Elsevier

Comprehensive Psychiatry

Volume 55, Issue 8, November 2014, Pages 1891-1899
Comprehensive Psychiatry

Seasonal variation of depressive symptoms in unipolar major depressive disorder

https://doi.org/10.1016/j.comppsych.2014.07.021Get rights and content

Abstract

Objectives

Retrospective and cross-sectional studies of seasonal variation of depressive symptoms in unipolar major depression have yielded conflicting results. We examined seasonal variation of mood symptoms in a long-term prospective cohort – the Collaborative Depression Study (CDS).

Methods

The sample included 298 CDS participants from five academic centers with a prospectively derived diagnosis of unipolar major depression who were followed for at least ten years of annual or semi-annual assessments. Generalized linear mixed models were utilized to investigate the presence of seasonal patterns. In a subset of 271 participants followed for at least 20 years, the stability of a winter depressive pattern was assessed across the first two decades of follow-up.

Results

A small increase in proportion of time depressed was found in the months surrounding the winter solstice, although the greatest symptom burden was seen in December through April with a peak in March. The relative burden of winter depressive symptoms in the first decade demonstrated no relationship to that of the second decade. The onset of new episodes was highest October through January, peaking in January.

Conclusions

There exists a small but statistically significant peak in depressive symptoms from the month of the winter solstice to the month of the spring equinox. However, the predominance of winter depressive symptoms did not appear stable over the long-term course of illness.

Introduction

Documentation of seasonal variation in mood states dates back to the time of Hippocrates. Evidence for this phenomenon ranges from prospective symptom tracking to retrospective interrogation with the Seasonal Patterns of Affective Disorders Questionnaire (SPAQ) to global Internet search patterns – all of which have reported seasonal mood patterns in patients and in the general population [1], [2], [3], [4], [5], [6]. This “seasonality” of mood seems to lie on a spectrum of severity [7], with the more extreme cases falling under the description of “seasonal affective disorder,” or SAD, as established by Rosenthal et al. in 1984 [8]. It has been estimated that in any given year, 5% of the U.S. population and up to 9.7% of the population in other countries may suffer from SAD [9], [10], while the prevalence of SAD in patients with major depression has been estimated at between 10 and 20% [10], suggesting greater seasonal mood fluctuation in those with unipolar major depressive disorder (MDD).

As the first criterion in Rosenthal's proposed definition of SAD is “A history of major affective disorder, according to the RDC” (Research Diagnostic Criteria) [8], an increased incidence of SAD within those with MDD is not only to be expected, but by at least this definition must be the case since those with syndromal depression cannot meet the Rosenthal criteria. However, much of the epidemiological data on SAD to date has been generated using the SPAQ, which assays seasonality independent of a mood disorder diagnosis. High scores could thus reflect seasonal variation in specific symptoms rather than changes in point prevalence of SAD, and the SPAQ may therefore overestimate the prevalence of MDD, seasonal pattern (MDD-SP) [1], [11], [12]. In fact, one study found that neither the Global Seasonality Score (GSS) nor the report of season change as a problem on the SPAQ predicted longitudinal mood ratings [13]. Other key limitations of the SPAQ include its retrospective and seasonality-specific nature, which subjects it to recall and measurement biases, respectively. Indeed, the SPAQ has been shown to exaggerate seasonal mood differences as compared to prospective assessments in certain populations [1].

To address these limitations in studying the seasonality of major depressive episodes, some have administered non-seasonality-specific mood assessments to depressed patient populations in a cross-sectional manner throughout the different seasons. The evidence of seasonality from these investigations – even within single studies – has been inconclusive. For example, data from the U.S. National Comorbidity Survey showed that 10–20% of people with MDD had symptoms that recurred at consistent times each year [11], but only 0.4% met strict Diagnostic and Statistical Manual (DSM) criteria for MDD-SP. Similarly, a study of 2225 general practice patients in London showed that while those with RDC major depression had significant peaks for episode onset in the winter and recovery in the summer [14], corresponding winter and summer changes in General Health Questionnaire scores did not cross the threshold of statistical significance.

Retrospective chart review was utilized to construct course of illness by Faedda et al., who applied DSM-III-R MDD-SP criteria to clinical records of 557 outpatients with recurrent depression. Over an average of 12 years of documented illness course, 75 (13.5%) with recurrent depression had a seasonal pattern [15], with high intra-individual stability in timing of depressive episode onset and remission. Based upon the large sample, longitudinal nature and substantial “follow-up” period, this study offers the most compelling current evidence of seasonal patterns in unipolar depression.

This finding was not replicated, however, in a similar setting. Posternak et al. retrospectively examined presentation patterns of 1500 consecutive patients at a Rhode Island outpatient psychiatric clinic and reported no significant seasonal changes in the rate of depressive symptoms or proportion of patients diagnosed with MDD [16]. Similarly, a large cross-sectional study in the Netherlands found no significant effect of season of administration on overall scores on the Inventory of Depressive Symptoms (IDS), though atypical and melancholic IDS scores were heightened during the winter [17]. Additionally, a study by Hardin et al. reported no significant difference between depressed patients and controls on SPAQ global seasonality scores [18].

The existing literature on seasonality in MDD is problematic not only due to these discordant results, but in that much of the research is cross-sectional or based on patterns of patient presentation or admission to health care facilities, and not on systematic, prospective follow-up. Those studies which have examined the same patients over a number of years are either retrospective or focused on individuals already diagnosed with SAD or recurrent depression-seasonal pattern to study illness course and diagnostic stability [19], [20], [21], [22]. Prospective studies are further limited by inadequate duration, small sample sizes and confounding effects of treatment. For example, Sakamoto et al., which offers the longest prospective look at SAD patients with a mean follow-up of 6 years, did not systematically control for treatment and included only 25 patients, analyzing those with bipolar disorder and unipolar major depression together [19].

In sum, the degree to which patients with unipolar major depression experience varying symptom severity coincidental with the changing seasons has not been adequately examined in a prospective manner over an extended period using a standardized, non-seasonality-specific assessment. We sought to assess the monthly burden of clinically significant depressive symptoms over long-term follow-up in a clinical sample with unipolar MDD. Although some studies report spring and/or fall peaks in depression onset [15], [23], most of the literature on MDD-SP and SAD suggests that depressive symptoms are worst in the winter (variably defined in different studies as spanning November or December through January or February), at least in certain subgroups [1], [2], [3], [14], [24], [25], [26], [27], [28]; this encompasses a wide range of data, including hospital admission rates, SPAQ responses and standardized mood assessments. Thus, we hypothesized that those with MDD would have a peak in depressive symptomatology in the months surrounding the winter solstice (e.g. November, December, January), which would be consistent with our findings in bipolar disorder [29]. Lastly, we attempted to identify whether this pattern would persist over 20 years of follow-up.

Section snippets

Participants

The CDS included individuals with mood disorders from the following academic centers: Harvard University (Boston), Rush Presbyterian-St. Luke's Medical Center (Chicago), University of Iowa (Iowa City), New York State Psychiatric Institute and Columbia University (New York City), and Washington University School of Medicine (St. Louis). Participants were European-American (genetic hypotheses were tested), spoke English, had an IQ score of at least 70, and no evidence of terminal medical illness

Results

Our sample included 298 participants with unipolar major depression and was predominantly female (63%) as shown in Table 3. When contrasted to the 174 participants with a prospective diagnosis of unipolar major depression who did not complete 10 years of follow-up, our sample was more likely to be female (χ2 = 6.2, df = 1, p = 0.01) and less likely to have a diagnosis of alcoholism at intake (χ2 = 8.0, df = 1, p < 0.01). They also tended to have a younger age of onset (26.7 vs. 32.1 years, Wilcoxon Z = 3.4, p < 

Discussion

In the present study we found that, on average, participants with unipolar major depression spent a greater proportion of time depressed in the months surrounding the winter solstice, though this difference only reached significance when using the post hoc December–April seasonal indicator. Statistics for the December–April indicator are subsequently best framed as hypothesis-generating and the observed peak was considered most appropriate for the assessment of the long-term stability of

Acknowledgment

This study was funded by NIMH grants 5R01MH025416-33 (W Coryell), 5R01MH023864-35 (J Endicott), 5R01MH025478-33 (M Keller), 5R01MH025430-33 (J Rice), and 5R01MH029957-30 (WA Scheftner). Dr. Fiedorowicz is supported by the National Institutes of Health (1K23MH083695-01A210).

Dr. Solomon serves as Deputy Editor to UpToDate.com. Dr. Keller has served as a consultant or received honoraria for CENEREX, Medtronic, and Sierra Neuropharmaceuticals. He has received grant/research support from Pfizer. He

References (48)

  • T.A. Wehr et al.

    Contrasts between symptoms of summer depression and winter depression

    J Affect Disord

    (1991)
  • A.J. Levitt et al.

    Anxiety disorders and anxiety symptoms in a clinic sample of seasonal and non-seasonal depressives

    J Affect Disord

    (1993)
  • K. Nayyar et al.

    Seasonal changes in affective state measured prospectively and retrospectively

    Br J Psychiatry

    (1996)
  • S. Kasper et al.

    Epidemiological findings of seasonal changes in mood and behavior. A telephone survey of Montgomery County, Maryland

    Arch Gen Psychiatry

    (1989)
  • M.G. Harmatz et al.

    Seasonal variation of depression and other moods: a longitudinal approach

    J Biol Rhythms

    (2000)
  • G. Murray et al.

    A longitudinal investigation of seasonal variation in mood

    Chronobiol Int

    (2001)
  • A.C. Yang et al.

    Do seasons have an influence on the incidence of depression? The use of an internet search engine query data as a proxy of human affect

    PLoS One

    (2010)
  • T.A. Wehr et al.

    Seasonality and affective illness

    Am J Psychiatry

    (1989)
  • N.E. Rosenthal et al.

    Seasonal affective disorder. A description of the syndrome and preliminary findings with light therapy

    Arch Gen Psychiatry

    (1984)
  • S.L. Kurlansik et al.

    Seasonal affective disorder

    Am Fam Physician

    (2012)
  • A. Magnusson

    An overview of epidemiological studies on seasonal affective disorder

    Acta Psychiatr Scand

    (2000)
  • D.G. Blazer et al.

    Epidemiology of recurrent major and minor depression with a seasonal pattern. The National Comorbidity Survey

    Br J Psychiatry

    (1998)
  • A.J. Levitt et al.

    Estimated prevalence of the seasonal subtype of major depression in a Canadian community sample

    Can J Psychiatry

    (2000)
  • G.L. Faedda et al.

    Seasonal mood disorders. Patterns of seasonal recurrence in mania and depression

    Arch Gen Psychiatry

    (1993)
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