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.

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).

Rest-activity rhythms characteristics and seasonal changes in seasonal affective disorder.

Identifying objectively measurable seasonal changes in 24-h activity patterns (rest-activity rhythms or RARs) that occur in seasonal affective disorder (SAD) could help guide research and practice towards new monitoring tools or prevention targets. We quantified RARs from actigraphy data using non-parametric and extended cosine based approaches, then compared RARs between people with SAD and healthy controls in the summer (n = 70) and winter seasons (n = 84). We also characterized the within-person seasonal RAR changes that occurred in the SAD (n = 19) and control (n = 26) participants who contributed repeated measures. Only controls had significant winter increases in RAR fragmentation (intra-daily variability; in controls mean winter-summer changes (log scale) = 0.05, 0.21 standard deviation, p = 0.03). In SAD participants only, estimated evening settling times (down-mesor) were an average of 30 min earlier in the winter compared with the summer (1-h standard deviation, p = 0.045). These RAR characteristics correlated with greater fatigue (Spearman r = 0.36) but not depression symptom severity. Additional research is needed to ascertain why healthy controls, but not people with SAD, appear to have increased RAR fragmentation in the winter. People with SAD lacked this increase in RAR fragmentation, and instead had earlier evening setting in the winter. Prospective and intervention studies with greater temporal resolution are warranted to ascertain how these seasonal behavioral differences relate to fatigue pathophysiology in SAD. Future research is needed to determine whether extending the winter active period, even in relatively fragmented bouts, could help reduce the fatigue symptoms common in SAD.

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

BACKGROUND: Ever since a new photoreceptor was discovered with a highest sensitivity to 470-490 nm blue light, it has been speculated that blue light has some advantages in the treatment of Seasonal Affective Disorder (SAD) over more traditional treatments. In this study we compared the effects of exposure to narrow-band blue light (BLUE) to those of broad-wavelength white light (BLT) in the treatment of SAD. METHODS: In a 15-day design, 45 patients suffering from SAD completed 30-min sessions of light treatment on 5 consecutive days. 21 subjects received white-light treatment (BLT, broad-wavelength without UV, 10 000 lx, irradiance 31.7 W/m2), 24 subjects received narrow-band blue light (BLUE, 100 lx, irradiance 1.0 W/m2). All participants completed weekly questionnaires concerning mood and energy levels, and were also assessed by means of the SIGH-SAD, which is the primary outcome measure. RESULTS: On day 15, SIGH-SAD ratings were significantly lower than on day 1 (BLT 73.2%, effect size 3.37; BLUE 67%, effect size 2.63), which outcomes were not statistically significant different between both conditions. LIMITATIONS: Small sample size. CONCLUSIONS: Light treatment is an effective treatment for SAD. The use of narrow-band blue light is equally effective as a treatment using bright white-light.

Efficacy of bright light therapy in bipolar depression.

For 30 years, bright light therapy (BLT) has been considered as an effective, well-tolerated treatment for seasonal affective disorder (SAD). Because of low response rates, new treatment strategies are needed for bipolar depression (BD), which resembles SAD in certain respects. Few placebo-controlled studies of BLT efficacy have been carried out for BD. Accordingly, this study evaluates the efficacy and safety of BLT as an add-on treatment for BD. Thirty-two BD outpatients were randomly assigned to BLT (10000lx) or dim light (DL, < 500lx). During a two-week period, light was administered each morning for 30min. The Hamilton Rating Scale for Depression and the Montgomery-Ǻsberg Depression Rating Scale assessed clinical outcome, and the UKU Side Effects Rating Scale evaluated side effects. No significant difference was observed in baseline depression scores in the two groups. Response rates for BLT and DL were 81% and 19%, and remission rates were 44% and 12.5%, respectively. Analyses showed statistically significant reductions in depression scores for the BLT group compared with the DL group on all scales. Side effects were similar in both groups, with headache as the most common side effect. The results suggest that BLT is an effective and safe add-on treatment for BD.

Altered soluble epoxide hydrolase-derived oxylipins in patients with seasonal major depression: An exploratory study.

Many cytochrome p450-derived lipids promote resolution of inflammation, in contrast to their soluble epoxide hydrolase(sEH)-derived oxylipin breakdown products. Here we compare plasma oxylipins and precursor fatty acids between seasons in participants with major depressive disorder with seasonal pattern (MDD-s). Euthymic participants with a history of MDD-s recruited in summer-fall were followed-up in winter. At both visits, a structured clinical interview (DSM-5 criteria) and the Beck Depression Inventory II (BDI-II) were administered. Unesterified and total oxylipin pools were assayed by liquid chromatography tandem mass-spectrometry (LC-MS/MS). Precursor fatty acids were measured by gas chromatography. In nine unmedicated participants euthymic at baseline who met depression criteria in winter, BDI-II scores increased from 4.9±4.4 to 19.9±7.7. Four sEH-derived oxylipins increased in winter compared to summer-fall with moderate to large effect sizes. An auto-oxidation product (unesterified epoxyketooctadecadienoic acid) and lipoxygenase-derived 13-hydroxyoctadecadienoic acid also increased in winter. The cytochrome p450-derived 20-COOH-leukotriene B4 (unesterified) and total 14(15)-epoxyeicosatetraenoic acid, and the sEH-derived 14,15-dihydroxyeicostrienoic acid (unesterified), decreased in winter. We conclude that winter depression was associated with changes in cytochrome p450- and sEH-derived oxylipins, suggesting that seasonal shifts in omega-6 and omega-3 fatty acid metabolism mediated by sEH may underlie inflammatory states in symptomatic MDD-s.

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

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.

Dawn simulation vs. bright light in seasonal affective disorder: Treatment effects and subjective preference.

BACKGROUND: Studies comparing the efficacy of dawn simulation to conventional bright light for the treatment of seasonal affective disorder (in parallel groups) have yielded conflicting results. This crossover study investigated treatment outcomes and long-term treatment preference. METHODS: Forty winter depressives were treated for a week with bright light (4.300lx for 30-45min shortly after awakening) or dawn simulation (gradually increasing light during the last 30min of sleep achieving 100lx before alarm beep, with the dawn simulator placed closer to the open eyes for a further 15min: 250lx). The depression level was self-rated using SIGH-SAD-SR. RESULTS: Depression scores reduced similarly following bright light and dawn simulation: for 43.8% and 42.2% (medians), respectively; efficacy ratio was 23:17. The preference was also similar (21:19). Among those who preferred bright light, the most common reason was that they perceived the bright light to be more effective (19/21; it was more effective, p=0.0096; this subgroup tended to have more severe depression) and ease of use (6/21). Among those who preferred the dawn simulator, the reasons were a more "natural" action (9/19), device compactness and/or time-saving (10/19) and in 4 cases where bright light caused eyestrain. LIMITATIONS: Not overhead naturalistic light for dawn simulation, self-rating of depression. CONCLUSIONS: Dawn simulation is similarly effective to bright light in the treatment of winter depression. Patients with more severe depression tended to report greater improvement with bright light; in such cases, this would outweigh the non-clinical advantages of dawn simulation.

Mindfulness-based cognitive therapy for seasonal affective disorder: a pilot study.

BACKGROUND: The best available treatment for seasonal affective disorder (SAD) is light therapy. Yet, this treatment does not prevent recurrence of depression in subsequent seasons. The aim of the study is to gain preliminary insight in the efficacy of Mindfulness Based Cognitive Therapy (MBCT) in the prevention of SAD recurrence. METHODS: This is a randomized controlled pilot study, in which SAD patients in remission were randomly allocated to an individual format of MBCT or a control condition (i.e. treatment as usual). MBCT was given between May and June 2011, when there was no presence of depressive symptoms. The Inventory for Depressive Symptomatology Self-Report (IDS-SR), which patients received on a weekly basis from September 2011 to April 2012, was used to assess moment of recurrence (≥20) and severity at moment of recurrence. RESULTS: 23 SAD patients were randomized to MBCT and 23 to the control condition. Kaplan-Meier survival curve showed that the groups did not differ in moment of recurrence (χ²(1).41, p=.52). T-tests showed no group difference in mean IDS-SR scores at moment of recurrence (t(31)=-.52, p=.61). LIMITATIONS: The results are limited by small sample size (n=46) and missing data of weekly IDS-SR assessments. CONCLUSION: The findings of this pilot RCT suggest that individual MBCT is not effective in preventing a SAD recurrence when offered in a symptom free period (i.e. spring).

Effects of five-element music therapy on elderly people with seasonal affective disorder in a Chinese nursing home.

OBJECTIVE: To explore the effects of five-element music therapy on elderly patients with seasonal affective disorder in a Chinese nursing home. METHODS: The patients (n = 50) were recruited from a Shijingshan district nursing home in Beijing, China. They were randomly assigned to two groups, a treatment group and a control group, with 25 participants in each group. The patients received music therapy for 1-2 h each week over an 8-week period. The music therapy involved four phases: introduction, activities, listening to the Chinese five-element music, and a concluding phase. The participants in the control group did not listen to the five-element music. This study consisted of two parts: (a) a qualitative study that used focus groups to understand the feelings of the patients with seasonal affective disorder; (b) a quantitative study that involved administration of the self-rating depression scale (SDS) and Hamilton depression scale (HAMD) before and after treatment. RESULTS: (a) Qualitative analysis results: strength derived from the five-element group music therapy and emotional adjustment. The five-element group music therapy can reduce patients' psychological distress and let them feel inner peace and enhance their life satisfaction. (b) No significant difference in SDS and HAMD scores was found between the two groups (P > 0.05) prior to treatment. After treatment, the mean SDS score of the control group was 49.9 +/- 18.8, while the treatment group's score was 40.2 +/- 18.1. The HAMD score of the control group was 11.2 +/-3.1, and the treatment group's score was 8.8 +/- 4.9. Following 8 weeks of music therapy, the SDS and HAMD scores of the treatment group were significantly lower than those for the control group (P < 0.05). CONCLUSION: Five-element music therapy alleviated the symptoms of seasonal affective disorder in the elderly patients.

Bright light therapy for depression: a review of its effects on chronobiology and the autonomic nervous system.

Bright light therapy (BLT) is considered among the first-line treatments for seasonal affective disorder (SAD), yet a growing body of literature supports its use in other neuropsychiatric conditions including non-seasonal depression. Despite evidence of its antidepressant efficacy, clinical use of BLT remains highly variable internationally. In this article, we explore the autonomic effects of BLT and suggest that such effects may play a role in its antidepressant and chronotherapeutic properties. After providing a brief introduction on the clinical application of BLT, we review the chronobiological effects of BLT on depression and on the autonomic nervous system in depressed and non-depressed individuals with an emphasis on non-seasonal depression. Such a theory of autonomic modulation via BLT could serve to integrate aspects of recent work centered on alleviating allostatic load, the polyvagal theory, the neurovisceral integration model and emerging evidence on the roles of glutamate and gamma-hydroxybutyric acid (GABA).

The influence of light administration on interpersonal behavior and affect in people with mild to moderate seasonality.

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 21days with a washout period of 14days 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.

Cognitive predictors and moderators of winter depression treatment outcomes in cognitive-behavioral therapy vs. light therapy.

There is no empirical basis for determining which seasonal affective disorder (SAD) patients are best suited for what type of treatment. Using data from a parent clinical trial comparing light therapy (LT), cognitive-behavioral therapy (CBT), and their combination (CBT + LT) for SAD, we constructed hierarchical linear regression models to explore baseline cognitive vulnerability constructs (i.e., dysfunctional attitudes, negative automatic thoughts, response styles) as prognostic and prescriptive factors of acute and next winter depression outcomes. Cognitive constructs did not predict or moderate acute treatment outcomes. Baseline dysfunctional attitudes and negative automatic thoughts were prescriptive of next winter treatment outcomes. Participants with higher baseline levels of dysfunctional attitudes and negative automatic thoughts had less severe depression the next winter if treated with CBT than if treated with LT. In addition, participants randomized to solo LT who scored at or above the sample mean on these cognitive measures at baseline had more severe depressive symptoms the next winter relative to those who scored below the mean. Baseline dysfunctional attitudes and negative automatic thoughts did not predict treatment outcomes in participants assigned to solo CBT or CBT + LT. Therefore, SAD patients with extremely rigid cognitions did not fare as well in the subsequent winter if treated initially with solo LT. Such patients may be better suited for initial treatment with CBT, which directly targets cognitive vulnerability processes.