What is it?
Seasonal affective disorder (also called SAD) is a type of depression that occurs at the same time every year. If you're like most people with seasonal affective disorder, your symptoms start in the fall and may continue into the winter months, sapping your energy and making you feel moody. Less often, seasonal affective disorder causes depression in the spring or early summer.
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 — you may have seasonal affective disorder. Treatment for seasonal affective disorder includes light therapy (phototherapy), psychotherapy and medications. Addressing the problem can help you keep your mood and motivation steady throughout the year.
Seasonal affective disorder is a cyclic, seasonal condition. This means that signs and symptoms come back and go away at the same time every year. Usually, seasonal affective disorder symptoms appear during late fall or early winter and go away during the sunnier days of spring and summer. Some people have the opposite pattern and become depressed with the onset of spring or summer. In either case, problems may start out mild and become more severe as the season progresses.
Autumn and winter seasonal affective disorder (winter depression)Winter-onset seasonal affective disorder symptoms include:
- Loss of energy
- Social withdrawal
- Loss of interest in activities you once enjoyed
- Appetite changes, especially a craving for foods high in carbohydrates
- Weight gain
- Difficulty concentrating and processing information
Spring and summer seasonal affective disorder (summer depression)Summer-onset seasonal affective disorder symptoms include:
- Trouble sleeping (insomnia)
- Weight loss
- Poor appetite
- Increased sex drive
Reverse seasonal affective disorder
In some people, spring and summer can bring on symptoms of mania or a less intense form of mania (hypomania). These can include elevated mood, agitation, and rapid thoughts and speech. Reverse seasonal affective disorder is a form of bipolar disorder.
Signs and symptoms of reverse seasonal affective disorder include:
- Persistently elevated mood
- Increased social activity
- Unbridled enthusiasm out of proportion to the situation
The specific cause of seasonal affective disorder remains unknown. It's likely, as with many mental health conditions, that genetics, age and, perhaps most importantly, your body's natural chemical makeup all play a role in developing the condition. A few specific factors that may come into play include:
- Your biological clock (circadian rhythm). The reduced level of sunlight in fall and winter may disrupt your body's internal clock, which lets you know when you should sleep or be awake. This disruption of your circadian rhythm may lead to feelings of depression.
- Melatonin levels. The change in season can disrupt the balance of the natural hormone melatonin, which plays a role in sleep patterns and mood. Talk to your doctor to see whether taking melatonin supplements is a good option.
- Serotonin levels. A drop in serotonin, a brain chemical (neurotransmitter) that affects mood, might play a role in seasonal affective disorder. Reduced sunlight can cause a drop in serotonin, perhaps leading to depression.
Factors that may increase your risk of seasonal affective disorder include:
- Being female. Some studies show that seasonal affective disorder is diagnosed more often in women than in men, but that men may have more-severe symptoms.
- Living far from the equator. Seasonal affective disorder 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 the longer days of summer.
- Family history. As with other types of depression, some studies have shown that people with seasonal affective disorder are more likely to have blood relatives with the condition.
Take signs and symptoms of seasonal affective disorder seriously. As with other types of depression, seasonal affective disorder can worsen 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 seasonal affective disorder is diagnosed and treated before symptoms get bad.
To help diagnose seasonal affective disorder, your doctor or mental health provider will do a thorough evaluation, which generally includes:
- Detailed questions. Your doctor or mental health provider may ask about your mood, seasonal changes in your thoughts and behavior, your lifestyle and social situation, and sleeping and eating patterns, for example. You may also fill out psychological questionnaires.
- Physical exam. Your doctor or mental health provider may do a physical examination to check for any underlying physical issues that could be linked to your depression.
- Medical tests. There's no medical test for seasonal affective disorder, but if your doctor suspects a physical condition may be causing or worsening your depression, you may need blood tests or other tests to rule out an underlying problem.
Seasonal affective disorder is considered a subtype of depression or bipolar disorder. Even with a thorough evaluation, it can sometimes be difficult for your doctor or mental health provider to diagnose seasonal affective disorder because other types of depression or mental health conditions may mimic seasonal affective disorder.
To be diagnosed with seasonal affective disorder, you must meet criteria spelled out in the Diagnostic and Statistical Manual of Mental Disorders (DSM). This manual is published by the American Psychiatric Association and is used by mental health professionals to diagnose mental conditions and by insurance companies to reimburse for treatment.
The following criteria must be met for a diagnosis of seasonal affective disorder:
- You've experienced depression and other symptoms for at least two consecutive years, during the same season every year.
- The periods of depression have been followed by periods without depression.
- There are no other explanations for the changes in your mood or behavior.