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 of 30°N (or S) and higher.
|
Contents
- 1 Pathophysiology
- 2 Treatment
- 3 History
- 4 SAD and Bipolar Disorder
- 5 Famous sufferers
- 6 See also
- 7 Notes
- 8 External links
|
Pathophysiology
Seasonal mood variations are believed to be related mostly to daylight, 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 is a serious disorder, sometimes triggering dysthymia or clinical depression. It may require hospitalization.
Norman Rosenthal, MD, pioneer in SAD research, 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.[1] 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.[2],[3] Another theory is that melatonin produced in the pineal gland is the primary cause,[4],[5] 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[6],[7] and melatonin receptor ligands produce antidepressant-like effect in mice[8]. Light therapy appears to be effective in treating SAD, but the exact mechanism of the effect is still unknown.
Although Dr. Rosenthal first called this disorder "winter blues", this term is more often used to describe something felt 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 during the winter.
Treatment
A number of treatments exist for SAD. These include light therapies, medication, ionized-air reception and cognitive therapy.
Treatments using light are the most common, and of these bright-light therapies tend to be the treatment of choicecitation needed]. The use of a bright light-box is the most effective, leading to around 85% success rates [9]. 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, and be used for 30-60 minutes daily. The sufferer should remain within sight of the light-box, with their eyes open and unshielded, but not directly staring at the lights. The best time to administer light therapy is still a matter of debate, though use in the morning has been suggested to mimic the effects of normal dawn on the patient. In fact, some studies have shown dawn simulation to be as effective as bright lights in treating SAD. [10] 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 springcitation needed].
If light therapy has little or no effect, medication can used as an additional treatment when prescribed. Selective serotonin reuptake inhibitors (SSRIs) have proven effective in treating SAD. Examples of these antidepressants are fluoxetine (Prozac), sertraline (Zoloft, Lustral), or paroxetine (Paxil). [11] Bupropion (Wellbutrin XL), an antidepressant of the aminoketone class, is also effective. [12] Fluoxetine does not appear to be any more effective than light therapy in direct head-to-head trials.[13]
Studies by Michael Terman show the benefit of negative air ionization, where people passively receive charged particles from an electronic device. [14]. In addition, recent studies of University of Vermont psychologist Kelly Rohan showed that cognitive therapy can relieve the symptoms of SAD. [15]
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 hereditary. It was first described by the 6th century Goth scholar Jordanes in his Getica where he described the inhabitants of Scandza (Scandinavia).citation needed]
In the USA 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.
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. [1]
Famous sufferers
Famous sufferers of SAD include Miriam Taffel, renowned for her work in the fields of psychology and intelligent systems.
Jillian Barberie of Good Day L.A. has mentioned during the program that she suffered from SAD when she lived in Ontario, Canada.
Johnny Briggs, who played Mike Baldwin in Coronation Street, also suffers from SAD.
Musician Rick Strom has credited his most creative periods to SAD.
Norman E. Rosenthal, MD, first researcher into the effect of light upon mood.
Natalie Imbruglia, famous australian singer, suffered from SAD during a longer stay in London, England.[16]
See also
- Depression (mood)
- Human factors
- Human reliability
- Circadian rhythm sleep disorder
Notes
- ^ Seasonal affective disorder: autumn onset, winter gloom - board review
- ^ Johansson C, et al. (2001) Seasonal affective disorder and serotonin-related polymorphisms. Neurobiol Dis. 8(2):351–7.
- ^ Johansson C, et al. (2003) The serotonin transporter promoter repeat length polymorphism, seasonal affective disorder and seasonality. Psychol Med. 33(5):785–92.
- ^ The Merck manual
- ^ National mental health association article
- ^ Prolonged swim-test immobility of serotonin N-acetyltransferase (AANAT)-mutant mice
- ^ Reliability assessment of an automated forced swim test device using two mouse strains
- ^ The antidepressant-like effect of the melatonin receptor ligand luzindole in mice during forced swimming requires expression of MT2 but not MT1 melatonin receptors
- ^ Literature from the SADA website
- ^ Avery DH et al. (2001) Dawn simulation and bright light in the treatment of SAD: a controlled study. Biol Psychiatry. 50(3):205–16.
- ^ SAD information from the WSC Counseling Center
- ^ [http://www.biopsychiatry.com/bupropionxl-sad.htm Seasonal affective disorder and its prevention by anticipatory treatment with bupropion XL ]
- ^ 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.
- ^ Controlled trial of bright light and negative air ions for chronic depression
- ^ Cognitiv Reactivity In Seasonal Affecive Disorder
- ^ Interview with Natalie Imbruglia 17th June 2005
External links
- A non profit site dedicated to Seasonal Affective Disorder created by chronobiological researchers, including lightbox criterias, individual professional advice and newest clinical studies
- Seasonal Affective Disorder at the Open Directory Project
- Light Therapy as a home S.A.D. Treatment
- Articles including clinical studies, press articles and advice on Seasonal Affective Disorder
- Information on Seasonal Affective Disorder. A high quality 10,000 lux light box is also available for purchase
- The Seasonal Affective Disorder Association (SADA), a UK-based charitable organisation
Categories: Articles with unsourced statements | Mood disorders | Circadian rhythms
