Seasonal Affective Disorder & the Winter Blues


When the season moves into winter, the days grow shorter, and the skies turn gray, do you find that your mood darkens as well? If so, you’re not alone. Approximately 10% of Americans experience a lower mood during the winter months, and this rate is as high as 20-30% of people in more Northern latitudes such as Oregon. For many people, the “winter blues” can develop into something more serious. In a given year, approximately 5% of Americans develop what’s called ‘Seasonal Affective Disorder (SAD),’ with this rate increasing in more Northern latitudes, such as Oregon. For example, around 1% of people living in Florida experience SAD, whereas around 9% of people living in Alaska experience SAD. Dark indoor work environments may also contribute to SAD.

What is Seasonal Affective Disorder?

SAD is a form of depression that begins and ends during a specific season each year. Here, we discuss the most common type of SAD, which occurs during the fall/winter, and is caused by the decrease in natural light during these seasons. It usually subsides by the spring or summer. Symptoms of SAD include increased need for sleep, daytime fatigue, irritability, decreased activity, decreased concentration and ability to think clearly, decreased sex drive, and increased appetite, particularly for sweets and starchy carbohydrates.

How can I learn more about SAD?

You can find out more information about SAD online at our Portland Depression Treatment program website: In addition, Norman E. Rosenthal, MD, the person who first described SAD in a study published in 1984, has information and resources about SAD on his website: If you’re looking for a book devoted to SAD, we recommend Dr. Rosenthal’s book, Winter Blues: Everything You Need to Know to Beat Seasonal Affective Disorder.

What can I do about SAD?

We all can’t move to the Southwest during the winter months, but there are many simple changes you can make to lessen the impact of SAD. The most tried and true treatment that we know of for SAD is “Light Therapy.” Since Light Therapy is one of the most well-researched and cost-effective treatment options, and has minimal adverse side effects, we’ll discuss it in the most detail below. At the end, we’ll also discuss other treatment options that can be helpful and important to consider, especially if Light Therapy doesn’t seem to be doing the trick.

What’s light therapy?

Light therapy involves using devices specifically made to treat SAD can provide daily doses of artificial light. These devices can be purchased without a doctor’s prescription, and you can find them over the Internet. They are sometimes available at Costco, but unfortunately Costco also sells some devices that are poorly made and aren’t likely to work. So, be careful about what device you buy. Costs range from $120 to $300. Be sure to buy one made to target SAD, and manufactured by a reputable company. In addition to the standard white light boxes, manufacturers are beginning to make blue light devices. Although there is some promising research supporting the use of blue light boxes, for now, broad-spectrum white light boxes are probably the better choice because there is larger evidence base for their use. They are also just as cheap or even cheaper than the blue light devices that have been tested.

How do I use a light therapy device?

Most people have a good response by sitting in front of a light box for 20 to 90 minutes a day. One session in the early morning, ideally before the sun comes up, is enough for many people, although some people find they need to also sit in front of the box again in the afternoon or early evening. All you need to do is sit in front of the light at the proper distance and engage in regular activities, such as eating breakfast, working, talking on the phone, or reading. You don’t need to stare into the light, though you should be facing the device. Most people begin to notice improvements within a week of regular use.

Steps to implement light therapy:

  1. Obtain a reliable light box (see below for recommendations)
  2. Set up the box in a convenient location at home or work
  3. Sit in front of the box for enough time and at the right distance for your device (usually 20-90 minutes/day)
  4. Try to sit in front of the box in the early morning (usually 6-7am, or so)
  5. Monitor whether your current plan is working. If not, consider adding an afternoon/evening session and/or increasing your time spent in front of the device
  6. Sit at the proper distance and at the right height, so that at least some of the light comes into your eyes from above
  7. Repeat each day through the season of risk
  8. To prevent SAD in following years, start light therapy in the early autumn before you experience any symptoms

Another option is dawn simulation. Dawn simulators work like a soundless alarm clock. Programmed to begin 30 minutes to an hour before you wake up, dawn simulators time lights to gradually come on before you wake up, mimicking a sunrise. The added benefit of a dawn simulator is that the treatment is over when you wake up and begin your day. While dawn simulators have been shown to be helpful, the evidence for their effectiveness is not as strong as it is for light boxes and therefore it works for fewer people. Many people use both a dawn simulator to make it easier to get up in the morning and a light box.

Is light therapy safe?

For the most part, light therapy appears to be safe. Side effects, if present, tend to be minimal and may include headaches, eye strain, and mild nausea—and even these tend disappear after a few days of use. Although well researched, people with eye problems are usually not included in studies, so problems cannot be completely ruled out. While side effects are generally minimal, it’s always good to talk to a professional before starting light therapy, but especially if you have an eye condition that makes your eyes vulnerable to light damage, you have a condition that makes your skin especially sensitive to light, or if you take medications that increase your sensitivity to sunlight, such as certain antibiotics, anti-inflammatories, or the herbal supplement St. John’s Wort.

Where can I learn more about light therapy?

An educational video that I made about SAD:

The Mayo Clinic has a page about how use light therapy:

Recommended light therapy devices

Below are some devices that I’ve tested and should work if used properly:

  • ** White light therapy — this is the kind of device that is used in research and has the best support for being effective. If you can afford it, it’s the one that I would recommend. Prices have really dropped a lot lately, so it’s becoming more affordable.
  • Smaller white light therapy deviceIf you can’t afford the one above, a smaller white light therapy device emits enough light, but only if it’s six inches from your eyes. You’ll have to be very careful to position it above your eyes and make sure it’s close enough (about six inches away). This makes it very difficult to use in a practical fashion, so I’d highly recommend spending the extra money for the one above.
  • Blue light therapy — has some research support, but not as much data. It’s more expensive to buy and may not be quite as effective.
  • Dawn simulators — very easy to use for those who have a hard time getting out of bed. However, they are probably not as effective for everyone. This can be a good place to start, but if it doesn’t work, you’d want to move onto a regular light therapy device.

Other Treatments for SAD

While light therapy is the most proven treatment for SAD, there is also evidence that cognitive behavioral therapy (like that delivered at the Depression Treatment Program at Portland Psychotherapy) can be helpful. Some research even suggests that these options are just as effective as light therapy. While some antidepressant have also been shown to help with SAD, they tend to come with more severe side effects than those associated with light or behavioral therapies, and therefore should be considered second line treatments. However, if light therapy or other treatments do not work, then it may be worth trying an antidepressant. Although research shows a link between vitamin D deficiency and depression, it isn’t yet clear whether taking vitamin D supplements improves SAD symptoms. However, for anyone with depression symptoms, it’s a good idea to get a medical workup, including laboratory tests, to see if your Vitamin D levels are excessively low.

All in all, if light therapy is not for you, or doesn’t work for you; you may want to consider one, or a combination of, these other options.

NOTE: This information page is educational in nature. If you’re experiencing severe depression or having suicidal thoughts, we urge you to seek professional services.