Prospectively assessed summer mood status in major depression, recurrent with seasonal pattern: Evidence for SAD's construct validity.

OBJECTIVE: Seasonal patterns are often undetectable in population-based depression studies, calling into question the existence of winter seasonal affective disorder (SAD). If SAD has construct validity, individuals with SAD should show spontaneous depression remission in the summer. Data are sparse on prospectively assessed summer mood status in confirmed SAD patients. METHOD: We conducted prospective summer followup of community adults who, the winter before, were diagnosed with Major Depression, Recurrent with Seasonal Pattern on the Structured Clinical Interview for DSM-IV Axis I Disorders, developed a current SAD episode on the Structured Interview Guide for the Hamilton Rating Scale for Depression-Seasonal Affective Disorder Version (SIGH-SAD), and enrolled in a clinical trial comparing group cognitive-behavioral therapy for SAD and light therapy. In July/August after treatment, 143/153 (93.5 %) participants provided data on the SIGH-SAD, the Beck Depression Inventory-Second Edition, and the Longitudinal Interval Followup Evaluation (LIFE). RESULTS: Summer mean depression scores were in the normal range, with the substantial majority in remission across different measures. On the LIFE, 113/143 (79.0 %) experienced complete summer remission, 19/143 (13.3 %) experienced partial summer remission, and 11/143 (7.7 %) had major depression in the summer. Depression scores were significantly lower at summer than post-treatment in both treatments, indicating incomplete treatment response. LIMITATIONS: This was a single-site study with a relatively homogeneous sample. CONCLUSIONS: Supporting construct validity for SAD, the substantial majority experienced complete summer remission, with a minority in partial remission and a very small minority in episode. Both treatments left residual symptoms at treatment endpoint compared to summer.

Change in Seasonal Beliefs Mediates the Durability Advantage of Cognitive-Behavioral Therapy Over Light Therapy for Winter Depression.

In treating an acute episode of winter depression, cognitive-behavioral therapy for seasonal affective disorder (CBT-SAD) and light therapy are comparably efficacious, with improvement in depression symptoms during CBT-SAD mediated by reduced seasonal beliefs (i.e., maladaptive thoughts about the seasons, light availability, and weather). Here, we tested whether the enduring benefit of CBT-SAD over light therapy following treatment is associated with offsetting seasonal beliefs during CBT-SAD. Currently depressed adults with Major Depression, Recurrent with Seasonal Pattern (N = 177) were randomized to 6 weeks of light therapy or group CBT-SAD and followedup one and two winters after treatment. Outcomes measured during treatment and at each follow-up included depression symptoms on the Structured Clinical Interview for the Hamilton Rating Scale for Depression-SAD Version and Beck Depression Inventory-Second Edition. Candidate mediators measured at pre-, mid-, and posttreatment were SAD-specific negative cognitions (Seasonal Beliefs Questionnaire; SBQ); general depressogenic cognitions (Dysfunctional Attitudes Scale; DAS); brooding rumination (Ruminative Response Scale-Brooding subscale; RRS-B); and chronotype (Morningness-Eveningness Questionnaire; MEQ). Latent growth curve mediation models found a significant positive path from treatment group to the slope of SBQ during treatment, with CBT-SAD showing larger improvements in seasonal beliefs with overall change in seasonal beliefs in the medium-effect range, and significant positive paths from SBQ slope to depression scores at the first and second winter follow-ups, indicating greater change towards more flexible seasonal beliefs during active treatment was associated with less severe depression symptoms following treatment. Estimated indirect effects (treatment group → SBQ change * SBQ change → outcome) were also significant at each follow-up for each outcome with ßindirect ranging from .091 to .162. Models also found significant positive paths from treatment group to the slope of MEQ and RRS-B during treatment, with light therapy showing a greater increase in "morningness" and CBT-SAD showing a greater decrease in brooding during active treatment; however, neither construct emerged as a mediator of follow-up depression scores. Change in seasonal beliefs during treatment mediates both the acute antidepressant and long-term effects of CBT-SAD and explains lower depression severity following CBT-SAD relative to light therapy.

Elucidating treatment targets and mediators within a confirmatory efficacy trial: study protocol for a randomized controlled trial of cognitive-behavioral therapy vs. light therapy for winter depression.

BACKGROUND: This study is a confirmatory efficacy trial of two treatments for winter seasonal affective disorder (SAD): SAD-tailored group cognitive-behavioral therapy (CBT-SAD) and light therapy (LT). In our previous efficacy trial, post-treatment outcomes for CBT-SAD and LT were very similar, but CBT-SAD was associated with fewer depression recurrences two winters later than LT (27.3% in CBT-SAD vs. 45.6% in LT). CBT-SAD engaged and altered a specific mechanism of action, seasonal beliefs, which mediated CBT-SAD's acute antidepressant effects and CBT-SAD's enduring benefit over LT. Seasonal beliefs are theoretically distinct from LT's assumed target and mechanism: correction of circadian phase. This study applies the experimental therapeutics approach to determine how each treatment works when it is effective and to identify the best candidates for each. Biomarkers of LT's target and effect include circadian phase angle difference and the post-illumination pupil response. Biomarkers of CBT-SAD's target and effect include decreased pupillary and sustained frontal gamma-band EEG responses to seasonal words, which are hypothesized as biomarkers of seasonal beliefs, reflecting less engagement with seasonal stimuli following CBT-SAD. In addition to determining change mechanisms, this study tests the efficacy of a "switch" decision rule upon recurrence to inform clinical decision-making in practice. METHODS: Adults with SAD (target N = 160) will be randomzied to 6-weeks of CBT-SAD or LT in winter 1; followed in winter 2; and, if a depression recurrence occurs, offered cross-over into the alternate treatment (i.e., switch from LT➔CBT-SAD or CBT-SAD➔LT). All subjects will be followed in winter 3. Biomarker assessments occur at pre-, mid-, and post-treatment in winter 1, at winter 2 follow-up (and again at mid-/post-treatment for those crossed-over), and at winter 3 follow-up. Primary efficacy analyses will test superiority of CBT-SAD over LT on depression recurrence status (the primary outcome). Mediation analyses will use parallel process latent growth curve modeling. DISCUSSION: Consistent with the National Institute of Mental Health's priorities for demonstrating target engagement at the level of Research Domain Criteria-relevant biomarkers, this work aims to confirm the targets and mechanisms of LT and CBT-SAD to maximize the impact of future dissemination efforts. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03691792 . Registered on October 2, 2018.

Light therapy for seasonal affective disorder in visual impairment and blindness - a pilot study.

OBJECTIVE: Seasonal and non-seasonal depression are prevalent conditions in visual impairment (VI). We assessed the effects and side effects of light therapy in persons with severe VI/blindness who experienced recurrent depressive symptoms in winter corresponding to seasonal affective disorder (SAD) or subsyndromal SAD (sSAD). RESULTS: We included 18 persons (11 with severe VI, 3 with light perception and 4 with no light perception) who met screening criteria for sSAD/SAD in a single-arm, assessor-blinded trial of 6 weeks light therapy. In the 12 persons who completed the 6 weeks of treatment, the post-treatment depression score was reduced (p < 0.001), and subjective wellbeing (p = 0.01) and sleep quality were improved (p = 0.03). In 6/12 participants (50%), the post-treatment depression score was below the cut-off set for remission. In four participants with VI, side effects (glare or transiently altered visual function) led to dropout or exclusion. CONCLUSION: Light therapy was associated with a reduction in depressive symptoms in persons with severe VI/blindness. Eye safety remains a concern in persons with residual sight.

Seasonal Affective Disorder: Common Questions and Answers.

Seasonal affective disorder is a mood disorder that is a subtype or qualifier of major depressive disorder or bipolar disorder in the Diagnostic and Statistical Manual of Mental Disorders. It is characterized by depressive symptoms that occur at a specific time of year (typically fall or winter) with full remission at other times of year (typically spring or summer). Possible risk factors include family history, female sex, living at a more northern latitude, and young adulthood (18 to 30 years of age). With the temporal nature of the mood episodes, diagnosis requires full remission when the specified season ends and two consecutive years of episodes in the same season. First-line therapy for seasonal affective disorder includes light therapy, antidepressants, and cognitive behavior therapy, alone or in combination. Commercial devices are available for administering light therapy or dawn simulation. The light intensity and duration of treatment depend on the device and the patient's initial response, but 2,500 to 10,000 lux for 30 to 60 minutes at the same time every day is typically effective. Lifestyle interventions, such as increasing exercise and exposure to natural light, are also recommended. If seasonal affective disorder recurs, long-term treatment or preventive intervention is typically indicated, and bupropion appears to have the strongest evidence supporting long-term use. Continuing light therapy or other antidepressants is likely beneficial, although evidence is inconclusive. Evidence is also inconclusive for psychotherapy and vitamin D supplementation.

Light therapy in non-seasonal depression: An update meta-analysis.

The effect of light therapy in treating seasonal affective disorder has been demonstrated amongst previous studies. However, the effect of light therapy in treating non-seasonal depression remains unclear. This meta-analysis aimed to determine the efficacy of light therapy in non-seasonal depression. We searched for randomized controlled trials (RCTs) in the PubMed, Web of Science, Chinese National Knowledge Infrastructure, and Chinese Biomedical Database up to February 2020. The pooled post-trial standardized mean difference in depression scores with corresponding 95% confidence intervals was calculated to evaluate the efficacy of light therapy in non-seasonal depression. A total of 23 RCTs with 1120 participants were included. The meta-analysis demonstrated the light therapy was significantly more effective than comparative treatments. Subgroup analyses revealed that none of the factors explained the significantly heterogeneity. Light therapy has a statistically significant mild to moderate treatment effect in reducing depressive symptoms, can be used as a clinical therapy in treating non-seasonal depression. But the quality of evidence is still low, more well-designed studies with larger sample size and high quality are needed to confirm the efficiency of light therapy in treating non-seasonal depression.

A measure of cognitions specific to seasonal depression: Development and validation of the Seasonal Beliefs Questionnaire.

We introduce the Seasonal Beliefs Questionnaire (SBQ), a self-report inventory of maladaptive thoughts about the seasons, light availability, and weather conditions, proposed to constitute a unique cognitive vulnerability to winter seasonal affective disorder (SAD; Rohan, Roecklein, & Haaga, 2009). Potential items were derived from a qualitative analysis of self-reported thoughts during SAD-tailored cognitive-behavioral therapy (CBT-SAD) and subsequently refined based on qualitative feedback from 48 SAD patients. In the psychometric study (N = 536 college students), exploratory and confirmatory factor analyses pruned the items to a 26-item scale with a 5-factor solution, demonstrating good internal consistency, convergent and divergent validity, and 2-week test-retest reliability. In a known groups comparison, the SBQ discriminated SAD patients (n = 86) from both nonseasonal major depressive disorder (MDD) patients (n = 30) and healthy controls (n = 110), whereas a generic measure of depressogenic cognitive vulnerability (the Dysfunctional Attitudes Scale [DAS]) discriminated MDD patients from the other groups. In a randomized clinical trial comparing CBT-SAD with light therapy (N = 177), SBQ scores improved at twice the rate in CBT-SAD than in light therapy. Greater change in SBQ scores during CBT-SAD, but not during light therapy, was associated with a lower risk of depression recurrence 2 winters later. In contrast, DAS scores improved comparably during CBT-SAD and light therapy, and DAS change was unrelated to recurrence following either treatment. These results support using the SBQ as a brief assessment tool for a SAD-specific cognitive vulnerability and as a treatment target in CBT-SAD. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Precision Light for the Treatment of Psychiatric Disorders.

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

Stability of the diagnosis of seasonal affective disorder in a long-term prospective study.

BACKGROUND: Seasonal affective disorder (SAD) is mainly characterized by a seasonal pattern of depressive recurrences over the years. However, few studies have been conducted on the long-term course of patients with SAD, whose findings raised questions about the diagnosis stability over time. This study aimed to better characterize the diagnosis evolution, and determine prognosis markers. METHODS: An initial cohort of 225 outpatients diagnosed as having a SAD, was assessed at baseline (T1) for clinical symptoms and response to bright light therapy. One hundred and nineteen patients (53%) were interviewed 2-12 years after (T2). RESULTS: Of 119 patients reached at follow-up (T2), only 32 patients (27%) still fulfilled the DSM-IV criteria for a stable SAD (S-SAD). A large proportion (59%) of the follow up cohort was in remission and 14% still suffered from a non-seasonal mood disorder. Family history of depression, previous suicide attempt, carbohydrate craving and HAD-depression score at baseline were associated with a stable SAD (S-SAD) diagnosis at T2, the HAD-depression score being the only one still significantly predictive (p=0.025) of a later stable SAD, with a multivariate approach. Carbohydrate craving, a core symptom of SAD, showed a trend (p=0.100) to predict diagnosis stability. LIMITATIONS: Only 53% patients from the initial cohort were assessed at follow-up. CONCLUSIONS: Patients with eventual stable SAD show more subjective severity (higher HAD-Depression score) and carbohydrate craving at baseline. A low predictive validity of diagnosis criteria suggests that SAD is a temporary expression of a mood disorder rather than a specific disorder.

The relation between chronotype and treatment outcome with light therapy on a fixed time schedule.

BACKGROUND: Seasonal affective disorder (SAD) is characterized by recurrent episodes of major depression in a seasonal pattern. The therapy of choice is light therapy (LT). It is suggested that LT should be administered relative to the chronotype of the patient, with the optimal timing earlier for morning than for evening types. This study aims to retrospectively investigate the relation between chronotype and the effect of LT on a fixed time in the morning in a population of SAD patients. METHODS: Data from four different studies conducted at the University Center of Psychiatry in Groningen, the Netherlands was used. Data from 132 patients was used (103 women). Depression score was determined by a structured interview (SIGH-SAD) prior to LT and after LT. Prior to LT morningness/eveningness preference of the patient was determined by the 'Morningness/Eveningness Questionnaire' (MEQ). All patients received LT at 8:00 AM at the clinic, independent of chronotype. RESULTS: Patients had an average MEQ score of 51.5±8.2. There was no significant relationship between MEQ score and therapy success as measured with the SIGH-SAD (F2,129=0.05, ns). When patients were divided by chronotype (ranging from definite morning to moderate evening) no significant relation between MEQ score and therapy success was found (F2,129=0.02, ns). LIMITATIONS: Retrospective design. CONCLUSIONS: The lack of a significant relationship between chronotype, as measured with the MEQ, and therapy success with LT at a fixed timepoint may indicate that the anti-depressive effect of morning light in SAD patients is not explained by a phase shift of the biological clock.

Treatment expectations for cognitive-behavioral therapy and light therapy for seasonal affective disorder: Change across treatment and relation to outcome.

OBJECTIVE: To examine the dynamic relationship between treatment expectations and treatment outcome over the course of a clinical trial for winter seasonal affective disorder (SAD). METHOD: Currently depressed adults with Major Depression, Recurrent with Seasonal Pattern (N = 177) were randomized to 6 weeks of group-delivered cognitive-behavioral therapy for SAD (CBT-SAD) or light therapy (LT). The majority were female (83.6%) and white (92.1%), with a mean age of 45.6 years. Treatment expectations for CBT-SAD and LT were assessed using a modification of the Treatment Expectancy and Credibility Survey (Borkovec & Nau, 1972). Depression severity was assessed using the Beck Depression Inventory-Second Edition (Beck, Steer, & Brown, 1996). All measures were administered at pretreatment, midtreatment, and posttreatment. RESULTS: As treatment progressed, expectations for the treatment received increased across time steeply in CBT-SAD patients and moderately in LT patients. Collapsing across time, patients with higher treatment expectations had lower depression severity than those with lower treatment expectations. In a cross-lagged panel path analysis, there was a significant effect of treatment expectations at midtreatment on depression severity at posttreatment among CBT-SAD patients. CONCLUSIONS: Treatment expectations changed across treatment, affected outcome, and should be assessed and monitored repeatedly throughout treatment. Findings suggest that treatment expectations at midtreatment are a mechanism by which CBT-SAD reduces depression, which should be replicated in SAD samples and examined for generalizability to nonseasonal depression. These findings underscore the importance of further research examining treatment expectations in mediating CBT's effects in depression and other types of psychopathology. (PsycINFO Database Record

The effects of low-intensity narrow-band blue-light treatment compared to bright white-light treatment in sub-syndromal seasonal affective disorder.

BACKGROUND: The discovery of a novel photoreceptor in the retinal ganglion cells with a highest sensitivity of 470-490 nm blue light has led to research on the effects of short-wavelength light in humans. Several studies have explored the efficacy of monochromatic blue or blue-enriched light in the treatment of SAD. In this study, a comparison has been made between the effects of broad-wavelength light without ultraviolet (UV) wavelengths compared to narrow-band blue light in the treatment of sub-syndromal seasonal affective disorder (Sub-SAD). METHOD: In a 15-day design, 48 participants suffering from Sub-SAD completed 20-minute sessions of light treatment on five consecutive days. 22 participants were given bright white-light treatment (BLT, broad-wavelength light without UV 10 000 lux, irradiance 31.7 Watt/m(2)) and 26 participants received narrow-band blue light (BLUE, 100 lux, irradiance 1.0 Watt/m(2)). All participants completed daily and weekly questionnaires concerning mood, activation, sleep quality, sleepiness and energy. Also, mood and energy levels were assessed by means of the SIGH-SAD, the primary outcome measure. RESULTS: On day 15, SIGH-SAD ratings were significantly lower than on day 1 (BLT 54.8 %, effect size 1.7 and BLUE 50.7 %, effect size 1.9). No statistically significant differences were found on the main outcome measures. CONCLUSION: Light treatment is an effective treatment for Sub-SAD. The use of narrow-band blue-light treatment is equally effective as bright white-light treatment. TRIAL REGISTRATION: This study was registered in the Dutch Trial Register (Nederlands Trial Register TC = 4342 ) (20-12-2013).

Outcomes One and Two Winters Following Cognitive-Behavioral Therapy or Light Therapy for Seasonal Affective Disorder.

OBJECTIVE: The central public health challenge for winter seasonal affective disorder (SAD) is recurrence prevention. Preliminary studies suggest better long-term outcomes following cognitive-behavioral therapy tailored for SAD (CBT-SAD) than light therapy. The present study is a large, randomized head-to-head comparison of these treatments on outcomes one and two winters after acute treatment. METHOD: Community adults with major depression, recurrent with seasonal pattern (N=177) were followed one and two winters after a randomized trial of 6 weeks of CBT-SAD (N=88) or light therapy (N=89). Prospective follow-up visits occurred in January or February of each year, and major depression status was assessed by telephone in October and December of the first year. The primary outcome was winter depression recurrence status on the Structured Interview Guide for the Hamilton Depression Rating Scale-Seasonal Affective Disorder Version (SIGH-SAD). Other outcomes were depression severity on the SIGH-SAD and the Beck Depression Inventory-Second Edition (BDI-II), remission status based on severity cutoff scores, and major depression status from tracking calls. RESULTS: The treatments did not differ on any outcome during the first year of follow-up. At the second winter, CBT-SAD was associated with a smaller proportion of SIGH-SAD recurrences (27.3% compared with 45.6%), less severe symptoms on both measures, and a larger proportion of remissions defined as a BDI-II score ≤8 (68.3% compared with 44.5%) compared with light therapy. Nonrecurrence at the next winter was more highly associated with nonrecurrence at the second winter among CBT-SAD participants (relative risk=5.12) compared with light therapy participants (relative risk=1.92). CONCLUSIONS: CBT-SAD was superior to light therapy two winters following acute treatment, suggesting greater durability for CBT-SAD.

Seasonal affective disorder, grief reaction, and adjustment disorder.

Seasonal affective disorder is a subtype of other affective disorders. The most studied treatment is light therapy, although second-generation antidepressants are also an option. Grief reactions are normal for patients experiencing loss, and primary care providers (PCPs) should be aware of both the expected course of grief and the more severe symptoms that indicate complex grief. Adjustment disorder is a time-limited abnormal response to a stressor. PCPs can manage patients with adjustment disorder by arranging counseling, screening for suicidality, assessing for substance abuse, and ruling out other psychiatric diagnoses. At present there are no reliable data to suggest medication management.

Seasonal affective disorder: is there light at the end of the tunnel?

Seasonal affective disorder, which is underdiagnosed in the primary care setting, is a mood disorder subtype characterized by episodic major depression that typically develops in winter when daylight hours are short. Patients with SAD experience increased morbidity and decreased quality of life. This article focuses on recognition and management of this condition. Light therapy is the preferred treatment for SAD because it is safe and easy to administer; light therapy may be combined with pharmacologic therapy. Cognitive behavioral therapy (CBT) also has a positive therapeutic effect when combined with light therapy and may help prevent SAD in subsequent seasons.

Cognitive-behavioral therapy vs. light therapy for preventing winter depression recurrence: study protocol for a randomized controlled trial.

BACKGROUND: Seasonal affective disorder (SAD) is a subtype of recurrent depression involving major depressive episodes during the fall and/or winter months that remit in the spring. The central public health challenge in the management of SAD is prevention of winter depression recurrence. Light therapy (LT) is the established and best available acute SAD treatment. However, long-term compliance with daily LT from first symptom through spontaneous springtime remission every fall/winter season is poor. Time-limited alternative treatments with effects that endure beyond the cessation of acute treatment are needed to prevent the annual recurrence of SAD. METHODS/DESIGN: This is an NIMH-funded R01-level randomized clinical trial to test the efficacy of a novel, SAD-tailored cognitive-behavioral group therapy (CBT) against LT in a head-to-head comparison on next winter outcomes. This project is designed to test for a clinically meaningful difference between CBT and LT on depression recurrence in the next winter (the primary outcome). This is a concurrent two-arm study that will randomize 160 currently symptomatic community adults with major depression, recurrent with seasonal pattern, to CBT or LT. After 6 weeks of treatment in the initial winter, participants are followed in the subsequent summer, the next winter, and two winters later. Key methodological issues surround timing study procedures for a predictably recurrent and time-limited disorder with a focus on long-term outcomes. DISCUSSION: The chosen design answers the primary question of whether prior exposure to CBT is associated with a substantially lower likelihood of depression recurrence the next winter than LT. This design does not test the relative contributions of the cognitive-behavioral treatment components vs. nonspecific factors to CBT's outcomes and is not adequately powered to test for differences or equivalence between cells at treatment endpoint. Alternative designs addressing these limitations would have required more patients, increased costs, and reduced power to detect a difference in the primary outcome. TRIAL REGISTRATION: Clinicaltrials.gov identifier NCT01714050.

Seasonal affective disorder.

Seasonal affective disorder is a combination of biologic and mood disturbances with a seasonal pattern, typically occurring in the autumn and winter with remission in the spring or summer. In a given year, about 5 percent of the U.S. population experiences seasonal affective disorder, with symptoms present for about 40 percent of the year. Although the condition is seasonally limited, patients may have significant impairment from the associated depressive symptoms. Treatment can improve these symptoms and also may be used as prophylaxis before the subsequent autumn and winter seasons. Light therapy is generally well tolerated, with most patients experiencing clinical improvement within one to two weeks after the start of treatment. To avoid relapse, light therapy should continue through the end of the winter season until spontaneous remission of symptoms in the spring or summer. Pharmacotherapy with antidepressants and cognitive behavior therapy are also appropriate treatment options and have been shown to be as effective as light therapy. Because of the comparable effectiveness of treatment options, first-line management should be guided by patient preference.

Improvement in depression scores after 1 hour of light therapy treatment in patients with seasonal affective disorder.

The purpose of this study was to investigate possible rapid effects of light therapy on depressed mood in patients with seasonal affective disorder. Participants received 1 hour of bright light therapy and 1 hour of placebo dim red light in a randomized order crossover design. Depressed mood was measured at baseline and after each hour of light treatment using two self-report depression scales (Profile of Mood States-Depression-Dejection [POMS-D] subscale and the Beck Depression Inventory II [BDI-II]). When light effects were grouped for the two sessions, there was significantly greater reduction in self-report depression scores by -1.3 (p = 0.02) on the BDI-II and -1.2 (p = 0.02) on the POMS-D. A significant but modest improvement was detected after a single active light session. This is the first study, to our knowledge, to document an immediate improvement with light treatment using a placebo-controlled design with a clinical sample of depressed individuals.