A Guide To Getting Help For Your Seasonal Depression

Seasonal affective disorder (SAD) is also known as seasonal depression or the “winter blues.” It involves depressive symptoms that occur during particular seasons and is a subtype of major depressive disorder.

Many people can manage minor seasonal affective disorder symptoms at home, but severe cases require treatment from a trained healthcare professional. 

Have you considered clinical trials for Seasonal affective disorder (SAD)?

We make it easy for you to participate in a clinical trial for Seasonal affective disorder (SAD), and get access to the latest treatments not yet widely available - and be a part of finding a cure.

What is seasonal affective disorder?

SAD is a subtype of major depressive and bipolar disorders and affects about 5% of the US population.¹

Symptoms of SAD are caused by seasonal weather changes. Symptoms appear for approximately 40% of the year² and reoccur each year during the same season. SAD usually starts to present between October and November when the days become shorter and darker. Many experience symptoms of SAD throughout the winter until March or April.³ 

While seasonal affective disorder is most common in the winter months, about 10% of people diagnosed with SAD experience symptoms in summer⁴ instead.


The most common symptoms of seasonal affective disorder are feeling sad, having a low mood, and losing interest in things you previously found enjoyable. It is also quite common to feel fatigued or more tired than usual, even if you are sleeping enough. 

Other symptoms of SAD include: 

  • Change in appetite (such as increased appetite, especially for carbohydrates) 

  • Weight change (gaining weight is most common in winter)

  • Lack of energy

  • Difficulty concentrating or making decisions 

  • Changes in sleep such as oversleeping

  • Social withdrawal 

  • Feelings of hopelessness or worthlessness

  • Irritability or anxiety (more common with spring and summer onset SAD)

Risk factors

Risk factors for developing SAD include: 

  • Low levels of vitamin D

  • Young age (risk decreases for those aged over 50)

  • Female sex 

  • Living far from the equator 

  • Family history of SAD

  • Personal history of depressive or mood disorders


The exact cause of seasonal affective disorder is not known. However, it is thought to be at least in part due to a shift in circadian rhythm, an increase in melatonin production,⁵ and a reduction in vitamin D levels.

Increase in melatonin production

Increased melatonin production is associated with SAD. Melatonin is a hormone produced by the pineal gland in your brain which regulates sleep. 

As the production of melatonin is inhibited by light, it is usually only produced at night.

During the winter months, there is less sunlight compared to summer. The days become shorter and darker, which may cause your body to activate melatonin production even during the daytime. 

This extra melatonin production can cause sleepiness and fatigue during the day — a common symptom of seasonal affective disorder. 

Decrease in vitamin D

The primary source of vitamin D is sunlight. During the winter, there is less sunlight, which reduces vitamin D availability. Vitamin D is essential in the synthesis of a molecule called serotonin that is important for regulating your mood. If you do not have sufficient vitamin D to synthesize enough serotonin, you may experience problems with mood regulation, resulting in depressive symptoms of seasonal affective disorder. 

When to see a doctor

You should seek help from your doctor if you notice depressive symptoms starting to appear. This will allow you and your doctor to monitor your symptoms and create a treatment plan as soon as possible before symptoms worsen.

If your symptoms disappear at the end of the season — as they would with seasonal affective disorder — you should record if and when they return.

Keeping track of your symptoms will help your doctor to give you the right diagnosis and treatment.

If you are struggling with SAD or feel that your current treatment plan is not working for you, you should ask your doctor for more support or to change your treatment. It is important to see a doctor if your symptoms are negatively impacting your quality of life and well-being. 


Your doctor will ask you questions about the types, intensity, and duration of your symptoms to determine if you meet the criteria for major depressive disorder.

Seasonal affective disorder is now labeled in the DSM-5 as a major depressive disorder with seasonal patterns. 

You will not be diagnosed with SAD during the first season³ you experience symptoms, as the criteria for diagnosis requires at least two consecutive years of depressive symptoms during a particular season with full remission in between. 

To diagnose seasonal affective disorder, your doctor may perform several tests, including a blood test and a physical exam, to rule out any underlying health issues that may be causing depressive symptoms. 


Once you have been diagnosed, your doctor will provide you with a treatment plan to meet your specific needs. Treatment may include antidepressant medication, cognitive behavioral therapy (CBT), seeing a psychologist, or at-home treatments such as light therapy. 

Selective serotonin reuptake inhibitors (SSRIs)

SSRIs are a type of antidepressant medication that help to restore levels of serotonin in order to improve your mood, sleep, and overall well-being. 

SSRIs may help to relieve depressive symptoms caused by lower levels of serotonin. With SAD, low levels of serotonin may be caused by reduced sunlight. 

Some of the SSRIs approved by the FDA for treating depressive symptoms are: 

  • Citalopram

  • Escitalopram

  • Fluoxetine (Prozac)

  • Sertraline

  • Paroxetine

Antidepressants sometimes cause negative side effects which vary depending on the specific medication. Make sure to discuss any side effects with your doctor if you are considering taking medication. Other classes of antidepressants may also be used to treat seasonal affective disorder, depending on your specific needs and symptoms.

Cognitive behavioral therapy (CBT)

CBT involves working with a trained therapist to change your thought and behavioral patterns in order to overcome depressive symptoms. 

During CBT, you will learn to relax your mind and body, develop problem-solving skills, and gain confidence in your ability to navigate tough experiences. CBT has been proven to help reduce symptoms of depression and improve overall well-being. It can be used alongside all other forms of treatment as a complementary therapy.


Some people who experience seasonal affective disorder benefit from regular appointments with a psychologist or other therapist to work through their depressive symptoms and learn coping techniques. There are various styles of therapy that are available in-person or online to help you find the right support. 

At-home treatments

Light therapy

Light therapy has been used to treat depressive symptoms of seasonal affective disorder since the 1980s. It involves the use of light boxes that mimic morning sunlight in order to regulate circadian rhythm and temporarily halt the production of melatonin.⁵ These light boxes should be used for 30 minutes in the morning.

Some medications can increase your sensitivity to light. Make sure to discuss with your doctor any medications you are taking before starting light therapy. 

Use the following table as a guide for finding the best light box to help treat your seasonal affective disorder

Light therapy has very few side effects. Any side effects you experience are typically minor and tend to disappear after a few days of use. Using the light box at the same time every day (usually in the morning around 9 am) can help to minimize the development of any side effects, regulate your sleep cycle, and ease symptoms of SAD.

Light therapy is safe to use in combination with antidepressant medication. It is also safe if you cannot be prescribed antidepressants, such as if you are pregnant and breastfeeding, or aged under 18.

Keep a regular sleep schedule

Going to sleep and waking up at the same time each day helps to regulate your circadian rhythm and may assist in relieving symptoms of SAD. If you find it hard to go to bed at the same time every night, aim to wake up at the same time every morning. 

Exercise regularly

Regular exercise has been shown to improve mood and depressive symptoms.⁶ If you have SAD, you may benefit from adding exercise to your daily routine.

Maintain a healthy diet 

Regularly consuming highly processed foods has been shown to increase⁷ the likelihood of developing mood disorders such as depression

Try to consume more:

  • Fruits and vegetables 

  • Fish, flax, or hemp seeds that are high in omega-3 fatty acids

  • Whole grain foods 

  • Foods and beverages high in antioxidants

Plan ahead

If you know that you tend to experience depressive symptoms during an upcoming season, implement at-home treatment tips early in order to prevent or minimize the onset of SAD symptoms. For instance, you could start exercising more or using your light box a few weeks before you expect symptoms to start.

The lowdown

Seasonal affective disorder primarily occurs in the winter and may be caused by a disruption to your circadian rhythm and melatonin and serotonin production. 

Doctors and psychologists can provide support and treatment for SAD, such as medication or psychotherapy. 

There are also treatments you can try at home, such as light therapy, exercising regularly, and eating a healthy, balanced diet.

If you experience depressive symptoms that are reoccurring or causing you distress, you should contact your doctor for support.

Have you considered clinical trials for Seasonal affective disorder (SAD)?

We make it easy for you to participate in a clinical trial for Seasonal affective disorder (SAD), and get access to the latest treatments not yet widely available - and be a part of finding a cure.

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