Follow-up study of seasonal affective disorder in Switzerland. Seasonal depression: the dual vulnerability hypothesis revisited. Seasonal affective disorder. A description of the syndrome and preliminary findings with light therapy. An attempt to prevent winter depression by light exposure at the end of September Estimated Prevalence of the Seasonal Subtype of Major Depression in a Canadian Community Sample Prevention of winter seasonal affective disorder by bright-light treatment. Reboxetine in seasonal affective disorder: an open trial Cognitive-behavioral therapy vs. light therapy for preventing winter depression recurrence: study protocol for a randomized controlled trial Prevalence of seasonal affective disorder at four latitudes The circadian basis of winter depression. Mindfulness-based cognitive therapy for seasonal affective disorder: a pilot study. Lack of seasonal mood change in the Icelandic population: results of a cross-sectional study. Cognitive-behavioral therapy, light therapy, and their combination in treating seasonal affective disorder. Controlled trial of bright light and negative air ions for chronic depression. Seasonality and circadian phase delay: prospective evidence that winter lowering of mood is associated with a shift towards Eveningness. The Impact of Latitude on the Prevalence of Seasonal Depression Epidemiological findings of seasonal changes in mood and behavior. A telephone survey of Montgomery County, Maryland.
Of 39 diagnosed Seasonal Affective Disorder ( SAD ) patients who were interviewed 2 - 5 years after participation in a light therapy trial , 10 continued to have recurrent  major depressive episodes  in winter , and 17 manifested sub-syndromal SAD ( 2 patients also had recurrent brief depression , seasonal type ) . 8 patients had recovered , and 4 had shifted in symptomatology . Thus , over a number of years , the clinical diagnosis changed for the better in 64 % of the patients , suggesting that SAD is not a prodromal form of a more chronic major affective disorder , and that light therapy ( and perhaps also light-oriented behaviour ) reduced the incidence and depth of subsequent depressive episodes . Further evidence for this was the large reduction in use of conventional antidepressant drugs ( from 17 to 1 ) during the follow-up period . Diagnosis of SAD was stable and reliable 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 st and ardized 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 Seasonal affective disorder ( SAD ) is a syndrome characterized by recurrent depressions that occur annually at the same time each year . We describe 29 patients with SAD ; most of them had a bipolar affective disorder , especially bipolar II , and their depressions were generally characterized by hypersomnia , overeating , and carbohydrate craving and seemed to respond to changes in climate and latitude . Sleep recordings in nine depressed patients confirmed the presence of hypersomnia and showed increased sleep latency and reduced slow-wave ( delta ) sleep . Preliminary studies in 11 patients suggest that extending the photoperiod with bright artificial light has an antidepressant effect Seasonal affective disorder ( SAD ) , winter type , is characterized by the occurrence of depression in autumn/winter , followed by a complete recovery in spring/summer . In SAD patients , some atyp- ical symptoms are highly characteristic , such as hypersomnia , carbohydrate craving , weight gain , fatigue , and loss of social inter- actions ( Rosenthal et ai 1984 ) . The repeated occurrence of symp- toms during successive winters is one of the diagnostic criteria , l ~ lot every SAD patient becomes depressed every year , however . In prospect i ve studies it was found that 70,4 % of the SAD diagnosed subjects who were followed from a symptom-free moment at the end of September , became depressed during the following winter ( Meesters et al 1991 ; 1993a ) , In a previous study it was found that severe winter depression can be prevented by light treatment administered at the first signs of an emerging winter depression , that is , the moment subjects reported complaints of slight depression ( Meesters et al 1991 ; 1993a ) . In the present study , the question was raised whether light exposure given at the beginning of the winter season , when sub- jeers are still free of symptoms , could be successful in preventing the development of a winter depressmn during the rest of the season . Such a ueatment , which might prevent depression alto- gether , would be highly advantageous Objective : To examine estimates of lifetime prevalence of  seasonal affective disorder ( SAD ) in Toronto , Ontario . Method R and om 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 In patients with winter seasonal affective disorder ( SAD ) the onset of a depressive episode is probably associated with the decreasing amount of light during the autumn . A highly predictable onset of a recurrent depressive episode with seasonal pattern provides a rationale for testing the efficacy of bright-light treatment as a preventive measure . Twelve out- patients with winter SAD were assigned to start bright light treatment either when they were well , or not to start it until the first symptoms of depression had already emerged . The severity of depressive symptoms was prospect ively rated for a parallel r and omized comparison . Bright light given well in advance of the emerging symptoms prevented a depressive episode . Clinical remission was significantly more frequent in the former subgroup of the patients in January and in March . To sum up , bright light can be successfully administered as prophylactic treatment for the prevention of winter SAD Seasonal affective disorder ( SAD ) , winter type , is a condition characterized by the annual recurrence of depressive episodes during fall/winter , alternating with spring/summer euthymia or hypomania . Various neurotransmitters have been implicated in the etiology of SAD , the strongest evidence involving serotonin . Recently , increasing attention has been paid to the potential role of catecholaminergic pathways in the pathophysiology of SAD . We investigated the efficacy and tolerability of  reboxetine  , a selective noradrenaline inhibitor , in patients with SAD . Eleven out of sixteen patients who were included in a 6-week drug surveillance during winter season experienced full remission of depressive symptoms . Nine patients reported a rapid relief of preexistent severe atypical depressive symptoms within the first treatment week . Reboxetine might therefore be an effective and well-tolerated treatment option for SAD patients . In conclusion , our preliminary results are in line with evidence from recent studies suggesting that catecholaminergic systems might also be involved in the pathophysiology of SAD 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 r and omized 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 design ed to test for a clinical ly 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 r and omize 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 method ological 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 design s addressing these limitations would have required more patients , increased costs , and reduced power to detect a difference in the primary outcome .Trial registration Clinical trials.gov identifier The Seasonal Pattern Assessment Question naire ( SPAQ ) was mailed to a sample population balanced for sex and r and omly selected from local telephone directories in four areas : Nashua , NH , New York , NY , Montgomery County , MD , and Sarasota , FL . On the basis of responses to this question naire , prevalence rates of winter seasonal affective disorder ( winter SAD ) , summer seasonal affective disorder ( summer SAD ) , and subsyndromal winter SAD were estimated for the four areas . Rates of winter SAD and subsyndromal SAD were found to be significantly higher at the more northern latitudes , while no correlation was found between latitude and summer SAD . The positive correlation between latitude and prevalence of winter SAD applied predominantly to the age groups over 35 The following test of the circadian phase-shift hypothesis for patients with winter depression ( seasonal affective disorder , or SAD ) uses low-dose melatonin administration in the morning or afternoon/evening to induce phase delays or phase advances , respectively , without causing sleepiness . Correlations between depression ratings and circadian phase revealed a therapeutic window for optimal alignment of circadian rhythms that also appears to be useful for phase-typing SAD patients for the purpose of administering treatment at the correct time . These analyses also provide estimates of the circadian component of SAD that may apply to the antidepressant mechanism of action of appropriately timed bright light exposure , the treatment of choice . SAD may be the first psychiatric disorder in which a physiological marker correlates with symptom severity before , and in the course of , treatment in the same patients . The findings support the phase-shift hypothesis for SAD , as well as suggest a way to assess the circadian component of other psychiatric , sleep , and chronobiologic disorders BACKGROUND The best available treatment for seasonal affective disorder ( SAD ) is light therapy . Yet , this treatment does not prevent recurrence of depression in subsequent seasons . The aim of the study is to gain preliminary insight in the efficacy of Mindfulness Based Cognitive Therapy ( MBCT ) in the prevention of SAD recurrence . METHODS This is a r and omized controlled pilot study , in which SAD patients in remission were r and omly allocated to an individual format of MBCT or a control condition ( i.e. treatment as usual ) . MBCT was given between May and June 2011 , when there was no presence of depressive symptoms . The Inventory for Depressive Symptomatology Self-Report ( IDS-SR ) , which patients received on a weekly basis from September 2011 to April 2012 , was used to assess moment of recurrence ( ≥20 ) and severity at moment of recurrence . RESULTS 23 SAD patients were r and omized to MBCT and 23 to the control condition . Kaplan-Meier survival curve showed that the groups did not differ in moment of recurrence ( χ²(1).41 , p=.52 ) . T-tests showed no group difference in mean IDS-SR scores at moment of recurrence ( t(31)=-.52 , p=.61 ) . LIMITATIONS The results are limited by small sample size ( n=46 ) and missing data of weekly IDS-SR assessment s. CONCLUSION The findings of this pilot RCT suggest that individual MBCT is not effective in preventing a SAD recurrence when offered in a symptom free period ( i.e. spring ) OBJECTIVE The prevalence of seasonal affective disorder-as measured by the Seasonal Pattern Assessment Question naire-has been found to be unexpectedly low among Icel and ers . The aim of this cross-sectional study was to measure seasonal variations in the prevalence of anxiety and depression among Icel and ers assessed with the Hospital Anxiety and Depression Question naire . METHOD Four 1 , 000-person cohorts , age 20 - 70 years , selected at r and om from the Icel and ic National Register , were sent the Hospital Anxiety and Depression Scale by mail in either January , April , July , or October . Only responses from the 4-week period after each mailing were considered in the subsequent analysis . RESULTS The mean anxiety and depression scores in winter were not higher than those in summer for either sex . There was no significant difference between winter and summer in rates of actual or borderline cases of anxiety or depression or for the two categories combined . CONCLUSIONS This lack of seasonality in anxiety and depression is in sharp contrast to findings from similar cross-sectional studies and may reflect the low propensity for seasonal affective disorder that has been described in the Icel and ic population BACKGROUND The need to develop supplementary or alternative treatments for seasonal affective disorder ( SAD ) is underscored by the significant minority ( 47 % ) of SAD patients that is refractory to light therapy , the persistence of residual symptoms despite light treatment , and poor long-term compliance with light use . Because preliminary studies suggest that cognitive and behavioral factors are involved in SAD , cognitive-behavioral therapy ( CBT ) warrants investigation as a possible treatment option . METHODS We piloted a 6-week r and omized clinical trial to compare a st and ard light therapy protocol ; a novel , SAD-tailored , group CBT intervention ; and their combination in ameliorating and remitting a current SAD episode and as prophylaxis against episode recurrence . Depressive symptom severity and remission rates were assessed at post-treatment and at a 1-year follow-up visit to examine long-term treatment durability . RESULTS CBT , light therapy , and their combination all demonstrated significant reductions in depressive symptoms on two different outcome measures . Remission rates varied by measure , but did not reach statistical significance . During the subsequent winter , CBT , particularly in combination with light therapy , appeared to improve long-term outcome regarding symptom severity , remission rates , and relapse rates . No CBT-treated participant , with or without light , experienced a full SAD relapse compared to over 60 % of those treated with light alone . LIMITATIONS These results should be viewed as preliminary and are limited by the small sample size ( n=23 ) and lack of a control group . CONCLUSIONS The nearly half of SAD patients who do not remit with light alone may benefit from CBT as an adjunct or alternative treatment , especially as a prophylaxis against episode recurrence BACKGROUND This r and omized controlled trial investigates the efficacy of two non-pharmacologic treatments , bright light and high-density negative air ions for non-seasonal chronic depression .  Both methods have shown clinical success for seasonal affective disorder ( SAD ) . METHOD Patients were 24 ( 75 % ) women and 8 ( 25 % ) men , ages 22 - 65 years ( mean age + /- S.D. , 43.7 + /- 12.4 years ) , with Major Depressive Disorder , Single Episode ( DSM-IV code , 296.2 ) , Chronic ( episode duration > or = 2 years ) . Patients were entered throughout the year and r and omly assigned to exposure to bright light ( 10 000 lux , n = 10 ) , or high-density ( 4.5 x 10(14 ) ions/s flow rate , n = 12 ) or low-density ( 1.7 x 10(11 ) ions/s , n = 10 , placebo control ) negative air ions . Home treatment sessions occurred for 1 h upon awakening for 5 weeks . Blinded raters assessed symptom severity weekly with the Structured Interview Guide for the Hamilton Depression Rating Scale -- Seasonal Affective Disorder ( SIGH-SAD ) version . Evening saliva sample s were obtained before and after treatment for ascertainment of circadian melatonin rhythm phase . RESULTS SIGH-SAD score improvement was 53.7 % for bright light and 51.1 % for high-density ions v. 17.0 % for low-density ions . Remission rates were 50 % , 50 % and 0 % respectively . The presence or severity of atypical symptoms did not predict response to either treatment modality , nor were phase advances to light associated with positive response . CONCLUSIONS Both bright light and negative air ions are effective for treatment of chronic depression . Remission rates are similar to those for SAD , but without a seasonal dependency or apparent mediation by circadian rhythm phase shifts . Combination treatment with antidepressant drugs may further enhance clinical response BACKGROUND Lewy 's phase shift hypothesis ( PSH ) of seasonal affective disorder ( SAD ) asserts that winter depression is caused by an abnormal delay of circadian phase in winter . The aim of this study was to further investigate the PSH by testing the novel hypothesis that winter pattern seasonality of mood in the general population is associated with a phase delay of circadian rhythms in winter . METHODS Using a r and om community sample of 244 adults in Melbourne , seasonality of mood was measured prospect ively as the within-subject difference between self-reports of behavioural engagement in summer and winter across 3 years . The  Horne-Ostberg Morningness-Eveningness question naire ( MEQ )  was used as a  self-report estimate of circadian phase . Phase delay in winter was measured as the within-subject difference between summer and winter estimates of circadian phase , with relative shifts towards Eveningness being interpreted as phase delay . RESULTS As expected , a significant association was found between winter pattern seasonality of mood and within-subject phase delay in winter ( r=0.17 , P<0.01 ) . LIMITATIONS Circadian phase was operationalised on the MEQ . While a number of studies have shown the MEQ to correlate with physiological measures of circadian phase , the findings await replication using a more direct measure of the circadian system . CONCLUSIONS A positive association was found between lowered mood in winter and winter phase delay amongst a r and om community sample . This provisional finding adds support to Lewy 's PSH by demonstrating that phase delay may be causally important not just in clinical cases of SAD , but across the continuum of mood seasonality Background : This study sought to determine whether the prevalence of the seasonal subtype of major depression ( SAD ) in the community varied as a function of latitude . Methods : R and om telephone numbers were generated across 8 degrees of latitude ( 41.5 ° N to 49.5 ° N ) for the province of Ontario . Eight strata of 1 degree each were sample d equally throughout a 12-month period . Using a vali date d and structured diagnostic interview , we interviewed by telephone  respondents over 20 years of age who had lived in the region for 3 years or more . We evaluated patterns of symptom change across seasons to establish a diagnosis of SAD according to DSM-IV criteria . Results : Of the 2078 households that were assessed for eligibility , 1605 ( 77 % ) completed the interview . The crude prevalence of lifetime SAD was 2.6 % ( 95 % CI , 1.9 to 3.5 ) . There was no impact of latitude on prevalence of either major depression or the seasonal subtype across the 8 strata , although the global measure of the severity of seasonal change in mood was significantly negatively correlated with latitude . Conclusions : SAD is a common subtype of major depression in Ontario , but there is no evidence to support an increase in prevalence with increasing latitude . Context e : Cette étude visait à déterminer si la prévalence du caractère saisonnier de la dépression majeure ( DMS ) dans la communauté variait selon la latitude . Méthodes : Des numéros de téléphone aléatoires ont été fournis sur 8 degrés de latitude ( de 41,5 ° N. à 49,5 ° N. ) dans la province de l'Ontario . Huit b and es de 1 degré chacune ont été échantillonnées également sur une période de 12 mois . À l'aide d'une entrevue diagnostique validée et structurée , nous avons interviewé par téléphone des répondants âgés de plus de 20 ans qui habitaient la région depuis 3 ans ou plus . Nous avons évalué les changements des modèles de symptômes selon les saisons pour établir un diagnostic de DMS selon les critères du DSM-IV . Résultats : Sur les 2 078 ménages admissibles , 1 605 ( 77 % ) ont terminé l'entrevue . La prévalence brute de la DMS à vie était de 2,6 % ( 95 % IC , 1,9 à 3,5 ) . La latitude n'influait pas sur la prévalence de la dépression majeure ou du caractère saisonnier dans les 8 b and es , bien que la mesure globale de la sévérité du changement saisonnier de l'humeur ait indiqué une corrélation négative significative à la latitude . Conclusions : La dépression majeure saisonnière est un sous-type rép and u de la dépression majeure en Ontario , mais aucune preuve ne soutient une augmentation de la prévalence parallèle à l'accroissement de la latitude Patterns of seasonal changes in  mood and behavior in Montgomery County , Maryl and , were evaluated in r and omly selected household sample s by lay interviewers using a telephone version of the Seasonal Pattern Assessment Question naire . The method for selecting the sample unit was r and om-digit dialing . We found that 92 % of the survey subjects noticed seasonal changes of mood and behavior to varying degrees . For 27 % of the sample seasonal changes were a problem and 4.3 % to 10 % of subjects , depending on the case-finding definition , rated a degree of seasonal impairment equivalent to that of patients with seasonal affective disorder . The seasonal pattern of " feeling worst " exhibited a bimodal distribution with a greater winter and a substantially lower summer peak ( ratio , 4.5:1 ) . Younger women who have a problem with seasonal changes and who feel worse on short days tended to exhibit the highest seasonality scores . It is apparent from our study that seasonal affective disorder represents the extreme end of the spectrum of seasonality that affects a large percentage of the general population . The influence of environmental factors on mood disorders and mood changes in the general population might provide valuable insight into pathogenesis , treatment , and prevention of affective illness
Recent systematic review s have shown that  light therapy  is an efficacious and well-tolerated treatment for SAD .
There is also evidence for efficacy of pharmacotherapy to treat and prevent SAD .
SAD is a common condition with significant psychosocial impairment .
BACKGROUND Seasonal affective disorder ( SAD ) consists of recurrent major depressive episodes in the fall/winter with remissions in spring/summer .
RESULTS A careful history is important to make the diagnosis and differentiate SAD from other similar conditions such as subsyndromal SAD and atypical depression .
Seasonal patterns with winter worsening are also recognized in " nonseasonal " depression as well as many other psychiatric conditions , and comorbidity with SAD is common .
The pathophysiology of SAD seems to be heterogeneous as research on circadian , neurotransmitter function and genetic hypotheses have shown discrepant results .
A dual vulnerability model with differential loading on separate seasonal and depression factors has been proposed to explain these findings .