Seasonal Affective Disorder

Seasonal Affective Disorder

At first, Maggie's parents thought she was slacking off. After the Thanksgiving break, she couldn't concentrate in class, and after school all she wanted to do was sleep. Her grades began to drop and she rarely felt like socializing anymore. They were upset with her, but figured it was just a phase — especially because her energy finally seemed fine in the spring.

But when the same thing happened the next fall, and Maggie's mood and her grades plummeted again, they took her to the doctor, who diagnosed her with a type of depression called seasonal affective disorder (SAD).

About Seasonal Affective Disorder

A form of depression that follows a seasonal pattern, SAD appears and disappears at the same times each year. People with SAD usually have symptoms of depression as winter approaches and daylight hours become shorter. When spring returns and the days become longer again, they experience relief from the symptoms and a return to a normal mood and energy level.

Signs and Symptoms

Like other forms of depression, the symptoms of SAD can be mild, severe, or anywhere in between. Milder symptoms minimally interfere with someone's ability to participate in everyday activities, while more severe symptoms can interfere much more.

The symptoms of SAD are the same as those of depression, but occur during a specific time of year. It's the seasonal pattern of SAD — the fact that symptoms occur only for a few months each winter (for at least 2 years in a row) but not during other seasons — that distinguishes it from other forms of depression.

Symptoms of SAD may include:

The problems caused by SAD — such as lower-than-usual grades or less energy for socializing with friends — can affect self-esteem and leave people feeling disappointed, isolated, and lonely, especially if they don't realize what's causing the changes in energy, mood, and motivation.

Causes of SAD

It's believed that with SAD, depression is somehow triggered by the brain's response to decreased daylight exposure. How and why this happens isn't yet fully understood. Current theories focus on the role of sunlight in the brain's production of certain key hormones that help regulate sleep-wake cycles, energy, and mood.

Two chemicals that occur naturally in the body are thought to be involved in SAD:

  1. Melatonin, which is linked to sleep. It's produced in greater quantities when it's dark or when days are shorter. Increased production of melatonin can cause sleepiness and lethargy.
  2. Serotonin, the production of which increases with exposure to sunlight. Low levels of serotonin are associated with depression, so increasing the availability of serotonin helps to combat depression.

Shorter days and longer hours of darkness in fall and winter can increase melatonin levels and decrease serotonin levels, which may create the biological conditions for depression.

Who Gets It?

About 6 in every 100 people (6%) experience SAD. Although it can affect kids and young teens, it's most common in older teens and young adults, usually starting in the early twenties. Like other forms of depression, females are about four times more likely than males to develop SAD, as are people with relatives who have had depression. Individual biology, brain chemistry, family history, environment, and life experiences also might make certain people more prone to SAD and other forms of depression.

The prevalence of SAD varies from region to region, and it's far more abundant among people who live in higher latitudes. For instance, one study found the rates of SAD were seven times higher among people in New Hampshire than in Florida, suggesting that life farther from the equator is a risk factor for SAD.

However, most people don't experience seasonal depression, even if they live in areas where days are much shorter during winter months. Those who do might be more sensitive to the variations in light, and undergo more dramatic shifts in hormone production depending on their exposure to light.


Treatment for SAD, which varies depending on the severity of the symptoms, includes:

Increased light exposure. Because the symptoms of SAD are triggered by lack of exposure to light and tend to go away on their own when available light increases, treatment for SAD often involves increased exposure to light during winter months. For someone with mild symptoms, it may be enough to spend more time outside during the daylight hours, perhaps by exercising outdoors or taking a daily walk. Full-spectrum (daylight) lightbulbs that fit in regular lamps can help bring a bit more daylight into winter months and might help with mild symptoms.

Light therapy (phototherapy). More troublesome symptoms may be treated with a stronger light that simulates daylight. A special lightbox or panel is placed on a tabletop or desk, and the person sits in front of it briefly every day (45 minutes or so, usually in the morning) with eyes open, glancing — not staring — occasionally at the light (to work, the light has to be absorbed through the retinas). Symptoms tend to improve within a few days or weeks. Generally, light therapy is used until enough sunlight is available outdoors. Mild side effects of phototherapy might include headache or eyestrain.

Lights used for SAD phototherapy must filter out harmful UV rays. Tanning beds or booths should not be used to relieve symptoms of SAD. Their ultraviolet rays can damage skin and cause wrinkles and age spots, and even lead to skin cancer such as melanoma. Phototherapy should be used with caution if someone has another type of depressive disorder, skin that's sensitive to light, or medical conditions that may make the eyes vulnerable to light damage.

Like any treatment, phototherapy should be used under a doctor's supervision.

Medication (pharmacotherapy). Medications, which might be used in combination with talk therapy and light therapy, may be prescribed for a child or teen with SAD and should be monitored by a doctor. Antidepressant medications help to regulate the balance of serotonin and other neurotransmitters in the brain that affect mood and energy. Tell your doctor about any other medications your child takes, including over-the-counter or herbal medicines, which could interfere with prescription medications.

Talk therapy (psychotherapy). Helping to ease the sense of isolation or loneliness, talk therapy focuses on revising the negative thoughts and feelings associated with depression. It also can help people with SAD understand their condition and learn ways to prevent or minimize future bouts.

What Parents Can Do

Talk to your doctor if you suspect your child has SAD. Doctors and mental health professionals make a diagnosis of SAD after a careful evaluation and a checkup to ensure that symptoms aren't due to a medical condition that needs treatment. Tiredness, fatigue, changes in appetite and sleep, and low energy can be signs of other medical problems, such as hypothyroidism, hypoglycemia, or mononucleosis.

When symptoms of SAD first develop, parents might attribute low motivation, energy, and interest to an intentional poor attitude. Learning about SAD can help them understand another possible reason for the changes, easing feelings of blame or impatience with their child or teen.

Parents sometimes are unsure about how to discuss their concerns and observations. The best approach is usually one that's supportive and not judgmental. Try opening the discussion with something like, "You haven't seemed yourself lately — you've been so sad and grouchy and tired, and you don't seem to be having much fun or getting enough sleep. So, I've made an appointment for you to get a checkup. I want to help you to feel better and get back to doing your best and enjoying yourself again."

Here are a few things you can do if your child or teen has been diagnosed with SAD:

Reviewed by: D'Arcy Lyness, PhD
Date reviewed: May 2013

Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.

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Related Resources
OrganizationNational Mental Health Association (NMHA) NMHA works to improve the mental health of all Americans through advocacy, education, research, and service.
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OrganizationAmerican Psychological Association (APA) The APA provides information and education about a variety of mental health issues for people of all ages.
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