive episode only. This represents also the first report of a biological therapeutic effect of light therapy on retinal function. Although the origin of the seasonal change in retina function in SAD patient is still unclear, we believe that a neurotransmitter imbalance (such as serotonin) could explain both the presence of the symptoms observed in these patients and the ERG findings.
Bright light is used to treat winter depression and may also have positive effects on mood in some healthy individuals. However, there is little information on how bright light treatment influences social behavior. We performed a cross-over study in winter comparing the effects of morning bright light administration with placebo (exposure to negative ions) on mood and social behavior in 38 healthy people with mild to moderate seasonality. Each treatment was given for 21 days with a washout period of 14 days between treatments. An event-contingent recording assessment was used to measure mood, and social behavior along two axes, agreeable-quarrelsome and dominant–submissive, during each 21-day treatment period. During treatments, participants wore a combined light-sensor and accelerometer to test this method for adherence to light treatment self-administered at home. Data were analyzed using multilevel modeling. Bright light improved mood but increased quarrelsome behavior and decreased submissiveness. Data from the light monitor and accelerometer suggested that 21% of the participants did not adhere to bright light treatment; when this group was analyzed separately, there was no change in quarrelsomeness or mood. However, results for individuals who followed the procedure were similar to those reported for the whole sample.
BACKGROUND Retinal sensitivity anomalies have been reported in patients affected by seasonal affective disorder (SAD). We used the electroretinogram (ERG) to assess seasonal change in retinal function in patients with SAD and healthy participants, as well as in patients following 4 weeks of light therapy.
METHOD ERG assessments were obtained in 22 SAD patients (2 men, 20 women, mean age 31 9 years) in the fall/winter season before and after 2 and 4 weeks of light therapy and in summertime. Matched healthy participants (2 men, 14 women; mean age 29 8 years) were evaluated once in the fall/winter and once in summer. The 29-item Structured Interview Guide for the Hamilton Depression Rating Scale, Seasonal Affective Disorder version was administered. Standard ERG parameters were derived from the photopic and scotopic luminance response functions. Salivary melatonin concentration during ERG was assessed in both groups but during fall/winter assessments only.
RESULTS A significantly lower cone ERG maximal amplitude and lower rod sensitivity was found in SAD patients before light therapy compared with healthy participants. Following 4 weeks of light therapy, a normalization of cone and rod ERG function occurred. ERG parameters in the summer and melatonin concentrations in fall/winter were not significantly different between groups.
CONCLUSION Depressed patients with SAD demonstrate ERG changes in the winter compared with healthy comparison subjects with lower rod retinal sensitivity and lower cone maximal amplitude. These changes normalized following 4 weeks of light therapy and during the summer, suggesting that ERG changes are state markers for SAD.
Desautels, C., Savard, J., Ivers, H., Savard, M. H., & Caplette-Gingras, A. (2018). Treatment of depressive symptoms in patients with breast cancer: A randomized controlled trial comparing cognitive therapy and bright light therapy. Health Psychology, 37(1), 1.
OBJECTIVE Seasonal affective disorder (SAD) is defined as a form of recurrent depressive or bipolar affective disorder characterized by recurrent affective episodes that occur annually at the same time of the year (Kasper et al., 1988). Guidelines for SAD have proposed bright light therapy (BLT) as the treatment of choice (Terman et al., 1989). However conventional antidepressant treatment has also been found to be effective in this condition (Kasper et al., 2001). The aim of this investigation was to assess the importance of drug treatment in a clinical sample of SAD patients.
METHOD We examined the psychopharmacologic treatment of 578 outpatients (446 females, 132 males) suffering from SAD (unipolar depression: 77.9%, bipolar-II disorder: 19.6%, bipolar-I disorder: 2.2%) that had been treated with BLT at the Department of General Psychiatry (University of Vienna).
RESULTS 47.9% of all patients received psychopharmacologic treatment in addition to BLT. 34.6% were treated with antidepressants (24.9% SSRI [selective serotonin reuptake inhibitors], 6.6% NaSSA [noradrenergic and specific serotonergic antidepressants], 5.2% tricyclic antidepressants, 3.3% tetracyclic antidepressants, 1.4% SNRI [serotonin and noradrenalin reuptake inhibitors], 1.2% RIMA [reversible inhibitors of monoaminoxydase A], 0.2% NARI [noradrenalin reuptake inhibitors]), 5.2% received phase prophylaxis with lithium or antiepileptics, 9.0% were treated with anxiolytic substances (mostly benzodiazepines), 7.6% with phytopharmaceutical medication (7.4% hypericum extract, 0.5% valerian extract), 3.3% with typical neuroleptics, 1.0% with atypical neuroleptics, 3.3% with other medication. No significant differences in medication were observed in regard to gender, age, duration of hospitalization or number of affective episodes. Patients suffering from bipolar disorder received phase prophylactic medication more frequently (bipolar-I: 38.5%, bipolar-II: 8.0%) than patients with unipolar depression (3.6%; Likelihood ratio χ2=17.591, df=3, p=0.0005).
CONCLUSION A substantial part (about one third) of our patients was treated with antidepressant medication concomitant to BLT. Obviously BLT does not suffice as only antidepressant regimen for all SAD patients. Opposed to the guidelines for the treatment of depression patients with several depressive episodes did not receive antidepressant long-term medication or phase prophylaxis more often than patients with only a few episodes. Our results also show, that the majority of patients with bipolar disorder still does not receive any phase prophylactic medication, which could indicate the need for further treatment.
OBJECTIVE To investigate whether or not brief bright light (BL) exposure on workday mornings can improve health, performance and safety in nurses with rapidly rotating shifts.
METHOD We conducted a randomized crossover study involving registered nurses at a teaching hospital working a two-shift system including the night shift. Participants were instructed to expose themselves to BL for 10 min on workday mornings.
RESULTS A total of 61 participants were enrolled in the present study. Thirty-one participants received BL exposure in the first month, and the other 30 received it in the second month. Significant improvements were noted in the BL periods compared with the non-BL periods for self-assessed sleepiness at 10:00 on day-shift days evaluated using the Karolinska Sleepiness Scale, self-assessment of night sleep for day-shift days using the Visual Analogue Scale and for fatigue assessed using the Checklist Individual Strength Questionnaire. The estimated mean difference for each scale (95% confidence interval) was –0.55 (–0.91, –0.20), 0.37 (0.04, 0.70) and –2.13 (–3.78, –0.48), respectively. Mean response time evaluated using the psychomotor vigilance task test (PVT) showed significant improvement in the BL periods compared with the non-BL periods. No statistically significant differences were observed for sleepiness at 14:00, depression, number of PVT lapses or frequency of perceived adverse events and near misses.
CONCLUSION Our findings suggest that brief BL exposure on mornings preceding a day shift is effective in improving sleepiness and performance during day-shift work, subjective nighttime sleep on day-shift days, and perceived fatigue for the preceding two weeks in rapidly rotating shift nurses.
OBJECTIVE To examine the affect of ambulatory daytime light exposure on phase delays and advances produced by timed exposure to bright evening or morning light.
METHOD As a subset of a larger study, 32 older (63.0 ± 6.43 years) adults with primary insomnia were randomized to an at-home, single-blind, twelve-week, parallel-group study entailing daily exposure to 45 minutes of scheduled evening or morning bright (~4000 lux) light. Light exposure patterns during baseline and the last week of treatment were monitored using actigraphs with built-in illuminance detectors. Circadian phase was determined through analysis of in-laboratory collected plasma melatonin.
RESULTS Less daytime light exposure during the last week of treatment was significantly associated with larger phase delays in response to evening light (r’s>0.78). Less daytime light exposure during the last week of treatment was also associated with a significant delay in wake time (r’s>−0.75). There were no such relationships between light exposure history and phase advances in response to morning light.
CONCLUSION Greater light exposure during the daytime may decrease the ability of evening light, but not morning light, exposure to engender meaningful changes of circadian phase.
OBJECTIVE Seasonal affective disorder (SAD) is characterized by a mood lowering in autumn and/or winter followed by spontaneous remission in spring or summer. Bright light (BL) is recognized as the treatment of choice for individuals affected with this disease. It was speculated that BL acts on photosensitive retinal ganglion cells, particularly sensitive to blue light, which led to the emergence of apparatus enriched with blue light. However, blue light is more at risk to cause retinal damage. In addition, we reported using electroretinography (ERG) that a 60 min exposure of BL could reduce rod sensitivity. The goal of the present study was to verify if this decreased in sensitivity could be a consequence of the blue light portion present in the white light therapy lamps. We also wanted to assess the effect of monochromatic blue light vs red light in both healthy controls and patients with SAD.
METHOD 10 healthy subjects and 10 patients with SAD were exposed in a random order for 60 min to two different light colors (red or blue) separated by an interval of at least 1 day. Cone and rod ERG luminance-response function was assessed after light exposure.
RESULTS A two-way ANOVA indicates that blue light decreases the maximal ERG response (Vmax) in both groups in photopic (p < 0.05) and scotopic conditions (p < 0.01).
CONCLUSION The main finding of this experiment is that blue light reduces photoreceptor responses after only a single administration. This brings important concerns with regard to blue-enriched light therapy lamps used to treat SAD symptoms and other disorders.
OBJECTIVE To review from an architectural lighting perspective the effects of indoor lighting on the health and well-being of people in senior living environments.
BACKGROUND The role of circadian rhythms in people with chronic disorders continues to be a focus of laboratory research and clinical trials. Beneficial, evidence-based indoor lighting design strategies are being considered for senior living environments, particularly for residents who have limited access to natural bright light.
METHOD Articles published 2002–2012 reporting the results of prospective, randomized, controlled clinical trials (RCTs) were accessed using the U.S. National Library of Medicine PubMed site using the following search terms: “light, sleep, circadian, randomized, controlled, nursing home” and “light, sleep, circadian, randomized, controlled, elderly.”
RESULTS The search resulted in 48 citations, of which 18 meet our pre-search criteria. Data from these RCTs indicate options such as programmable, 24-hour lighting algorithms that may involve light intensity, lighting duration, spectra (wavelength) and lighting timing sequences
CONCLUSION Valid and actionable data are available about circadian rhythms, sleep, and human health and well-being that can inform the design of lighting for long-term care. Evidence-based architectural design of a 24-hour light/dark environment for residents may mitigate symptoms of circadian disruption; evidence-based management of darkness is as important as evidence-based management of light. Further research is needed into the long-term circadian health needs of night staff members in order to understand the effects of shift work while, at the same time providing the highest level of care.
