Story at a glance
- The lack of daylight from shorter days during the winter can lead to symptoms of depression.
- Up to 20 percent of people may experience mild seasonal affective disorder.
- Light therapy can help with symptoms of seasonal depression, though the biology behind it isn’t well understood.
Winter is here, and in some parts of the world it has already stamped its presence with snow. For some of us, that comes with seasonal blues or dips in mood. Around 4 to 6 percent of people may experience seasonal depression, and up to 20 percent may experience mild seasonal affective disorder, according to the American Academy of Family Physicians. What counts as seasonal depression, and what can we do about it?
You may have heard the term seasonal affective disorder (SAD). Essentially, it is a specific kind of depression or episode of depression that is brought on by the changes in seasons and daylight. “We say that someone has winter depression or seasonal affective disorder if they have this pattern of depressive symptoms consistently in the winter months,” says clinical psychologist and associate professor Philip Gehrman of the University of Pennsylvania.
Symptoms of depression include low mood, loss of interest in activities, low energy, difficulty sleeping and suicidal thoughts or actions. To be considered seasonal affective disorder, a person needs to be experiencing at least five symptoms of depression, Gehrman tells Changing America. This may seem like a lot, but a depression diagnosis is a serious thing.
But feeling down during winter may not always be linked to seasons and could be a general episode of depression, says Gehrman. That’s why it’s easier to diagnose seasonal depression if it has happened over more than one winter. It’s hard to know if it’s a seasonal pattern until it’s happened at least twice. It also doesn’t have to occur consistently every year.
So what happens if you think you do have a case of seasonal depression? First of all, if you think you might have depression, see a professional for medical advice. They are the only ones who can actually give you a diagnosis.
And if you do have seasonal depression, there are simple treatments available. “The main treatment, if someone does go in for treatment…is light therapy,” says Gehrman. “Since this seems to be triggered by the shorter day length in the winter, essentially what you’re doing with light therapy is trying to trick the brain into thinking that the sun’s up for longer.” In the clinic, patients are exposed to light boxes that have light intensity of at least 10,000 lux, says Gehrman. So the idea is that when nature shortens the day length, you can supplement with light boxes that can mimic extra hours of sunlight.
What’s going on in our bodies?
It’s actually not very well understood what is happening in our bodies and why light therapy works. There has been some research into special light receptors in our eyes called called melanopsin ganglion cells, which are very sensitive to blue light. It’s what sends signals to our brain that it’s time to be awake and active, explaining why too much blue light from screens at night are bad for falling asleep.
But besides that, we don’t know much about the mechanisms for how light affects our moods and why lack of light can lead to symptoms of depression. Gehrman says he’s heard of people who moved from places close to the equator to places farther from the equator and subsequently developed seasonal affective disorder. He’s also heard of cases where people moved closer to the equator and their seasonal depression went away.
Studies on wake-up lamps show that they can improve symptoms. “Cognitive performance is better after being woken up with a wake-up light and well-being is better,” says light researcher Oliver Stefani of the Centre for Chronobiology at the University of Basel. There are also new blue light lamps on the market that in theory may work similarly to light therapy lamps without requiring such high intensity, but there isn’t any research yet to show that they are more efficient, says Gehrman.
What can you do?
Before you think seriously about a big move, you may benefit from treatment. If you think you have symptoms of depression from lack of daylight during winter, light therapy may help. You have to be aware of what type of light you are using and when. As Gehrman outlines, you should use a light box or bulb that has high intensity, ideally 10,000 lux. The light bulb should produce full spectrum light, says Stefani, so including all blue light to help activate the melanopsin cells. And you should only use it in the mornings, otherwise it could affect your circadian rhythm (especially if you have trouble getting to sleep in the evening).
Feeling down in the winter can become a vicious cycle where you keep yourself from doing things that would help like spending time outdoors and seeing friends. If you have the self awareness to figure out that it’s happening to you, you might benefit from trying out light therapy. But if you really are experiencing depression, don’t hesitate to talk to a clinical psychologist.
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