Light visor treatment for seasonal affective disorder: a multicenter study

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.

"Shedding Light on Light": A Review on the Effects on Mental Health of Exposure to Optical Radiation

In relation to human health and functioning, light, or more specifically optical radiation, plays many roles, beyond allowing vision. These may be summarized as: regulation of circadian rhythms; consequences of direct exposure to the skin; and more indirect effects on well-being and functioning, also related to lifestyle and contact with natural and urban environments. Impact on mental health is relevant for any of these specifications and supports a clinical use of this knowledge for the treatment of psychiatric conditions, such as depression or anxiety, somatic symptom disorder, and others, with reference to light therapy in particular. The scope of this narrative review is to provide a summary of recent findings and evidence on the regulating functions of light on human beings’ biology, with a specific focus on mental health, its prevention and care.

Light therapy for preventing seasonal affective disorder

BACKGROUND

Seasonal affective disorder (SAD) is a seasonal pattern of recurrent major depressive episodes that most commonly occurs during autumn or winter and remits in spring. The prevalence of SAD ranges from 1.5% to 9%, depending on latitude. The predictable seasonal aspect of SAD provides a promising opportunity for prevention. This review - one of four reviews on efficacy and safety of interventions to prevent SAD - focuses on light therapy as a preventive intervention. Light therapy is a non-pharmacological treatment that exposes people to artificial light. Mode of delivery and form of light vary.

OBJECTIVES

To assess the efficacy and safety of light therapy (in comparison with no treatment, other types of light therapy, second-generation antidepressants, melatonin, agomelatine, psychological therapies, lifestyle interventions and negative ion generators) in preventing SAD and improving patient-centred outcomes among adults with a history of SAD.

SEARCH METHODS

We searched Ovid MEDLINE (1950- ), Embase (1974- ), PsycINFO (1967- ) and the Cochrane Central Register of Controlled Trials (CENTRAL) to 19 June 2018. An earlier search of these databases was conducted via the Cochrane Common Mental Disorders Controlled Trial Register (CCMD-CTR) (all years to 11 August 2015). Furthermore, we searched the Cumulative Index to Nursing and Allied Health Literature, Web of Science, the Cochrane Library, the Allied and Complementary Medicine Database and international trial registers (to 19 June 2018). We also conducted a grey literature search and handsearched the reference lists of included studies and pertinent review articles.

SELECTION CRITERIA

For efficacy, we included randomised controlled trials (RCTs) on adults with a history of winter-type SAD who were free of symptoms at the beginning of the study. For adverse events, we also intended to include non-randomised studies. We intended to include studies that compared any type of light therapy (e.g. bright white light, administered by visors or light boxes, infrared light, dawn stimulation) versus no treatment/placebo, second-generation antidepressants, psychological therapies, melatonin, agomelatine, lifestyle changes, negative ion generators or another of the aforementioned light therapies. We also planned to include studies that looked at light therapy in combination with any comparator intervention.

DATA COLLECTION AND ANALYSIS

Two review authors screened abstracts and full-text publications, independently abstracted data and assessed risk of bias of included studies.

MAIN RESULTS

We identified 3745 citations after de-duplication of search results. We excluded 3619 records during title and abstract review. We assessed 126 full-text papers for inclusion in the review, but only one study providing data from 46 people met our eligibility criteria. The included RCT had methodological limitations. We rated it as having high risk of performance and detection bias because of lack of blinding, and as having high risk of attrition bias because study authors did not report reasons for dropouts and did not integrate data from dropouts into the analysis.The included RCT compared preventive use of bright white light (2500 lux via visors), infrared light (0.18 lux via visors) and no light treatment. Overall, white light and infrared light therapy reduced the incidence of SAD numerically compared with no light therapy. In all, 43% (6/14) of participants in the bright light group developed SAD, as well as 33% (5/15) in the infrared light group and 67% (6/9) in the non-treatment group. Bright light therapy reduced the risk of SAD incidence by 36%; however, the 95% confidence interval (CI) was very broad and included both possible effect sizes in favour of bright light therapy and those in favour of no light therapy (risk ratio (RR) 0.64, 95% CI 0.30 to 1.38; 23 participants, very low-quality evidence). Infrared light reduced the risk of SAD by 50% compared with no light therapy, but the CI was also too broad to allow precise estimations of effect size (RR 0.50, 95% CI 0.21 to 1.17; 24 participants, very low-quality evidence). Comparison of both forms of preventive light therapy versus each other yielded similar rates of incidence of depressive episodes in both groups (RR 1.29, 95% CI 0.50 to 3.28; 29 participants, very low-quality evidence). Reasons for downgrading evidence quality included high risk of bias of the included study, imprecision and other limitations, such as self-rating of outcomes, lack of checking of compliance throughout the study duration and insufficient reporting of participant characteristics.Investigators provided no information on adverse events. We could find no studies that compared light therapy versus other interventions of interest such as second-generation antidepressants, psychological therapies, melatonin or agomelatine.

AUTHORS' CONCLUSIONS

Evidence on light therapy as preventive treatment for people with a history of SAD is limited. Methodological limitations and the small sample size of the only available study have precluded review author conclusions on effects of light therapy for SAD. Given that comparative evidence for light therapy versus other preventive options is limited, the decision for or against initiating preventive treatment of SAD and the treatment selected should be strongly based on patient preferences.

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

Light therapy (LT) is efficacious for bipolar depression with effect sizes equivalent to those in antidepressant pharmacotherapy trials. Patients with bipolar disorder (BD) show a 15-40% rate of manic switches during antidepressant drug treatment. The rate of manic switches during LT has never been estimated. We searched all the literature studies reporting effects of antidepressant LT in BD. 41 studies described 799 patients with BD treated with antidepressant LT, from among which 7 (0.9%) switched into mania and 11 (1.4%) switched into hypomania. The method of assessment of treatment-emergent symptoms significantly influenced the detection of switches into mania: 0% when no method was reported, 0.8% with clinical mental state examination, and 3% with rating scales (χ² = 14.805, d.f. 4, p = 0.005). The rate of switch increased to 18.8% when considering the 16 patients with rapid-cycling BD. Switches occurred independent of treatment modality (light intensity, duration, and circadian timing of administration). The available literature shows that the highest reported rate of switch from bipolar depression into mania after LT is closely similar to the 4% switch rate expected during the placebo treatment of BD, thus not justifying specific concerns when using this treatment option.

Light therapy: is it safe for the eyes?

OBJECTIVE

Light therapy has become an increasingly popular treatment for depression and a range of other neuropsychiatric conditions. Yet, concerns have been raised about the ocular safety of light therapy.

METHOD

We conducted the first systematic review into the ocular safety of light therapy. A PubMed search on January 4, 2017, identified 6708 articles, of which 161 were full-text reviewed. In total, 43 articles reporting on ocular complaints and ocular examinations were included in the analyses.

RESULTS

Ocular complaints, including ocular discomfort and vision problems, were reported in about 0% to 45% of the participants of studies involving light therapy. Based on individual studies, no evident relationship between the occurrence of complaints and light therapy dose was found. There was no evidence for ocular damage due to light therapy, with the exception of one case report that documented the development of a maculopathy in a person treated with the photosensitizing antidepressant clomipramine.

CONCLUSION

Results suggest that light therapy is safe for the eyes in physically healthy, unmedicated persons. The ocular safety of light therapy in persons with preexisting ocular abnormalities or increased photosensitivity warrants further study. However, theoretical considerations do not substantiate stringent ocular safety-related contraindications for light therapy.

Light therapy for preventing seasonal affective disorder

BACKGROUND

Seasonal affective disorder (SAD) is a seasonal pattern of recurrent major depressive episodes that most commonly occurs during autumn or winter and remits in spring. The prevalence of SAD ranges from 1.5% to 9%, depending on latitude. The predictable seasonal aspect of SAD provides a promising opportunity for prevention. This review - one of four reviews on efficacy and safety of interventions to prevent SAD - focuses on light therapy as a preventive intervention. Light therapy is a non-pharmacological treatment that exposes people to artificial light. Mode of delivery (e.g. visors, light boxes) and form of light (e.g. bright white light) vary.

OBJECTIVES

To assess the efficacy and safety of light therapy (in comparison with no treatment, other types of light therapy, second-generation antidepressants, melatonin, agomelatine, psychological therapies, lifestyle interventions and negative ion generators) in preventing SAD and improving patient-centred outcomes among adults with a history of SAD.

SEARCH METHODS

A search of the Specialised Register of the Cochrane Depression, Anxiety and Neuorosis Review Group (CCDANCTR) included all years to 11 August 2015. The CCDANCTR contains reports of relevant randomised controlled trials derived from EMBASE (1974 to date), MEDLINE (1950 to date), PsycINFO (1967 to date) and the Cochrane Central Register of Controlled Trails (CENTRAL). Furthermore, we searched the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Knowledge, The Cochrane Library and the Allied and Complementary Medicine Database (AMED) (to 26 May 2014). We also conducted a grey literature search and handsearched the reference lists of all included studies and pertinent review articles.

SELECTION CRITERIA

For efficacy, we included randomised controlled trials on adults with a history of winter-type SAD who were free of symptoms at the beginning of the study. For adverse events, we also intended to include non-randomised studies. We intended to include studies that compared any type of light therapy (e.g. bright white light, administered by visors or light boxes, infrared light, dawn stimulation) versus no treatment/placebo, second-generation antidepressants (SGAs), psychological therapies, melatonin, agomelatine, lifestyle changes, negative ion generators or another of the aforementioned light therapies. We also planned to include studies that looked at light therapy in combination with any comparator intervention and compared this with the same comparator intervention as monotherapy.

DATA COLLECTION AND ANALYSIS

Two review authors screened abstracts and full-text publications against the inclusion criteria. Two review authors independently abstracted data and assessed risk of bias of included studies.

MAIN RESULTS

We identified 2986 citations after de-duplication of search results. We excluded 2895 records during title and abstract review. We assessed 91 full-text papers for inclusion in the review, but only one study providing data from 46 people met our eligibility criteria. The included randomised controlled trial (RCT) had methodological limitations. We rated it as having high risk of performance and detection bias because of lack of blinding, and as having high risk of attrition bias because study authors did not report reasons for dropouts and did not integrate data from dropouts into the analysis.The included RCT compared preventive use of bright white light (2500 lux via visors), infrared light (0.18 lux via visors) and no light treatment. Overall, both forms of preventive light therapy reduced the incidence of SAD numerically compared with no light therapy. In all, 43% (6/14) of participants in the bright light group developed SAD, as well as 33% (5/15) in the infrared light group and 67% (6/9) in the non-treatment group. Bright light therapy reduced the risk of SAD incidence by 36%; however, the 95% confidence interval (CI) was very broad and included both possible effect sizes in favour of bright light therapy and those in favour of no light therapy (risk ratio (RR) 0.64, 95% CI 0.30 to 1.38). Infrared light reduced the risk of SAD by 50% compared with no light therapy, but in this case also the CI was too broad to allow precise estimations of effect size (RR 0.50, 95% CI 0.21 to 1.17). Comparison of both forms of preventive light therapy versus each other yielded similar rates of incidence of depressive episodes in both groups (RR 1.29, 95% CI 0.50 to 3.28). The quality of evidence for all outcomes was very low. Reasons for downgrading evidence quality included high risk of bias of the included study, imprecision and other limitations, such as self rating of outcomes, lack of checking of compliance throughout the study duration and insufficient reporting of participant characteristics.Investigators provided no information on adverse events. We could find no studies that compared light therapy versus other interventions of interest such as SGA, psychological therapies, melatonin or agomelatine.

AUTHORS' CONCLUSIONS

Evidence on light therapy as preventive treatment for patients with a history of SAD is limited. Methodological limitations and the small sample size of the only available study have precluded review author conclusions on effects of light therapy for SAD. Given that comparative evidence for light therapy versus other preventive options is limited, the decision for or against initiating preventive treatment of SAD and the treatment selected should be strongly based on patient preferences.

Treatment of seasonal affective disorder

Seasonal affective disorder (SAD), winter type, is characterized by the regular annual onset of major depressive episodes during fall or winter, followed by spontaneous remission and sometimes hypomanic or manic episodes during spring and summer. SAD is clinically important, since approximately 2-5% of the general population in temperate climates are affected. Since the first description of the syndrome, researchers have made attempts to elucidate the pathophysiological background of SAD. Bright light therapy has been proposed as the treatment of choice for this disorder. However, numerous studies have also investigated suitable psychopharmacological treatments for SAD. This report is aimed to provide an overview on the clinical management and current therapeutic options for SAD.

Bright-light therapy in the treatment of mood disorders

Bright-light therapy (BLT) is established as the treatment of choice for seasonal affective disorder/winter type (SAD). In the last two decades, the use of BLT has expanded beyond SAD: there is evidence for efficacy in chronic depression, antepartum depression, premenstrual depression, bipolar depression and disturbances of the sleep-wake cycle. Data on the usefulness of BLT in non-seasonal depression are promising; however, further systematic studies are still warranted. In this review, the authors present a comprehensive overview of the literature on BLT in mood disorders. The first part elucidates the neurobiology of circadian and seasonal adaptive mechanisms focusing on the suprachiasmatic nucleus (SCN), the indolamines melatonin and serotonin, and the chronobiology of mood disorders. The SCN is the primary oscillator in humans. Indolamines are known to transduce light signals into cells and organisms since early in evolution, and their role in signalling change of season is still preserved in humans: melatonin is synthesized primarily in the pineal gland and is the central hormone for internal clock circuitries. The melatonin precursor serotonin is known to modulate many behaviours that vary with season. The second part discusses the pathophysiology and clinical specifiers of SAD, which can be seen as a model disorder for chronobiological disturbances and the mechanism of action of BLT. In the third part, the mode of action, application, efficacy, tolerability and safety of BLT in SAD and other mood disorders are explored.

Bright Light Therapy for Winter Depression—Is Phase Advancing Beneficial?

Bright light is the recommended treatment for winter seasonal affective disorder (SAD). Previously we showed that the antidepressant effect of morning (but not evening) light was greater than placebo after 3 weeks of treatment. Here, we determined if the magnitude and direction of circadian rhythm phase shifts produced by the bright light in the previous study were related to the antidepressant effects. Twenty-six SAD patients from the original sample of 96 had their rectal temperature continuously monitored while they participated in a placebo-controlled parallel design conducted over six winters. After a baseline week, there were three treatments for 4 weeks-morning light, evening light, or morning placebo. Bright light was produced by light boxes (approximately 6000 lux). Placebos were sham negative ion generators. All treatments were 1.5 h in duration. Depression ratings were made weekly by blind raters. Circadian phase shifts were determined from changes in the timing of the core body temperature minimum (Tmin). Morning light advanced and evening light delayed the Tmin by about 1 h. The placebo treatment did not alter circadian phase. As the sleep schedule was held constant, morning light increased and evening light decreased the Tmin to wake interval, or phase angle between circadian rhythms and sleep. Phase advance shifts and increases in the phase angle were only weakly associated with antidepressant response. However, there was an inverted U-shaped function showing that regardless of treatment assignment the greatest antidepressant effects occurred when the phase angle was about 3h, and that patients who moved closer to this phase angle benefited more than those who moved farther from it. However 46% of our sample had a phase angle within 30 min of this 3 h interval at baseline. So it does not appear that an abnormal phase angle can entirely account for the etiology of SAD. A majority (75%) of the responders by strict joint criteria had a phase angle within this range after treatment, so it appears that obtaining the ideal phase relationship may account for some, but not all of the antidepressant response. In any case, regardless of the mechanism for the antidepressant effect of morning light, it can be enhanced when patients sleep at the ideal circadian phase and reduced when they sleep at a more abnormal circadian phase.

Light therapy for seasonal and nonseasonal depression: efficacy, protocol, safety, and side effects

Bright light therapy for seasonal affective disorder (SAD) has been investigated and applied for over 20 years. Physicians and clinicians are increasingly confident that bright light therapy is a potent, specifically active, nonpharmaceutical treatment modality. Indeed, the domain of light treatment is moving beyond SAD, to nonseasonal depression (unipolar and bipolar), seasonal flare-ups of bulimia nervosa, circadian sleep phase disorders, and more. Light therapy is simple to deliver to outpatients and inpatients alike, although the optimum dosing of light and treatment time of day requires individual adjustment. The side-effect profile is favorable in comparison with medications, although the clinician must remain vigilant about emergent hypomania and autonomic hyperactivation, especially during the first few days of treatment. Importantly, light therapy provides a compatible adjunct to antidepressant medication, which can result in accelerated improvement and fewer residual symptoms.

Treatment of seasonal affective disorder: unipolar versus bipolar differences

Evidence-based treatments for seasonal affective disorder (SAD) include light therapy and pharmacotherapy. We briefly review the diagnosis and treatment of SAD, focusing on clinical and treatment differences between patients with unipolar and bipolar illness. Special considerations for the management of SAD in patients with bipolar disorder are discussed, including the need to monitor for emergence of manic and hypomanic mood switches, to use mood stabilizers in patients with bipolar I disorder, and to be aware of potential interactions between bright light and medications used in treating bipolar disorder. Chronobiological treatments such as bright light therapy may be combined with pharmacotherapy to enhance therapeutic effects, reduce adverse side effects, and optimize treatment in patients with seasonal and nonseasonal bipolar disorder.

Light treatment of mood disorders

In 1981, seven patients with nonseasonal depression were treated with bright white light in 1982, bright artificial light was used to treat a manic-depressive patient with a seasonal mood cycle. In the last 20 years, a plethora of studies have further defined the depressive populations, who are responsive to light treatment; the optimal timing, intensity, spectral frequency, and duration of treatment; its comparison with other pharmacological interventions; predictors of response; side-effect profiles; viable placebo-control conditions; alternative devices and forms of administration; potential mechanisms and anatomical pathways mediating light's physiological effects; and its application to other disorders and subsyndromaI states. These studies have been conducted across multiple countries with surprisingly consistent results. Further work is needed, as highlighted in this review, to clarify the specific mechanism of action in subtypes of depressive disorders and differential age and gender effects. Although the majority of work in this area is relatively new, it behooves the reader to remember that Solomon, almost 3000 years ago, wrote in Ecclesiastes: "Truly the light is sweet and a pleasant thing it is for the eyes to behold the sun" (11:7).

Seasonal affective disorder: an overview

Seasonal Affective Disorder (SAD) is a condition of regularly occurring depressions in winter with a remission the following spring or summer. In addition to depressed mood, the patients tend to experience increased appetite and an increased duration of sleep during the winter. SAD is a relatively common condition, affecting 1-3% of adults in temperate climates, and it is more prevalent in women. The pathological mechanisms underlying SAD are incompletely understood. Certain neurotransmitters have been implicated; a dysfunction in the serotonin system in particular has been demonstrated by a variety of approaches. The role of circadian rhythms in SAD needs to be clarified. The phase-delay hypothesis holds that SAD patients' circadian rhythms are delayed relative to the sleep/wake or rest/activity cycle. This hypothesis predicts that the symptoms of SAD will improve if the circadian rhythms can be phase-advanced. There is some experimental support for this. SAD can be treated successfully with light therapy. In classical light therapy, the SAD sufferer sits in front of a light box, exposed to 2000-10,000 lux for 30-120 min daily during the winter. Other forms of light treatments, pharmacotherapy, and other therapies are currently being tested for SAD.

Light therapy for seasonal affective disorder in primary care: randomised controlled trial

BACKGROUND

Studies of light therapy have not been conducted previously in primary care.

AIMS

To evaluate light therapy in primary care.

METHOD

Fifty-seven participants with seasonal affective disorder were randomly allocated to 4 weeks of bright white or dim red light. Baseline expectations for treatment were assessed. Outcome was assessed with the Structured Interview Guide for the Hamilton Depression Scale, Seasonal Affective Disorder Version.

RESULTS

Both groups showed decreases in symptom scores of more than 40%. There were no differences in proportions of responders in either group, regardless of the remission criteria applied, with around 60% (74% white light, 57% red light) meeting broad criteria for response and 31% (30% white light, 33% red light) meeting strict criteria. There were no differences in treatment expectations.

CONCLUSIONS

Primary care patients with seasonal affective disorder improve after light therapy, but bright white light is not associated with greater improvements.

Prophylactic treatment of seasonal affective disorder (SAD) by using light visors: bright white or infrared light?

BACKGROUND

Thirty-eight patients with SAD participated in a light visor study addressing two questions. 1. Can the development of a depressive episode be prevented by daily exposure to bright light started before symptom onset in early fall and continued throughout the winter? 2. Does the light have to be visible in order to have beneficial effects?

METHODS

Three groups participated in the study: I (n = 14) received bright white light (2500 lux); II, (n = 15) received infrared light (0.18 lux); III (n = 9, control group) did not receive any light treatment at all.

RESULTS

Infrared light is just as effective as bright white light. Both are more effective than the control condition.

CONCLUSIONS

Light visors can be effectively used to prevent the development of SAD. The fact that exposure to infrared light was as effective as exposure to bright white light questions the specific role of visible light in the treatment of SAD.

A controlled study of light therapy in women with late luteal phase dysphoric disorder

Previous studies suggest that light therapy, as used to treat seasonal affective disorder, may be beneficial for pre-menstrual depressive disorders. We conducted a six-menstrual cycle randomized, double-blind, counter-balanced, crossover study of dim vs. bright light therapy in women with late luteal phase dysphoric disorder (LLPDD). Fourteen women who met DSM-III-R criteria for LLPDD completed two menstrual cycles of prospective baseline monitoring of pre-menstrual symptoms, followed by two cycles of each treatment. During the 2-week luteal phase of each treatment cycle, patients were randomized to receive 30 min of evening light therapy using: (1) 10000 lx cool-white fluorescent light (active condition); or (2) 500 lx red fluorescent light (placebo condition), administered by a light box at their homes. After two menstrual cycles of treatment, patients were immediately crossed over to the other condition for another two cycles. Outcome measures were assessed at the mid-follicular and luteal phases of each cycle. Results showed that the active bright white light condition significantly reduced depression and pre-menstrual tension scores during the symptomatic luteal phase, compared to baseline, while the placebo dim red light condition did not. These results suggest that bright light therapy is an effective treatment for LLPDD.

Dose-response relationship of phototherapy for seasonal affective disorder: a meta-analysis

OBJECTIVE

The therapeutic effect of phototherapy for seasonal affective disorder (SAD) has been widely investigated. However, the antidepressant effect of various light intensities is inconclusive. The purpose of this study was to evaluate the dose-response relationship of phototherapy for SAD.

METHOD

A meta-analytical methodology was applied to 39 studies of phototherapy for SAD. The studies collected were screened for study quality by a threats-to-validity method before inclusion. The fixed-effects-model analysis of variance procedures were used for data analysis.

RESULTS

The results indicated that different light intensities produced different effects in reducing the typical symptoms, as measured by the Hamilton Depression Rating Scale, of patients with SAD. However, no significant differences in these effects were revealed between strong, medium and dim light in reducing the atypical symptoms of patients.

CONCLUSION

These findings showed that light intensity varied positively with the antidepressant effect for typical but not for atypical symptoms of SAD, suggesting that light intensity tended to have different therapeutic effects on the typical and atypical symptoms of SAD.

Platelet [3H]paroxetine and [3H]lysergic acid diethylamide binding in seasonal affective disorder and the effect of bright light therapy

BACKGROUND

Seasonal affective disorder (SAD) has been regarded as a melatonin disorder, but the pathophysiological mechanisms of SAD are to a large extent unclarified. Serotonergic mechanisms have also been studied, but they have shown inconsistent results.

METHODS

We have compared [3H]paroxetine and [3H]lysergic acid diethylamide (LSD) binding in platelets from 23 SAD patients and 23 controls. Then SAD patients had 4 weeks of light therapy. On the last treatment day new blood samples were drawn. Symptoms before and after light treatment were measured by SIGH-SAD.

RESULTS

Bmax for paroxetine binding before light treatment was higher in SAD patients compared to controls and also higher in responders than in nonresponders. Bmax decreased significantly during light treatment. We also found a negative correlation between the two Bmax values before but not after light treatment. There was a negative correlation between Bmax for paroxetine binding before treatment and clinical status after treatment. Patients with reduced Bmax for LSD binding after treatment had a better clinical treatment response.

CONCLUSIONS

The present study indicates that serotonin receptor parameters might be suitable in the prediction of clinical response to light treatment.

Dawn simulation vs. lightbox treatment in winter depression: a comparative study

Dawn simulation, with gradually increasing bedside light in the morning, has shown promising results as an alternative to bright light treatment for winter depression. To compare these treatments, 61 out-patients with winter depression (20-70 years of age, 80% women) were randomized to receive either lightbox treatment with 1500-2500 lux white light for 2 h in the morning for 6 days on an out-patient basis (n=34), or dawn simulation treatment in their homes, with 60 or 90 min of light augmentation time to 100-300 lux, for 2 weeks (n=27). Patients' ratings of improvement on a visual analogue scale (correlating strongly with percentage reduction in an extended Montgomery-Asberg Depression Rating Scale (MADRS) score) at the end of treatment showed a mean of 40.0% (SD 27.7%) in the dawn simulation group and 57.4% (SD 29.9%) in the lightbox group (P=0.02). The majority of the patients in both groups maintained their improvement during a 9-week follow-up. Age, sex, current major depression or current use of antidepressants did not predict outcome in either group. No serious side-effects were observed.

Pathophysiological mechanism of seasonal affective disorder

Despite the long history in medicine, the pathophysiological mechanism(s) of seasonal affective disorder (SAD) remain largely unknown. By employing a meta-analytic methodology, the authors of this study attempted to verify the validity of different pathophysiological mechanism(s) proposed for SAD. The findings showed that for phototherapy of medium light intensity, a combination of morning-evening therapy regime yielded the best therapeutic effect, and the antidepressant effect of the morning-evening light regime was superior to a single pulse of light administered at other times of day. Furthermore, the data showed that the antidepressant effect of a single pulse of light was similar for morning, midday, and evening light. These findings supported the photon-count hypothesis and refuted the proposed photoperiod, melatonin, and phase-shifting models of SAD.

Influence of phototherapy treatment duration for seasonal affective disorder: outcome at one vs. two weeks

Most previous phototherapy research has been conducted on trials of 1 week duration. This study compares response to phototherapy at weeks 1 and 2. All subjects (n = 26) were between 18 and 65 years and met Diagnostic and Statistical Manual of Mental Disorders, 3rd ed, revised, (DSM III-R) criteria for major depression, recurrent, seasonal pattern and had a Hamilton Depression Rating Scale score (HAM-D) > or = 20. A rater blinded to treatment schedule and study hypothesis repeated the HAM-D-31 1 and 2 weeks after baseline to assess treatment response to bright light. Response rates at week 1 defined by 50% reduction in HAM-D-31 and HAM-D-31 score < 8 were 62% and 27%, respectively. At week 2, however, 65% had a 50% reduction in HAM-D-31 and 62% had a HAM-D-31 < score 8 (chi-square = 6, p = 0.01). Four patients (15%) who were nonresponders at week 1 responded after 2 weeks. The results show a statistically different outcome after 2 weeks of treatment and suggest the necessity of longer trials of phototherapy.

Treatment of seasonal affective disorder: a review

OBJECTIVE

To review the status of current treatment of seasonal affective disorder (SAD).

METHOD

Treatment studies of SAD published between January 1989 and March 1995 were identified using a computerized MEDLINE literature search. Additional citations were obtained from the reference sections of these articles. Studies included in this review were selected using operational methodologic criteria.

RESULTS

Many studies support the efficacy of bright light therapy using a fluorescent light box. The best studied protocol is > 2500 lux white light for 2 hours per day, but newer protocols using 10,000 lux for 30 minutes have comparable response rates. Studies of light visors and other head-mounted devices also report similar response rates, but have not yet shown superiority over putative control conditions. There are fewer medication studies in SAD, but controlled studies suggest that fluoxetine, d-fenfluramine and propranolol are effective. Other treatments such as dawn simulation require further study. No studies of psychological treatments for SAD were found. Many studies had methodologic limitations, including brief treatment periods, small sample sizes, and lack of replication, that limit the generalizability of findings.

CONCLUSION

There are several well-studied, effective treatments for SAD, including light therapy and medications. However, further research must be done to demonstrate sustained treatment response over time, to clarify the intensity-response relationship of light therapy, to clarify the role of light therapy and medications, and to assess combination treatments.

Dawn simulation compared with a dim red signal in the treatment of winter depression

In a randomized, parallel design, 19 patients with winter depression were treated with either a week of a white 1.5-hr dawn simulation peaking at 250 lux or a week of a red, 1.5-hr dawn signal peaking at 2 lux. The subjects were told that they would receive either a white or red dawn reaching in intensity that would be dimmer than standard bright light treatment. At the end of both the baseline week and the treatment week subjects were blindly assessed with the Hamilton Rating Scale for Depression (HDRS). Analysis of covariance was used to compare the two dawn treatments. The white, 1.5-hr, 250 lux dawn simulation resulted in significantly (p < 0.05) lower HDRS scores compared to the red, 1.5-hr, 2 lux dawn. This is the second controlled study which indicates that dawn simulation is an effective treatment for winter depression.

Dim versus bright red (light-emitting diode) light in the treatment of seasonal affective disorder

Forty-three subjects with seasonal affective disorder were randomly assigned to receive 2 weeks of treatment with either bright- (mean 4106 lx) or dim-light (mean 96 lx) therapy, using red light-emitting diode light sources, in a head-mounted unit. Defining response as a 50% reduction in the 21-item Hamilton Depression Rating Scale score to a post-treatment score of less than 8, there was no significant difference in response rate between patients receiving bright light (67%) as compared with patients receiving dim light (68%). Possible explanations for the similar response rate to 2 very different illuminances of red light are discussed.

Morning light therapy for winter depression: predictors of response

Bright-light therapy is widely regarded as an effective treatment for winter seasonal affective disorder (SAD). We attempted to identify predictors of light therapy response in 54 depressed, drug-free outpatients diagnosed with SAD by DSM-III-R criteria. After a baseline week, patients were treated for 2 weeks with 2500-lx cool-white fluorescent light exposure from 0600 to 0800 daily. The results showed that light therapy significantly reduced depression scores. Several indices of atypical and typical symptoms correlated with response, but none was clearly superior to the pre-treatment depression score. A multiple regression analysis identified 3 factors (hypersomnia, increased eating and younger age) that predicted light-therapy response. These results suggest that specific symptoms of hypersomnia and hyperphagia are predictors of response to morning bright-light therapy in SAD.

Is hypersomnolence a feature of seasonal affective disorder?

We examined hypersomnolence as experienced among individuals meeting standardized diagnostic criteria for Seasonal Affective Disorder (SAD). Data were available from 115 individuals attending a mood disorders clinic specializing in treatment of this disorder. Three modes of assessment were employed: retrospective self-reports (Seasonal Patterns Assessment Questionnaire), cross-sectional interviews (Standardized Interview Guide for the Hamilton Depression Scale, SAD Version), and prospective sleep diaries. Results indicated that self-reported total hours of sleep varied significantly across the seasons, with longest sleep occurring in winter and shortest sleep in summer. Seasonal sleep changes, as indicated by the SPAQ did not correlate significantly, however, with severity of depressive symptoms as indicated by the Hamilton scale. Multiple regression analyses indicated that only social activity levels (one of seven SPAQ items) was significantly and uniquely related to the severity of depression. When data obtained by the three instruments were compared, self-reported hours of sleep (whether measured by SPAQ or Hamilton interview) were significantly higher than indicated by prospective sleep diaries. We conclude that hypersomnolence may not be a central feature of SAD and that the validity of the SPAQ as an index of this disorder requires further investigation.

Treatment of winter depression in Norway. I. Short- and long-term effects of 1500-lux white light for 6 days

Patients with seasonal affective disorder (winter depression) from the Oslo area (at about 60 degrees N) recruited through mass media advertising were treated with 1500-lx white full-spectrum light for 2 h in the morning for 6 days. Their clinical state was assessed at baseline and 1, 3, 6, 10 and 14 weeks after commencement of treatment with an extended version of Montgomery-Asberg Depression Rating Scale (MADRS) and Clinical Global Impression. Forty patients (35 women, 5 men, age range 24 to 64 years) completed 1 week of light treatment. A subgroup of 9 patients received light in addition to ongoing drug treatment. The mean reduction in total extended MADRS score at week 1 was 48% in patients receiving only light and 56% in patients receiving light in addition to drugs. In spite of the low dose of light given, this is comparable to other reported results using light treatment for winter depression. In contrast to most other studies, however, the improvement at week 1 was maintained for the rest of the season in most patients. Only 5 patients were given another light treatment course, and another 5 were switched to drug treatment due to their unsatisfactory response to light treatment.