Seasonal Affective Disorder
Also indexed as: SAD, Seasonal Depression, Winter
Depression
A cold and dark winter can trigger depression in people who
suffer from SAD. According to research or other evidence, the following self-care steps may
help you weather the storm and beat your blues:
- Add more D to your diet
- See a qualified health practitioner to find out if you are low in
vitamin D, and if you should take large amounts under medical supervision to help improve mood
and well-being
- Soak in the sun
- Spend more time outdoors to help improve the regulation of
important brain chemicals that affect mood
- Try light therapy
- Reduce symptoms by using a full-spectrum fluorescent light during
dark mornings or evenings
- Check out St. John’s wort
- This well-known herbal remedy may improve mild to moderate
depression; take 900 mg a day of a standardized extract
- Work in a workout
- Get an hour of aerobic or anaerobic exercise three times a week in
bright light to improve mood
These recommendations are not comprehensive and are not intended to replace
the advice of your doctor or pharmacist. Continue reading the full seasonal affective disorder
article for more in-depth, fully-referenced information on medicines, vitamins, herbs, and
dietary and lifestyle changes that may be helpful.
About seasonal affective disorder
Seasonal affective disorder (SAD) is an extreme form of common seasonal mood cycles, in
which depression develops during the winter months.
How seasonal changes cause depression is unknown, but most of the research into mechanisms
and treatment has focused on changes in levels of the brain chemicals melatonin and serotonin in response to changing
exposure to light and darkness.
Product ratings for seasonal
affective disorder
What are the symptoms?
SAD is characterized by typical symptoms of
depression, such as sadness, hopelessness, and thoughts of suicide (in some cases), and
“atypical” depressive symptoms such as excessive sleep, lethargy, carbohydrate
cravings, overeating, and weight gain. The
symptoms usually occur the same time of year, typically fall and winter, and disappear with
the onset of spring and summer.
Light exposure research and treatment measures in “lux” units. For
example, the intensity of light on a high mountain at the equator at midday is greater than
100,000 lux, compared with less than 11 lux generated by a moonlit night. A well-lit kitchen
or office may be around 500 lux.
Medical options
Some healthcare practitioners might prescribe antidepressants, such as fluoxetine (Prozac®), paroxetine (Paxil®), sertraline (Zoloft®), citalopram (Celexa®), escitalopram (Lexapro®), and Venlafaxine (Effexor®) to people with severe
depression who are not responding to nondrug therapies.
Treatment includes daily exposure to bright light, often 2,500 lux administered in two-hour
increments. Individuals with SAD should spend as much time as possible outside during the day.
Use of a “dawn simulator,” a light programmed to slowly increase in intensity in
the morning, is also recommended. Some healthcare providers might also recommend aerobic
exercise under bright lights.
Dietary changes that may be helpful
Cravings for simple carbohydrates are increased in SAD, and women diagnosed with this form
of winter depression have been found to eat more carbohydrates, both sweets and starches, than do healthy women. These
women also report eating in response to emotionally difficult conditions, anxiety, depression, and loneliness more frequently
than healthy women, but eating patterns associated with SAD are distinct from those of women
with eating disorders.1
People with SAD process sugar differently
in winter compared with summer or after light
therapy in winter.2 Changes in neurotransmitters that may affect cravings also
occur in women with SAD.3 Because consumption of carbohydrates can influence
neurotransmitter levels,4 some authorities have speculated that eating simple
carbohydrates may be a form of self-medication in people with SAD. A review of the research on
diet and mood found that, while eating simple carbohydrates in reaction to depressed mood does
bring about a temporary lift in mood, other evidence suggests that long-term control of
negative moods is, for some people, best achieved by eliminating simple carbohydrates from the
diet.5 No research has yet been conducted, however, to evaluate the benefits of a
diet low in simple carbohydrates (or any other dietary intervention) for people with SAD.
Lifestyle changes that may be helpful
Exercise can ease depression and improve
well being, in some cases as effectively as antidepressant medications.6 One study
found that both one hour of aerobic exercise three times per week and the same amount of
anaerobic exercise were significantly and equally effective in reducing symptoms of
depression.7 In a preliminary study of women with SAD, exercise while exposed to
light was more likely to be associated with fewer seasonal depressive symptoms than was
exercise performed with little light exposure.8 A controlled study of 120 indoor
employees used relaxation training as the placebo in a study of fitness training, light
exposure, and winter depressive symptoms. Fitness training was performed two to three times
per week while exposed to either bright light (2,500–4,000 lux) or ordinary light
(400–600 lux). Compared to relaxation, exercise in bright light improved general mental
health, social functioning, depressive symptoms, and vitality, while exercise in ordinary
light improved vitality only.
Vitamins that may be helpful
L-tryptophan is the amino acid used by the
body to manufacture serotonin. Several trials, some controlled, have shown that experimentally
inducing a tryptophan deficiency in people with SAD who are in remission brings about a
relapse of depressive symptoms.9
10 11 12 13 This suggests that supplemental
L-tryptophan might be helpful in SAD. In small, preliminary trials, 4 to 6 grams of
L-tryptophan given in divided amounts daily was as effective as light therapy14
15 and more effective than placebo.16 L-tryptophan may be of particular
use in people with winter depression who do not benefit from light therapy. In a preliminary trial, people with SAD
who responded only partially or not at all to bright light therapy were given 1,000 mg of
L-tryptophan three times daily in addition to 10,000 lux light therapy for 30 minutes every
morning. Sixty-four percent of them had significant improvement in depressive symptoms while
receiving both L-tryptophan and bright light therapy.17 L-tryptophan is currently
available by prescription only.
5-HTP is a substance related to
L-tryptophan that increases serotonin production and has shown antidepressant
activity.18 It may also be useful in the treatment of SAD, but there is currently
no research testing this possibility.
Vitamin D is well known for its effects on
helping to maintain normal calcium levels, but
it also exerts influence on the brain, spinal cord, and hormone-producing tissues of the body
that may be important in the regulation of mood.19 A double-blind study found that
mood improved in healthy people without SAD who received 400 or 800 IU per day of vitamin D
for five days in late winter.20
In another study, people with SAD were randomly assigned to receive either 100,000 IU of
vitamin D one time only or two hours of bright-light therapy every day for one month. After
one month, researchers observed a significant improvement in depression in the group that
received vitamin D, but not in the group given light therapy.21 However, a one-year
study of healthy postmenopausal women found that supplementation with 400 IU of vitamin D per
day did not prevent the mood decline that often occurs in the winter.22 Certain
differences in these studies might account for the different results: In the study in which
vitamin D was beneficial, the participants suffered from SAD and their pretreatment vitamin D
blood levels tended to be low. In the negative study, the participants did not have SAD, and
their pretreatment vitamin D blood levels were higher. Although additional research needs to
be done, the available evidence suggests that people with SAD who have marginal or deficient
vitamin D levels might benefit from supplementation. This treatment should be supervised by a
doctor to assure that the amount of vitamin D used is high enough to be effective, but not so
high as to cause adverse effects.
Depression can be one of the first symptoms
of vitamin B12 deficiency.23
Vitamin B12, in the form of cyanocobalamin, given orally in the amount of 1,500 mcg three
times daily to patients with seasonal depression, showed no superiority over placebo in a
double-blind trial.24 Vitamin B12 cannot be recommended for the treatment of
SAD.
Melatonin is a hormone produced in the body
in response to the rhythms of light and darkness. Changes in melatonin levels are believed to
be an important factor in seasonal depression. Supplementation with melatonin, however, has
been ineffective when taken at night or in the morning.25 Melatonin may even
reverse the benefits of light therapy in people with SAD.26 A small, double-blind
study, however, found that 125 mcg of melatonin taken both 8 and 12 hours after awakening was
effective for reducing depression’s symptoms.27
Are there any side effects or interactions?
Refer to the individual supplement for information about any side effects or interactions.
Herbs that may be helpful
St. John’s wort, an herb well known
for its antidepressant activity,28 has been examined for its effectiveness in
treating SAD. In a preliminary trial, patients with seasonal depression were given 900 mg per
day of St. John’s wort in addition to either bright light (3,000 lux for two hours) or a
dim light (300 lux for two hours) placebo.29 Both groups had significant
improvement in depressive symptoms, but there
was no difference between the groups. The authors concluded that St. John’s wort was
beneficial with or without bright light
therapy, but a placebo effect from the herb cannot be ruled out in this study. Another
preliminary study asked 301 SAD patients to report the changes in their symptoms resulting
from the use of St. John’s wort at 300 mg three times daily.30 Significant
overall improvement was reported by these patients. Some of the subjects used light therapy in
addition to St. John’s wort. They reported more improvement in sleep, but overall
improvement was not significantly different from those using St. John’s wort alone.
Double-blind research is needed to confirm the usefulness of St. John’s wort for
treating SAD.
Are there any side effects or interactions?
Refer to the individual herb for information about any side effects or interactions.
Holistic approaches that may be helpful
Diminished sunlight exposure in winter contributes to changes in brain chemistry and plays
a role in seasonal mood changes. Artificial lights have been widely used to increase light
exposure during winter months. Many studies show the benefit of light therapy in the treatment of SAD.31
32 33 34 In a controlled trial, 96 patients with SAD were
treated with light at 6,000 lux for 1.5 hours in either morning or evening, or with a sham
negative ion generator, which was used as the placebo. After three weeks of treatment, morning
light produced complete or near-complete remission for 61% of patients, while evening light
helped 50%, and placebo helped 32%.35 Another study similarly found morning light
to have more antidepressant activity than evening light for people with SAD. This study also
found that patterns of melatonin production
were altered in seasonal depression, and that morning light therapy shifted this pattern
toward those of control subjects who did not have seasonal depression.36 Blood flow
to certain regions of the brain was measured after light therapy and was increased in seasonal
depression patients who benefited from the light therapy. The increase in regional brain blood
flow did not occur in those patients who did not respond to the light therapy.37
Light therapy begun prior to the onset of winter depression appears to have a preventive
effect in people susceptible to SAD.38
A review of clinical trials of light therapy for SAD concluded that the intensity of the
light is related to the effectiveness of the treatmnent.39 A higher response rate
was seen in trials where light intensity was greater, compared with trials that used light
therapy of lower intensity. Red and potentially harmful ultraviolet wavelengths are not
necessary for a response to light therapy.40
A study of the adverse side effects from high-intensity light therapy found them to be
common, mild and brief. Among people who underwent brief treatment with 10,000 lux, 45%
experienced side effects such as headaches and eye and vision changes. Described as mild and
temporary, they did not interfere with treatment.41
Dawn simulation is a form of light therapy involving gradually increasing bedside light in
the morning. In a comparison study, dawn simulation using 100–300 lux for 60–90
minutes every morning improved symptoms of SAD similarly to bright light therapy using
1,500–2,500 lux for two hours every morning.42
A negative ionizer is a device that emits negatively charged particles into the air.
Negative air ionization may be useful in treating SAD. One double-blind trial compared the
benefits of high-density negative ionization, providing 2.7 million ions per cubic centimeter,
and low-density negative ionization, providing 10,000 ions per cubic centimeter, for people
with SAD. Atypical depressive symptoms improved by 50% or more for 58% of patients receiving
the high-density ionization for 30 minutes daily, while only 15% of those receiving
low-density ionization had 50% or greater improvement. There were no side effects, and all of
the patients who responded to the therapy relapsed when ionization was
discontinued.43 In another controlled trial, high-density ionization was found
equally as effective as light therapy, and both were significantly more effective than
low-density ionization.44
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