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 be helpful.
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
About This Condition
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.
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.
Healthy Lifestyle Tips
Exercise can ease depression and improve well being, in some cases as effectively as antidepressant medications.1 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.2 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.3 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.
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.4, 5, 6, 7 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%.8 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.9 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.10 Light therapy begun prior to the onset of winter depression appears to have a preventive effect in people susceptible to SAD.11
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.12 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.13
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.14
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.15
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.16 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.17
The right diet is the key to managing many diseases and to improving general quality of life. For this condition, scientific research has found benefit in the following healthy eating tips.
Choose complex carbs
Replacing simple carbohydrates, such as sweets and processed foods made with white flours, with unrefined, whole grain options may help achieve long-term control over negative mood.
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.18
People with SAD process sugar differently in winter compared with summer or after light therapy in winter.19 Changes in neurotransmitters that may affect cravings also occur in women with SAD.20 Because consumption of carbohydrates can influence neurotransmitter levels,21 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.22 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.
Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.
For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.
3 StarsReliable and relatively consistent scientific data showing a substantial health benefit.
2 StarsContradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1 StarFor an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.
With doctor's supervision, 2 to 4 grams per day, increasing up to 6 grams if no improvement
Some research suggests that L-tryptophan alone or in combination with light therapy may improve SAD symptoms.
Since disturbances of serotonin metabolism may be part of the cause of SAD,23 and creating a deficiency of L-tryptophan, a precursor of serotonin, worsens symptoms of SAD,24 L-tryptophan supplementation might be helpful. One case report describes a patient with SAD who improved after taking L-tryptophan daily, 1 gram with dinner and 1 gram at bedtime.25 In a small, preliminary study, people with SAD who responded poorly or not at all to bright light therapy were given 3 grams per day of L-tryptophan for two weeks, in addition to light therapy. Nine of 14 people responded well to this combination.26 Another small preliminary study found that one of five SAD patients that did not respond to light therapy did improve after L-tryptophan supplementation in the amount of 4 grams per day, increased to 6 grams per day if no improvement occurred at the lower dose.27 A small controlled trial found that a combination of 1.5 grams of L-tryptophan, 50 mg of vitamin B6, 300 mg vitamin C, and eight ounces of fruit juice, taken three times daily, was more effective for reducing symptoms of SAD than the same combination without L-tryptophan.285-HTP (5-hydroxytryptophan) is a substance related to L-tryptophan that also increases serotonin production and has shown antidepressant activity.29 It may also be useful in the treatment of SAD, but there is currently no research testing this possibility.
St. John’s Wort
Consult a qualified healthcare practitioner
St. John’s wort, an herb well known for its antidepressant activity, may improve SAD symptoms.
Caution: It is likely that there are many drug interactions with St. John's wort that have not yet been identified. St. John's wort stimulates a drug-metabolizing enzyme (cytochrome P450 3A4) that metabolizes at least 50% of the drugs on the market.30 Therefore, it could potentially cause a number of drug interactions that have not yet been reported. People taking any medication should consult with a doctor or pharmacist before taking St. John's wort.
St. John’s wort, an herb well known for its antidepressant activity,31 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.32 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.33 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.
Refer to label instructions
Supplementing with vitamin D may improve mood and well-being, especially among people with low levels of the vitamin.
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.34 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.35
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.36 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.37 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.
900 mg a day of a standardized extract
The supplement 5-Hydroxytryptophan increases serotonin production and has shown antidepressant activity. It may be useful in the treatment of SAD.
5-HTP is a substance that increases serotonin production and has shown antidepressant activity.38 It may also be useful in the treatment of SAD, but there is currently no research testing this possibility.
Find Drug Interaction Information
1. Blumenthal JA, Babyak MA, Moore KA, et al. Effects of exercise training on older patients with major depression. Arch Intern Med 1999;159:2349–56.
2. Martinsen EW, Hoffart A, Solberg O. Comparing aerobic with nonaerobic forms of exercise in the treatment of clinical depression: a randomized trial. Compr Psychiatry 1989;30:324–31.
3. Groom KN, O’Connor ME. Relation of light and exercise to seasonal depressive symptoms: preliminary development of a scale. Percept Mot Skills 1996;83:379–83.
4. Lee TM, Chan CC. Dose-response relationship of phototherapy for seasonal affective disorder: a meta-analysis. Acta Psychiatr Scand 1999;99:315–23 [review].
5. Lewy AJ, Bauer VK, Cutler NL, et al. Morning vs evening light treatment of patients with winter depression. Arch Gen Psychiatry 1998;55:890–6.
6. Eastman CI, Young MA, Fogg LF, et al. Bright light treatment of winter depression: a placebo-controlled trial. Arch Gen Psychiatry 1998;55:883–9.
7. Lingjaerde O, Foreland AR, Dankertsen J. Dawn simulation vs. lightbox treatment in winter depression: a comparative study. Acta Psychiatr Scand 1998;98:73–80.
8. Eastman CI, Young MA, Fogg LF, et al. Bright light treatment of winter depression: a placebo-controlled trial. Arch Gen Psychiatry 1998;55:883–9.
9. Lewy AJ, Bauer VK, Cutler NL, et al. Morning vs evening light treatment of patients with winter depression. Arch Gen Psychiatry 1998;55:890–6.
10. Vasile RG, Sachs G, Anderson JL, et al. Changes in regional cerebral blood flow following light treatment for seasonal affective disorder: responders versus nonresponders. Biol Psychiatry 1997;42:1000–5.
11. Partonen T, Lonnqvist J. Prevention of winter seasonal affective disorder by bright-light treatment. Psychol Med 1996;26:1075–80.
12. Lee TM, Chan CC. Dose-response relationship of phototherapy for seasonal affective disorder: a meta-analysis. Acta Psychiatr Scand 1999;99:315–23 [review].
13. Lee TM, Chan CC, Paterson JG, et al. Spectral properties of phototherapy for seasonal affective disorder: a meta-analysis. Acta Psychiatr Scand 1997;96:117–21 [review].
14. Kogan AO, Guilford PM. Side effects of short-term 10,000-lux light therapy. Am J Psychiatry 1998;155:293–4.
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16. Terman M, Terman JS. Treatment of seasonal affective disorder with a high-output negative ionizer. J Altern Complement Med 1995;1:87–92.
17. Terman M, Terman JS, Ross DC. A controlled trial of timed bright light and negative air ionization for treatment of winter depression. Arch Gen Psychiatry 1998;55:875–82.
18. Krauchi K, Reich S, Wirz-Justice A. Eating style in seasonal affective disorder: who will gain weight in winter? Compr Psychiatry 1997;38:80–7.
19. Krauchi K, Keller U, Leonhardt G, et al. Accelerated post-glucose glycaemia and altered alliesthesia-test in Seasonal Affective Disorder. J Affect Disord 1999;53:23–6.
20. Danilenko KV, Putilov AA, Russkikh GS, et al. Diurnal and seasonal variations of melatonin and serotonin in women with seasonal affective disorder. Arctic Med Res 1994;53:137–45.
21. Blum I, Vered Y, Graff E, et al. The influence of meal composition on plasma serotonin and norepinephrine concentrations. Metabolism 1992;41:137–40.
22. Christensen L. Effects of eating behavior on mood: a review of the literature. Int J Eat Disord 1993;14:171–83 [review].
23. Neumeister A, Konstantinidis A, Praschak-Rieder N, et al. Monoaminergic function in the pathogenesis of seasonal affective disorder. Int J Neuropsychopharmacol 2001;4:409-20.
24. Van der Does AJ. The effects of tryptophan depletion on mood and psychiatric symptoms. J Affect Disord 2001;64:107-19.
25. Levitt AJ, Brown GM, Kennedy SH, Stern K. Tryptophan treatment and melatonin response in a patient with seasonal affective disorder. J Clin Psychopharmacol 1991;11:74-5.
26. Lam RW, Levitan RD, Tam EM, et al. L-tryptophan augmentation of light therapy in patients with seasonal affective disorder. Can J Psychiatry 1997;42:303-6.
27. Ghadirian AM, Murphy BE, Gendron MJ. Efficacy of light versus tryptophan therapy in seasonal affective disorder. J Affect Disord 1998;50:23-7.
28. McGrath RE, Buckwald B, Resnick EV. The effect of L-tryptophan on seasonal affective disorder. J Clin Psychiatry 1990;51:162-3.
29. Birdsall TC. 5-Hydroxytryptophan: a clinically-effective serotonin precursor. Alternative Med Rev 1998;3:271–80.
30. Markowitz JS, Donovan JL, DeVane CL, et al. Effect of St John's wort on drug metabolism by induction of cytochrome P450 3A4 enzyme. JAMA 2003;290:1500–4.
31. Kim HL, Streltzer J, Goebert D. St. John’s wort for depression: a meta-analysis of well-defined clinical trials. J Nerv Ment Dis 1999;187:532–8 [review].
32. Martinez B, Kasper S, Ruhrmann S, Moller HJ. Hypericum in the treatment of seasonal affective disorders. J Geriatr Psychiatry Neurol 1994;7:S29–33.
33. Wheatley D. Hypericum in seasonal affective disorder (SAD). Curr Med Res Opin 1999;15:33–7.
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38. Birdsall TC. 5-Hydroxytryptophan: a clinically-effective serotonin precursor. Alternative Med Rev 1998;3:271–80.
The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2014.
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