Seasonal affective disorder (SAD) is a type of depression that's related to changes in seasons — SAD begins and ends at about the same times every year. If you're like most people with SAD, your symptoms start in the fall and continue into the winter months, sapping your energy and making you feel moody. Less often, SAD causes depression in the spring or early summer.
Treatment for SAD may include light therapy (phototherapy), psychotherapy and medications.
Don't brush off that yearly feeling as simply a case of the "winter blues" or a seasonal funk that you have to tough out on your own. Take steps to keep your mood and motivation steady throughout the year.
In most cases, seasonal affective disorder symptoms appear during late fall or early winter and go away during the sunnier days of spring and summer. However, some people with the opposite pattern have symptoms that begin in spring or summer. In either case, symptoms may start out mild and become more severe as the season progresses.
Seasonal affective disorder is a subtype of major depression that comes and goes based on seasons. So symptoms of major depression may be part of SAD, such as:
- Feeling depressed most of the day, nearly every day
- Feeling hopeless or worthless
- Having low energy
- Losing interest in activities you once enjoyed
- Having problems with sleeping
- Experiencing changes in your appetite or weight
- Feeling sluggish or agitated
- Having difficulty concentrating
- Having frequent thoughts of death or suicide
Fall and winter SAD
Symptoms specific to winter-onset SAD, sometimes called winter depression, may include:
- Tiredness or low energy
- Problems getting along with other people
- Hypersensitivity to rejection
- Heavy, "leaden" feeling in the arms or legs
- Appetite changes, especially a craving for foods high in carbohydrates
- Weight gain
Spring and summer SAD
Symptoms specific to summer-onset seasonal affective disorder, sometimes called summer depression, may include:
- Trouble sleeping (insomnia)
- Weight loss
- Poor appetite
- Agitation or anxiety
Seasonal changes in bipolar disorder
In some people with bipolar disorder, spring and summer can bring on symptoms of mania or a less intense form of mania (hypomania), and fall and winter can be a time of depression.
When to see a doctor
It's normal to have some days when you feel down. But if you feel down for days at a time and you can't get motivated to do activities you normally enjoy, see your doctor. This is especially important if your sleep patterns and appetite have changed or if you feel hopeless, think about suicide, or turn to alcohol for comfort or relaxation.
The specific cause of seasonal affective disorder remains unknown. Some factors that may come into play include:
- Your biological clock (circadian rhythm). The reduced level of sunlight in fall and winter may cause winter-onset SAD. This decrease in sunlight may disrupt your body's internal clock and lead to feelings of depression.
- Serotonin levels. A drop in serotonin, a brain chemical (neurotransmitter) that affects mood, might play a role in SAD. Reduced sunlight can cause a drop in serotonin that may trigger depression.
- Melatonin levels. The change in season can disrupt the balance of the body's level of melatonin, which plays a role in sleep patterns and mood.
Factors that may increase your risk of seasonal affective disorder include:
- Being female. SAD is diagnosed more often in women than in men, but men may have more-severe symptoms.
- Age. Young people have a higher risk of winter SAD, and winter SAD is less likely to occur in older adults.
- Family history. People with SAD may be more likely to have blood relatives with SAD or another form of depression.
- Having clinical depression or bipolar disorder. Symptoms of depression may worsen seasonally if you have one of these conditions.
- Living far from the equator. SAD appears to be more common among people who live far north or south of the equator. This may be due to decreased sunlight during the winter and longer days during the summer months.
Take signs and symptoms of seasonal affective disorder seriously. As with other types of depression, SAD can get worse and lead to problems if it's not treated. These can include:
- Suicidal thoughts or behavior
- Social withdrawal
- School or work problems
- Substance abuse
Treatment can help prevent complications, especially if SAD is diagnosed and treated before symptoms get bad.
You're likely to start by seeing your family doctor or primary care provider. Or you may start by seeing a mental health provider such as a psychiatrist or psychologist.
Here's some information to help you get ready for your appointment.
What you can do
Before your appointment, make a list of:
- Your symptoms, such as feeling down or having a lack of energy
- Your depression patterns, such as when your depression starts and what seems to make it better or worse
- Any other mental or physical health problems you have — both can affect mood
- Any major stressors or life changes you've had recently
- All medications, vitamins or supplements you're taking, including dosages
- Questions to ask your doctor, in order of priority
For seasonal affective disorder, some basic questions to ask include:
- Are my symptoms likely caused by SAD, or could they be due to something else?
- What else could be causing or worsening my symptoms of depression?
- What are the best treatment options?
- Are there any restrictions that I need to follow or steps I should take to help improve my mood?
- Should I see a psychiatrist, psychologist or other mental health provider?
- Are medications likely to improve my symptoms?
- Is there a generic alternative to the medication you're prescribing me?
- Are there any brochures or other printed material that I can have? What websites do you recommend?
Don't hesitate to ask questions anytime during your appointment.
What to expect from your doctor
Your doctor is likely to ask you a number of questions. Be ready to answer them to reserve time to go over any points you want to spend more time on. Your doctor may ask:
- What are your symptoms?
- When did you first begin having symptoms?
- Have your symptoms been continuous or occasional?
- How severe are your symptoms?
- What, if anything, seems to improve your symptoms?
- What, if anything, appears to worsen your symptoms?
- Do you have any other physical or mental health conditions?
- Are you taking any medications, supplements or herbal remedies?
- Do you use alcohol or drugs?
- Do any of your blood relatives have SAD or another mental health condition?
To help diagnose seasonal affective disorder, your doctor or mental health provider may do a thorough evaluation, which generally includes:
- Physical exam. Your doctor may do a physical exam and ask in-depth questions about your health. In some cases, depression may be linked to an underlying physical health problem.
- Lab tests. For example, your doctor may do a blood test called a complete blood count (CBC) or test your thyroid to make sure it's functioning properly.
- Psychological evaluation. To check for signs of depression, your doctor or mental health provider asks about your symptoms, thoughts, feelings and behavior patterns. Your doctor may have you fill out a questionnaire to help answer these questions.
Seasonal affective disorder is considered a subtype of major depression or bipolar disorder. Even with a thorough evaluation, it can sometimes be difficult for your doctor or mental health provider to diagnose SAD because other types of depression or other mental health conditions can cause similar symptoms.
Many mental health professionals use the criteria in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published by the American Psychiatric Association, to diagnose mental conditions. This manual is also used by insurance companies to reimburse for treatment.
The DSM-5 criteria for diagnosing depression with a seasonal pattern includes having these experiences for at least the last two years:
- Depression that begins during a specific season every year
- Depression that ends during a specific season every year
- No episodes of depression during the season in which you experience a normal mood
- Many more seasons of depression than seasons without depression over the lifetime of your illness
Treatment for seasonal affective disorder may include light therapy, medications and psychotherapy. If you have bipolar disorder, tell your doctor — this is critical to know when prescribing light therapy or an antidepressant. Both treatments can potentially trigger a manic episode.
In light therapy, also called phototherapy, you sit a few feet from a special light therapy box so that you're exposed to bright light. Light therapy mimics natural outdoor light and appears to cause a change in brain chemicals linked to mood.
Light therapy is one of the first line treatments for fall-onset SAD. It generally starts working in a few days to two weeks and causes few side effects. Research on light therapy is limited, but it appears to be effective for most people in relieving SAD symptoms.
Before you purchase a light therapy box, talk with your doctor about the best one for you, and familiarize yourself with the variety of features and options so that you buy a high-quality product that's safe and effective.
Some people with SAD benefit from antidepressant treatment, especially if symptoms are severe.
An extended-release version of the antidepressant bupropion (Wellbutrin XL, Aplenzin) may help prevent depressive episodes in people with a history of SAD. Other antidepressants also may commonly be used to treat SAD.
Your doctor may recommend starting treatment with an antidepressant before your symptoms typically begin each year. He or she may also recommend that you continue to take the antidepressant beyond the time your symptoms normally go away.
Keep in mind that it may take several weeks to notice full benefits from an antidepressant. In addition, you may have to try different medications before you find one that works well for you and has the fewest side effects.
Psychotherapy, also called talk therapy, is another option to treat SAD. Psychotherapy can help you:
- Identify and change negative thoughts and behaviors that may be making you feel worse
- Learn healthy ways to cope with SAD
- Learn how to manage stress
In addition to your treatment plan for seasonal affective disorder, try the following:
- Make your environment sunnier and brighter. Open blinds, trim tree branches that block sunlight or add skylights to your home. Sit closer to bright windows while at home or in the office.
- Get outside. Take a long walk, eat lunch at a nearby park, or simply sit on a bench and soak up the sun. Even on cold or cloudy days, outdoor light can help — especially if you spend some time outside within two hours of getting up in the morning.
- Exercise regularly. Exercise and other types of physical activity help relieve stress and anxiety, both of which can increase SAD symptoms. Being more fit can make you feel better about yourself, too, which can lift your mood.
Some people are interested in trying alternative medicine (a nonconventional approach instead of conventional medicine) or complementary medicine (a nonconventional approach used along with conventional medicine).
Certain herbal remedies, supplements or mind-body techniques are sometimes used to try to relieve depression symptoms, though it's not clear how effective these treatments are for seasonal affective disorder.
Keep in mind, alternative treatments alone may not be enough to relieve your symptoms. Some alternative treatments may not be safe if you have other health conditions or take certain medications.
Some people choose to take a supplement to treat depression, such as:
- St. John's wort. This herb is not approved by the Food and Drug Administration (FDA) to treat depression in the United States, but it's a popular depression treatment in Europe. It may be helpful if you have mild or moderate depression, but St. John's wort should be used with caution. It can interfere with a number of medications, including antidepressants, HIV/AIDS medications, drugs to prevent organ rejection after an organ transplant, birth control pills, blood-thinning medications and chemotherapy drugs.
- SAMe. Pronounced "sam-E," this dietary supplement is a synthetic form of a chemical that occurs naturally in the body. The name is short for S-adenosyl–L-methionine (es-uh-den-o-sul-el-muh-THIE-o-neen). Like St. John's wort, SAMe isn't approved by the FDA to treat depression in the United States, but it's used in Europe as a prescription drug to treat depression. SAMe may be helpful, but more research is needed. SAMe may trigger mania in people with bipolar disorder.
- Melatonin. This dietary supplement is a synthetic form of a hormone occurring naturally in the body that helps regulate mood. A change in the season to less light may change the level of melatonin in your body. Taking melatonin could decrease winter-onset SAD, but more research is needed. Safety in children or with long-term use in adults has not been determined.
- Omega-3 fatty acids. These healthy fats are found in cold-water fish, flaxseed, flax oil, walnuts and some other foods. Omega-3 supplements are being studied as a possible treatment for depression. While considered generally safe, in high doses, omega-3 supplements may interact with other medications. More research is needed to determine if eating foods with omega-3 fatty acids can help relieve depression.
Keep in mind that nutritional and dietary products aren't monitored by the FDA. You can't always be certain of what you're getting and if it's safe. Also, because some herbal and dietary supplements can interfere with prescription medications or cause dangerous interactions, talk to your health care provider before taking any supplements.
Mind-body therapies that may help relieve depression symptoms include:
- Guided imagery
- Massage therapy
These steps can help you manage seasonal affective disorder:
- Stick to your treatment plan. Take medications as directed and attend therapy appointments as scheduled.
- Take care of yourself. Get enough rest and take time to relax. Participate in an exercise program or engage in another form of regular physical activity. Make healthy choices for meals and snacks. Don't turn to alcohol or illegal drugs for relief.
- Practice stress management. Learn techniques to manage your stress better. Unmanaged stress can lead to depression, overeating, or other unhealthy thoughts and behaviors.
- Socialize. When you're feeling down, it can be hard to be social. Make an effort to connect with people you enjoy being around. They can offer support, a shoulder to cry on or a joke to give you a little boost.
- Take a trip. If possible, take winter vacations in sunny, warm locations if you have winter SAD or to cooler locations if you have summer SAD.
There's no known way to prevent the development of seasonal affective disorder. However, if you take steps early on to manage symptoms, you may be able to prevent them from getting worse over time.
Some people find it helpful to begin treatment before symptoms would normally start in the fall or winter, and then continue treatment past the time symptoms would normally go away. Other people need continuous treatment to prevent symptoms from returning.
If you can get control of your symptoms before they get worse, you may be able to head off serious changes in mood, appetite and energy levels.