Validation of the Seasonal Pattern Assessment Questionnaire (SPAQ)

The validity of the Seasonal Pattern Assessment Questionnaire (SPAQ) was examined by interviewing 81 individuals who had participated in an earlier community survey of seasonal affective disorder (SAD) in Iceland. When SAD and subsyndromal SAD (S-SAD) were combined into a ‘winter problem’ group, the questionnaire's sensitivity, specificity and positive predictive value for that group were 94%, 73% and 45%, respectively. The SPAQ discriminated poorly between SAD and S-SAD, and hence it had a poor case-finding ability for SAD. Clinical evaluation verified a diagnosis of SAD in individuals who had no previous information about this syndrome. The questionnaire furthermore identified a group of individuals who had generalized anxiety and marked seasonal variations. Clinical evaluation arrived at a similar prevalence rate of SAD as the questionnaire.     

Cross-regional survey of seasonal affective disorders in adults and high-school students in Japan

BACKGROUND: In Asian countries, there is no epidemiological report on seasonal affective disorder (SAD) in different age groups and different geographic regions surveyed at the same time. The aim of this study was to estimate the prevalence rates of SAD and risk factors for SAD in adults and high-school students, with special reference to the difference of winter SAD between northern and southern regions in Japan. METHODS: A total of 3237 high-school students and 4858 workers living in Japan (31.3-43.5 degrees N) responded to this epidemiological survey using Japanese version of the Seasonal Pattern Assessment Questionnaire (SPAQ). RESULTS: The overall prevalence rates of winter SAD (subsyndromal winter SAD) and summer SAD (subsyndromal summer SAD) in high-school students were 0.91(2.21) and 0.81(2.57)%, respectively. In workers, these rates were 0.45(1.16) and 0.43(0.71)%, respectively. Although no regional difference was noted in high-school students with winter seasonal type, the estimated odds ratio of this type for northern workers was nearly 3-fold higher than the southern counterparts. The prevalence rates of each seasonal type were not significantly different between two sexes in both age groups. No clear dependence on latitude was seen with regard to summer SAD in both age groups. LIMITATIONS: The effect of climate on SAD could not be entirely excluded from geophysical factor as indexed by latitude. CONCLUSIONS: SAD was less common in adults than in high-school students. While latitude was a major determinant of winter type in adults, socio-cultural factors or other contributing factors might affect the development of this type in high-school students.     

Prevalence of seasonal affective disorder in primary care; a comparison of the seasonal health questionnaire and the seasonal pattern assessment questionnaire

BACKGROUND: Prevalence rates of SAD suggested by previous studies have ranged from 1 to 12% depending on the diagnostic criteria used. The Seasonal Pattern Assessment Questionnaire (SPAQ), a widely used screening tool, has been shown to have low specificity for SAD. The Seasonal Health Questionnaire (SHQ) was designed to better reflect the clinical criteria for SAD and has been shown to have a higher specificity then the SPAQ in a psychiatric outpatient setting. OBJECTIVE: The current study was designed to assess the validity of the SHQ in general practice against systematic research interviews, to compare the sensitivity, specificity and positive predictive values of the SHQ and the SPAQ and to use these data to estimate the prevalence of SAD in primary care. METHODS: 809 subjects in a consecutive series of patients attending Southampton general practices in winter 2000/01 completed the SHQ followed by the SPAQ; 56 were interviewed using the Structured Clinical Interview for DSM (SCID). RESULTS: The SHQ was more sensitive and specific than the SPAQ and had higher positive and negative predictive values in screening for SAD. The SPAQ indicated a prevalence of SAD of 10.7% (95% CI 8.6-13.1) while the SHQ provided a significantly lower estimate of 5.6% (95% CI 4.2-7.4).     

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.     

Seasonal variations in mood and behaviour: epidemiological findings in the north tropics.

BACKGROUND: There has been no epidemiological study of seasonal affective disorder (SAD) in the north tropics. METHODS: The investigators randomly mailed the Seasonal Pattern Assessment Questionnaire (SPAQ) to 520 residents in Chiang Mai Municipality. RESULTS: The prevalence rates of summer SAD, subsyndromal summer SAD and winter SAD are 6.19%, 8.25% and 1.03%, respectively. CONCLUSIONS: The epidemiological study of SAD in the north tropics finds a high prevalence of summer SAD, low prevalence of winter SAD and the correlation between 'feel worst' response and temperature. LIMITATIONS: The reliability and validity of SPAQ in diagnosing summer SAD is probably low. The response rate from the studied sample is low. CLINICAL RELEVANCE: The prevalence of summer SAD in the tropics is much higher than that in the temperate zone and may relate to temperature.     

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.     

Seasonal mood patterns in a northeastern college sample

Given that seasonality can be conceptualized along a developmental continuum, it is surprising that the college population has been largely excluded from previous epidemiological research on Seasonal Affective Disorder (SAD). In this study, college students completed the Seasonal Pattern Assessment Questionnaire (SPAQ) and Beck Depression Inventory twice during either the Fall or Spring academic semester. SAD prevalence rates were similar to those of nearby adult samples. The SPAQ demonstrated high test-retest reliability when administered during different seasons; however, gender differences only emerged during winter SPAQ administrations.     

A dual vulnerability hypothesis for seasonal depression is supported by the seasonal pattern assessment questionnaire in relation to the temperament and character inventory of personality in a general population

BACKGROUND: Personality structure obtained from the psychobiological Temperament and Character Inventory (TCI) was studied in relation to self-reported seasonal variations in mood and behavior measured by the Seasonal Pattern Assessment Questionnaire (SPAQ). METHODS: The subjects comprised 1761 adults (57.6% women) in the age range 35-85 years, enrolled in the Betula prospective random cohort study of Umea, Sweden. RESULTS: Personality profiles of subjects who reported the occurrence of a high degree of seasonal variation as such were associated with a combination of high self-transcendence (ST) and high persistence (PS), irrespective of the level of harm avoidance (HA). Subjects who reported feeling worst in winter were associated with high HA, irrespective of the levels of ST and PS. Also, subjects feeling worst in summer or experiencing overall problems with seasonal variation were associated with high HA in their personality profiles. Using the SPAQ criteria to define seasonal affective disorder (SAD) or subsyndromal SAD (S-SAD), subjects with these disorders often had combinations of high self-transcendence (ST) and high persistence (PS), but with different associations with HA. LIMITATIONS: No evaluations were made for SAD or subsyndromal SAD according to the DSM-IV or ICD 10 criteria. CONCLUSIONS: Our results relating SPAQ with TCI give support for a dual vulnerability hypothesis for seasonal depression proposed in the literature, where it is attributed to a combination of a seasonal factor and a depression factor. Examining the literature regarding the relationships between the different TCI scales and monoamine neurotransmitter functions, those relationships suggest that these two vulnerability factors for seasonal depression may be modulated by different neurotransmitter systems.     

The Seasonal Health Questionnaire: a preliminary validation of a new instrument to screen for seasonal affective disorder

BACKGROUND: The main screening tool for Seasonal Affective Disorder (SAD) is the Seasonal Pattern Assessment Questionnaire, but its reliability and validity have been thrown into doubt by several studies. METHOD: In this study we developed a new questionnaire, the Seasonal Health Questionnaire (SHQ), which is scored by computer to derive the four main operational criteria for diagnosis of SAD. A group of clinically diagnosed SAD patients was contrasted with a group of patients with recurrent non-seasonal depressive disorder using the SPAQ and the SHQ. RESULTS: The SHQ could be completed without difficulty by patients with long histories of recurrent mood disorder. The SPAQ and the Rosenthal Criteria were the least specific of the criteria for identifying SAD - misclassifying many non-seasonal patients. CONCLUSIONS: After further development the SHQ may be a more appropriate screening instrument for SAD. The SPAQ should no longer be used for this purpose as it gives misleadingly high estimates of prevalence.     

Comparison of consultation rates in primary care attenders with and without seasonal affective disorder

BACKGROUND: There is a lack of published information about the consultation patterns of patients with seasonal affective disorder (SAD) in primary care, when compared with non-seasonal controls (NSCs). METHODS: Interview-confirmed SAD cases (n=90) were age- and sex-matched to two controls without significant seasonal morbidity on the Seasonal Pattern Assessment Questionnaire (SPAQ) (non-seasonal controls, NSCs). A comparison of their consultation rates was made using data abstracted from primary care records over 4 years. RESULTS: The monthly rate of general practice consultations for SAD cases was significantly higher than that for NSCs. There was a significant difference in the median number of consultations in winter and autumn between the two groups. The matched multivariate analysis revealed that February and April were the independent months in which cases of SAD had significantly more consultations than NSCs. LIMITATIONS: Optimal diagnostic criteria for SAD have not been determined and our criteria may have been over-inclusive. CONCLUSION: In addition to a marked difference in monthly consultation rates between SAD cases and NSCs, the data demonstrate a difference in the pattern of seasonality of these rates. It is possible that increased frequency of consultation, in particular during the winter months (in patients who score as a case SPAQ), could be used as an indication of SAD in primary care.     

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.     

Personality of seasonal affective disorder analyzed by Tri-dimensional Personality Questionnaire

BACKGROUND: Although there have been numerous reports in personality of mood disorders, there have been few reports in regard with personality of winter seasonal affective disorder (SAD). Furthermore, no reports have been published concerning summer SAD personality characteristics. Thus, this study was conducted to assess the personality of winter and summer SAD using Tri-dimensional Personality Questionnaire (TPQ) that have been used in a variety of mental disorders. METHODS: A total of 6135 Japanese were evaluated with TPQ, the Seasonal Pattern Assessment Questionnaire (SPAQ) and the Self-rating Depression Scale (SDS). Winter, summer and non-SAD groups were classified by SPAQ. We compared the difference of personality trait among these three groups in consideration of gender, age and SDS score influence. RESULTS: Winter SAD demonstrated higher "Novelty Seeking" and "Harm Avoidance"; summer SAD showed higher "Harm Avoidance" than the non-SAD group. "Harm Avoidance" in both SAD groups was re-analyzed using SDS score as a covariate, and "Novelty Seeking" in winter SAD using age as a covariate. As a result, the significance of high "Novelty Seeking" and high "Harm Avoidance" in winter SAD was excluded. However, "Harm Avoidance" remained the significant difference between summer and non-SAD. LIMITATION: SAD was diagnosed only by SPAQ and not by interview. The state-dependency of "Harm Avoidance" was not confirmed in identical patients over lapse of time. CONCLUSION: Patients with winter SAD have high "Harm Avoidance" dependent on the depressive state that is in accordance with non-seasonal depression. Patients with summer SAD have high "Harm Avoidance" possibly independent from the depressive state.     

Seasonality of mood disorders in adults with lifetime attention-deficit/hyperactivity disorder (ADHD)

BACKGROUND: The objective of this study was to estimate the prevalence of Seasonal Affective Disorder (SAD) in adults with lifetime Attention-Deficit/Hyperactivity Disorder (ADHD). METHOD: Patients eligible for this study had lifetime impairing symptoms of ADHD and a current and/or past co-morbid mood disorder according to their medical record. The Seasonal Pattern Assessment Questionnaire (SPAQ) was administered by a telephone interview to assess seasonality. RESULTS: The overall rate of SAD in this clinical population of adults with ADHD was estimated at 27%. Females were more at risk to develop SAD than men. LIMITATIONS: The SPAQ is a screening, not a diagnostic instrument. CONCLUSIONS: SAD symptoms are frequently comorbid with ADHD in adults. These results have clinical relevance for the recognition and treatment of SAD with bright light therapy in adults with ADHD.     

Light room therapy effective in mild forms of seasonal affective disorder--a randomised controlled study

BACKGROUND: The most common way to provide bright light therapy to Swedish patients with Seasonal Affective Disorder (SAD), is treatment in a light therapy room. Since few studies have evaluated treatment provided in this setting and few have evaluated the effect of bright light in sub-clinical SAD (S-SAD), such a study including a one-month follow-up was designed. METHODS: Fifty adults recruited from a previous prevalence study and clinically assessed as having SAD or S-SAD, were randomised to treatment in a light room or to a three-week waiting-list control group. The Hamilton Depression Rating Scale-Seasonal Affective Disorders Self-rating 29-items Version (SIGH-SAD/SR) was used to measure depressive mood at baseline, directly following treatment and at the one-month follow-up. RESULTS: ANCOVA with adjustment for baseline depression score, showed a significant main effect for the light room therapy group (p<0.001). Fifty-four percent (n=13/24) improved > or = 50% while no such improvement was seen in the control condition (n=0/24). After merging the two groups, repeated measures ANOVA confirmed the experimental analysis (p<0.001). At the one-month follow-up, 83.0% (n=39/47) had improved > or = 50% and 63.8% (n=30/47) had normal depression scores, i.e. < or = 8. CONCLUSIONS: Light room therapy was effective in reducing depressive symptoms in subjects with winter depressive mood. Results were maintained over a period of one month.     

Sleep characteristics,chronotype and winter depression in 10–20‐year‐olds in northern European Russia

The purpose of this work was to examine the relationships between geographical coordinates and the prevalence of winter depression (SAD_W), and to compare the sleep characteristics and chronotype of youths with and without SAD_W. We conducted a cross‐sectional study of self‐reported sleep characteristics, chronotype and winter depression in northern European Russia. Two questionnaires, the Munich Chronotype Questionnaire (MCTQ) and the Seasonal Pattern Assessment Questionnaire (SPAQ), were administered to a total of 3435 adolescents aged 10–20 years (1517 males and 1918 females). The prevalence of SAD_W in the study population was 8.4% and sub‐SAD_W 11.8%. Four variables predicted the likelihood of SAD_W in youths: sex [higher in females: odds ratio (OR): 1.87, P < 0.0001], age (increases with age: OR: 1.09, P < 0.001), latitude (higher in the North: OR: 1.49, P < 0.029) and position in the time zone (higher in the West: OR: 1.61, P < 0.001). Later sleeping and waking, longer sleep latencies, more severe sleep inertia, shorter total sleep times and lower sleep efficiencies were observed in both males and females with SAD_W. The influence of SAD_W on sleep characteristics was more pronounced on school days. Significant phase delays of the sleep–wake rhythm and severe social jetlag (the difference between the mid‐point of sleep phase at weekends and on workdays) were observed in females with SAD_W, but not in males. There are significant differences in sleep characteristics and chronotype between people with SAD_W and no‐SAD. We demonstrate that both latitude of residence and location within the time zone are significant predictors of SAD_W in young inhabitants of the North.     

Mood-worsening with high-pollen-counts and seasonality: a preliminary report

BACKGROUND: Because aeroallergens produce inflammation in the respiratory airways, and inflammation triggers depression in vulnerable individuals, we hypothesized that mood sensitivity to pollen, the most seasonal aeroallergen, will be associated with a greater seasonality of mood. Since pollen is absent during winter, we specifically predicted that mood sensitivity to tree pollen will predict non-winter SAD but not winter SAD. METHODS: A convenience sample of African and African American college students who lived in the Washington DC metropolitan area for at least the past 3 years completed the Seasonal Pattern Assessment Questionnaire (SPAQ), from which the Global Seasonality Score (GSS) was calculated, a diagnosis of cumulative SAD (syndromal or subsyndromal SAD) was derived, a seasonal pattern (winter vs non-winter) identified, and self-reported mood changes during high pollen counts obtained. A Mann-Whitney test was used to compare GSS between participants with vs without mood worsening during high pollen counts. The capability of mood worsening with high pollen counts, gender, ethnicity, and age to predict non-winter SAD was analyzed with logistic regressions. RESULTS: GSS was greater (z=5.232, p<0.001) in those who reported mood worsening with high pollen counts. Mood sensitivity to pollen predicted non-winter SAD (p=0.017), but not winter SAD. LIMITATIONS: The SPAQ is not a definitive tool to assess seasonality, and self-reported mood worsening with high pollen counts relies on recollection. No direct measures of depression scores or pollen counts were collected. The non-winter SAD concept has not been previously established. CONCLUSIONS: Our study, which should be considered preliminary in light of its limitations, suggests that self-reported mood-worsening with high pollen count is associated with a greater seasonality of mood, and predicts SAD of non-winter type.     

Seasonal affective disorder and latitude: a review of the literature.

BACKGROUND: The aim of the study is to investigate the relationship between the prevalence of SAD and latitude. METHODS: An overview of the epidemiological literature on the prevalence of SAD is given and studies relevant for the latitudinal dependency of prevalence will be analyzed and discussed. RESULTS: The mean prevalence of SAD is two times higher in North America compared to Europe. Over all prevalence studies, the correlation between prevalence and latitude was not significant. A significant positive correlation was found between prevalence and latitude in North America. For Europe there was a trend in the same direction. CONCLUSIONS: The influence of latitude on prevalence seems to be small and other factors like climate, genetic vulnerability and social-cultural context can be expected to play a more important role. Additional controlled studies taking these factors into account are necessary to identify their influence.     

Prevalence and genetic and environmental influences on anxiety disorders in 6-year-old twins

BACKGROUND: Prevalence of childhood anxiety disorders at specific ages and genetic etiological influences on anxiety disorders in young children have been little studied. The present study reports prevalence estimates in a community sample of 6-year-old twins, and patterns of genetic and environmental influences on these early-onset anxiety disorders. METHOD: Using a two-phase design 4,662 twin-pairs were sampled and 854 pairs were assessed in the second phase by maternal-informant diagnostic interview using DSM-IV criteria. RESULTS: The most common conditions were separation anxiety disorder (SAD) [2.8%, 95% confidence interval (CI) 2.1-3.8, for current disorder] and specific phobia (10.8%, 95% CI 8.4-13.6, for current disorder). Behavioral genetic modeling was feasible for these two conditions, applied to two phenotypes: symptom syndrome (regardless of impairment) and the narrower one of diagnostic status (symptom syndrome with associated impairment). The heritability estimate for SAD diagnostic status was high, 73%, with remaining variance attributed to non-shared environment. The heritability estimates for specific phobia were also high, 80% for the symptom syndrome and 60% for diagnostic status, with remaining variance attributed in both cases to non-shared environment. CONCLUSIONS: Compared with previous epidemiological surveys of children and adolescents in wide age-bands, the current estimates suggest that rates of anxiety disorders assessed in young childhood are generally at least as high and perhaps higher compared with those found in older children. The heritability estimates suggest that the genetic effects on these early-onset anxiety disorders are substantial and more significant than environmental effects, whether shared or non-shared.     

Delayed sleep phase syndrome is related to seasonal affective disorder

Background

Both delayed sleep phase syndrome (DSPS) and seasonal affective disorder (SAD) may manifest similar delayed circadian phase problems. However, the relationships and co-morbidity between the two conditions have not been fully studied. The authors examined the comorbidity between DSPS and SAD.

Methods

We recruited a case series of 327 DSPS and 331 controls with normal sleep, roughly matched for age, gender, and ancestry. Both DSPS and controls completed extensive questionnaires about sleep, the morningness-eveningness trait, depression, mania, seasonality of symptoms, etc.

Results

The prevalences of SAD and subsyndromal SAD (S-SAD) were higher in DSPS compared to controls (χ² = 12.65, p = 0.002). DSPS were 3.3 times more likely to report SAD (odds ratio, 3.34; 95% CI, 1.41-7.93) compared to controls as defined by the Seasonal Pattern Assessment Questionnaire (SPAQ). Correspondingly, DSPS showed significantly higher seasonality scores compared to controls in mood, appetite, and energy level subscores and the global seasonality score (t = 3.12, t = 0.002; t = 2.04, p = 0.041; t = 2.64, p = 0.008; and t = 2.15, p = 0.032, respectively). Weight fluctuation during seasons and winter-summer sleep length differences were also significantly higher in DSPS than controls (t = 5.16, p < 0.001 and t = 2.64, p = 0.009, respectively). SAD and S-SAD reported significantly higher eveningness, higher depression self-ratings, and more previous mania symptoms compared to non-seasonal subjects regardless of whether they were DSPS or controls.

Conclusions

These cases suggested that DSPS is partially comorbid with SAD. These data support the hypothesis that DSPS and SAD may share a pathophysiological mechanism causing delayed circadian phase.     

Seasonal affective disorder and social deprivation in Aberdeen

Background: Unlike non-seasonal depression, there is some evidence that seasonal affective disorder (SAD) is more common among more affluent socioeconomic groups. Methods: In primary care settings in Aberdeen, 4557 subjects had previously completed a Seasonal Pattern Assessment Questionnaire (SPAQ). From the subjects’ postcodes they were allocated a Carstairs score which placed them in one of seven categories of socioeconomic deprivation. These categories were compared with regard to seasonal pathology from the SPAQ ratings. Results: Complete postcodes and Carstairs scores were established for 3772 (83%) of the 4557 subjects. No statistically significant relationship between socioeconomic deprivation and SPAQ ratings was detected. Limitations: The study population was an affluent one relative to Scotland as a whole which may have reduced the likelihood of a positive finding. The study was conducted 7 years after the census on which postcode deprivation scores were calculated, and changes therein may have occurred. Conclusions: SAD either has no relationship to social deprivation or is associated with affluence and this distinguishes it from non-seasonal depression.