It’s normal to feel sad or down from time to time. However, if these feelings persist for weeks or months, it could be a sign of seasonal affective disorder (SAD). SAD is a type of depression that occurs during the same season each year, typically fall or winter. Here’s what you need to know about how long it’s normal to feel sad vs. when it may be SAD.
What is Seasonal Affective Disorder (SAD)?
Seasonal affective disorder (SAD) is a type of depression that comes and goes in a seasonal pattern. SAD most commonly occurs in the fall and winter months, when there is less natural sunlight. Symptoms typically start in the late fall or early winter and go away during the spring and summer.
To be diagnosed with SAD, you must meet the following criteria:
- Depressed mood and/or loss of interest in usual activities, along with at least four of the following symptoms:
- Changes in appetite and/or weight
- Sleep disturbances (sleeping too much or too little)
- Low energy
- Feelings of worthlessness or guilt
- Difficulty concentrating
- Suicidal thoughts
- Symptoms start and end around the same time every year for at least 2 years. They typically begin in fall or winter and remit in spring or summer.
- These seasonal mood changes are more severe than fluctuations that many people experience normally throughout the year.
- Seasonal symptoms significantly impair your ability to function at work, socially, or in other areas during the period when they are present.
SAD is sometimes referred to as the “winter blues” or winter depression. However, SAD is more severe and impairing than simply feeling down when the days get shorter and colder. It’s a form of clinical depression that requires treatment.
What Causes SAD?
The exact causes of SAD are still being researched, but these key factors are believed to play a role:
- Reduced sunlight in fall and winter – Less natural sunlight exposure can disrupt your body’s internal clock and lead to feelings of depression. Sunlight helps regulate serotonin and melatonin levels in the brain, which affect mood.
- Melatonin imbalance – The change in seasons can throw off the balance of melatonin, a sleep-related hormone, causing feelings of sleepiness and lethargy.
- Serotonin deficiency – Reduced sunlight in fall and winter can cause a dip in serotonin, a neurotransmitter that regulates mood.
In addition, some people may be biologically more vulnerable to SAD due to genetic factors that make them sensitive to seasonal light changes. Stress, vitamin D deficiency, and inactivity during the winter months may also increase SAD risk.
SAD Symptoms
The most common symptoms of seasonal affective disorder include:
- Feeling depressed, sad, down, or hopeless nearly every day
- Losing interest in activities you used to enjoy
- Low energy and increased fatigue despite excessive sleep
- Sleep disturbances – sleeping too much or trouble staying asleep
- Significant weight gain or increase in appetite
- Difficulty concentrating or making decisions
- Feelings of agitation or slowed movements
- Feelings of worthlessness, guilt, or work-related anxiety
- Suicidal thoughts in severe cases
These symptoms start in the late fall or early winter months and typically resolve by summer. Some people with winter-pattern SAD can experience atypical symptoms like hypersomnia (excessive sleepiness), increased appetite, and weight gain. People with summer-pattern SAD may have trouble sleeping, weight loss, poor appetite, and agitation. SAD symptoms are recurrent, occurring during the same season each year.
SAD vs. Feeling Down
It’s normal for your mood and energy levels to fluctuate throughout the year. Many people feel a bit down when the days get shorter and colder in the winter. However, there’s a difference between normal “winter blues” and seasonal depression:
| Normal Winter Blues | Seasonal Affective Disorder (SAD) |
|---|---|
| Lasts for short periods | Persists most of the day, nearly every day |
| Doesn’t significantly affect your work, social life, or relationships | Impairs your ability to function |
| Doesn’t require treatment | Requires treatment to relieve symptoms |
The winter blues are usually mild, short-lived drops in mood that most people adjust to on their own. SAD causes more severe symptoms that can disrupt your ability to work, go to school, and manage daily tasks. The symptoms take a real toll on your functioning and relationships.
When to Seek Help
It’s normal for your mood to dip sometimes when seasons change or daylight decreases. However, if sad or depressed feelings persist most of the day, nearly every day for weeks at a time, it may be SAD. Seek help from a doctor or mental health professional if you experience the following:
- Depressed mood plus four or more of the symptoms listed above for most of the day, nearly every day, for at least two weeks
- Recurring seasonal symptoms that consistently appear around the same time each year
- Inability to function normally at school, work, or in social settings due to symptoms
- Thoughts of death or suicide
Don’t brush off recurring seasonal depression as laziness or a phase. Talk to your doctor if wintertime blues repeatedly get in the way of your life. With proper treatment, you can manage SAD symptoms and regain your mental well-being.
SAD Diagnosis and Treatment
If you think you may have SAD, visit your doctor or mental health professional. Be prepared to discuss your symptoms, including when they started and how long they last each season. Keeping a mood journal for a few months can help identify any seasonal patterns.
To diagnose SAD, your doctor will ask about your symptoms and medical history. No lab tests are required to confirm SAD, but blood work may be done to rule out other causes like thyroid disorders. You may be referred to a psychiatrist or psychologist for evaluation and treatment. Treatment options for SAD include:
- Light therapy – Daily exposure to a special light box that emits bright light can suppress melatonin, boost serotonin, and shift circadian rhythms.
- Psychotherapy – Talk therapy helps patients better understand SAD and develop coping strategies.
- Antidepressants – SSRI or bupropion prescribing during active SAD months may relieve symptoms.
- Vitamin D – Supplements can make up for sunshine deficiency in winter months.
- Exercise and outdoor activity – Being active and getting natural daylight can improve mood.
Most people with SAD start to feel relief of symptoms within a few weeks of consistent treatment. A combination approach of light therapy, psychotherapy, and/or medication generally provides the best results.
Coping with Seasonal Depression
In addition to professional SAD treatment, making certain lifestyle adjustments can help you manage seasonal depression on your own:
- Spend time outdoors in natural sunlight when possible
- Exercise regularly – at least 20-30 minutes per day
- Maintain a healthy sleep routine
- Eat a balanced, nutritious diet
- Practice stress management and relaxation techniques
- Set manageable goals to stay productive
- Socialize and avoid isolation
- Try a sun lamp for light therapy at home
With commitment to treatment and a few coping strategies, most people with SAD can feel like themselves again once the season changes. Don’t hesitate to get professional help if seasonal depression keeps interfering with your life.
Preventing Seasonal Affective Disorder
Experiencing SAD once doesn’t necessarily mean you’ll get it every year. But if you’ve had recurring major depression that correlates with the seasons, there are some things you can do to try to prevent SAD episodes:
- Talk to your doctor in early fall about starting light therapy or antidepressants before symptoms begin
- Be consistent with light therapy, ideally once per day
- Manage stress proactively and make time to unwind
- Eat a nutrient-rich diet and take vitamin D supplements
- Exercise regularly to increase endorphins
- Wake up at a consistent time each morning
- Spend time outside when possible
- Set realistic goals and break up big tasks
- Plan social activities even when you don’t feel like it
Making sustainable lifestyle changes and sticking to a daily routine can lessen the impacts of seasons on your mood. Stay in touch with loved ones and ask for help when you need it. Addressing seasonal depression proactively reduces the likelihood of going through debilitating episodes year after year.
The Takeaway
It’s normal to feel a little down when the weather gets colder and days become shorter. But if depressed mood and other symptoms persist day after day and impair functioning, it could be seasonal affective disorder (SAD). Don’t ignore recurring seasonal depression that disrupts work, school, and relationships. See a doctor to discuss treatment options like light therapy, medication, vitamin D, and psychotherapy. With consistent treatment and healthy lifestyle habits, you can overcome seasonal depressive symptoms and feel like yourself again.