Seasonal affective disorder (SAD) is depression that gets triggered by a change in seasons, usually when fall starts. This seasonal depression gets worse in the winter before ending in the spring.
Some people may get a mild version of SAD known as the “winter blues.” It’s normal to feel a little down during colder months. You may be stuck inside, and it gets dark early.
But full SAD goes beyond that — it’s a form of depression. Unlike the winter blues, SAD affects your daily life, including how you feel and think. Fortunately, treatment can help you get through this challenging time.
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. Less commonly, 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.
Signs and symptoms of SAD may include:
- Feeling depressed most of the day, nearly every day
- Losing interest in activities you once enjoyed
- Having low energy
- Having problems with sleeping
- Experiencing changes in your appetite or weight
- Feeling sluggish or agitated
- Having difficulty concentrating
- Feeling hopeless, worthless or guilty
- Having frequent thoughts of death or suicide
Fall and winter SAD
Symptoms specific to winter-onset SAD, sometimes called winter depression, may include:
- Appetite changes, especially a craving for foods high in carbohydrates
- Weight gain
- Tiredness or low energy
Spring and summer SAD
Symptoms specific to summer-onset seasonal affective disorder, sometimes called summer depression, may include:
- Trouble sleeping (insomnia)
- Poor appetite
- Weight loss
- 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, you turn to alcohol for comfort or relaxation, or you feel hopeless or think about suicide.
Researchers don’t know exactly what causes seasonal depression. The lack of sunlight may trigger the condition in people who are prone to getting it. The theories suggest:
- Biological clock change: When someone has less exposure to sunlight, their biological clock shifts. This internal clock regulates mood, sleep and hormones. When it changes, people may have trouble regulating their moods.
- Brain chemical imbalance: Brain chemicals called neurotransmitters send communications between nerves. These chemicals include serotonin, which contributes to feelings of happiness. People at risk of SAD may already have less serotonin activity. Since sunlight helps regulate serotonin, the lack of winter sun can make the situation worse. Serotonin levels can fall further, leading to mood changes.
- Vitamin D deficit: Serotonin also gets a boost from vitamin D. Since sunlight helps us produce vitamin D, less sun in the winter can lead to a vitamin D deficiency. That change can affect serotonin and mood.
- Melatonin boost: Melatonin is a chemical that affects sleep patterns. The lack of sunlight may stimulate an overproduction of melatonin in some people. They may feel sluggish and sleepy during the winter.
- Negative thoughts: People with SAD often have stress, anxiety and negative thoughts about the winter. Researchers aren’t sure if these negative thoughts are a cause or effect of seasonal depression
Seasonal affective disorder is diagnosed more often in women than in men. And SAD occurs more frequently in younger adults than in older adults.
Factors that may increase your risk of seasonal affective disorder include:
- Family history. People with SAD may be more likely to have blood relatives with SAD or another form of depression.
- Having major 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.
If you have symptoms of SAD, don’t try to diagnose yourself. See a healthcare provider for a thorough evaluation. You may have a physical issue that’s causing depression. But many times, seasonal affective disorder is part of a more complex mental health issue.
Your provider may refer you to a psychiatrist or psychologist. These mental health professionals talk to you about your symptoms. They consider the pattern of symptoms and decide if you have seasonal depression or another mood disorder. You may need to fill out a questionnaire to determine if you have SAD.
Your provider may diagnose you with SAD if you have:
- Symptoms of major depression.
- Depressive episodes that occur during specific seasons for at least two consecutive years.
- Depressive episodes that happen more frequently during a specific season than during the rest of the year.
Your provider will talk to you about treatment options. You may need a combination of treatments, including:
- Phototherapy: Bright light therapy, using a special lamp, can treat SAD.
- Cognitive behavioral therapy (CBT): A type of talk therapy called CBT can also effectively treat SAD. Research has shown that CBT produces the longest-lasting effects of any treatment approach.
- Antidepressant medication: Sometimes, providers recommend medication for depression , either alone or with light therapy.
- Spending time outdoors: Getting more sunlight can help improve symptoms. Try to get out during the day. Also increase the amount of sunlight that enters your home or office.
- Vitamin D: A vitamin D supplement may help improve symptoms.
How does light therapy work?
To use light therapy, or phototherapy, you get a special lamp. It has white fluorescent light tubes covered with a plastic screen to block ultraviolet rays. The light is about 20 times brighter than regular indoor light. The intensity of light emitted should be 10,000 lux.
To use phototherapy, don’t look directly into the light. Place the lamp about 2 or 3 feet away while you read, eat or do other activities.
What time of day should I use light therapy?
When you use light therapy may impact how effective it is. Morning light therapy seems to work better. Plus, using it later in the day may cause insomnia. Many health professionals recommend 10,000 lux for 15 to 30 minutes every morning.
How long will it take light therapy to work?
People who use a lamp for SAD often see results within two to four days. It may take about two weeks to reach the full benefits.
How long do I use light therapy for?
Healthcare providers often recommend using light therapy through the entire winter. SAD symptoms can return quickly after stopping light therapy. Continuing to use the therapy can help you feel your best throughout the season.
Is light therapy safe?
Light therapy is typically safe and well-tolerated. But you may need to avoid light therapy if you:
- Have diabetes or retinopathies: If you have diabetes or a retina condition, there’s a potential risk of damaging the retina, the back of your eye.
- Take some medications: Certain antibiotic and anti-inflammatories can make you more sensitive to sunlight. Light therapy can then cause harm.
- Have bipolar disorder: Bright light therapy can trigger hypomania or mania, uncontrolled boosts in mood and energy level. People with bipolar disorder need medical supervision to use light therapy.
What are the side effects of light therapy?
You may experience:
Can I use a tanning bed instead of light therapy to treat seasonal affective disorder (SAD)?
Don’t use tanning beds to treat SAD. Tanning beds do generate enough light, but they can cause other harm. They produce a high amount of UV rays that can hurt your skin and eyes.
What type of antidepressants can help with seasonal affective disorder (SAD)?
Medications called selective serotonin reuptake inhibitors (SSRIs) can treat SAD. They improve mood by regulating serotonin levels in your body.
Another approved antidepressant called bupropion comes as an extended-release tablet. It can prevent seasonal depression episodes when people take it daily from fall to early spring.
Can I prevent seasonal affective disorder (SAD)?
You may not be able to prevent the first episode of SAD. But once your provider has diagnosed you with seasonal depression, you can take steps to help keep it from coming back:
- Use your light box: Start using light therapy at the beginning of fall, before you feel SAD symptoms.
- Get out: Spend time outside every day, even if it’s cloudy. Daylight can help you feel better.
- Eat a well-balanced diet: Even though your body may crave starchy and sweet foods, stick to nutritious choices. A healthy diet with enough vitamins and mineralscan give you the energy you need.
- Exercise: Try to get 30 minutes of exercise, three times a week.
- See friends: Stay involved with your social circle and regular activities. They can provide support during the winter months.
- Find help: Consider seeing a mental health professional who’s trained in CBT. This treatment can be very effective for seasonal affective disorder.
- Consider medications: Talk to your healthcare provider about taking an antidepressant. Medications can help if your symptoms are severe or if they continue after other treatments. In some cases, taking the medication before SAD begins can prevent episodes.
Talk to your healthcare provider to find out if starting treatment early, as a preventive measure, is right for you.
What’s the outlook for people with seasonal affective disorder (SAD)?
The outlook is positive. Treatments are available for SAD. People who get the right diagnosis and combination of treatments can find relief from symptoms. Talk to your healthcare provider to figure out the treatment that will work best for you.
Can seasonal affective disorder (SAD) come back?
People who are prone to seasonal affective disorder can get it every year. But you can take steps to prevent or lessen symptoms.
How can I best take care of myself if I have seasonal affective disorder?
Talk to your healthcare provider. By planning ahead, you can manage your symptoms and feel your best.
- Stick to your treatment plan: If you have medications or a lamp for SAD, use them as directed. Follow up with your healthcare provider if you don’t see an improvement in your symptoms.
- Care for yourself: Eat a well-balanced diet. Get enough sleep. Exercise regularly. Try to manage stress, perhaps by talking to a counselor or therapist.
- Plan ahead: Make a plan for what you’ll do if your symptoms get worse. If you notice signs of depression, take action. It might help to plan a lot of activities during these months. Having a busy schedule keeps you from hunkering down at home.
- Start treatment early: Talk to your healthcare provider about preventive treatment. If you know your symptoms start in October, consider starting treatment in September.
- Isolate yourself: Being alone can make your symptoms worse. Even though you may not feel like going out or being social, try to reach out to friends and loved ones.
- Use alcohol or drugs: They might make symptoms worse. And they can interact negatively with antidepressants.
- Avery D. Seasonal affective disorder: Epidemiology, clinical features, assessment, and diagnosis. https://www.uptodate.com/contents/search. Accessed July 25, 2017.
- Seasonal affective disorder. National Institute of Mental Health. https://www.nimh.nih.gov/health/topics/seasonal-affective-disorder/index.shtml. Accessed July 25, 2017.
- Avery D. Seasonal affective disorder: Treatment. https://www.uptodate.com/contents/search. Accessed July 25, 2017.
- Seasonal affective disorder. American Academy of Family Physicians. https://familydoctor.org/condition/seasonal-affective-disorder/. Accessed July 25, 2017.
- Specifiers for depressive disorders: With seasonal pattern. In: Diagnostic and Statistical Manual of Mental Disorders DSM-5. 5th ed. Arlington, Va.: American Psychiatric Association; 2013. http://dsm.psychiatryonline.org. Accessed July 25, 2017.
- Seasonal affective disorder. American Psychological Association. http://www.apa.org/helpcenter/seasonal-affective-disorder.aspx. Accessed July 25, 2017.
- Seasonal affective disorder (SAD). American Psychiatric Association. https://www.psychiatry.org/patients-families/depression/seasonal-affective-disorder. Accessed July 25, 2017.
- Melrose S. Seasonal affective disorder: An overview of assessment and treatment approaches. Depression Research and Treatment. https://www.hindawi.com/journals/drt/2015/178564/. Accessed July 25, 2017.
- Magovern M, et al. Extended-release bupropion for preventing seasonal affective disorder in adults. American Family Physician. 2017;95:10.
- Meesters Y, et al. Seasonal affective disorder, winter type: Current insights and treatment options. Psychology Research and Behavior Management. 2016;9:317.
- Natural medicines in the clinical management of depression. Natural Medicines. https://naturalmedicines.therapeuticresearch.com. Accessed July 25, 2017.
- Natural Medicines. https://naturalmedicines.therapeuticresearch.com. Accessed July 25, 2017.
- Depression and complementary health approaches: What the science says. National Center for Complementary and Integrative Health. https://nccih.nih.gov/health/providers/digest/depression-science. Accessed July 25, 2017.
- Natural Medicines. https://naturalmedicines.therapeuticresearch.com. Accessed July 25, 2017.
- Asher GN, et al. Comparative benefits and harms of complementary and alternative medicine therapies for initial treatment of major depressive disorder: Systematic review and meta-analysis. The Journal of Alternative and Complementary Medicine. In press. Accessed July 25, 2017.