Seasonal affective disorder: prevalence, detection and current treatment in North Wales

100,000 lumens to treat seasonal affective disorder: A proof of concept RCT of Bright, whole-ROom, All-Day (BROAD) light therapy

BACKGROUND

Seasonal affective disorder (SAD) is common and debilitating. The standard of care includes light therapy provided by a light box; however, this treatment is restrictive and only moderately effective. Advances in LED technology enable lighting solutions that emit vastly more light than traditional light boxes. Here, we assess the feasibility of BROAD (Bright, whole-ROom, All-Day) light therapy and get a first estimate for its potential effectiveness.

METHODS

Patients were randomly assigned to a treatment for 4 weeks; either a very brightly illuminated room in their home for at least 6 h per day (BROAD light therapy) or 30 min in front of a standard 10,000 lux SAD light box. Feasibility was assessed by monitoring recruitment, adherence, and side effects. SAD symptoms were measured at baseline and after 2 and 4 weeks, with the Hamilton Depression Rating Scale-Seasonal Affective Disorders 29-items, self-report version.

RESULTS

All 62 patients who started treatment were available at 4-week follow-up and no significant adverse effects were reported. SAD symptoms of both groups improved similarly and considerably, in line with previous results. Exploratory analyses indicate that a higher illuminance (lux) is associated with a larger symptom improvement in the BROAD light therapy group.

CONCLUSIONS

BROAD light therapy is feasible and seems similarly effective as the standard of care while not confining the participants to 30 min in front of a light box. In follow-up trials, BROAD light therapy could be modified for increased illuminance, which would likely improve its effectiveness.

A new approach for seasonal pattern: is it related to bipolarity dimension? Findings from an Italian multicenter study

OBJECTIVE

The aims of this study were to assess the impact of seasonal pattern on several clinical dimensions in inpatients with a current major depressive episode and to evaluate clinical differences between unipolar and bipolar depression according to seasonal pattern.

METHODS

Study participants were 300 patients affected by major depressive disorder (MDD) or bipolar disorder (BD) currently experiencing a major depressive episode (MDE) and were recruited at three University Medical Centres in Italy. All study subjects completed several evaluation scales for depressive and hypomanic symptoms, quality of life and functioning, impulsiveness, and seasonal pattern.

RESULTS

Several differences between BD with and without seasonal pattern, MDD with and without seasonal pattern but in particular between BD and MDD with seasonal pattern were found. Patients with MDE with seasonal pattern had more frequently received a longitudinal diagnosis of BD.

CONCLUSIONS

A large number of patients with BD and seasonal pattern, but also a considerable number of patients with MDD and seasonal pattern, endorsed manic items during a current MDE. Seasonal pattern should be associated with a concept of bipolarity in mood disorders and not only related to bipolar disorder. A correct identification of seasonal patterns may lead to the implementation of personalised pharmacological treatment approaches.KEY POINTSHigh prevalence of mixed features in mood disorders with seasonal pattern, supporting the need for a dimensional approach to major depressive disorder and bipolar disorder.Significant percentage of patients with a primary diagnosis of major depressive disorder had seasonal pattern.Significant percentage of patients with a primary diagnosis of major depressive disorder reported (hypo)manic symptomatology.

Prevalence of seasonal depression in a prospective cohort study

The prevalence of autumn/winter seasonality in depression has been documented in the longitudinal Zurich cohort study by five comprehensive diagnostic interviews at intervals over more than 20 years (N = 499). Repeated winter major depressive episodes (MDE-unipolar + bipolar) showed a prevalence of 3.44% (5× more women than men), whereas MDE with a single winter episode was much higher (9.96%). A total of 7.52% suffered from autumn/winter seasonality in major and minor depressive mood states. The clinical interviews revealed novel findings: high comorbidity of Social Anxiety Disorder and Agoraphobia within the repeated seasonal MDE group, high incidence of classic diurnal variation of mood (with evening improvement), as well as a high rate of oversensitivity to light, noise, or smell. Nearly twice as many of these individuals as in the other MDE groups manifested the syndrome of atypical depression (DSM-V), which supports the prior description of seasonal affective disorder (SAD) as presenting primarily atypical symptoms (which include hypersomnia and increase in appetite and weight). This long-term database of regular structured interviews provides important confirmation of SAD as a valid diagnosis, predominantly found in women, and with atypical vegetative symptoms.

Seasonality of antidepressant prescriptions and sick leaves

The aim of the present study was to estimate the number of patients with a seasonal prescription pattern of antidepressants, which might be taken as a surrogate marker for medicated patients with seasonal affective disorder (SAD). Furthermore, we examined the time course of sick leaves for patients with seasonal and non-seasonal prescriptions of antidepressants. A retrospective analysis of prescription data of all patients insured by the Sickness Fund Burgenland (BGKK) between 2005 and 2016 was performed. Patients with treatment initiation of an antidepressant in the last and first quarter of the year for at least two consecutive years were selected (SAD-med). Patients with continuation treatment in the third quarter and patients with initiation of antidepressant medication in the second and third quarter of the year were excluded. The mean yearly prescription rate for antidepressants was 9.6% in the insured population. 3.0% of patients treated with antidepressants and 0.9% of insured cases satisfied the definition of SAD-med. The mean number of yearly sick leave days was similar for SAD-med patients and those with non-seasonal prescriptions. Time series analysis showed that sick leaves in SAD-med were influenced by seasonal fluctuations for several years after the first antidepressant prescription. Our study sheds light on antidepressant prescription and sick leave patterns in the general population. Compared to the prevalence of SAD, the estimated rate of SAD-med is substantial. Sick leaves appear to be closely linked to antidepressant prescriptions, and show a characteristic time course before and after the initial prescription.

Implementing prevention of seasonal affective disorder from patients' and physicians' perspectives - a qualitative study

BACKGROUND

Seasonal affective disorder (SAD) is a seasonally recurrent type of major depression that has detrimental effects on patients' lives during winter. Little is known about how it affects patients during summer and about patients' and physicians' perspectives on preventive SAD treatment. The aim of our study was to explore how SAD patients experience summers, what type of preventive treatment patients implement, which preventive treatment methods, if any, physicians recommend, and what factors facilitate or hinder implementation/recommendation of SAD prevention.

METHODS

We conducted 15 semi-structured interviews, ten with adult patients with a history of SAD and five with physicians. Transcripts were analyzed by two researchers using an inductive thematic analysis approach.

RESULTS

One group of patients was able to enjoy summer and ignore thoughts of the upcoming winter. The other group feared the impending depressive episode in winter, and this fear negatively impacted these patients' well-being during the summer. Preventive treatment was a relevant issue for all patients, and all but one person implemented SAD prevention during summer. We identified six factors that influenced patient use of preventive treatment of SAD. Four factors occur on an individual level (knowledge about disease and preventive treatment options, experience with treatment in acute phase, acceptability of intervention, willingness to take responsibility for oneself), one on an interpersonal level (social and work environment), and one on a structural level (healthcare system). All psychiatrists recommended some kind of preventive intervention, most commonly, lifestyle changes. Four factors influenced psychiatrists in recommending prevention of SAD (patient expectations, disease history and stability, risk/benefit ratio, lack of evidence).

CONCLUSIONS

Success in the implementation of SAD prevention does not solely depend on the willingness of the patients, but is also influenced by external factors. Raising awareness of SAD among general practitioners and low-level access to mental-health support could help patients find appropriate help sooner. To better guide the optimal treatment choice, comparative effectiveness research on treatments to prevent a new onset in patients with a history of SAD and clinical practice guidelines on SAD are needed.

Pharmacotherapy and nutritional supplements for seasonal affective disorders: a systematic review

INTRODUCTION

A seasonal affective disorder (SAD) is a subtype of unipolar and bipolar major depressive disorders. It is characterized by its annual recurrence of depressive episodes at a particular season, mostly seen in winter and is responsible for 10-20% of the prevalence of major depressive disorders. Some pathophysiological hypotheses, such as the phase delay and the monoamine depletion hypotheses, have been postulated but the exact cause has not been fully unraveled yet. Studies on treatment for SAD in the last decade are lacking. To tackle this chronic disease, attention needs to be drawn to the gaps in this research field.

AREAS COVERED

In this systematic review, the authors give a broad overview of the pharmacological therapy available for SAD. Also, nutritional substances fitting well with the postulated hypotheses are reviewed for the treatment and prevention of SAD. There is a specific focus on the quality of the currently performed studies.

EXPERT OPINION

Light therapy and fluoxetine are the only proven and effective acute treatment options for SAD, while bupropion is the only registered drug for prevention of SAD. This area of research is in dire need of valid large-scale and sufficiently reproducible randomized control trials.

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.

Light therapy and the management of winter depression

Much the most common type of seasonal affective disorder at temperate latitudes is recurrent winter depression, which probably affects around 3% of adults in the UK to a clinically significant degree. In this article, diagnosis and presentation are discussed and symptoms are contrasted with those of non-seasonal depression. Aetiology and epidemiology, with regard to age, gender and latitude of residence, are described. Sufferers are often treated with light therapy, and this is described in some detail, with mention of effectiveness, prediction of outcome, timescales of response, side-effects, use of lightboxes and alternatives to lightboxes. Other general aspects of the management of seasonal affective disorder, including the use of antidepressant medication, are also outlined.

Prevention of seasonal affective disorder in daily clinical practice: results of a survey in German-speaking countries

BACKGROUND

Seasonal affective disorder (SAD) is a seasonally recurrent type of major depression. This predictable aspect makes it promising for preventive treatment. However, evidence for the efficacy and harm of preventive treatment of SAD is scarce, as are recommendations from clinical practice guidelines. The aim of this study was to assess the current use of preventive treatment of SAD in clinical practice in German-speaking countries for the first time.

METHODS

We conducted a postal and web-based survey sent to the heads of all psychiatric institutions listed in the inventory "Deutsches Krankenhaus Adressbuch, 2015" that contains all psychiatric hospitals in Germany, Austria, and Switzerland.

RESULTS

One hundred institutions (out of 533 institutions, 19%), which treated in total more than 3100 SAD patients in the years 2014/2015, responded. Of those, 81 reported recommending preventive treatment to patients with a history of SAD. There was no consensus on the optimal starting point for preventive treatment. Most of the institutions that implemented prevention of SAD, recommended lifestyle changes (85%), antidepressants (84%), psychotherapy (73%), and light therapy (72%) to their patients. The situation was similar in northern and southern regions.

CONCLUSIONS

Most hospitals recommended the use of preventive treatment to SAD patients, although evidence on efficacy and harm is limited. A wide variety of interventions were recommended, although guidelines only include recommendations for acute treatment. To assist psychiatrists and patients in future decision making, controlled studies on preventive treatment for SAD that compare different interventions with one another are needed.

Patients' Experience of Winter Depression and Light Room Treatment

Background. There is a need for more knowledge on the effects of light room treatment in patients with seasonal affective disorder and to explore patients' subjective experience of the disease and the treatment. Methods. This was a descriptive and explorative study applying qualitative content analysis. A purposeful sample of 18 psychiatric outpatients with a major depressive disorder with a seasonal pattern and a pretreatment score ≥12 on the 9-item Montgomery-Åsberg Depression self-rating scale was included (10 women and 8 men, aged 24-65 years). All patients had completed light room treatment (≥7/10 consecutive weekdays). Data was collected two weeks after treatment using a semistructured interview guide. Results. Patients described a clear seasonal pattern and a profound struggle to adapt to seasonal changes during the winter, including deterioration in sleep, daily rhythms, energy level, mood, activity, and cognitive functioning. Everyday life was affected with reduced work capacity, social withdrawal, and disturbed relations with family and friends. The light room treatment resulted in a radical and rapid improvement in all the major symptoms with only mild and transient side effects. Discussion. The results indicate that light room treatment is essential for some patients' ability to cope with seasonal affective disorder.

Seasonality in mood and behaviours of Japanese residents in high-latitude regions: transnational cross-sectional study

BACKGROUND

Daylight hours in high-latitude regions tend to be longer than those in Japan in summer, and shorter than those in Japan in winter. For example, daylight hours in London in winter are one-third those of Tokyo. Therefore, this study investigated and compared seasonal changes in mood and behaviours of Japanese individuals living in and outside Japan.

METHODS

Surveys were conducted with Japanese residents in summer and winter in the UK (n = 106), Nordic countries (n = 40), Southeast Asia (n = 50), and Japan (n = 96). First, summer and winter General Health Questionnaire-28 (GHQ28) scores of each regional group were analysed. Subsequently, month-wise differences in mood and behaviours were compared across the four geographical regions.

RESULTS

Summer and winter GHQ28 scores of participants living in the UK and Nordic countries differed significantly, while no seasonal differences were observed for residents in Japan and Southeast Asia. Further, in the UK and Nordic countries, summer was associated with better mood and more activity, while winter was linked to lowered mood and reduced activity.

CONCLUSION

The results indicate that Japanese living in the UK and Nordic countries (high-latitude regions) experience seasonal fluctuations in depressive symptoms that may be linked to drastic seasonal environmental changes. Observed over a 12-month period, their mood and behaviour declined in winter and improved in summer. Therefore, considering the prevalence of overseas stressors that differ from those in their home country, it is necessary to investigate the effectiveness of support systems that help migrants adapt to seasonal changes in high-latitude regions.

Epidemiology and socioeconomic impact of seasonal affective disorder in Austria

BACKGROUND

Seasonal affective disorder (SAD) is a subtype of recurrent depressive or bipolar disorder that is characterized by regular onset and remission of affective episodes at the same time of the year. The aim of the present study was to provide epidemiological data and data on the socioeconomic impact of SAD in the general population of Austria.

METHODS

We conducted a computer-assisted telephone interview in 910 randomly selected subjects (577 females and 333 males) using the Seasonal Health Questionnaire (SHQ), the Seasonal Pattern Assessment Questionnaire (SPAQ), and the Sheehan Disability Scale (SDS). Telephone numbers were randomly drawn from all Austrian telephone books and transformed using the random last digits method. The last birthday method was employed to choose the target person for the interviews.

RESULTS

Out of our subjects, 2.5% fulfilled criteria for the seasonal pattern specifier according to DSM-5 and 2.4% (95% CI=1.4-3.5%) were diagnosed with SAD. When applying the ICD-10 criteria 1.9% (95% CI=0.9-2.8%) fulfilled SAD diagnostic criteria. The prevalence of fall-winter depression according to the Kasper-Rosenthal criteria was determined to be 3.5%. The criteria was fulfilled by 15.1% for subsyndromal SAD (s-SAD). We did not find any statistically significant gender differences in prevalence rates. When using the DSM-5 as a gold standard for the diagnosis of SAD, diagnosis derived from the SPAQ yielded a sensitivity of 31.8% and a specificity of 97.2%. Subjects with SAD had significantly higher scores on the SDS and higher rates of sick leave and days with reduced productivity than healthy subjects.

CONCLUSIONS

Prevalence estimates for SAD with the SHQ are lower than with the SPAQ. Our data are indicative of the substantial burden of disease and the socioeconomic impact of SAD. This epidemiological data shows a lack of gender differences in SAD prevalence. The higher rates of females in clinical SAD samples might, at least in part, be explained by lower help seeking behaviour in males.

Prevalence, behavioral manifestations and associated individual and climatic factors of seasonality in the Korean general population

BACKGROUNDS

Seasonality, an individual trait of seasonal variations in mood and behavior, has received clinical attention for its association with mood disorders. This study aimed to explore the prevalence, specific manifestation, and associated individual and climatic factors of seasonality in the non-elderly adult population.

METHODS

Five hundred fifty-two participants [male n=220; female n=332; mean age 34.92years, standard deviation (SD) 10.18] with no psychiatric history were recruited from the Seoul metropolitan area (37°33'58.87″N 126°58'40.63″E). Seasonality was evaluated using the Seasonal Pattern Assessment Questionnaire. Climatic variables used in analyses were averaged over recent 5years (from 2008 to 2013) on a monthly basis.

RESULTS

The mean global seasonality score (GSS) was 5.53 (SD 3.91), and 16.2% (n=89) of participants had seasonal affective disorder (SAD) or sub-SAD. The "feeling worst" month in most of the participants with significant seasonality were winter (41.6%) or summer (38.2%). Socio-demographic factors including age and sex were not related to the seasonality. Decreased sunlight amount and diurnal temperature range in a given and previous month, and increased humidity in a previous month showed significant associations with the percentage of participants with the worst mood. The most frequently reported symptom related to seasonality was 'changes in energy level'. Specific manifestations were not significantly different between the winter type and the summer type.

CONCLUSION

The summer and winter type seasonality in the non-clinical adult population did not differ in terms of behavioral manifestations. Decreased sunlight amount, diurnal temperature range, and increased humidity appeared to be major climatic factors associated with seasonality.

Ethnic differences in seasonal affective disorder and associated factors among five immigrant groups in Norway

BACKGROUND

Research studies on seasonal affective disorder (SAD) among immigrant populations are scarce. The objective of this article was to explore the associated risk and protective factors on prevalence of winter SAD (W-SAD), sub syndromal SAD (S-SAD) and Summer-SAD among five immigrant groups living in Oslo, Norway.

METHODS

The Oslo Immigrants Health study (innvandrer HUBRO, 2002), is a large cross sectional epidemiological survey conducted among five of the largest immigrant groups living in Oslo. 1047 subjects were included in the analysis out of 3019 who participated in the survey. Mailed questionnaire which included selected items of the seasonal pattern assessment questionnaire (SPAQ), Hopkins symptom check list (HSCL) and other variables were used in the analysis.

RESULTS

The lowest levels of W-SAD were found among Sri Lankan men and women and the highest among Iranians. W-SAD was significantly associated with country of birth, younger age, smoking, presence of mental distress, frequent visits to general practitioner or psychiatrist, self reported poor health and presence of chronic disorders. S-SAD was significantly associated with country of birth, smoking and higher levels of alcohol consumption.

LIMITATIONS

SPAQ was not culturally validated. Poor response rate (39.7%) can also be considered as a limitation.

CONCLUSIONS

Ethnic differences in W-SAD and S-SAD were observed. Sri Lankans had the lowest levels of W-SAD. However, there is a need for culturally validated instruments and further research must focus on exploring protective factors for SAD.

The seasonality of bipolar affective disorder: comparison with a primary care sample using the Seasonal Pattern Assessment Questionnaire

BACKGROUND

In contrast with recurrent unipolar depression, relatively little is known about the seasonality of depressive episodes in bipolar affective disorder (BAD).

METHOD

We compared responses on the Seasonal Pattern Assessment Questionnaire (SPAQ) between a cohort of 183 patients with BAD and a large sample of patients in primary care (N=4746). Comparisons were adjusted for age and gender.

RESULTS

27% of the BAD patients fulfilled SPAQ criteria for Seasonal Affective Disorder (SAD. This gave an adjusted odds ratio of 3.73 (95% confidence intervals 2.64 to 5.27) in comparison with the rate among the primary care samples. Global seasonality scores were significantly higher among BAD patients (adjusted mean difference 1.73, 95% CI 0.97 to 2.49, p<0.001).

LIMITATIONS

The SPAQ was originally designed as a screening instrument rather than as a case-finding instrument.

CONCLUSIONS

Vigilance for seasonal symptom recurrence in BAD may be important with regard to management and relapse prevention.

Prevalence of self-reported seasonal affective disorders and the validity of the seasonal pattern assessment questionnaire in young adults Findings from a Swiss community study

BACKGROUND

The objective of this study was to expand the knowledge on the prevalence of self-reported Seasonal Affective Disorder (SAD) and to further study the validity of the Seasonal Pattern Assessment Questionnaire (SPAQ).

METHODS

A total of N=844 young adults were assessed in a Swiss community study by use of the SPAQ, a Seasonal Affective Disorders Questionnaire (SADQ), the Young Adult Self Report (YASR), the Centre for Epidemiologic Depression Scale (CES-D), and scales for measuring self-esteem, self-awareness and life events. At a second stage, a total of N=534 screen positives and controls were subjected to the Composite International Diagnostic Interview (M-CIDI) for the assessment of mental disorders. According to the SPAQ classification a group of SAD subjects and a group of subsyndromal SAD subjects (S-SAD) were defined. In addition, a third group of high-scoring depressives (HSD) subjects scoring above the 75th percentile of the CES-D was defined. Comparisons included these three groups and the rest of the sample serving as controls.

RESULTS

The weighted prevalence for SAD in this sample was 7.84% based on the SPAQ alone. With the addition of the SADQ, weighted prevalence rates dropped to 2.22%. Weighted subsyndromal SAD was 33.04%. Across the vast majority of scales, the SAD group was indistinguishable from the HSD group. These two groups scored highest, whereas the S-SAD group had an intermediate position and the controls had the lowest scores. SAD was best predicted by the CES-D total score.

CONCLUSIONS

The SPAQ as a single measure leads to an overestimation of SAD which, nevertheless, is a rather common phenomenon also in this central European population. The findings on the validity of the SPAQ are extended by showing that predominantly general aspects of depression are measured.

The prevalence of seasonal affective disorder (SAD) in Greenland is related to latitude

The aim of this study was to determine the prevalence of seasonal affective disorder (SAD) in Greenlanders and Danes living at four different latitudes in Greenland. A Seasonal Pattern Assessment Questionnaire (SPAQ) was mailed to 6021 men and women between the ages of 18 and 59 years living in four different municipalities in Greenland. The recipients were randomly selected from the National Population Register. Approximately 9% of the respondents met the criteria for SAD, and the incidence of SAD varied between a southern municipality and three northern municipalities. The prevalence of SAD was particularly high in northern municipalities. No significant difference was found in the prevalence of SAD between Greenlanders and Danes. The results are comparable with other population studies that have reported a high prevalence of SAD in arctic areas. The clinical implications of our findings and the possibilities for introducing light therapy should be assessed in future studies.

A pilot study of adherence with light treatment for seasonal affective disorder

Non-adherence with antidepressant medication regimens is now recognised as a substantial problem when evaluating depression outcome. Given the behavioural demands of light treatment (LT), it might be expected that non-adherence would be even more pronounced in LT, a form of intervention for seasonal affective disorder (SAD). However, little research has focused upon the extent to which patients in light treatment protocols adhere to set regimens. Nineteen patients with SAD were allocated to either treatment with bright white light (intervention) or dim red light (control condition) in a four-week protocol. Light exposure was estimated automatically (without participants' knowledge) with elapsed time meters built into the light box. Daily diaries were also used to measure self-reported light box use. Participants were instructed to use the light box for 30 min each day during week 1, 45 during week 2 and one hour during weeks 3 and 4 (total duration of prescribed light exposure 1365 min). The results indicated that mean duration of light box operation for the entire sample was 59.3% of the prescribed 1365 min. Six of nineteen (31.6%) patients dropped out of treatment. Amongst those completing treatment, adherence to the prescribed duration of exposure averaged 83.3% (S.D.=31.4). A trend was found for the intervention condition to generate a lower dropout rate, as well as a trend for the degree of adherence to be greater in the intervention condition. Importantly, there was no association between adherence as measured automatically and the higher rates of self-reported adherence as measured in diaries. In summary, the results of this pilot study suggest that adherence with light treatment is of a similar order of magnitude to antidepressant medication adherence. Patient self-report was found to be unrelated to objectively estimated duration of light box use, a finding with significant research and clinical implications. Future research studies should routinely measure and evaluate adherence with light therapy and evidence-based techniques for maximising treatment adherence should be incorporated into routine clinical practice.

High prevalence of self-reported winter depression in a Swedish county

The prevalence of winter depression was unknown in Sweden, therefore prevalence figures of seasonal affective disorder (SAD) and subsyndromal SAD (S-SAD) were estimated. Age and gender differences, prevalence in the group of non-responders and some psychometric qualities of the Seasonal Pattern Assessment Questionnaire (SPAQ) were calculated. A modified version of the SPAQ was sent to a random sample of 2500 persons (response rate 66.3%, n=1657) between 18 and 64 years residing in Dalarna, a county in central Sweden. The sample was proportionally stratified according to age, gender and home municipality. The prevalence of winter SAD was estimated at 8% and S-SAD at 10.8%. It was approximately twice as common among women and younger persons. A total of 3.1% reported seasonal problems to be severe or disabling and 19.3% that everyday life was negatively affected. Experiencing seasonally changing depressive symptoms was common in the population. Factor analysis of the Global Seasonal Score resulted in one factor and the internal consistency was 0.88 (Cronbach's alpha). The results indicate that self-reported recurrent depression during winter is common in Sweden and should therefore receive more attention from health care authorities.

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.

How common is seasonal affective disorder in temperate Australia? A comparison of BDI and SPAQ estimates

BACKGROUND

The frequency of winter Seasonal Affective Disorder (SAD) in temperate Australia is unknown.

METHOD

A random community sample in Melbourne completed four waves of data collection (winter and summer across two years). The presence of winter SAD was estimated in three ways: (i) self-reports on the Seasonal Pattern Assessment Questionnaire (SPAQ), (ii) evidence of significant depression as assessed on the Beck Depression Inventory (BDI) in winters and not summers, and (iii) a combined definition based on both SPAQ and BDI estimates.

RESULTS

Of 1080 questionnaires originally mailed, complete four-wave BDI data was obtained from 380 respondents, and complete SPAQ data from 297. The frequency of winter SAD as estimated from SPAQ data was 0.7% and from BDI data was 0.5%. One participant (1 of 297, 0.3%) met BDI criteria and approached caseness on SPAQ criteria.

LIMITATIONS

A larger sample is necessary to definitively estimate prevalence.

CONCLUSIONS

Winter SAD appears to be rare in temperate Australia. The best estimate from the current study (0.3%) is an advance on simple self-report estimates and provides a necessary reference point for clinicians and researchers.

The reliability and validity of the Seasonal Pattern Assessment Questionnaire: a comparison between patient groups

BACKGROUND

The Seasonal Pattern Assessment Questionnaire (SPAQ) is a frequently used screening instrument in the research on Seasonal Affective Disorder (SAD). Nevertheless, studies on its reliability and validity are relatively scarce. In the present study the reliability and the contrast validity of the SPAQ are investigated.

METHODS

SAD patients, selected by means of a clinical interview, non-seasonal depressed out-patients, non-depressed out-patients, and a control group, are contrasted to estimate the discriminating power of the SPAQ. Also, the reliability and factor structure of the seasonality and the climate subscales are investigated. To study food intake the Seasonal Food Preference Questionnaire (SFPQ) was developed.

RESULTS

The SAD criterion of the SPAQ shows good specificity (94%), but a low sensitivity (44%). Discriminant analysis shows sufficient ability to classify subjects (81% correctly classified). The Global Seasonality Scale has a good internal consistency. It consists of two factors, a psychological factor and a food factor. The SFPQ is sensitive for carbohydrate intake by SAD patients.

LIMITATIONS

Most SAD patients had received treatment and completed the SPAQ while they were not depressed, which may have influenced the sensitivity.

CONCLUSIONS

The SPAQ is not sensitive enough to be considered a diagnostic instrument for SAD. Nevertheless, it is accurate enough to be used as a screenings instrument. The only false positives were found in the depressive group. The accuracy of prevalence Figs. can be improved by completion of the SPAQ in the summer months, combined with the completion of a depression scale.

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.

Seasonal affective disorder: an overview

Seasonal Affective Disorder (SAD) is a condition of regularly occurring depressions in winter with a remission the following spring or summer. In addition to depressed mood, the patients tend to experience increased appetite and an increased duration of sleep during the winter. SAD is a relatively common condition, affecting 1-3% of adults in temperate climates, and it is more prevalent in women. The pathological mechanisms underlying SAD are incompletely understood. Certain neurotransmitters have been implicated; a dysfunction in the serotonin system in particular has been demonstrated by a variety of approaches. The role of circadian rhythms in SAD needs to be clarified. The phase-delay hypothesis holds that SAD patients' circadian rhythms are delayed relative to the sleep/wake or rest/activity cycle. This hypothesis predicts that the symptoms of SAD will improve if the circadian rhythms can be phase-advanced. There is some experimental support for this. SAD can be treated successfully with light therapy. In classical light therapy, the SAD sufferer sits in front of a light box, exposed to 2000-10,000 lux for 30-120 min daily during the winter. Other forms of light treatments, pharmacotherapy, and other therapies are currently being tested for SAD.

Seasonal affective disorder among general practice attenders

In this issue, Eagles et al report that people suffering from seasonal affective disorder (SAD) are heavy users of primary health care services (Eagles et al, 2002, this issue). Nearly 10% of patients attending practices in Aberdeen screened positive for SAD using the Seasonal Pattern Assessment Questionnaire (SPAQ; Rosenthal et al, 1987), among whom around half of those attending for interview fulfilled DSM–IV (American Psychiatric Association, 1994) criteria for recurrent major depression with seasonal pattern. The patients with SAD had consulted significantly more frequently over a 5-year period, with a variety of symptoms both related and unrelated to SAD, and had received significantly more prescriptions, investigations and referrals than patients found not to fulfil the criteria for SAD.