Seasonal Affective Disorder (SAD): Symptoms, Causes, and Treatment

Seasonal affective disorder is a type of depression that occurs in the winter in countries that are far from the equator.

Also known as SAD, it is sometimes referred to as winter depression. As winter approaches, the mornings start later and the evenings begin earlier, so there is less sunlight each day. Experts say SAD is most likely caused by lack of sunlight alone and not by cold temperatures.

Depressive symptoms usually build up slowly as days start getting shorter, and they gradually subside in early spring, as the amount of sunlight rises each day.

Fast facts on SAD:

  • SAD did not receive a clinical name until the early 1980s.
  • The symptoms of SAD are similar to those of depression.
  • Common symptoms include low mood, lethargy, and social withdrawal.

What is SAD?

SAD (seasonal affective disorder) is a common seasonal issue affecting people who don't get enough natural sunlight.

SAD (seasonal affective disorder) is a subtype of depression.

SAD was first mentioned in scientific literature in 1845 but the condition did not get a clinical name until the early 1980s.

We know that seasonal variations in sunlight have an impact on animal behavior, for example, hibernation, reproduction, and seeking out a mate. Seasonal changes in sunlight affect our circadian rhythms, which are also referred to as our internal biological clocks.

SAD is thought to affect 4-6 percent of people in the United States and is more common among young adults with onset typically between 20-30 years of age. It is often seen in females more than males, although depression is more common, generally, in females.

It also occurs more in areas that are further north. For example, it is seven times more common in Washington State than in Florida.

Interestingly, people can have SAD during the summer, although this is rare.

Symptoms of SAD

The signs and symptoms of SAD are similar to those of depression, but they come on as winter approaches and go away during springtime. In the majority of cases, symptoms come back each year at around the same time.

Symptoms are usually mild as autumn advances, and they worsen as the number of daylight drops. The severity, characteristics, and patterns of SAD can vary considerably from person-to-person.

About four-fifths of people who experience SAD develop unipolar depression, while the rest have bipolar depression. Unipolar means they have persistent depressive symptoms, while bipolar involves swinging from high or manic periods to very low or depressive ones.

The signs and symptoms of SAD include:

  • anxiety
  • feeling guilty and worthless
  • feeling stressed
  • indecision
  • irritability
  • low moods and despair
  • reduced libido
  • crying
  • lethargy, fatigue, hypersomnia
  • increased appetite
  • social withdrawal
  • difficulty concentrating
  • weight gain

Symptoms of spring and summer SAD

Insomnia is a common symptom of spring and summmer SAD.

Insomnia is a common symptom of spring and summer SAD.

Rather than feeling depressed during the winter, some people have symptoms in the spring and summer. This type of SAD is rare, but symptoms can include:

  • insomnia
  • low mood
  • reduced appetite
  • weight loss
  • anxiety
  • agitation

Who has a higher risk of developing SAD?

There are factors that can affect who gets SAD and who is less likely to have the condition.

Sex – females are more likely than males to suffer from SAD, although this may be due to a greater prevalence of depression among women. Males may have more severe symptoms.

Geography – some studies suggest that the further someone lives from the equator, the higher the chances of developing SAD. Put simply, those who live in places where days are considerably shorter in winter are more susceptible.

Genetics – individuals with a close relative who has or had SAD have a greater risk.

Having, or having had depression – people with a history of depression or bipolar depression are more likely to develop SAD than those with no such history.

Causes of SAD

Experts are still unsure of the exact causes of SAD. However, studies have pointed to the following:

  • Circadian rhythm – our body clock. Each of us has an internal body clock that tells us when to be awake and asleep. Less sunlight in the winter is thought to disrupt our circadian rhythm, causing depressive symptoms.
  • Melatonin levels – melatonin is a hormone that influences our sleep patterns and mood. Experts believe that reduced exposure to sunlight through shorter days in winter disrupts our melatonin balance. People with SAD also have decreased serotonin levels during the winter months.
  • The hypothalamus – sunlight is thought to stimulate the hypothalamus, a part of the brain that controls sleep, mood, and appetite, all of which impact on how we feel. Similarly, production of serotonin, a brain chemical (neurotransmitter) that affects mood, may be affected by low sunlight.

Diagnosis of SAD

The doctor may carry out a physical exam and ask questions covering:

  • How long symptoms have been present, how severe they are, and how they affect daily activities.
  • What eating patterns are like.
  • General lifestyle questions.
  • Sleeping patterns and if they have changed.
  • How thoughts and behaviors change with the seasons.
  • Details about family medical history, such as depression, SAD, etc.

As there are several types of depression, diagnosing SAD accurately may take time. There is no medical or laboratory test that can diagnose the condition. The doctor may order some diagnostic tests, including blood tests, to rule out other illnesses or underlying conditions.

The American Psychiatric Association do not class SAD as a separate disorder under the DSM-5 criteria, but a “course specifier.” They refer to it as “depression with a seasonal pattern.”

Treatments for SAD

According to the American Psychiatric Association, people may alleviate SAD symptoms by boosting their exposure to sunlight. For example, going for long walks outdoors when there is still some sunlight could help.

The National Institute for Health and Care Excellence (NICE) in the United Kingdom recommend that SAD treatment should be the same as for other types of depression, involving psychosocial and antidepressant medication.

Bright light therapy

If symptoms are so severe that they affect a person’s daily life, light therapy is sometimes recommended. Bright light therapy, also known as phototherapy, can help restore circadian rhythm.

With this kind of therapy, a person sits in front of a special light for 30-90 minutes each day. It is important to purchase a light box that is designed for treating SAD. UV lamps, full-spectrum lights, and tanning lamps will not do the same job.

In general, light therapy is required from 30 minutes to 2 hours per day, depending on the strength of the light. Doctors say exposure in the mornings tends to give the best results.

A similar treatment is known as dawn simulation when a special light in the bedroom is programmed to get slowly lighter in the mornings, to simulate dawn.

Experts say this type of phototherapy also helps restore brain chemistry balance. Nobody is sure how all this occurs.

Psychotherapy

Although SAD involves a change in a person’s brain chemistry, therapy that focuses on mood and behavior can also help.

Cognitive behavioral therapy (CBT) is based on the premise that it is how a person thinks and reacts to things that cause unhappiness rather than the situation. For example, if the way a person perceives certain situations can be altered, their behavior will change, and their symptoms will be reduced.

CBT usually includes an individual program of self-help, and another for the person and their partner, if appropriate. Sometimes a group program can also be helpful.

Medication

A doctor may prescribe an antidepressant, usually a selective serotonin reuptake inhibitor (SSRI), which raises serotonin levels.

Antidepressants do not work straight away; they can take from 10 days to 1 month to work well. Experts say antidepressants for SAD are more effective if taken at the beginning of the SAD season before symptoms appear. Usually, they are taken daily until springtime.

People should always follow their doctor’s instruction when taking these drugs.

Self-help

Some people have found that making their environment sunnier and brighter helps alleviate symptoms. Examples include opening blinds and curtains, trimming trees around the house, and sitting closer to the window during daytime.

Even in winter, the sun still comes up, and there is more sunlight outdoors than indoors. So, getting out every day for a long spell in the open air may help.

Similarly, exercise is not only good for the health but alleviates symptoms of anxiety and aids proper sleep. Exercises can also help people nurture a better self-image, which tends to lift their mood.

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How Can You Cope with Seasonal Affective Disorder?

With just 30 days left until Christmas, stores have started to sell their festive treats and decorations. But amid the general sense of enthusiasm, many of us will experience low moods, often to a debilitating extent. Why is that, and how can we cope?
girl looking out the window at the snow

Does winter bring you down every year? We give you some tips on how to manage seasonal affective disorder.

Seasonal affective disorder (SAD) is a type of depression that comes and goes with the four seasons, typically manifesting during the cold autumn and winter months, when the days are shorter, darker, and chillier.

According to the National Institute of Mental Health, the main risk factors for SAD are age, sex, distance from the equator (since regions farther to the north and south tend to have shorter days and less sunlight in winter), and a history of depression or other mood disorders.

Studies have shown that “[y]oung adults and women are most likely to experience SAD with the reported gender difference ranging from 2:1 to 9:1.”

People with SAD can experience a range of symptoms, but some of the most commonly reported ones include a sense of fatigue paired with oversleeping, chronically low moods, and strong cravings for carbohydrates, which can lead to excessive weight gain.

SAD can seriously impact productivity and day-to-day lifestyle, as the symptoms — if severe — can prevent individuals from going out, seeing other people, and engaging in some of the normal activities that they would otherwise pursue.

So what can you do if the winter months are getting you down? How can you cope with the lack of motivation, feelings of hopelessness, and debilitating fatigue? Here, we give you some tips on how to tackle SAD head-on.

Hunt down that light

Lack of exposure to natural light is one of the apparent reasons behind winter SAD, so it doesn’t come as a surprise that light therapy — also known as “phototherapy” — would be beneficial in keeping the symptoms at bay.

light box for phototherapy

A light box can help to reduce the symptoms of SAD.

Many studies have indicated that light therapy is usually helpful in treating this seasonal disorder, and for this purpose, you can use one of the many dedicated light boxes that are now available on the market.

But to be effective, you should make sure that the lightbox generates at least 10,000 lux — 100 times stronger than a normal lightbulb, meaning that a regular desk lamp won’t do — and that it has white or blue (not yellow) light.

Also, check that the lightbox was specially made to treat SAD, depression, and other mood disorders and that it’s not made for a different purpose (such as treating psoriasis or other skin conditions).

Lightboxes for skin treatments are another kettle of fish altogether, as they emit ultraviolet (UV) B, which is not safe for the retina. Instead, dedicated SAD treatment light boxes filter out UVs, so they’re safe to use.

Dr. Norman Ronsenthal — who first described SAD’s symptoms and pushed for it to be recognized as a valid disorder — offers some advice on how to use light therapy in his book, Winter Blues: Everything You Need to Know to Beat Seasonal Affective Disorder. He writes:

  1. Obtain a suitable lightbox.
  2. Set the light box up in a convenient place at home or at work, or both.
  3. Sit in front of the light box […] between 20 and 90 minutes each day.
  4. Try to get as much of your light therapy as early in the morning as possible.
  5. Be sure to sit in such a way that the correct amount of light falls on your eyes. [Dr. Marlynn Wei says it should be placed at eye level or higher, 2 feet away from you.]
  6. Repeat this procedure each day throughout the season of risk.

At the same time, you can add to the beneficial effects of light therapy by making a little extra effort to “hunt down” natural daylight, if possible, and take advantage of it as much as you can.

You could do this by waking up earlier in the morning and going outside where the sunshine is, for as long as it lasts, to allow yourself to feel as though you’re soaking in the light and taking advantage of the whole day.

Eat well, and watch out for the carbs

Research has shown that individuals with SAD tend to eat more carbohydrate-rich foods, especially sweets and starchy foods. They also have a tendency to overeat during these periods of “seasonal lows,” so it’s important that they look after their diets in order to feel more energized.

vegan suitable food

Cut down on the carbs and pile on the fruit and vegetables to feel better.

Over the winter months, as we get less and less sunlight, vitamin D is insufficiently produced in our bodies. Research has also suggested that ensuring we get enough vitamin D may help to prevent and manage depression.

To make sure that you’re getting enough vitamin D during autumn and winter, you could take dietary supplements. Vitamin D is also found in a range of foods that you can easily incorporate into your daily meals.

Salmon, for instance, is naturally rich in D-3, though some studies suggest that wild-caught salmon contains much larger amounts of the vitamin than farmed salmon.

Eggs are a good source of the vitamins D-2 and D-3, and mushrooms also have a high D-2 content, though research suggests that we should stick to wild mushrooms rather than cultivated ones.

Some studies also suggest that people with mood disorders may have an omega-3 fatty aciddeficit, and so supplementation of this nutrient may help to keep symptoms in check.

According to the National Institutes of Health (NIH), some good food sources of omega-3 include various types of fish (salmon, herring trout, and mackerel), chia seeds, flaxseed, and soybean.

Also, research published last year in the American Journal of Public Health points to fruit and vegetables as the foods of choice when it comes to increasing happiness and well-being.

“Eating fruit and vegetables apparently boosts our happiness far more quickly than it improves human [physical] health,” notes study co-author Prof. Andrew Oswald.

The psychological benefits of fruit and vegetable consumption were confirmed by a recent study, from February this year, which focused on the positive effect of a “green” diet on young adults — one of the groups most at risk of SAD.

Make an effort to stay active

Precisely because some of the main symptoms of SAD are fatigue and lethargy, specialists advise that making an effort to stay physically active can offer a boost of energy and improve mood.

review of existing studies surrounding SAD and the effects of exercise on this disorder suggests that the low moods and other symptoms involved in it may be caused by disruptions to the body’s circadian rhythm. The circadian rhythm regulates our sleep, eating, and activity patterns according to day-night cycles.

Review author Benny Peiser — from the Research Institute for Sport and Exercise Sciences at Liverpool John Moore University in the United Kingdom — explains that taking part in a regular physical exercise during the autumn and winter months can help to maintain an appropriate circadian rhythm, thereby keeping SAD symptoms at bay.

A study recently covered by Medical News Today also demonstrates that even low-intensity exercise done for as little as 1 hour per week can effectively counteract depression.

Don’t give in to reclusiveness

On those dark, cold days, you may be sorely tempted to just stay inside and hide from the weather and world alike. If you have more severe SAD symptoms, going out may seem unachievable, but if you want to keep the low moods and lethargy at bay, then you should do your best to resist these solitary tendencies.

man and woman hanging out in winter

Try not to give up on seeing people and doing things.

Much the same as light exercise, studies show that a leisurely walk in the great outdoors can improve your mood and well-being.

Just taking one moment every day to notice a detail in your natural surroundings, and asking yourself what feelings it elicits, can make you feel happier and more sociable, according to research from the University of British Columbia in Canada.

The American Psychological Association advise that you keep in touch with friends and family, go out with them, and speak to trusted people about what you’re experiencing. Enlisting someone else’s help in keeping you active, and helping you get out of your shell during the cold months, may make it easier to cope with the effects of SAD.

Advice regarding how best to cope with SAD from Johns Hopkins Medicine also includes finding a winter-appropriate hobby that will both keep you busy and give you pleasure, such as a DIY project or a winter sport.

Moreover, don’t forget that there is help available for people who experience SAD. Cognitive behavioral therapy has been proven to be effective in the treatment of this disorder, and a specialist will be able to recommend antidepressants if you find yourself struggling.

If you experience SAD, let us know what your strategy is for managing the symptoms and making the most of the holiday season.