Friday, January 4, 2013

Seasonal affective disorder: An extreme case of the winter blues

Though the shortest day of the winter is behind us, in many areas of the United States, the days continue to be painfully short. Where I live, the sun will set at 4:41 pm today – during my summer vacations, I still have a few more hours of fun in the sun at that time! As someone who enjoys being outside and the light and warmth of the sun, I do have the tendency to get a little fatigued and saddened by Northeastern winters. According to the American Psychiatric Association, I am not alone: about 25% of people living in the middle and northern latitudes of the United States exhibit such winter blues.

Unfortunately, though, for some, these symptoms can be so serious that they are considered to be indicative of a mood disorder. The condition, marked by seasonal symptoms of depression, is known as seasonal affective disorder (SAD). Prevalence estimates for SAD range from 0 to 9.7 percent, depending on the population studied (rates tend to be higher farther from the equator) and the method used for diagnosis.  

What are the symptoms of SAD and how does it relate to depression? 

The symptoms of SAD are the same as those of depression, such as unhappiness, low energy, changes in sleep or appetite, poorer concentration, and diminished interest in pleasurable activities. However, people with SAD exhibit a connection between depressive symptoms and time of year. For most people, this means that symptoms occur when days are shorter and disappear when days are longer.

According to the last published version of the Diagnostic and Statistical Manual for Mental Disorders (abbreviated as DSM, this is a manual that provides standard classifications for mental disorders), SAD is not an independent condition. This means that patients exhibiting symptoms of SAD are not given a simple, stand-alone diagnosis of SAD. Instead, SAD is considered to be a specifier of major depression or bipolar disorder. This means that a person would be diagnosed with depression or bipolar disorder, with the additional specification that this mood disorder only occurs at certain times of the year. There is debate about whether this is an accurate classification, with some researchers arguing that SAD is an independent disorder that is different from major depression or bipolar disorder. As always, new research is being conducted that may prompt revision of this classification in future versions of the DSM.

What causes SAD?

One hypothesis about the development of SAD is that shifts in daylight result in biochemical imbalances in the brain, which then impact mood. For example, during dark hours, the body produces melatonin, a sleep hormone linked to depression. So, during the winter, when the days are shorter, the body produces more of this hormone than it usually does, potentially causing people to feel a little more tired and depressed than normal.

In addition, disruption of people’s “biological clocks” may lead to feelings of depression. As the amount of daylight decreases, people’s bodies may be more confused about when to be awake and when to be asleep. On top of that, the hours of daylight do not always match up with the hours people need to be awake for work and school. Having a biological clock that is out of sync with one’s daily schedule can be troublesome. 

What are the treatments for SAD?

One of the most common and helpful treatments for SAD is light therapy. With this option, people sit in front of a bright light for around 30 minutes daily, usually in the morning. To be beneficial, light therapy must involve the use of lamps specially designed to emit the proper intensity of light. Sitting close to these special lamps can limit the secretion of melatonin in the brain, helping to improve mood. Though these lights can be expensive, they are easy to incorporate into daily life, as people can read and do other activities in front of them.

People have also found that greater exposure to natural sunlight is beneficial. It often helps people to change their schedules and workspaces to achieve this. For example, going for a walk outside in the morning or trying to work in front of a window can both increase exposure to natural light. For people like college students who tend to sleep in and stay up late, it may be better in the winters to shift sleeping patterns earlier in order to take advantage of daylight.

Exercise in general helps improve mood, and for people suffering from SAD, exercise outside is doubly helpful in that it also increases exposure to the sun. Therefore, in the winter, it may be better to run outside early in the morning or during lunch breaks than to hit the gym after work when it’s already dark outside. For those of you who have to shovel snow, try to do it during the day and consider improved mood to be a potential bonus of this chore!

Finally, typical treatments for depression, such as psychotherapy and antidepressants, have also been effective in treating SAD. Often, multiple treatment options are used in conjunction in order to optimize results. Of course, if you think you may be suffering from SAD, it is important to discuss symptoms and treatments with health care professionals. They can help you with a treatment plan that is best for you and your lifestyle and ensure that your symptoms are not mistaken for those of a more serious condition.

One of the most important points to remember about SAD is that it is a manageable condition with some very easy-to-implement treatment options. For people who know they suffer from SAD or even the subclinical version known as “winter blues,” they can take preventative measures in the fall. Exercising outside and adopting early to bed, early to rise sleeping patterns can help prevent symptoms before they even begin. 

As we wait for the days to get longer and look forward to sunsets that occur after dinner, try to enjoy the sunlight when you can and exercise outside. Hopefully you will be able to make it through (and even appreciate) the winter!

Do you experience the winter blues? What are some techniques you use to elevate your mood in the fall and winter? Let us know in the comments!

Further reading:

Harald B, & Gordon P (2012). Meta-review of depressive subtyping models. Journal of affective disorders, 139 (2), 126-40 PMID: 21885128

Lurie, S. J., Gawinski, B., Pierce, D., & Rousseau, S. J. (2006). Seasonal affective disorder American Family Physician, 74 (9), 1521-1524

Rosenthal NE (2009). Issues for DSM-V: seasonal affective disorder and seasonality. The American journal of psychiatry, 166 (8), 852-3 PMID: 19651748


  1. Thanks for the straightforward and enjoyable explanations. Fortunately, I'm one of those people who is unaffected by SAD, even during six full winters in Fairbanks, Alaska. Some of my graduate students, however, were unusually impacted, reaching a condition bordering on waking-hibernation. Were I do clinical research on this topic, I'd opt for a high-latitude setting.

  2. Thank you for reading! SAD is particularly pronounced among students, I'm guessing because of their sleep habits. Students far from the equator might be the best population to study if one is looking for high rates. Glad to hear you don't feel affected in Alaska!

  3. There is one other technique I'm hoping to try: taking a trip to Hawaii. Let me know if you need a test subject. CMA

    1. Perfect!! I tried that last year, and it worked wonderfully. I'll let you know once I get the research funding for that :)