What’s seasonal affective disorder and how’s it treated?

1) Hi Alice,

I am concerned that I have that seasonal depression thing — SAD (I wish I knew what that acronym stands for). I have heard that light therapy is a legitimate option. This seems to be consistent with what I have read about melatonin and its possible connection to serotonin, a chemical associated with depression. Is it true that more melatonin can mean less depression and anxiety?

If I do have SAD, during the winter can I just go to a tanning parlor as opposed to a more expensive light therapy clinic? Are UV tanning parlors really more expensive/dangerous than suntanning on the beach? What about clinical light therapy stations? (Yes, I don't know their official name). I realize that it is summer now, but after last winter, which was truly traumatic for me, I want to come up with a plan for next winter well in advance.

—Guy who needs a really dark tan bad

2) Alice,

Every winter, especially when the days are short, I feel tired, depressed, and unproductive. Then the spring comes and I start feeling myself again. Is this just a normal seasonal cycle? I've heard about SAD, Seasonal Affective Disorder, but don't know much about it.

— Melancholy Baby

Dear Guy who needs a really dark tan bad and Melancholy Baby, 

Sounds like it’s time to shed some light on seasonal affective disorder (SAD). SAD is a type of depression that comes and goes with the seasons, most commonly affecting people during the darker, colder months associated with winter. The hormone melatonin plays a role in how your body regulates day-to-day sleep-wake cycles, though there's some back and forth on how it functions. While it can be common to feel down as it gets darker and colder, SAD symptoms are more extreme and may affect your ability to carry out routine daily activities. There are ways to mitigate SAD symptoms such as light therapy (which uses minimal ultraviolet radiation), which is often considered an effective treatment. That said, exposure to ultraviolet (UV) radiation through something like indoor tanning is not an effective route. 

So, what exactly is the role of melatonin in SAD? Melatonin is a hormone which controls your body’s biological clock that regulates sleep and mood. Since depression is often linked to biological clock disruptions, some studies have found that increased melatonin levels improve biological clock function, in turn, reducing depressive symptoms. However, other studies have found the opposite—that more melatonin may actually worsen symptoms of depression. During darker winter months, melatonin secretions are prolonged and may shut off much later in the day because of reduced sunlight. Having more melatonin during the day may cause you to experience depressed mood and daytime fatigue. 

Apart from the role of melatonin, other potential SAD causes may include: 

  • Insufficient serotonin. Serotonin is a chemical associated with happiness. Some people may naturally have less serotonin activity, and with less sunlight during winter months, serotonin levels may decrease further and lead to depression. 
  • Vitamin D deficiency. Vitamin D boosts serotonin levels. With less sunlight in the winter, your body may produce less vitamin D and your serotonin levels and mood may fall. 

List adapted from Cleveland Clinic 

To fight these winter blues and stay on the bright side, many health care providers may recommend light therapy. Light therapy typically involves being near a light therapy lamp for 15 to 30 minutes every morning. The light mimics the brightness of natural sunlight (at 10,000 lux, it’s around 20 times brighter than regular indoor lights), but unlike the sun or tanning beds, it filters out harmful UV radiation. Tanning beds emit dangerously high amounts of ultraviolet (UV) radiation and not enough light, exposing you to similar, if not more intense, radiation as tanning in the direct sun. This radiation may accelerate skin aging and increase your risk of developing eye injuries and skin cancers. While light therapy is generally safe, minor side effects like eye strain, headaches, and insomnia are still possible. That said, you may want to avoid light therapy altogether if you have diabetes, retinopathy, bipolar disorder, or take certain medications that make you sensitive to light. 

In addition to light therapy, some additional treatment and prevention methods for SAD that you may want to consider include: 

  • Getting more sunlight. Being outside, even if it’s cloudy, or even increasing the amount of sunlight that enters your space may help improve your symptoms. 
  • Practicing self-care. Eating a variety of whole foods with enough vitamins and managing stress by exercising and getting enough sleep could prevent and treat SAD. 
  • Planning activities with friends. Your social circle can be a great resource for support, so you might consider planning activities during the winter to keep you from hunkering down at home. 
  • Taking antidepressant medications. Health care providers sometimes recommend medication for severe depression, either alone or with light therapy. In some cases, taking the medication before SAD begins can prevent it. 
  • Avoiding alcohol and drugs. These substances might make symptoms worse and could interact negatively with antidepressants. 
  • Taking vitamin D supplements. Vitamin D supplements may address potential vitamin D deficiencies and improve symptoms. 
  • Engaging in cognitive behavioral therapy (CBT). CBT is a type of talk therapy shown to treat SAD effectively with long-lasting effects. 

List adapted from Cleveland Clinic 

Ultimately, while light therapy is one way to battle the power of the dark side, it isn’t your only option. Noticing that your shift in moods might be related to seasonal changes is a great start. A next step to consider is making an appointment with a mental health professional. They can assess your symptoms, more accurately diagnose you, and if necessary, discuss treatment options that may help you get some spring back in your step. 

Here’s to a warmer, brighter winter,

Last updated Dec 01, 2023
Originally published Oct 06, 1994