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:

• Changes in mood: sadness, irritability, and/or feelings of hopelessness or worthlessness most of the time for at least 2 weeks; tendency to be more self-critical and more sensitive than usual to criticism; crying or getting upset more often or more easily
• Lack of enjoyment: loss of interest in things that are normally enjoyable; feeling like tasks can't be accomplished as well as before; feelings of dissatisfaction or guilt
• Low energy: unusual tiredness or unexplained fatigue
• Changes in sleep: sleeping much more than usual (which can make it difficult for kids with SAD to get up and get ready for school in the morning)
• Changes in eating: craving simple carbohydrates (i.e., comfort foods and sugary foods); tendency to overeat (which could result in weight gain during the winter months)
• Difficulty concentrating: more trouble than usual completing assignments on time; lack of usual motivation (which can affect school performance and grades)
• Less time socializing: spending less time with friends in social or extracurricular activities

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

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:

• Participate in your child's treatment. Ask the doctor how you can best help your child.
• Help your child understand SAD. Learn about the disorder and provide simple explanations. Remember, concentration might be difficult, so it's unlikely your child will want to read or study much about SAD — if so, just recap the main points.
• Encourage your child to get plenty of exercise and to spend time outdoors. Take a daily walk together.
• Find quality time. Spend a little extra time with your child — nothing special, just something low-key that doesn't require much energy. Bring home a movie you might enjoy or share a snack together. Your company and caring are important and provide personal contact and a sense of connection.
• Be patient. Don't expect symptoms to go away immediately. Remember that low motivation, low energy, and low mood are part of SAD — it's unlikely that your child will respond cheerfully to your efforts to help.
• Help with homework. You may have to temporarily provide hands-on assistance to help your child organize assignments or complete work. Explain that concentration problems are part of SAD and that things will get better again. Kids and teens with SAD may not realize this and worry that they're incapable of doing the schoolwork. You may also want to talk to the teachers and ask for extensions on assignments until things get better with treatment.
• Help your child to eat right. Encourage your child to avoid loading up on simple carbohydrates and sugary snacks. Provide plenty of whole grains, vegetables, and fruits.
• Establish a sleep routine. Encourage your child to stick to a regular bedtime every day to reap the mental health benefits of daytime light.
• Take it seriously. Don't put off evaluation if you suspect your child has SAD. If diagnosed, your child should learn about the seasonal pattern of the depression. Talk often about what's happening, and offer reassurance that things will get better, even though that may seem impossible right now.

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