Winter depression and functional impairment among ambulatory primary care patients

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. 

Development of a conceptual model for research on cyclical variation of patient reported outcome measurements (PROMs) in patients with chronic conditions: a scoping review

Background

Although circadian, seasonal, and other cycles have been observed for a number of chronic conditions, their impact on patient reported outcomes measurements (PROMs) has not been systematically explored, rendering our understanding of the effect of time of measurement on PROM scores very limited. The aim was to conduct a scoping review to determine what is known about how intra-individual cyclical variation might affect the way individuals with chronic conditions respond to patient-reported outcome measures.

Methods

A protocol of a systematic scoping review was registered on PROSPERO (CRD42017058365). We developed a search strategy based on previous relevant reviews and implemented it in: MEDLINE, Embase, PsycINFO, and CINAHL. No restrictions were placed on article types and backward and forward citation searches were conducted. Screening and data extraction were independently completed by up to four reviewers. An adapted version of CASP criteria was used to appraise the quality of included articles. Concepts that were important in understanding the impact of cyclical variation on PROM scores were elicited from the papers and iteratively refined through discussion amongst the authors.

Results

2420 references resulted from the searches, with 33 articles meeting the inclusion criteria. Most study designs included observational research (particularly ecological momentary assessment), 2 were RCTs and 2 were systematic reviews. Studies mainly focused on specific health conditions: mental health, respiratory and musculoskeletal. There was a lack of qualitative research and theoretical framework to explore these concepts more fully. Five overarching concepts emerged: variation in outcomes, variation of scores, psychological status, individual factors, and environmental/situational factors. A conceptual model was developed outlining the relationships between these concepts.

Conclusions

There is empirical evidence that supports cyclical variation in PROM scores across different chronic conditions, with potential very significant implications for administration and interpretation of PROMs. The proposed conceptual model can support further research in this area.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41687-021-00395-x.

Assessing impairment using a configural measure

Assessing impairment in daily functioning is an important part of a mental health evaluation and of monitoring progress in treatment. The Seasonality Assessment Form includes five yes/no impairment items written to reflect the ways that patients intuitively describe their levels of impairment. However, the items are not mutually exclusive and are not summative so that impairment severity is represented by the configural pattern of responses. This article used configural and graphical methods to examine the nature of response patterns and how to use them to generate an impairment severity score.

Depressive mood and circadian rhythms disturbances as outcomes of seasonal affective disorder treatment: A systematic review

BACKGROUND

The present systematic review was aimed at critically summarizing the evidence about interventions focused on circadian rhythms and mood symptoms in seasonal affective disorder (SAD).

METHODS

A systematic search of the electronic databases PUBMED, PsycINFO and Web of Science was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Original papers reporting data about the effects of treatments on both mood and circadian rhythms disturbances in SAD patients were considered for inclusion. The quality of the evidence provided by the eligible studies was assessed using the Revised Cochrane Risk of Bias Tool (RoB 2.0) and the Cochrane Risk of Bias in Non-Randomized Studies of Interventions Tool (ROBINS-I).

RESULTS

Forty papers were deemed eligible for the systematic review. The evidence of treatment outcomes referring to circadian disturbances was not robust. Despite this, bright light therapy (BLT) demonstrates to phase-advance delayed rhythms and to improve sleep-wake disorders. As for mood symptoms, both BLT and selective serotonin reuptake inhibitors (SSRIs) show evidence of efficacy. The possible connection between improvements of mood symptoms and changes in circadian outcomes seems controversial.

LIMITATIONS

The included studies presented considerable methodological heterogeneity, small sample sizes and non-optimal sample selection.

CONCLUSIONS

The effectiveness of BLT in depressive symptoms and circadian disturbances of SAD was outlined by the present systematic review. The evidence about other biological and pharmacological treatments, although promising, should be replicated. A multifactorial etiopathogenesis could explain the heterogeneous clinical presentations of SAD and the complex link between mood and circadian symptoms.

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.

Season-independent cognitive deficits in seasonal affective disorder and their relation to depressive symptoms

Although cognitive impairments are common in depressed individuals, it is unclear which aspects of cognition are affected and whether they represent state or trait features of depression. We here exploited a naturalistic model, namely the seasonal fluctuations in depressed status in individuals with Seasonal Affective Disorder (SAD), to study depression-related cognition, longitudinally. Twenty-nine medication-free individuals diagnosed with winter-SAD and 30 demographically matched healthy controls with no seasonality symptoms completed the Letter-number Sequencing task (LNS), the Symbol Digit Modalities Test (SDMT) and the Simple Reaction Time (SRT) twice; in summer and in winter. Compared to controls, SAD individuals showed significant season-independent impairments in tasks measuring working memory (LNS), cognitive processing speed (SDMT) and motor speed (SRT). In SAD individuals, cognitive processing speed was significantly negatively associated with the seasonal change in SAD depressive symptoms. We present novel evidence that in SAD individuals, working memory, cognitive processing- and motor speed is not only impaired in the winter but also in the summer. This suggests that certain cognitive impairments are SAD traits. Furthermore, impairments in cognitive processing speed appear to be related to depressive symptoms in SAD. Reduced processing speed may thus constitute a SAD vulnerability trait marker.

Short photoperiod condition increases susceptibility to stress in adolescent male rats

The seasonality of depressive symptoms is prevalent in children and adolescents. However, the mechanisms that underlie such susceptibility to seasonal influences on mood disorders are unclear. We examined the effects of a short photoperiod condition on the susceptibility to subchronic unpredictable mild stress (SCUS) and rhythmic alterations of plasma corticosterone (CORT), melatonin, and neuropeptide Y (NPY) in adolescent male rats. Compared with the 12h/12h light/dark photoperiod control (CON) rats, the 8h/16h photoperiod SCUS rats exhibited significant anhedonia, a core symptom of human depression, together with a blunted diurnal rhythm and elevation of 24h CORT, melatonin, and NPY levels. The 8h/16h photoperiod condition also blunted the rhythmicity of CORT, caused a phase inversion of melatonin, and caused a phase delay of NPY compared with 12h/12h CON rats. Such abnormalities of plasma CORT, NPY, and melatonin might cause adolescent individuals to present higher stress reactivity and greater vulnerability to stress over their lifetimes. The present study provides evidence of the susceptibility to the seasonality of stress-related disorders in adolescence.

Seasonality shows evidence for polygenic architecture and genetic correlation with schizophrenia and bipolar disorder

OBJECTIVE

To test common genetic variants for association with seasonality (seasonal changes in mood and behavior) and to investigate whether there are shared genetic risk factors between psychiatric disorders and seasonality.

METHOD

Genome-wide association studies (GWASs) were conducted in Australian (between 1988 and 1990 and between 2010 and 2013) and Amish (between May 2010 and December 2011) samples in whom the Seasonal Pattern Assessment Questionnaire (SPAQ) had been administered, and the results were meta-analyzed in a total sample of 4,156 individuals. Genetic risk scores based on results from prior large GWAS studies of bipolar disorder, major depressive disorder (MDD), and schizophrenia were calculated to test for overlap in risk between psychiatric disorders and seasonality.

RESULTS

The most significant association was with rs11825064 (P = 1.7 × 10⁻⁶, β = 0.64, standard error = 0.13), an intergenic single nucleotide polymorphism (SNP) found on chromosome 11. The evidence for overlap in risk factors was strongest for schizophrenia and seasonality, with the schizophrenia genetic profile scores explaining 3% of the variance in log-transformed global seasonality scores. Bipolar disorder genetic profile scores were also associated with seasonality, although at much weaker levels (minimum P value = 3.4 × 10⁻³), and no evidence for overlap in risk was detected between MDD and seasonality.

CONCLUSIONS

Common SNPs of large effect most likely do not exist for seasonality in the populations examined. As expected, there were overlapping genetic risk factors for bipolar disorder (but not MDD) with seasonality. Unexpectedly, the risk for schizophrenia and seasonality had the largest overlap, an unprecedented finding that requires replication in other populations and has potential clinical implications considering overlapping cognitive deficits in seasonal affective disorders and schizophrenia.

Self-attributed seasonality of mood and behavior: a report from the Netherlands study of depression and anxiety

BACKGROUND

Seasonal changes in mood and behavior are considered to be common in the general population and in patients with psychiatric disorders. However, in several studies this seasonality could not be demonstrated. The present study examined self-attributed seasonality of depressive symptoms among patients with a lifetime diagnosis of a depressive disorder (D), an anxiety disorder (A), a comorbid depressive and anxiety disorder (DA), and healthy controls (HC).

METHODS

The CIDI was used to establish diagnoses according to DSM-IV criteria in 2,168 participants of the Netherlands Study of Depression and Anxiety (NESDA). The Seasonal Pattern Assessment Questionnaire (SPAQ) was administered to assess variation in mood and behavior.

RESULTS

Of the 2,168 participants 53.5% reported seasonality of mood. Highest percentages of low mood were seen in the winter months. Although all groups showed this pattern of lowered mood during the winter months, D, A, and DA were significantly (P < .001) more likely to experience seasonality is this respect. This was also shown for seasonal changes in energy, social activities, sleeping, eating, weight and for the Global Seasonality Score. A limitation of this study was the cross-sectional design.

CONCLUSIONS

Seasonal variation in mood and behavior was demonstrated for both participants with a lifetime diagnosis of depression and/or anxiety disorder and for healthy controls, but patients with anxiety and/or depression were more likely to experience this seasonal variation. Clinicians should take into account that the time of the year could influence the feelings of well- and ill-being of their patients.

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.

Cognitive Change across Cognitive-Behavioral and Light Therapy Treatments for Seasonal Affective Disorder: What Accounts for Clinical Status the Next Winter?

Efficacious treatments for seasonal affective disorder include light therapy and a seasonal affective disorder-tailored form of cognitive-behavioral therapy. Using data from a parent clinical trial, these secondary analyses examined the relationship between cognitive change over treatment with cognitive-behavioral therapy, light therapy, or combination treatment and mood outcomes the next winter. Sixty-nine participants were randomly assigned to 6-weeks of cognitive-behavioral therapy, light therapy, or combination treatment. Cognitive constructs (i.e., dysfunctional attitudes, negative automatic thoughts, and rumination) were assessed at pre- and post-treatment. Dysfunctional attitudes, negative automatic thoughts, and rumination improved over acute treatment, regardless of modality; however, in participants randomized to solo cognitive-behavioral therapy, a greater degree of improvement in dysfunctional attitudes and automatic thoughts was uniquely associated with less severe depressive symptoms the next winter. Change in maladaptive thoughts during acute treatment appears mechanistic of solo cognitive-behavioral therapy's enduring effects the next winter, but is simply a consequence of diminished depression in light therapy and combination treatment.

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.

Winter depression recurrence one year after cognitive-behavioral therapy, light therapy, or combination treatment

The central public health challenge in the management of seasonal affective disorder (SAD) is prevention of depression recurrence each fall/winter season. The need for time-limited treatments with enduring effects is underscored by questionable long-term compliance with clinical practice guidelines recommending daily light therapy during the symptomatic months each year. We previously developed a SAD-tailored group cognitive-behavioral therapy (CBT) and tested its acute efficacy in 2 pilot studies. Here, we report an intent-to-treat (ITT) analysis of outcomes during the subsequent winter season (i.e., approximately 1 year after acute treatment) using participants randomized to CBT, light therapy, and combination treatment across our pilot studies (N=69). We used multiple imputation to estimate next winter outcomes for the 17 individuals who dropped out during treatment, were withdrawn from protocol, or were lost to follow-up. The CBT (7.0%) and combination treatment (5.5%) groups had significantly smaller proportions of winter depression recurrences than the light therapy group (36.7%). CBT alone, but not combination treatment, was also associated with significantly lower interviewer- and patient-rated depression severity at 1 year as compared to light therapy alone. Among completers who provided 1-year data, all statistically significant differences between the CBT and light therapy groups persisted after adjustment for ongoing treatment with light therapy, antidepressants, and psychotherapy. If these findings are replicated, CBT could represent a more effective, practical, and palatable approach to long-term SAD management than light therapy.

Seasonal vegetative and affective symptoms in the Finnish general population: testing the dual vulnerability and latitude effect hypotheses

BACKGROUND

Prior studies identified a seasonal pattern in symptoms of depression in clinical and population-based samples. The aims of our study were to estimate the prevalence rates of routine seasonal variations in mood and behavior and of current depressive symptoms in the Finnish general population over 30 years, and to find differences, if any, between the northern and southern regions of residence.

METHODS

5749 participants aged 30-97 (3156 women and 2593 men) were interviewed face to face and attended a health status examination. We included the modified Seasonal Pattern Assessment Questionnaire and the modified Beck Depression Inventory (BDI) for the analysis.

RESULTS

85% of the sample, representative of a general population, had seasonal variations in mood and behavior; 9% of the sample scored high on both scales, thus having the routine seasonal variations together with a current self-report of winter depression. Scoring high on the former scale yielded the odds ratio of 3.12 for scoring high on the BDI. Neither the global seasonality score nor the BDI sum score was associated with latitude. No significant differences in affective symptoms were found by the latitude. The seasonal variation in sleep duration (P<0.001) was more prevalent in the northern regions.

LIMITATIONS

The seasonal variations were assessed with a self-report only.

CONCLUSIONS

A seasonal pattern in mood and behaviors was detected in a general population. Implications of our findings include the assessment of the seasonal variations as a risk factor of depressive illness.

Long-term and preventative treatment for seasonal affective disorder

Recurrent major depressive disorder with regular seasonal patterns, commonly known as seasonal affective disorder (SAD), has evoked substantial research in the last two decades. It is now recognised that SAD is a common condition with prevalence rates between 0.4% and 2.9% of the general population, and that patients with SAD experience significant morbidity and impairment in psychosocial function. There is good evidence that bright light therapy and antidepressant medications are effective for the short-term treatment of SAD; however, given that SAD is characterised by recurrent major depressive episodes, long-term and maintenance treatment must be considered. Unfortunately, there are few studies of longer term (>8 weeks) and maintenance (preventative) treatments for SAD. The weight of evidence suggests that light therapy usually needs to be continued daily throughout the winter season because of rapid relapse when light is stopped too early in the treatment period. However, some studies support the use of antidepressants to continue the response from a brief (1-2 weeks) course of light therapy early in the depressive episode, as soon as the first symptoms emerge in autumn. Only small studies have examined preventative treatment (before onset of symptoms) with light therapy, all of which have methodological limitations. The best evidence for preventative treatment in SAD comes from antidepressant studies. Three large, randomised, placebo-controlled studies have shown that preventative treatment with bupropion XL reduces the recurrence rate of depressive episodes in patients with SAD. Given the limitations in the evidence base and the inconsistent recurrence rate of winter depressive episodes, clinical recommendations for long-term and preventative treatment must individualise treatment choices and weigh potential benefits against possible adverse effects.

The diagnosis, symptomatology, and epidemiology of seasonal affective disorder

The operational criteria for seasonal affective disorder (SAD) have undergone several changes since first proposed in 1984. SAD is currently included as a specifier of either bipolar or recurrent major depressive disorder in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. The International Classification of Diseases, Tenth Edition has provisional diagnostic criteria for SAD. The most characteristic quality of SAD is that the symptoms usually present during winter and remit in the spring. Furthermore, the symptoms tend to remit when the patients are exposed to daylight or bright light therapy. The cognitive and emotional symptoms are as in other types of depression but the vegetative symptoms are the reverse of classic depressive vegetative symptoms, namely increased sleep and increased appetite. SAD is a common condition, but the exact prevalence rates vary between different studies and countries and is consistently found to be more common in women and in youth. SAD probably possibly occurs in children although not as commonly as in young adults. Some studies have found that certain ethnic groups who live at high northern latitudes may have adapted to the long arctic winter.

Seasonality in affective disorders in Switzerland

OBJECTIVE

To estimate the prevalence of seasonal affective disorder (SAD) and its subsyndromal form (S-SAD) in Switzerland (47 degrees N).

METHOD

A representative sample from all three language areas of Switzerland (n = 980) were given a structured telephone interview using the extended Seasonal Pattern Assessment Questionnaire (SPAQ+). A smaller, but also representative sample in the city of Basel filled in the SPAQ+ form as well as undergoing a structured diagnostic interview.

RESULTS

In this Swiss sample, 2.2% of the population presented with symptom severity of SAD, 8.9% with S-SAD. In Basel, a much higher prevalence of SAD was found. Seasonal problems occurred more often in patients with the Diagnostic and Statistical Manual (DSM)-III diagnosis of major affective disorders than in those with pure anxiety disorders or no psychiatric diagnosis.

CONCLUSION

These estimates for SAD in Switzerland are similar to those found in the Zürich Study, using other methods, and for populations in the UK, with the limitations inherent in retrospective questionnaire studies.

Use of health care services in seasonal affective disorder

BACKGROUND

Little is known about the presentation and management of seasonal affective disorder (SAD) in primary care.

AIMS

To determine the use of health care services by people suffering from SAD.

METHOD

Following a screening of patients consulting in primary care, 123 were identified as suffering from SAD. Each was age- and gender-matched with two primary care consulters with minimal seasonal morbidity, yielding 246 non-seasonal controls. From primary care records, health care usage over a 5-year period was established.

RESULTS

Patients with SAD consulted in primary care significantly more often than controls and presented with a wider variety of symptoms. They received more prescriptions, underwent more investigations and had more referrals to secondary care.

CONCLUSIONS

Patients with SAD are heavy users of health care services. This may reflect the condition itself, its comorbidity or factors related to the personality or help-seeking behaviour of sufferers.

Seasonal depression: the dual vulnerability hypothesis revisited

OBJECTIVE

In DSM-IV, winter seasonal affective disorder (SAD) is classified as a seasonal pattern of recurrent major depressive episodes in winter with full remission of symptoms in summer. However, other groups with "winter depression" have been identified, including patients with incomplete summer remission (ISR) and subsyndromal SAD (sub-SAD, winter depressive symptoms that do not meet criteria for major depression). In this study, we compare the clinical characteristics of these three seasonal groups and their response to light therapy.

METHOD

558 patients assessed at a specialized SAD Clinic were diagnosed using DSM-III-R or DSM-IV criteria. Clinical information was recorded using a checklist at index assessment. A subset of patients (N=192) were treated with an open, 2 week trial of light therapy using a 10000 lux fluorescent light box for 30 min per day in the early morning. Patients were assessed before and after treatment with the 29 item modified Hamilton Depression Rating Scale and clinical response was defined as greater than 50% improvement in scores.

RESULTS

The rates of some melancholic symptoms, anxiety, panic, suicidal ideation, and family history of mood disorder were lowest in the sub-SAD group. The clinical response rates to light therapy were highest in the sub-SAD group (N=32, 78%), intermediate in the SAD group (N=113, 66%), and lowest in the ISR group (N=47, 51%).

LIMITATIONS

This was a retrospective study of patients seen in a specialty clinic, although information was obtained in a standardized format. The light therapy trial had an open design so that placebo response could not be determined.

CONCLUSIONS

There are differences in both the patterns of clinical symptoms and the response to light therapy in these three groups with winter depression. These results are consistent with a dual vulnerability hypothesis that considers these groups to result from interaction of separate factors for seasonality and depression.

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

OBJECTIVE

To examine estimates of lifetime prevalence of seasonal affective disorder (SAD) in Toronto, Ontario.

METHOD

Random telephone numbers were generated for the city of Toronto, and 781 respondents completed a telephone interview. Trained nonphysician interviewers conducted all interviews, which involved structured questions for diagnosing major depression. Patterns of symptom change across seasons were evaluated to establish a diagnosis of SAD according to DSM-III-R criteria.

RESULTS

Correcting for sex and age, the prevalence of SAD defined by DSM-III-R criteria was 2.9% (95% CI, 1.7% to 4.0%), and the overall lifetime prevalence of major depression in the sample was 26.4% (95% CI, 23.3% to 29.4%). Some subjects were contacted for a follow-up interview conducted in person; the positive predictive value for the diagnosis of major depression for the telephone interview was 100%, and the negative predictive value was 93%.

CONCLUSIONS

The seasonal subtype of depression represents 11% of all subjects with major depression, suggesting that SAD is a significant public health concern. The telephone interview demonstrated adequate reliability, indicating that it is appropriate for epidemiological surveys of this nature.

Bright light improves vitality and alleviates distress in healthy people

BACKGROUND

The relative shortage of light during the decreasing photoperiod may compromise well-being. Earlier studies suggest that bright-light exposure may be of help to alleviate winter-bound symptoms.

METHODS

We carried out a field study with exposure to bright light on office employees during winter.

RESULTS

Repeated bright-light exposure improved vitality and reduced depressive symptoms. The benefit was observed not only in healthy subjects with season-dependent symptoms but also in those not having the seasonal variation.

CONCLUSIONS

Bright-light exposure during winter appears to be effective at improving the health-related quality of life and alleviating distress in healthy subjects.

CLINICAL IMPLICATIONS

Administration of bright light is a useful option to improve vitality and mood among subjects working indoors in wintertime. LIMITATIONS OF STUDY: Our field setting used self-reports, not interviews, for the assessment of outcome.

Chronic fatigue syndrome and seasonal affective disorder: comorbidity, diagnostic overlap, and implications for treatment

This study aimed to determine symptom patterns in patients with chronic fatigue syndrome (CFS), in summer and winter. Comparison data for patients with seasonal affective disorder (SAD) were used to evaluate seasonal variation in mood and behavior, atypical neurovegetative symptoms characteristic of SAD, and somatic symptoms characteristic of CFS. Rating scale questionnaires were mailed to patients previously diagnosed with CFS. Instruments included the Personal Inventory for Depression and SAD (PIDS) and the Systematic Assessment for Treatment Emergent Effects (SAFTEE), which catalogs the current severity of a wide range of somatic, behavioral, and affective symptoms. Data sets from 110 CFS patients matched across seasons were entered into the analysis. Symptoms that conform with the Centers for Disease Control and Prevention (CDC) case definition of CFS were rated as moderate to very severe during the winter months by varying proportions of patients (from 43% for lymph node pain or enlargement, to 79% for muscle, joint, or bone pain). Fatigue was reported by 92%. Prominent affective symptoms included irritability (55%), depressed mood (52%), and anxiety (51%). Retrospective monthly ratings of mood, social activity, energy, sleep duration, amount eaten, and weight change showed a coherent pattern of winter worsening. Of patients with consistent summer and winter ratings (n = 73), 37% showed high global seasonality scores (GSS) > or = 10. About half this group reported symptoms indicative of major depressive disorder, which was strongly associated with high seasonality. Hierarchical cluster analysis of wintertime symptoms revealed 2 distinct clinical profiles among CFS patients: (a) those with high seasonality, for whom depressed mood clustered with atypical neurovegetative symptoms of hypersomnia and hyperphagia, as is seen in SAD; and (b) those with low seasonality, who showed a primary clustering of classic CFS symptoms (fatigue, aches, cognitive disturbance), with depressed mood most closely associated with irritability, insomnia, and anxiety. It appears that a subgroup of patients with CFS shows seasonal variation in symptoms resembling those of SAD, with winter exacerbation. Light therapy may provide patients with CFS an effective treatment alternative or adjunct to antidepressant drugs.

Seasonal affective disorder among primary care consulters in January: prevalence and month by month consultation patterns

BACKGROUND

Little is known about the prevalence or the consultation patterns of patients with seasonal affective disorder (SAD) in primary care settings.

METHODS

Patients aged 16-64 years consulting a general practitioner (G.P.) during a three week period in January were screened with the Seasonal Pattern Assessment Questionnaire (SPAQ). Interview-confirmed cases of SAD (N = 33) were matched by age and sex to controls without seasonal morbidity and primary care consultation patterns were compared over a 5 year period.

RESULTS

Of 692 patients screened, 64 (9.3%) satisfied SPAQ criteria for winter SAD. Patients with SAD showed no winter excess of consultations but were high year round consulters, averaging 1.8 times more consultations than controls.

CONCLUSIONS

High levels of SAD caseness on the SPAQ were found among patients consulting in primary care during January. Possible explanations for the high non-seasonal consultation patterns among SAD patients include somatisation and diagnostic inaccuracies.

LIMITATIONS

Diagnostic criteria for SAD, and the SPAQ in particular, may be over-inclusive. The SPAQ completion rate (about 39% of eligible patients consulting a G.P.) was relatively low.

CLINICAL RELEVANCE

Patients with SAD (using SPAQ criteria) commonly consult their G.P.s in winter but frequency, rather than seasonality, of consultation may be a better guide to diagnosing SAD in primary care.

Seasonal changes in psychological well-being in an elderly population

BACKGROUND

Little is known about seasonal fluctuations in psychological well-being among elderly people.

METHOD

Over a period of 21 months, 1466 elderly people completed the General Health Questionnaire and the Leeds Scales for Depression and Anxiety. Scores during the winter months (December to February) were compared with those during other months of the year.

RESULTS

Scores on all scales were significantly higher during the winter months, but there was no difference in rates of caseness. Unlike younger populations, elderly women did not exhibit greater seasonality in well-being than did elderly men.

CONCLUSIONS

Elderly people exhibit a small seasonal fluctuation in psychological well-being, which is probably of little clinical importance, and there is no gender difference. The findings support the contention that seasonal mood changes are most pronounced among females of reproductive age.