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.

Detecting Critical Decision Points during Cognitive-Behavioral Therapy and Light Therapy for Winter Depression Nonremission and Recurrence.

Using data from a clinical trial comparing cognitive-behavioral therapy (CBT-SAD) and light therapy (LT) for winter seasonal affective disorder (SAD; N = 177), we explored critical decision points, or treatment weeks, that predict likelihood of nonremission at post-treatment and depression recurrence following treatment. In receiver operator characteristic (ROC) curve analyses, we used weekly Structured Clinical Interview for the Hamilton Rating Scale for Depression-SAD Version (SIGH-SAD) scores during treatment to predict nonremission at post-treatment (Week 6) and recurrence one winter later (Winter 1), two winters later (Winter 2), and any recurrence. Although several C-statistics of ≥ .70 were found, only Week 4 SIGH-SAD scores in CBT-SAD for nonremission had enough predictive ability to inform clinical decision-making (C-statistic = .80; sensitivity = .91; specificity = .68). Week 4 of CBT-SAD may be a critical time point to identify likely nonremitters who need tailoring of intervention, based on SIGH-SAD cutpoint score ≥ 13. This study illustrates how clinical trial data can inform detecting optimal decision points in treatment for identifying patients unlikely to remit, a critical first step to developing adaptive treatment strategies using decision rules to operationalize when and for whom treatment should change to maximize clinical benefit.

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).