Seasonal Affective Disorder (SAD)

What is Seasonal Affective Disorder?

Seasonal affective disorder (SAD) is a type of depression with a seasonal pattern, with major depressive episodes that typically begin in late autumn or winter and clear by spring or summer.^[1] It is not a separate diagnosis in the current psychiatric manual but a specifier added to major depressive disorder or bipolar disorder.^[1] A meta-analysis of 24 studies estimated that about 5% of people are affected, with higher rates at higher latitudes.^[2]

Common symptoms

SAD has the usual symptoms of depression, plus a set of "atypical" features that are common in the winter pattern.^[1]

• Low mood and loss of interest in usual activities
• Low energy and significant fatigue
• Sleeping too much (hypersomnia)
• Overeating and craving carbohydrates
• Trouble concentrating

Symptoms remit when the season changes, and diagnosis requires full remission in the off-season and episodes in the same season for two consecutive years.^[3]

Causes and risk factors

The cause is not fully known. Proposed factors include disruption of the body clock (circadian rhythm), changes in melatonin and serotonin, and sensitivity to the length of daylight.^[1] Risk factors include a family history, female sex, living farther from the equator, and young adulthood (ages 18 to 30).^[3]

How it is diagnosed and treated conventionally

A physician or mental health professional makes the diagnosis from the pattern of symptoms over time, and other causes of low mood need to be considered.^[3] First-line treatment is light therapy, antidepressant medicine or cognitive-behavioral therapy, alone or in combination, and exercise and more natural light are also recommended.^[3]

A meta-analysis of 19 randomized trials found bright light therapy outperformed placebo for SAD, although the trials were small, varied and at moderate to high risk of bias.^[4] Typical use is a light box for 30 to 60 minutes at the same time each day.^[3] A systematic review found no evidence of eye damage from light therapy in healthy, unmedicated people.^[5] For prevention in people who have had SAD before, bupropion has moderate-quality trial support, but three out of four people do not benefit and side effects occur.^[6]

Why Seasonal Affective Disorder calls for a whole-person approach

SAD is more than a mood problem. Light, body clock, sleep, appetite, activity and nutrition all shift together with the seasons, and each can make the others worse.^[1]

Care that looks at daily rhythm, sleep and stress, alongside light therapy or other medical treatment, is a reasonable way to approach a pattern that returns each year.

Light and the body clock

Daylight exposure appears to play a role in SAD, since prevalence rises with latitude.^[2] Disrupted circadian rhythm and shifts in melatonin are among the proposed mechanisms.^[1]

Sleep, energy and appetite

SAD often shows up as heavy sleepiness, fatigue and carbohydrate craving rather than the insomnia and appetite loss of other depression.^[1] Regular sleep and meal times are therefore a practical part of planning.

Activity and time outdoors

Exercise and more exposure to natural light are recommended lifestyle steps in SAD.^[3]

Vitamin D and nutrition

SAD is associated with low sunlight exposure and vitamin D deficiency, but results of vitamin D supplements in SAD are inconsistent.^[7] Evidence for vitamin D supplementation is inconclusive, so any supplement should be discussed with your physician.^[3]

Acupuncture as supportive care in Seasonal Affective Disorder

What the research shows

We found no controlled trials of acupuncture for seasonal affective disorder, so it is not known whether it helps SAD itself. A PubMed search turned up only a 1999 overview of colored light therapy combined with acupuncture, which does not test whether acupuncture helps SAD.

There is research in depression in general. A Cochrane review of 64 studies with 7,104 participants found low-quality evidence that acupuncture may moderately reduce depression severity compared with no treatment, and a small reduction compared with sham acupuncture. Evidence for acupuncture versus medication, or added to medication, was very low in quality, and the review noted most trials were at high risk of bias.^[8] Those results apply to depression generally and cannot be assumed to apply to the seasonal type.

How acupuncture may work

How acupuncture might affect mood is not established, and no mechanism study in SAD was found. We therefore make no claim about a mechanism.

What treatment involves

Treatment uses fine, sterile, single-use needles at points chosen for the person, typically left in place for about 20 to 40 minutes. A course usually involves several visits, with reassessment partway through.

In prospective studies about 9 in 100 patients had a minor reaction such as soreness or bleeding at a needle site, and serious events occurred in about 1 in 10,000 patients.^[9] Tell the practitioner first if you have a bleeding disorder, take blood thinners, are pregnant, or have a pacemaker (relevant to electroacupuncture).

Ayurvedic medicine as supportive care in Seasonal Affective Disorder

The Ayurvedic view

Ayurveda does not have a condition that matches SAD exactly. It does describe the influence of the seasons (ritu), and the heavy, cold, damp qualities of late winter are traditionally linked to increased Kapha, with sluggishness, oversleeping and low drive. This is a traditional framework, not a biomedical diagnosis.

Therapies that may be used

Care is individualized and traditionally includes:

• A seasonal routine (ritucharya) with early rising, regular meals and daily activity to counter heaviness
• Lighter, warming foods and spices in the cold months
• Dry or warm oil massage, depending on the person
• Herbs such as ashwagandha (Withania somnifera), prescribed individually

Panchakarma is an intensive course of cleansing procedures. It is generally not appropriate during pregnancy, acute illness or frailty, and we would not use it for someone with depression that has not been medically assessed.

What the research shows

No trials of Ayurvedic medicine for seasonal affective disorder were found, so there is no evidence for Ayurveda in SAD. A review of herbal medicines for psychiatric disorders described ashwagandha as having preliminary evidence in affective disorders, which is not specific to SAD.^[10] Yoga comes from the same Indian tradition but is not Ayurvedic medicine itself. A review of yoga for depression found moderate evidence of short-term benefit compared with usual care, but it did not study the seasonal type, and only three of 12 trials had low risk of bias.^[11]

Herbal medicine as supportive care in Seasonal Affective Disorder

Herbs and formulas that have been studied

Herbal research in SAD is very sparse. Herbs studied for depression more generally include St. John's wort (Hypericum perforatum) and saffron (Crocus sativus), which one review rated as having high-quality evidence for major depressive disorder.^[10] Only St. John's wort has been looked at in people with SAD.

What the research shows

For SAD itself, the only study found was a 1999 postal survey of 301 members of a SAD association who took a hypericum product, with or without light therapy. Symptom scores fell over eight weeks, but there was no placebo or untreated group, so the study cannot show that the herb caused the change.^[12]

In depression in general, a meta-analysis of 27 trials found St. John's wort had response and remission rates comparable to SSRIs in mild to moderate depression, with trials lasting only 4 to 12 weeks.^[13] A meta-analysis of saffron found it more effective than placebo and not clearly different from antidepressants in mild to moderate depression.^[14] These findings come from non-seasonal depression and should not be assumed to hold for SAD.

Safety and herb-drug interactions

St. John's wort is the herb with the best-documented interactions. Reports include serotonin syndrome when combined with SSRIs, lowered blood levels of several drugs including cyclosporin, warfarin and digoxin, and bleeding between periods and unplanned pregnancy with oral contraceptives.^[15] Many people with SAD take antidepressants, so a full medicine review is essential before any herb.

Ashwagandha has been linked to liver injury in case reports, with jaundice and itching, and liver tests returned to normal within one to five months in four of the five patients.^[16] Tell us if you have liver disease, are pregnant or breastfeeding, or take thyroid or sedative medicines. About one fifth of Ayurvedic medicines bought online contained detectable lead, mercury or arsenic, so products should come from tested sources and be prescribed individually.^[17]

Translating traditional medicine into modern biological language

This section is interpretation, not equivalence. Chinese medicine may describe winter low mood as depleted yang or stagnant qi, and Ayurveda as increased Kapha. Researchers studying SAD instead point to light exposure, circadian rhythm, melatonin and serotonin.^[1]

Both traditions place weight on seasonal rhythm and on regular daily routines, which loosely parallels the biological idea that the body clock responds to daylight. No study has shown that a qi pattern or dosha corresponds to a particular biological process in SAD.

How this care fits with your medical care

Integrative care for seasonal affective disorder is complementary. For a condition like this, we ask that you are under a physician's care for it and that your treating team knows you are receiving complementary care. Light therapy, medicine and cognitive-behavioral therapy have far better evidence than the options described here, and we do not offer our services as a substitute for them.

We do not diagnose SAD or manage depression itself. Do not stop or change prescribed medicine without your prescriber. Please bring your diagnosis, a list of all medicines and supplements, and details of any light therapy you use. Because SAD can occur as part of bipolar disorder, tell your treating team about any history of unusually high-energy or elevated moods.^[1]

When to seek urgent medical care

Depression can become serious, so the following need prompt medical attention.^[3]

• Thoughts of suicide or of harming yourself
• Feeling hopeless or unable to function at work, school or home
• Symptoms that are getting worse despite treatment
• Unusually high energy, little need for sleep or racing thoughts, which can signal bipolar disorder
• Symptoms that do not lift when the season changes

If you are thinking about suicide, call or text 988, the Suicide and Crisis Lifeline. For any emergency, call 911 or go to the nearest emergency department.