Maggie started off her junior year of high school with great energy. She had no
trouble keeping up with her schoolwork and was involved in several after-school activities.
But after the Thanksgiving break, she began to have difficulty getting through her
assigned reading and had to work harder to apply herself. She couldn't concentrate
in class, and after school all she wanted to do was sleep.
Maggie's grades began to drop and she rarely felt like socializing. Even though
Maggie was always punctual before, she began to have trouble getting up on time and
was absent or late from school many days during the winter.
At first, Maggie's parents thought she was slacking off. They were upset with her,
but figured it was just a phase — especially since her energy finally seemed to return
in the spring. But when the same thing happened the following November, they took
Maggie to the doctor, who diagnosed her with a type of depression called seasonal
What Is Seasonal Affective Disorder?
Seasonal affective disorder (SAD) is a form of depression
that appears at the same time each year. With SAD, a person typically has symptoms
of depression and unexplained fatigue as winter approaches and daylight hours become
shorter. When spring returns and days become longer again, people with SAD experience
relief from their symptoms, returning to their usual mood and energy level.
What Causes SAD?
Experts believe that, with SAD, depression is somehow triggered by the brain's
response to decreased daylight exposure. No one really understands how and why this
happens. Current theories about what causes SAD focus on the role that sunlight might
play in the brain's production of key chemicals.
Experts think that two specific chemicals in the brain,
may be involved in SAD. These two chemicals help regulate a person's
sleep-wake cycles, energy, and mood. Shorter days and longer hours of darkness in
fall and winter may cause increased levels of melatonin and decreased levels of serotonin,
creating the biological conditions for depression.
Melatonin is linked to sleep. The body produces it in greater quantities when it's
dark or when days are shorter. This increased production of melatonin can cause a
person to feel sleepy and lethargic.
With serotonin, it's the reverse — serotonin production goes up when a person is
exposed to sunlight, so it's likely that a person will have lower levels
of serotonin during the winter when the days are shorter. Low levels of serotonin
are associated with depression, whereas increasing the availability of serotonin helps
to combat depression.
What Are the Symptoms of SAD?
Someone with SAD will show several particular changes from the way he or she normally
feels and acts. These changes occur in a predictable seasonal pattern. The symptoms
of SAD are the same as symptoms of depression, and a person with SAD may notice several
or all of these symptoms:
Changes in mood. A person may feel sad or be in an irritable
mood most of the time for at least 2 weeks during a specific time of year. During
that time, a guy or girl may feel a sense of hopelessness or worthlessness. As part
of the mood change that goes with SAD, people can be self-critical; they may also
be more sensitive than usual to criticism and cry or get upset more often or more
Lack of enjoyment. Someone with SAD may lose interest in things
he or she normally likes to do and may seem unable to enjoy things as before. People
with SAD can also feel like they no longer do certain tasks as well as they used to,
and they may have feelings of dissatisfaction or guilt. A person with SAD may seem
to lose interest in friends and may stop participating in social activities.
Low energy. Unusual tiredness or unexplained fatigue is also
part of SAD and can cause people to feel low on energy.
Changes in sleep. A person may sleep much more than usual. Excessive
sleeping can make it impossible for a student to get up and get ready for school in
Changes in eating. Changes in eating and appetite related to
SAD may include cravings for simple carbohydrates (think comfort foods and sugary
foods) and the tendency to overeat. Because of this change in eating, SAD can result
in weight gain during the winter months.
Difficulty concentrating. SAD can affect concentration, too,
interfering with a person's school performance and grades. A student may have more
trouble than usual completing assignments on time or seem to lack his or her usual
motivation. Someone with SAD may notice that his or her grades may drop, and teachers
may comment that the student seems less motivated or is making less effort in school.
Less time socializing. People with SAD may spend less time with
friends, in social activities, or in 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 a person feeling disappointed,
isolated, and lonely — especially if he or she doesn't realize what's causing the
changes in energy, mood, and motivation.
Like other forms of depression, the symptoms of SAD can be mild, severe, or anywhere
in between. Milder symptoms interfere less with someone's ability to participate in
everyday activities, but stronger symptoms can interfere much more. 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 SAD from
other forms of depression.
Who Gets SAD?
SAD can affect adults, teens, and children. It's estimated that about 6 in every
100 people (6%) experience SAD.
The number of people with SAD varies from region to region. One study of SAD
in the United States found the rates of SAD were seven times higher among people in
New Hampshire than in Florida, suggesting that the farther people live from the equator,
the more likely they are to develop SAD.
Interestingly, when people who get SAD travel to areas far south of the equator
that have longer daylight hours during winter months, they do not get their seasonal
symptoms. This supports the theory that SAD is related to light exposure.
Most people don't get seasonal depression, even if they live in areas where days
are shorter during winter months. Experts don't fully understand why certain people are
more likely to experience SAD than others. It may be that they're more sensitive than
others to variations in light, and therefore may experience more dramatic shifts in
hormone production according to their exposure to light.
Like other forms of depression, females are about four times more likely than males
to develop SAD. People with relatives who have experienced depression are also more
likely to develop it. Individual biology, brain chemistry, family history, environment,
and life experiences may also make certain individuals more prone to SAD and other
forms of depression.
Researchers are continuing to investigate what leads to SAD, as well as why some
people are more likely than others to experience it.
How Is SAD Diagnosed and Treated?
Doctors and mental health professionals make a diagnosis of SAD after a careful
evaluation. A medical checkup is also important to make sure that symptoms aren't
due to a medical condition that needs treatment. Tiredness, fatigue, and low energy
could be a sign of another medical condition such as hypothyroidism,
hypoglycemia, or mononucleosis.
Other medical conditions can cause appetite changes, sleep changes, or extreme fatigue.
Once a person's been diagnosed with SAD, doctors may recommend one of several treatments:
Increased Light Exposure
Because the symptoms of SAD are triggered by lack of exposure to light, and they
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 your home in winter months
and might help with mild symptoms.
Stronger symptoms of SAD may be treated with light therapy (also called phototherapy).
Light therapy involves the use of a special light that simulates daylight. A special
light box or panel is placed on a tabletop or desk, and the person sits in front of
the light for a short period of time every day (45 minutes a day or so, usually in
the morning). The person should occasionally glance at the light (the light has to
be absorbed through the retinas in order to work), but not stare into it for long
periods. Symptoms tend to improve within a few days in some cases or within a few
weeks in others. Generally, doctors recommend the use of light therapy until enough
sunlight is available outdoors.
Like any medical treatment, light treatment should only be used under the supervision
of a doctor. People who have another type of depressive disorder, skin that's sensitive
to light, or medical conditions that may make the eyes vulnerable to light damage
should use light therapy with caution. The lights that are used for SAD phototherapy
must filter out harmful UV rays. Tanning beds or booths should not be used to alleviate
symptoms of SAD. Some mild side effects of phototherapy might include headache or
Talk therapy (psychotherapy) is also used to treat people with SAD. Talk therapy
focuses on revising the negative thoughts and feelings associated with depression
and helps ease the sense of isolation or loneliness that people with depression often
feel. The support and guidance of a professional therapist can be helpful for someone
experiencing SAD. Talk therapy can also help someone to learn about and understand
their condition as well as learn what to do to prevent or minimize future bouts of
Doctors may also prescribe medications for teens with SAD. Antidepressant medications
help to regulate the balance of serotonin and other neurotransmitters in the brain
that affect mood and energy. Medications need to be prescribed and monitored by a
doctor. If your doctor prescribes medication for SAD or another form of depression,
be sure to let him or her know about any other medications or remedies you may be
taking, including over-the-counter or herbal medicines. These can interfere with prescription
Dealing With SAD
When symptoms of SAD first develop, it can be confusing, both for the person with
SAD and family and friends. Some parents or teachers may mistakenly think that teens
with SAD are slacking off or not trying their best. If you think you're experiencing
some of the symptoms of SAD, talk to a parent, guidance counselor, or other trusted
adult about what you're feeling.
If you've been diagnosed with SAD, there are a few things you can do to help:
Follow your doctor's recommendations for treatment.
Learn all you can about SAD and explain the condition to others so they can work
Get plenty of exercise, especially outdoors. Exercise can be a mood lifter.
Spend time with friends and loved ones who understand what you're going through
— they can help provide you with personal contact and a sense of connection.
Be patient. Don't expect your symptoms to go away immediately.
Ask for help with homework and other assignments if you need it. If you feel you
can't concentrate on things, remember that it's part of the disorder and that things
will get better again. Talk to your teachers and work out a plan to get your assignments
It may be hard, but avoiding simple carbohydrates and sugary snacks and concentrating
on plenty of whole grains, vegetables, and fruits can help you feel better in the
Develop a sleep routine. Regular bedtimes can help you reap the mental health
benefits of daytime light.
Depression in any form can be serious. If you think you have symptoms of any type
of depression, talk to someone who can help you get treatment.