Seasonal affective disorder

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Seasonal affective disorder, or SAD, also known as winter depression is an affective, or mood, disorder. Most SAD sufferers experience normal mental health throughout most of the year, but experience depressive symptoms in the winter or summer. SAD is rare, if existent at all, in the tropics, but is measurably present at latitudes north of 30°N, or south of 30°S.

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[edit] Pathophysiology

Seasonal mood variations are believed to be related mostly to light, not temperature. For this reason, SAD is prevalent even in mid-latitude places with mild winters, such as Seattle and Vancouver. People who live in the Arctic region are especially susceptible due to the effects of polar nights. Prolonged periods of overcast weather can also exacerbate SAD.

SAD can be a serious disorder and may require hospitalization. The symptoms of SAD mimic those of dysthymia or clinical depression. At times, patients may not feel depressed, but rather lack energy to get out of bed and do things. Norman Rosenthal, MD, pioneer in SAD research and author of Winter Blues: Everything You Need to Know to Beat Seasonal Affective Disorder, has described SAD as “an energy crisis.”[1] He has estimated that the prevalence of SAD in the adult US population is between 1.4 percent (in Florida) and 9.7 percent (in New Hampshire).

Various etiologies have been suggested.[2] One possibility is that SAD is related to a lack of serotonin and that exposure to full-spectrum artificial light may improve the condition by stimulating serotonin production, although this has been disputed.[3][4] Another theory is that melatonin produced in the pineal gland is the primary cause,[5][6] since there are direct connections between the retina and the pineal gland. Some studies show that melatonin levels do not appear to differ between those with and without SAD. However, mice incapable of synthesizing melatonin appear to express "depression-like" behaviors[7][8] and melatonin receptor ligands produce antidepressant-like effect in mice.[9]

Although Dr. Rosenthal first called this disorder "winter blues", this term is more often used to describe a milder form of SAD experienced by a greater number during the winter. This blue feeling can usually be dampened or extinguished by exercise and increased outdoor activity, particularly on sunny days, resulting in increased solar exposure. (Most people get less outdoor exercise during the winter.) Connections between human mood, as well as energy levels, and the seasons are well-documented, even in healthy individuals. Particularly in high latitudes (50°N or S) it is common for people to experience lower energy levels.

[edit] Treatment

A number of treatments exist for SAD. These include light therapies, medication, ionized-air reception and cognitive therapy.

Bright light therapy is a common treatment for SAD.
Bright light therapy is a common treatment for SAD.

Treatments using light are the most common, and of these bright light therapies tend to be the treatment of choice.[1] The use of a therapeutic light box is the most effective, leading to an approximately 85 percent success rate.[10] A specially designed light, many times brighter than normal office lighting, is placed near the sufferer. It should provide a dose of 10,000 lux. Many use it for 30-60 minutes daily. The sufferer should remain within sight of the light-box, with their eyes open and unshielded, only occasionally glancing at the light box. The best time to administer light therapy is still a matter of debate. Most patients use the light box in the morning, however discovering the best schedule on an individual basis is essential in reducing symptoms.[11]In fact, some studies have shown dawn simulation to be more effective than bright lights in treating SAD.[12] Light therapy may take several weeks to take full effect though some improvement should be noted within a week. It should be continued until natural daily light exposure becomes sufficient, usually during spring.[citation needed]

Another mode of treatment is prescription medication. SSRI (selective serotonin reuptake inhibitor) antidepressants have proven effective in treating SAD. Examples of these antidepressants are fluoxetine (Prozac), sertraline (Zoloft), or paroxetine (Paxil).[13] Bupropion (Wellbutrin), an antidepressant of the aminoketone class, is also effective.[14] Fluoxetine does not appear to be any more effective than light therapy in direct head-to-head trials.[15]

Negative air ionization, involving the release of charged particles into the sleep environment, has also been found effective.[16]

Depending upon the patient, one treatment (ie. lightbox) may be used in conjunction with another therapy (ie. medication and/or therapy).

[edit] History

Winter depression (or winter blues) is a common slump in the mood of Scandinavians. Doctors estimate that about 20% of all Swedes are affected, and it seems to be genetically heritable.[citation needed] It was first described by the 6th century Goth scholar Jordanes in his Getica where he described the inhabitants of Scandza (Scandinavia).[17]

In the United States of America the diagnosis of seasonal affective disorder was first proposed by Norman E. Rosenthal, MD in 1984. Rosenthal wondered why he became muggish during the winter after moving from sunny South Africa to New York. He started experimenting increasing exposure to artificial light, and found this made a difference.

[edit] SAD and Bipolar Disorder

Most people with SAD experience unipolar depression, but as many as 20% may have or go on to develop a bipolar or manic-depressive disorder.[18]

[edit] Famous sufferers

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  • Norman E. Rosenthal, MD, first researcher into the effect of light upon mood.
  • Musician Rick Strom has credited his most creative periods to SAD.
  • Musician Matt Hoffer, Rock Star: Supernova contestant who was eliminated from the show first. He has a song named 'Standing Eight Count' which explains his life with SAD.
  • Science fiction-fantasy author Barbara Hambly suffered with undiagnosed SAD for many years.[20]
  • Comedian and talk-show host Rosie O'Donnell shared on The View that she suffers from SAD.

[edit] References

  1. ^ a b Brody, Jane E. "Getting a Grip on the Winter Blues", New York Times, 2006-12-05.
  2. ^ Seasonal affective disorder: autumn onset, winter gloom - board review
  3. ^ Johansson C, et al. (2001) Seasonal affective disorder and serotonin-related polymorphisms. Neurobiol Dis. 8(2):351–7.
  4. ^ Johansson C, et al. (2003) The serotonin transporter promoter repeat length polymorphism, seasonal affective disorder and seasonality. Psychol Med. 33(5):785–92.
  5. ^ The Merck manual
  6. ^ Seasonal Affective Disorder (SAD). Mental Health America (February 1993).
  7. ^ Prolonged swim-test immobility of serotonin N-acetyltransferase (AANAT)-mutant mice
  8. ^ Reliability assessment of an automated forced swim test device using two mouse strains
  9. ^ The antidepressant-like effect of the melatonin receptor ligand luzindole in mice during forced swimming requires expression of MT2 but not MT1 melatonin receptors
  10. ^ Literature from the SADA website
  11. ^ Terman, Michael; Jamie Rifkin (2006-11-02). Light on Winter Darkness. About.com.
  12. ^ Avery DH et al. (2001) Dawn simulation and bright light in the treatment of SAD: a controlled study. Biol Psychiatry. 50(3):205–16.
  13. ^ SAD information from the WSC Counseling Center
  14. ^ Seasonal affective disorder and its prevention by anticipatory treatment with bupropion XL
  15. ^ Lam RW, Levitt AJ, Levitan RD, et al. (2006). "The Can-SAD study: a randomized controlled trial of the effectiveness of light therapy and fluoxetine in patients with winter seasonal affective disorder". Am J Psychiatry 163 (5): 805–12. 
  16. ^ Terman, M. & J.S. Terman (December, 2006), "Controlled trial of naturalistic dawn simulation and negative air ionization for seasonal affective disorder.", Amrican Journal of Psychiatry 163 (12): 2126-33
  17. ^ Jordanes, Getica, ed. Mommsen, Mon. Germanae historica, V, Berlin, 1882.
  18. ^ SAD and depression
  19. ^ Interview with Natalie Imbruglia 17th June 2005
  20. ^ Andromeda Spaceways interview with Barbara Hambly, discusses SAD

[edit] See also

[edit] External links

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