Seasonal Affective Disorder (SAD) was first named by Dr. Norman Rosenthal of the National Institutes of Health. It was in 1980, after a move from South Africa to New York to Maryland, that he first wrote about the feelings he and some of his patients and staff felt at the onset of winter.
But Rosenthal was not the first to identify seasonal mind and body changes. The philosopher Hippocrates declared that “whoever wishes to pursue science and medicine in a direct manner must first investigate the seasons of the year and what occurs in them.”
Clearly, seasonal changes affect us more than we know.
As its name implies, Seasonal Affective Disorder is seasonal—its symptoms appear during one season and go away with the next. And it’s not clear why, but more women suffer from SAD than men, and those who live in northern climates experience SAD symptoms more than those who live in southern climates.
There are four common types:
Traditional SAD. The more severe symptoms of SAD—depression, lethargy, fatigue, social withdrawal, food and carbohydrate cravings, sleep disturbances, weight gain, and headaches—affect about six percent of Americans.1 Symptoms appear in the fall and alleviate in the spring.
Sub-syndromal SAD (S-SAD, or winter blues). Like SAD, S-SAD has the same symptoms beginning in the fall and going away in the spring. But its symptoms are milder, affecting some 25 million.2
Reverse SAD (or summertime blues). Reverse SAD occurs in one in 10 people when the sun is at its brightest point. It features periods of mania or hypomania, a less intense form of mania. Symptoms include persistently elevated mood, hyperactivity, and inflated self-esteem.1
Hesperian Depression. Rarer than the other forms of SAD, Hesperian depression occurs when the sun goes down and the evening star Hesperus rises in the sky.2
This article will focus on the two more prevalent types of SAD: traditional SAD and S-SAD (winter blues).
Diagnosing Seasonal Affective Disorder
Because its symptoms are so similar to those for depression, SAD can be very difficult to diagnose. In addition, its seasonal nature causes SAD to go undiagnosed for years. Read more about ways to diagnose SAD.
Causes of SAD
While researchers do know that too little or, in some cases, too much sunlight can bring on symptoms associated with Seasonal Affective Disorder, they still don’t know how light influences the mind-body mechanisms and trigger symptoms. And some genetic types experience SAD symptoms, while others don’t.
The melatonin connection. Normally, daylight enters the retina and stimulates the hypothalamus which, in turn, keeps the pineal gland from converting serotonin to melatonin. In darkness, however, the pineal gland begins synthesizing melatonin (the “asleep” hormone) from serotonin (the “awake” hormone).
Researchers have found differences in melatonin synthesis of SAD and non-SAD patients. In one study, women with Seasonal Affective Disorder had longer periods of melatonin synthesis in the winter, while non-SAD women experienced no seasonal variance.3 SAD patients also experience elevated blood melatonin levels during the day, where non-SAD blood melatonin peak at night and level off during the day.3
Thus, during the winter, the body’s natural production of melatonin is altered in SAD patients causing abnormal production during the day and limited production at night.
The phase-shift hypothesis. At the same time, there appears to be a shift in body temperature, cortisol, and thyroid-stimulating hormone (TSH) related to longer nights in those with Seasonal Affective Disorder. In one study, both body temperature and cortisol levels were delayed compared to non-SAD patients. These delays were corrected with light therapy treatment. And while TSH did not appear to be affected in this study, another study did find delays in TSH in those with SAD.3
Thus, longer periods of darkness associated with seasonal changes appears to affect some people while others are not affected at all.
The serotonin theory. Since serotonin is not only involved in brain function but also helps to produce melatonin, researchers theorized that low levels of serotonin in the brain may have something to do with SAD symptoms. In addition, SAD patients often have food and carbohydrate cravings—a sign of low serotonin levels—that they often use to self-medicate their SAD symptoms.
One study showed that SAD patients were much more alert and felt less fatigue after a high-carbohydrate meal than non-SAD patients.3 Find out more about carb cravings and how to control them.
Several other studies sought to deplete the body of tryptophan, the precursor to serotonin. For SAD patients—both those in summer remission and after light therapy—depleting the body of tryptophan brought on symptoms similar to those they experienced during the winter.3
As you can see, those with Seasonal Affective Disorder likely possess a different genetic type that may predispose them to respond to the changing seasons differently than those without this genetic makeup. As Dr. Rosenthal reports, “we’ve now identified the brain’s location for the molecule of emotion. It’s near the brain’s mood regulator—both of which have become off kilter with SAD.”2
The Impact on Chronic Conditions
Those with SAD experience frustrating, seasonal symptoms—like depression, sleep disturbances, food and carbohydrate cravings, and weight gain—that may lead to other chronic conditions. Read more about conditions related to Seasonal Affective Disorder.
From SAD to Glad
Seasonal Affective Disorder sufferers can choose from several treatment options depending on their effectiveness in individual situations.
Phototherapy or light therapy. First discovered by Dr. Rosenthal, light therapy—used alone or in combination with other therapies—is a non-invasive therapy, without side effects, that has proven to be extremely effective in treating SAD patients. But it’s not just ordinary light. The intensity of the light must be at least 10,000 lux for it to be effective. And some research shows that intense blue light can be particularly effective. Read more about treating SAD with blue light therapy.
Medications. Although many patients experience unwanted side effects with medications, some have proven to be helpful—particularly the selective serotonin reuptake inhibitors (SSRIs) like Prozac® and Paxil®. Mood stabilizers like Depakote® and lithium may also help.
Psychotherapy. Psychotherapy may help uncover the best ways to deal with Seasonal Affective Disorder and reduce the stress that can exacerbate symptoms.
Nutritional supplements. With proper diet and exercise, nutritional supplements may be quite effective at treating SAD without the sometimes dangerous side effects of prescription drugs. Some alternatives include:
- L-tryptophan: As mentioned previously, tryptophan is a precursor to serotonin which helps to regulate moods. Low levels of serotonin can not only bring on depression, but also food and carbohydrate cravings that contribute to weight gain. Taking L-tryptophan—or 5-HTP, the advanced form of tryptophan—can help elevate serotonin levels and alleviate depression and food cravings.
- Melatonin: In several studies, using melatonin has been shown to help regulate melatonin production. Sustained-release melatonin was particularly effective at improving sleep and enhancing energy among SAD patients.3
Tips for Coping with Seasonal Affective Disorder
- Increase the amount of light in your home: open blinds and curtains, add skylights, and trim trees away from windows.1
- Go outside when it’s sunny to absorb as much sunlight you can.1
- Avoid wearing blue blocker sunglasses that block out the blue light necessary to reset your circadian rhythm.
- Avoid wearing sunscreen during moderate sun exposure to maximize vitamin D production and boost your serotonin levels.
- Exercise regularly and add pleasurable activities to de-stress and relax.1
- Display or cut into a fresh orange or other citrus fruit. This releases powerful citrus oils and colors that can stir your sense of sight and smell, and help ease symptoms.2
- Give yourself a facial massage to stimulate pressure points and promote relaxation.2
- Breathe deeply and from the abdomen to stimulate balance and improve blood flow.2
- And, best of all, vacation in a warm, sunny place in the winter—or go north in the summer if you experience summer SAD!1
1) “Seasonal Affective Disorder,” MayoClinic.com
Accessed October 2005
2) Kogan, B.A., “From sad to glad: Is your child suffering from seasonal affective disorder?,” Vibrant Life, 11/1/2004.
3) Miller, A.L., “Epidemiology, etiology, and natural treatment of seasonal affective disorder,” Alternative Medicine Review, 3/1/2005.
4) Rosenthal, N.E., MD, “Diagnosis and Treatment of Seasonal Affective Disorder,” Journal of the American
Medical Association, 12/8/93, Vol. 270, No. 22, 2717-2720.
Article ID: 121