Seasonal affective disorder

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Seasonal affective disorder
Light therapy lamp for the treatment of seasonal affective disorder (SAD)

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Vatsala Sharma; M.B.B.S[2] ; Haleigh Williams, B.S.

Synonyms and keywords: SAD, seasonal disorder, seasonal depression, winter blues, winter depression


Seasonal affective disorder (SAD), also known as winter depression, is a form of depression that is related to changes in the season. In the most common form of SAD, an individual experiences more frequent depressive periods between the late fall and early spring, with a return to normal baseline mood in the late spring and summer months. Less commonly, patients may experience depressive episodes in the summer; this type of disorder is known as reverse seasonal affective disorder (Reverse-SAD). The management options for SAD are phototherapy, medications, psychotherapy, or a combination of these.

Historical Perspective

  • The seasonal variation in mood is observed since ancient times.
  • Hippocrates circa (400 BC) first explained seasonal depression. [1]
  • The Greco-Roman physicians managed depression by focusing the sunlight toward the affected individual's eyes.[1]
  • In 1894, Cook described a disorder characterized by depressed mood, low energy, fatigue, and loss of libido, which Cook related to the seasonal loss of sunlight. [1]
  • Esquirol(1845) and Kraplein (1921) also described the seasonal variability in the mood.[1]
  • In the 1980s, SAD was systematically described for the first time and named by South African physician Normal Rosenthal. He noticed that he felt significantly less energetic during the winters and returned to his normal state during the spring.[2]
  • In 1984, a paper was published based on Rosenthal's idea of treating depression with artificial light therapy. [3]
  • Wehr's (1989) contribution in the form of a chapter in the book seasonal affective disorder and phototherapy is well-acknowledged. [4]
  • Wehr et al have also described a variant with the opposite pattern, depression in the summers and non-depressed phases in the winters. This condition is termed reverse-SAD.[5]
  • The Seasonal Pattern Assessment Questionnaire (SPAQ), developed by Rosenthal in 1984, is a self-administered screening tool for SAD.[2]



  1. Serotonin: Studies have shown that individuals with winter-occurring SAD produce more serotonin transporter proteins in the winters than in the summers, causing the lesser effect of serotonin in winters.[10][11]
  2. Norepinephrine: Catecholamine levels are also found to be low in these patients.
  3. Melatonin: In the winters, as days become shorter, and periods of darkness increase. The levels of melatonin that is produced during the night increases. This interferes with the circadian rhythm and induces lethargy.
  4. Vitamin D: Patients with SAD tend to have lower levels of vitamin D than controls. This deficiency plays a role in exacerbating depression through interference with serotonin action.[12]

Differential Diagnosis

SAD must be differentiated from diseases that present with similar symptoms, including:[13][14]

Epidemiology and Demographics

  • The prevalence of SAD ranges from 1.5% to 9%, depending on latitude.[15]
  • A higher positive correlation has been found with latitude and prevalence of winter SAD. This finding is prominent in the age groups over 35 years.[16]


  • The age of onset of SAD is generally between 18 and 30 years.[2]
  • In most of the studies, SAD has been diagnosed in younger adults.[2][17]
  • Compared to high-school students, SAD is found to be less prominent in adults. Winter type SAD is related to latitude in adults whereas sociocultural factors play a role in adolescents.[18]


  • SAD is more common in women as compared to men. Women are four times as likely as men to be diagnosed with SAD.[2][17]
  • The gender differences in SAD are the same as in non-seasonal depression.
  • For assessing the gender-based prevalence of SAD, importance should be given to case criteria such as diagnosis (unipolar vs. bipolar), and birth cohort.[19]


  • SAD has no specific racial predilection.

Risk Factors

Risk factors for SAD include:[20][2][21][22] [23][24][18]

  • Female gender
  • Age less than 40 years
  • Higher latitude
  • Family history of depression
  • 5-HTTLPR gene polymorphism
  • Sociocultural factors (for adolescents)


  • The Seasonal Health Questionnaire (SHQ) was found to be more sensitive and specific than SPAQ. It also had higher positive and negative predictive values. [25]
  • Other screening tools that can be used are[26]
    • Seasonal Pattern module of the Structured Clinical Interview for DSM Disorders (SCID)
    • Hypomania Interview Guide for Seasonal Affective Disorder (HIGH-SAD)
    • Structured Interview Guide for the Hamilton Depression Rating Scale—Seasonal Affective Disorder

Natural History, Complications, and Prognosis

  • SAD can be a very serious disorder and may require hospitalization.[23]
  • There is also a risk of suicide in some patients experiencing SAD.[27]
  • The symptoms mimic those of clinical depression, with seasonal variability.
  • The prognosis of SAD is generally good. However, it has been observed that an index episode with a short duration and the illness course with high frequency showed a seasonal relapse pattern. [28]
  • If appropriate treatment is started early with phototherapy, the prognosis is generally better in patients with predominant atypical symptoms than those having typical melancholic symptoms.[29]


Commonly comorbid conditions include:[13]


Diagnostic Criteria

A diagnosis of SAD is used for patients who meet all the criteria for major depression and have depression corresponding to the onset of specific seasons for a minimum duration of two years.[20][7]


General symptoms of major depression are:[20]

Symptoms of winter-occurring SAD are:[20][2]

Symptoms of summer-occurring SAD are:[20][2]

Diagnostic and Statistical Manual of Mental Disorders (DSM)

  • DSM-5 criteria for the diagnosis of SAD specifier requires [29]
    • Two or more episodes fulfilling the DSM-5 criteria of major depressive episode in bipolar I, bipolar II, or major depressive disorder (recurrent), with the last two episodes being consecutive.
    • Onset and remission of episodes must occur in the same season.
    • Seasonal episodes must outnumber the non-seasonal ones.
    • Non-seasonal episodes should be absent over the last two episodes.
    • Seasonal psychosocial stressors should be excluded.

International Classification of Diseases, Tenth Edition (ICD-10)

  • ICD-10 does not include specific clinical guidelines for diagnosing SAD.
  • Specific criteria are present in the research-version of ICD-10. These are [29]
    • These criteria can be applied to affective disorders category F30-33, the episodes must fulfill the diagnostic criteria for major depression.
    • Three or more affective episodes must occur within 90 days period of the year for 3 or more consecutive years.
    • Remission also occurring within 90 days period of the year.
    • Seasonal episodes outnumber the non-seasonal ones.


Light Therapy

  • SAD has been treated primarily with light therapy. It is also called bright light therapy (BLT) or phototherapy.[20][2]
  • The rationale behind the use of light therapy is that the depressive effect of decreased sunlight during the winter months can be counteracted through daily exposure to bright light. Phototherapy acts through the change in the amplitude and timing of melatonin secretion as well as serotonergic system modulation. [29]
  • Patients who undergo light therapy typically use a lightbox each morning from early fall until the start of spring.
  • The use of lightboxes generally requires 20 to 60 minutes of exposure to 10,000 lux of cool-white fluorescent light, which is approximately 20 times brighter than the standard light.[29]
  • Common side effects of light therapy include eye strain, insomnia, and headaches.[31]
  • If patients experience side effects, the therapy should be split multiple times a day or administered earlier in the day in case of insomnia. [29]
  • Light therapy is contraindicated if the patient is on photosensitizing medications.[2]
  • Light therapy is used daily and it may take up to two weeks for the complete therapeutic response. Maintenance treatment is usually needed daily for the rest of the winter. The treatment should be discontinued on remission otherwise may result in hypomania.[29]
  • Precipitation of hypomanic episodes with phototherapy is commonly seen with bipolar cases. These can be controlled by reducing the therapy dose.[29]
  • Patients with atypical symptoms of depression respond better to light therapy. [32]



  • Seasonal affective disorder is surrounded by treatment options with inadequate evidence. The prophylaxis and management measures warrant thorough long-term research to optimize patient well-being.


  1. 1.0 1.1 1.2 1.3 Sher, Leo (2000). "Seasonal Affective Disorder and Seasonality: A Review". Jefferson Journal of Psychiatry. 15 (1). doi:10.29046/JJP.015.1.001. ISSN 1935-0783.
  2. 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 Melrose S (2015). "Seasonal Affective Disorder: An Overview of Assessment and Treatment Approaches". Depress Res Treat. 2015: 178564. doi:10.1155/2015/178564. PMC 4673349. PMID 26688752.
  3. Rosenthal, Norman E. (1984). "Seasonal Affective Disorder". Archives of General Psychiatry. 41 (1): 72. doi:10.1001/archpsyc.1984.01790120076010. ISSN 0003-990X.
  4. Eagles, John M. (2018). "Seasonal affective disorder". British Journal of Psychiatry. 182 (2): 174–176. doi:10.1192/bjp.182.2.174. ISSN 0007-1250.
  5. Rosenthal, Norman E; Wehr, Thomas A (1987). "Seasonal Affective Disorders". Psychiatric Annals. 17 (10): 670–674. doi:10.3928/0048-5713-19871001-10. ISSN 0048-5713.
  6. 6.0 6.1 Magnusson, A. (2000). "An overview of epidemiological studies on seasonal affective disorder". Acta Psychiatrica Scandinavica. 101 (3): 176–184. doi:10.1034/j.1600-0447.2000.101003176.x. ISSN 0001-690X.
  7. 7.0 7.1 Diagnostic and statistical manual of mental disorders : DSM-5. Washington, D.C: American Psychiatric Association. 2013. ISBN 0890425558.
  8. Magnusson, Andres; Partonen, Timo (2014). "The Diagnosis, Symptomatology, and Epidemiology of Seasonal Affective Disorder". CNS Spectrums. 10 (8): 625–634. doi:10.1017/S1092852900019593. ISSN 1092-8529.
  9. 9.0 9.1 Lam RW, Levitan RD (2000). "Pathophysiology of seasonal affective disorder: a review". J Psychiatry Neurosci. 25 (5): 469–80. PMC 1408021. PMID 11109298.
  10. De Felice LJ (2016). "A current view of serotonin transporters". F1000Res. 5. doi:10.12688/f1000research.8384.1. PMC 4965693. PMID 27540474.
  11. Haase J, Killian AM, Magnani F, Williams C (2001). "Regulation of the serotonin transporter by interacting proteins". Biochem Soc Trans. 29 (Pt 6): 722–8. doi:10.1042/0300-5127:0290722. PMID 11709063.
  12. Penckofer S, Kouba J, Byrn M, Estwing Ferrans C (2010). "Vitamin D and depression: where is all the sunshine?". Issues Ment Health Nurs. 31 (6): 385–93. doi:10.3109/01612840903437657. PMC 2908269. PMID 20450340.
  13. 13.0 13.1 Lurie SJ, Gawinski B, Pierce D, Rousseau SJ (2006). "Seasonal affective disorder". Am Fam Physician. 74 (9): 1521–4. PMID 17111890.
  14. Stewart JW, Quitkin FM, Terman M, Terman JS (1990). "Is seasonal affective disorder a variant of atypical depression? Differential response to light therapy". Psychiatry Res. 33 (2): 121–8. doi:10.1016/0165-1781(90)90065-d. PMID 2243888.
  15. Nussbaumer B, Kaminski-Hartenthaler A, Forneris CA, Morgan LC, Sonis JH, Gaynes BN; et al. (2015). "Light therapy for preventing seasonal affective disorder". Cochrane Database Syst Rev (11): CD011269. doi:10.1002/14651858.CD011269.pub2. PMID 26558494.
  16. Rosen, Leora N.; Targum, Steven D.; Terman, Michael; Bryant, Michael J.; Hoffman, Howard; Kasper, Siegfried F.; Hamovit, Joelle R.; Docherty, John P.; Welch, Betty; Rosenthal, Norman E. (1990). "Prevalence of seasonal affective disorder at four latitudes". Psychiatry Research. 31 (2): 131–144. doi:10.1016/0165-1781(90)90116-M. ISSN 0165-1781.
  17. 17.0 17.1 Kane, Anna; Lowis, Michael J. (2016). "Seasonal Affective Disorder and Personality, Age, and Gender". South African Journal of Psychology. 29 (3): 124–127. doi:10.1177/008124639902900304. ISSN 0081-2463.
  18. 18.0 18.1 Imai, Makoto; Kayukawa, Yuhei; Ohta, Tatsuro; Li, Lan; Nakagawa, Takeo (2003). "Cross-regional survey of seasonal affective disorders in adults and high-school students in Japan". Journal of Affective Disorders. 77 (2): 127–133. doi:10.1016/S0165-0327(02)00110-6. ISSN 0165-0327.
  19. Lucht, M. J.; Kasper, S. (1999). "Gender differences in seasonal affective disorder (SAD)". Archives of Women's Mental Health. 2 (2): 83–89. doi:10.1007/s007370050040. ISSN 1434-1816.
  20. 20.0 20.1 20.2 20.3 20.4 20.5 National Institute of Mental Health. “Seasonal Affective Disorder.” 2016.
  21. "Prevalence of seasonal affective disorder in Alaska". American Journal of Psychiatry. 149 (9): 1176–1182. 1992. doi:10.1176/ajp.149.9.1176. ISSN 0002-953X.
  22. Avery, D H (2001). "Dawn simulation and bright light in the treatment of SAD: a controlled study". Biological Psychiatry. 50 (3): 205-216 = id = 11513820. Retrieved 2007-05-05. Unknown parameter |coauthors= ignored (help)
  23. 23.0 23.1 Modell, Jack (2005). "Seasonal affective disorder and its prevention by anticipatory treatment with bupropion XL Biological Psychiatry". 58 (8): 658–667. 16271314. Unknown parameter |coauthors= ignored (help)
  24. Sher, Leo; Goldman, David; Ozaki, Norio; Rosenthal, Norman E (1999). "The role of genetic factors in the etiology of seasonal affective disorder and seasonality". Journal of Affective Disorders. 53 (3): 203–210. doi:10.1016/S0165-0327(98)00194-3. ISSN 0165-0327.
  25. Thompson, Chris; Thompson, Susan; Smith, Rachel (2004). "Prevalence of seasonal affective disorder in primary care; a comparison of the seasonal health questionnaire and the seasonal pattern assessment questionnaire". Journal of Affective Disorders. 78 (3): 219–226. doi:10.1016/S0165-0327(02)00314-2. ISSN 0165-0327.
  26. Roecklein KA, Rohan KJ, Postolache TT (2010). "Is seasonal affective disorder a bipolar variant?". Curr Psychiatr. 9 (2): 42–54. PMC 2874241. PMID 20495687.
  27. Partonen, Timo; L??nnqvist, Jouko (1998). "Seasonal Affective Disorder". CNS Drugs. 9 (3): 203–212. doi:10.2165/00023210-199809030-00004. ISSN 1172-7047.
  28. Thompson, Christopher; Raheja, Sunil K.; King, Elizabeth A. (2018). "A Follow-up Study of Seasonal Affective Disorder". British Journal of Psychiatry. 167 (3): 380–384. doi:10.1192/bjp.167.3.380. ISSN 0007-1250.
  29. 29.0 29.1 29.2 29.3 29.4 29.5 29.6 29.7 29.8 29.9 Rodin, I.; Thompson, C. (2018). "Seasonal affective disorder". Advances in Psychiatric Treatment. 3 (6): 352–359. doi:10.1192/apt.3.6.352. ISSN 1355-5146.
  30. Praschak-Rieder N, Willeit M (2003). "Treatment of seasonal affective disorders". Dialogues Clin Neurosci. 5 (4): 389–98. PMC 3181778. PMID 22033639.
  31. "Side effects of light therapy in seasonal affective disorder". American Journal of Psychiatry. 150 (4): 650–652. 1993. doi:10.1176/ajp.150.4.650. ISSN 0002-953X.
  32. Terman, M (1989). "Light therapy for Seasonal Affective Disorder A review of efficacy". Neuropsychopharmacology. 2 (1): 1–22. doi:10.1016/0893-133X(89)90002-X. ISSN 0893-133X.
  33. Cascade E, Kalali AH, Kennedy SH (2009). "Real-World Data on SSRI Antidepressant Side Effects". Psychiatry (Edgmont). 6 (2): 16–8. PMC 2719451. PMID 19724743.
  34. Modell, Jack G.; Rosenthal, Norman E.; Harriett, April E.; Krishen, Alok; Asgharian, Afsaneh; Foster, Vicki J.; Metz, Alan; Rockett, Carol B.; Wightman, Donna S. (2005). "Seasonal Affective Disorder and Its Prevention by Anticipatory Treatment with Bupropion XL". Biological Psychiatry. 58 (8): 658–667. doi:10.1016/j.biopsych.2005.07.021. ISSN 0006-3223.
  35. Wilkes, S. (2006). "Bupropion". Drugs of Today. 42 (10): 671. doi:10.1358/dot.2006.42.10.1025701. ISSN 1699-3993.
  36. Gloth FM, Alam W, Hollis B (1999). "Vitamin D vs broad spectrum phototherapy in the treatment of seasonal affective disorder". J Nutr Health Aging. 3 (1): 5–7. PMID 10888476.
  37. Pjrek, Edda; Winkler, Dietmar; Konstantinidis, Anastasios; Willeit, Matthäus; Praschak-Rieder, Nicole; Kasper, Siegfried (2006). "Agomelatine in the treatment of seasonal affective disorder". Psychopharmacology. 190 (4): 575–579. doi:10.1007/s00213-006-0645-3. ISSN 0033-3158.
  38. Terman, Michael; Terman, Jiuan Su (1995). "Treatment of Seasonal Affective Disorder with a High-Output Negative Ionizer". The Journal of Alternative and Complementary Medicine. 1 (1): 87–92. doi:10.1089/acm.1995.1.87. ISSN 1075-5535.
  39. Partonen, T (1996). "Moclobemide and fluoxetine in treatment of seasonal affective disorder". Journal of Affective Disorders. 41 (2): 93–99. doi:10.1016/S0165-0327(96)00073-0. ISSN 0165-0327.
  40. Kasper, S. (2007). "Treatment of Seasonal Affective Disorder (SAD) with Hypericum Extract". Pharmacopsychiatry. 30 (S 2): 89–93. doi:10.1055/s-2007-979526. ISSN 0176-3679.
  41. Pjrek, E.; Willeit, M.; Praschak-Rieder, N.; Konstantinidis, A.; Semlitsch, H.; Kasper, S.; Winkler, D. (2008). "Treatment of Seasonal Affective Disorder with Duloxetine: An Open-Label Study". Pharmacopsychiatry. 41 (3): 100–105. doi:10.1055/s-2008-1058103. ISSN 0176-3679.
  42. Lundt, L (2004). "Modafinil treatment in patients with seasonal affective disorder/winter depression: an open-label pilot study". Journal of Affective Disorders. 81 (2): 173–178. doi:10.1016/S0165-0327(03)00162-9. ISSN 0165-0327.
  43. Rohan, Kelly J.; Roecklein, Kathryn A.; Tierney Lindsey, Kathryn; Johnson, Leigh G.; Lippy, Robert D.; Lacy, Timothy J.; Barton, Franca B. (2007). "A randomized controlled trial of cognitive-behavioral therapy, light therapy, and their combination for seasonal affective disorder". Journal of Consulting and Clinical Psychology. 75 (3): 489–500. doi:10.1037/0022-006X.75.3.489. ISSN 1939-2117.
  44. Forneris, Catherine A; Nussbaumer-Streit, Barbara; Morgan, Laura C; Greenblatt, Amy; Van Noord, Megan G; Gaynes, Bradley N; Wipplinger, Jörg; Lux, Linda J; Winkler, Dietmar; Gartlehner, Gerald (2019). "Psychological therapies for preventing seasonal affective disorder". Cochrane Database of Systematic Reviews. doi:10.1002/14651858.CD011270.pub3. ISSN 1465-1858.

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