February is a difficult month for many people in northern latitudes. According to WebMD, over 11 million people suffer from Seasonal Affective Disorder (SAD) and many of the rest of us have a less severe case of the winter blues, officially called subsyndromal SAD.
Winter mood-related issues are a most probably a response to the lack of sunlight when days are shorter. In 2009, an overview of more than 20 studies combined found that SAD is much more common for people living farthest from the equator. In one U.S. study, only 1% of Floridians but 9% of Alaskans reported SAD symptoms. The winter blues is even more prevalent, with 15% of Canadians reporting that they experience the blues, while 2–6% experience SAD.
I can attest to the fact that moving south has helped the winters be less of a downer for me. My sister has found south Florida even better. My brother in northern Indiana? He barely answers the phone in winter. And, yes, seasonal depression, like any kind of depression, runs in families.
Low mood and energy levels are the main symptoms of SAD. People may feel irritable, have a hard time concentrating, and cry frequently. They are tired and are less active than usual. They also sleep more, withdraw from social situations, crave carbohydrates, and gain weight. People with full-on SAD can be completely incapacitated with depression, even to the point of having suicidal thoughts. Those with the winter blues have milder symptoms.
The exact cause of SAD isn’t known, but sunlight is definitely a factor. Biochemically, The National Institute of Mental Health names three issues associated with SAD:
- Difficulty with regulating serotonin, a key brain chemical involved in mood;
- Overproduction of melatonin, which regulates sleep;
- Underproduction of Vitamin D.
Counseling, medication for serotonin regulation (SSRIs or other anti-depressants), Vitamin D supplementation, and light therapy are the most recommended treatments for SAD.
Psychotherapy is very important for people with depression, whether seasonal or otherwise. In addition to traditional talk therapy, there is a specific type of Cognitive Behavioral Therapy adapted for use with SAD (CBT-SAD). Research indicates that CBT-SAD and light therapy both work equally well, but CBT-SAD may have more long-lasting effects for future winters.
Anti-depressant medications help regulate serotonin and can work wonders, but they do have side effects. Talk to your doctor about the benefits and drawbacks of any medication. You may also have to try a number of different prescriptions before finding the one that works best for you; don’t give up on your first try.
There is some debate on whether Vitamin D supplements are effective for SAD, but I would recommend supplementation for anyone (with or without SAD) who a) lives in a cold climate; b) doesn’t get out into the sun for at least 15 minutes a day; or c) consistently uses sunscreen. The Harvard School of Public Health also calls for supplementation. They describe Vitamin D deficiency as “a global concern” that “may increase the risk of a host of chronic diseases, such as osteoporosis, heart disease, some cancers, and multiple sclerosis, as well as infectious diseases such as tuberculosis and even the flu.” Recent studies indicate that Vitamin D supplementation increases serotonin concentrations and may help symptoms of depression. Since people with SAD often have low levels of Vitamin D in their blood, taking a Vitamin D supplement is good for general health, even if it doesn’t cure SAD on its own.
Light box therapy has also been found to be effective for all types of depression, not just winter-related SAD. The Mayo Clinic provides useful guidelines for choosing and using a light therapy box. Generally, light therapy boxes should emit 10,000 lux of light and as little UV as possible. the boxes are about 20 times brighter than ordinary indoor lights. Light therapy works best if practiced first thing in the morning for at least 20–30 minutes, starting in fall and continuing until spring.
Additional alternative therapies might be helpful with SAD or the winter blues. There is limited evidence for using melatonin or St. John’s Wort as a treatment. Theoretically, melatonin can be used to adjust circadian rhythms and improve sleep in some patients with SAD, but only small trials with few patients have shown effectiveness. Those trials used careful dosing and timing, which I think would be important for the melatonin treatment to actually work. My take on it is “don’t try this at home.”
St. John’s Wort is often suggested as an alternative to prescription medications for depression, but study results are mixed. A few small studies do show that St. John’s Wort may improve SAD symptoms. However, St. John’s wort has some significant drawbacks. It can interact with many prescription medicines and make them less effective, can cause serious serotonin-related side effects if you are taking certain anti-depressants, and it can have some some uncomfortable side effects not unlike those of early generations of anti-depressants. Use a good drug interaction checker or ask your pharmacist before you start taking St. John’s wort with any medication.
For a mild case of the blues, smaller lifestyle changes can make a big difference. A vacation in a sunny place can make February much more bearable. In fact, when this post goes live, I will be on a cruise ship with my sister, heading for Central America. I will do some judicious sun-bathing, have some family time, and visit places I’ve never been to before. If you can’t take that kind of vacation, exercise, healthy food, and positive self-talk are also helpful. And don’t forget the Vitamin D.