A Complete Guide to Seasonal Affective Disorder (S.A.D.)

December 19, 2011

By Denise Lodge

Photo by Carter Fontaineleau.

Today the sky is dark and grey, and the sun is not in sight. Darkness is often associated with gloom. When a day is described as “gloomy,” images of a colourless sky, a sunless day, or grey, looming clouds may come to mind. Conversely, a “nice” or “beautiful” day usually implies warmth and sunny skies. We all may associate moods and feelings with the weather, but its effects on those with seasonal affective disorder (S.A.D.) are much stronger.

About S.A.D. Disorder

Fifteen per cent of Canadians may suffer from the “winter blues,” an experience of mood-change affected by changes in the weather; the “winter blues” cause discomfort, but are not incapacitating.

Conversely, S.A.D., a form of clinical depression triggered by the changing seasons, may affect the ability to cope with life. The Canadian Mental Health Association estimates that one to three per cent of Canadians suffer from cases of S.A.D. The condition can be debilitating, affecting personal and professional lives. However, the Canadian Mental Health Association states that there is treatment to “help people with S.A.D. live a productive life year-round.”

The term “winter blues” and the association of seasonal depression with winter can be misleading. S.A.D. does not only affect people in the winter; some people have a rarer form of the condition that begins in late spring or early summer.

Potential Causes of S.A.D.

While there is no confirmed cause of S.A.D., it is thought to be related to seasonal variations not in temperature, but in light. Before electricity, humans were active and alert during daylight, and slept when it became dark. Despite the technological allowances of working and remaining active during the night, our bodies may be biologically wired to shorten our waking time as the days grow shorter. This biological wiring that sets a sleep/wake cycle is known as the circadian rhythm, which is connected to the brain’s serotonin system.

Serotonin, the chemical reduced in people who suffer from depression and anxiety, has been shown to be increasingly produced during long periods of bright light.

Symptoms of S.A.D.

S.A.D. can be difficult to diagnose, as many of the symptoms coincide with symptoms of depression and bipolar disorder. According to the Canadian Mental Health Association, symptoms usually recur for at least two consecutive winters.

Symptoms may include:

  • Change in appetite, in particular a craving for sweet or starchy foods
  • Weight gain
  • Decreased energy
  • Fatigue
  • Tendency to oversleep
  • Difficulty concentrating
  • Irritability
  • Avoidance of social situations
  • Feelings of anxiety and despair

Symptoms of summer depression may include:

  • Poor appetite
  • Weight loss
  • Trouble sleeping

Treatments for S.A.D.

Because the cause and mechanisms of S.A.D. are neither confirmed nor straightforward, treatment is also somewhat experimental. Researchers are beginning to understand in greater detail the connections between the underlying mechanisms and the symptoms of S.A.D., which will ultimately allow for better, more targeted treatment methods.

Different treatments target different brain systems; two that play a role in S.A.D. are the circadian rhythm and the serotonin system. Sometimes two different treatments will be applied to target each system.

Sunlight as a treatment for S.A.D.

The Canadian Mental Health Association reports that S.A.D. is “more common in northern countries, where the winter day is shorter,” and that “people with S.A.D. find that spending time in a southerly location brings them relief from their symptoms.” However, if frequent trips closer to the equator do not fit into your schedule or budget, there are other ways of accessing maximum sunlight. Remember that UV rays can penetrate through clouds and windows, and that skin protection is always appropriate.

To maximize sunlight exposure:

  • Trim tree branches
  • Keep curtains open during the day
  • Move furniture to sit near a window


Diet Changes to Treat S.A.D.

Because decreased serotonin levels are considered a primary factor in S.A.D., try eating foods that contain tryptophan, a precursor of serotonin. One study published in Psychiatry Research reports that patients with S.A.D. had low levels of tryptophan. Another study published in the Archives of General Psychiatry found that the beneficial effects of light therapy were reversed by tryptophan depletion. Foods rich in tryptophan include turkey, milk, and egg whites.

Photo by Greg Mote.

Fruits such as apricots, apples, pears, grapes, plums, grapefruits, and oranges have been shown to gradually raise serotonin levels and help keep them raised.

Exercise to treat S.A.D.

Exercise relieves stress, builds energy, increases mental and physical well-being, and can help cope with the symptoms of S.A.D. Try building a walk into your noon-hour or your morning. Your neighbours may also be interested in walking, and you can walk in pairs or small groups. The exercise, increased exposure to natural light, and social interaction are strategies to combat S.A.D.

Light Therapy as a S.A.D. Treatment

According to the Canadian Mental Health Association, “many people with S.A.D. respond well to exposure to bright, artificial light.” Light therapy involves sitting near a light that simulates natural light for a certain period of time each day. Sessions usually extend between a half-hour to a few hours. The standard daily dose is thirty minutes of light at 10,000 lux, a measure of the intensity of light as perceived by the human eye.

As the light sits in front of the user, it is indirectly absorbed by the retina; light therapy does not appear to work by skin absorption, but by absorption into the eye-brain pathway, where it is believed to pass through serotonin receptors on its way to the part of the brain that acts as a clock. The effects of light therapy usually take only four to seven days. Like the sun, the light is not stared at directly. The light used in light therapy is not the same light found in tanning beds, so there is no risk of UV exposure.

Potential side effects of light therapy include nausea, hyperactivity, and eyestrain, so it is recommended that you consult a doctor about choosing light therapy. Moreover, the treatment may be covered by health insurance, in which case a prescription would be required.

Serotonin is not the only hormone that plays a role in S.A.D; the hormone melatonin has been considered a factor as well. Melatonin has been shown to decrease body temperature and increase drowsiness; in animals, melatonin regulates hibernation. Humans have more melatonin in their bloodstream during winter than during summer; it is speculated that light therapy halts melatonin production and thereby decreases symptoms of S.A.D., such as decreased energy and fatigue.

Cognitive behaviour therapy (C.B.T.), a type of psychotherapy that aims to replace negative or inaccurate thought patterns with more productive ones, is also an effective treatment for S.A.D., especially when paired with light therapy. One study published in the Journal of Affective Disorders found that the combination of light therapy and C.B.T. appeared to improve the long-term symptom severity, remission rates, and relapse rates of S.A.D.

Recommended Products to Treat S.A.D.

One of the less expensive products is the Lightphoria SAD Light Therapy Pad Sunlight Simulator. It boasts 10,000 lux, a programmable timer, and a tilt-back stand so you can read, use the computer, or watch TV while receiving the therapy.

The Philips HF3332/60 GoLITE Blu, like the Lightphoria, provides the freedom to engage in other activities while using the light, and includes a tilt-back stand and a programmable timer. Both the Lightphoria and the Philips GoLITE Blu are compact enough to pack away and travel with you, at about 18 x 18 centimetres and 500 grams.

The Philips Wake-Up Light HF3470 is unlike the Lightphoria and Philips GoLITE Blu in that it is not to be used when already awake, but while waking up. The light gradually increases thirty minutes before waking up; the aim is to gently prepare your body to wake up. Also included is the option to add the sound of chirping birds to your morning wake-up. There is an option to set the light at full brightness for your preferred wake-up time.

The Valkee, one exciting new type of light therapy, treats S.A.D. not through the eyes, but through the ears. Although more expensive than the previous treatments, the Valkee is the world’s first bright light headset; it channels bright light via the ear canal into the brain’s photosensitive areas to prevent and treat S.A.D. In two clinical trials performed at the University of Oulu, “92 per cent of the patients with [S.A.D.] achieved full remission […] with a daily 8-12-minute dose,” reported professor Markku Timonen, MD, PhD, the lead investigator for the trials, at the 11th International Forum for Mood and Anxiety Disorders in Budapest.

The Canadian Mental Health Association recommends contacting your doctor if your sleep and appetite patterns change dramatically, or if you find yourself thinking about suicide. The association encourages that there is effective treatment for S.A.D., and that “even people with severe symptoms can get rapid relief once they begin treatment.”

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  • http://WhatIsLightTherapy.com Carol Peterson

    Bright light treatment and even dawn simulation are two forms of seasonal affective disorder light therapy that can help. Bright light treatment calls for you to sit in front of a light simulator for a half an hour or even longer, usually in the morning. Dawn simulation is a created light that comes on each day and gets brighter with time, like a sunrise.

  • http://light-therapy-reviews.net meital

    Light therapy for SAD is wonderful. I use light every day – a wake up light to get up calmly earky in the morning, and a light box every day for 30 minutes to boost my energy. I haven’t experienced any side effects so far..I highly recommend it!

  • Lemole92

    The skeptic that I am, it took me a while to try light therapy but last fall/winter I caved. It changed my life. I was able to function all fall and winter for the first time in years.  I did have a slight feeling of nausea in the first week because of the light therapy but I just adjusted the brightness and it was fine. Another suggestion, if you are prone to migraines, place the light therapy unit facing the side you don’t get migraines on. With the form of SAD I have, I wake up as soon as it is light so in the winter, it can be at 9am and I’m lethargic all day and in the summer, especially June I’m wide awake at 5:30 and active all day. It’s like I’m on cortisone. I have so much energy but at the same time, I’m exhausted. Putting up thick curtains doesn’t help. Well, rather that than depression. 

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