What You Need To Know About Seasonal Affective Disorder (SAD)

What is seasonal affective disorder (SAD)?

Seasonal affective disorder (SAD) is also known as seasonal depression. This type of depression is thought to be influenced by shorter days and reduced sunlight exposure.

Most people with SAD experience symptoms during fall and winter and find they disappear in the spring and summer months. Rarely, people experience the opposite pattern (summer-onset SAD), with symptoms occurring during the spring and summer and resolving in the fall and winter.

If you experience SAD, there are practical steps you can take to seek support and treatment, manage your symptoms, and improve your quality of life.


Seasonal affective disorder symptoms vary from person to person. Many people find symptoms are mild in early fall and worsen to moderate or severe throughout winter as the days get shorter and colder.

Common SAD symptoms include:

  • Feeling down more often than not

  • Feeling lethargic or having low energy

  • Being uninterested in activities you usually enjoy

  • Sleeping more than usual

  • Difficulty concentrating

  • Feeling helpless, guilty, or unlovable

  • Overeating or binge-eating, especially carbohydrate-rich foods

  • Heaviness in your limbs

  • Having thoughts of self-harm

Summer-onset SAD may have a different pattern of symptoms, including:

  • Difficulty sleeping (insomnia)

  • Weight loss

  • Loss of appetite

  • Anxiety or agitation

  • Irritability or rage

Potential complications

You should take SAD symptoms seriously and seek professional help, even if they come and go. Like other mental health conditions, SAD can get worse over time and lead to more serious problems if left untreated. Potential complications include

  • Substance abuse

  • Issues in your professional life (work or school)

  • Problems in your personal life

  • Withdrawing from friends and family

  • Other mental health problems, such as anxiety

  • Self-harm or suicide


Research has identified several potential causes of seasonal affective disorder:

Circadian rhythm

During the fall and winter months, reduced exposure to natural sunlight could alter your circadian rhythm (your internal body clock), which could make you feel sad more often.


When the seasons change, so does the amount of melatonin in your body. This can disrupt your sleep pattern and impact your mood.


Your body’s serotonin levels may drop with less sunlight exposure, which can impact the way you feel and lower your mood.

Vitamin D levels

You get vitamin D from the food you eat and exposure to sunlight. When the days get shorter and darker, your vitamin D levels may drop, which could lower your mood.

Common risk factors

SAD can affect anyone, regardless of age or medical history. However, certain factors can increase the likelihood of SAD symptoms. These include:

Family history

You're more likely to experience SAD if depression runs in your family.


Women are more likely to experience SAD than men.


SAD affects more young people than older people.


You're more likely to experience SAD if you live somewhere with short winter days and lots of cloud cover.

Other mental health conditions

If you have been diagnosed with clinical depression or bipolar disorder, your risk of SAD may be higher.

Low vitamin D

Vitamin D¹ deficiency has been associated with symptoms of depression.


Speak to your doctor about your symptoms — this is the best way to get an accurate diagnosis. An assessment for SAD is likely to include:

Medical history and physical examination

Your doctor will look at your medical history and carry out a physical examination to rule out if another condition is causing SAD symptoms.

Lab tests

Your doctor may check your full blood count and thyroid function and test the iron, B12, and vitamin D levels in your blood. This is to rule out any abnormalities that could be causing your symptoms.

Mental health assessment

Your doctor will want to understand your mental health history and recent experiences. They may ask you to describe thoughts or feelings you’re having now or in the past. They may also ask about your behaviors, personal history, and background. This will help them rule out other mental health conditions, such as bipolar disorder.


When you are diagnosed with seasonal affective disorder, your doctor can help create a personalized treatment plan to help manage your symptoms. Common treatments for SAD include:


Also known as talk therapy, psychotherapy involves learning:

  • How to minimize stress

  • Coping mechanisms to help you in day-to-day life

  • How to identify thoughts and actions that might make you feel worse

  • The importance of healthy behaviors (like exercising and socializing)

Cognitive behavioral therapy (CBT) can give you tools to identify and change negative thoughts and behavioral patterns that are common in SAD.


If your SAD symptoms are moderate to severe, medication could help you feel better. Work closely with your doctor to find a medication that is safe and effective for you. Selective serotonin reuptake inhibitors (SSRIs), a type of antidepressant, are a common SAD treatment.

Light therapy

Light therapy¹, also known as phototherapy, has been used to treat SAD since the 1980s. It makes up for reduced light exposure during the winter months. The treatment is thought to boost mood by influencing your circadian rhythm and the chemicals in your brain linked to mood.

With this type of therapy, you will sit in front of a special light box every day to increase your light exposure. The light boxes are 10,000 lux, which is around 20 times brighter than ordinary indoor lighting. They are designed to filter harmful ultraviolet light, making them a safe treatment option for most. Exposure first thing in the morning for 30–45 minutes is usually recommended, and this should be part of your daily routine from fall to spring.

Light therapy may not suit everyone, particularly if you are light-sensitive or have an eye disease, diabetes, or bipolar disorder.

You should use light therapy under medical supervision. Discuss your suitability with your doctor, and ask them to recommend a safe and effective light box and treatment plan for you.

Managing seasonal affective disorder at home

There are steps you can take at home to minimize your symptoms and improve your quality of life throughout the year, such as:

Prioritize natural light

Let as much sunshine as possible enter your home. Don’t place bulky furniture or heavy curtains in front of your windows, and while you work, try sitting by a window with open blinds.

Stay active

Regular activity and exercise can help maintain your mood. You don’t need to exercise strenuously — simply take a walk in the park, go for a gentle swim, or do 20 minutes of yoga 3–4 times a week.

Spend time outdoors

Taking a walk with your pet, eating lunch at the park, or sitting in the sun for a few minutes each day is a great way to improve your mood and boost your vitamin D levels.

Improve your sleep routine

Try to go to sleep and wake up at the same time each day to help you get high-quality rest. If you're having difficulty falling asleep or waking up, try to stop taking afternoon naps and limit your caffeine intake.

Find a support system

Talk to a friend or family member about how you're feeling and let them know when socializing is difficult. Having someone who understands your challenges can encourage you to overcome them, and they can help you manage daily tasks when you’re struggling.


Changing your location can help ease your SAD symptoms. If you live somewhere with a particularly long or cold winter, consider taking a trip somewhere warm and sunny. If your SAD symptoms worsen in summer, take a trip somewhere cooler.

Practice self-care

Find activities that make you feel good and make time for them regularly, like getting a massage, practicing breathing techniques, or keeping a gratitude journal.

Stick to your treatment plan

Follow your doctor’s treatment plan carefully. If they have recommended ways to manage your symptoms, such as taking antidepressants or using light therapy, stick to the plan. Raise any questions or concerns with your doctor and tell them if you have side effects.

  1. What is seasonal affective disorder? | National Institute of Mental Health


There are steps you can take to minimize SAD symptoms and make them more manageable. The best way to combat your symptoms, including mood swings, low energy, and appetite changes, is to prepare for them before the seasons change. Recognizing your triggers and what helps you manage them is an effective way to keep your SAD under control throughout fall and winter.

Here are some tips to help you address your SAD symptoms:

  • Pay attention to your SAD triggers

  • See a therapist to discuss your triggers and learn coping mechanisms

  • Stay connected with friends and family to combat social withdrawal

  • Stick to a regular sleep and exercise routine

  • Regularly check in with your mental health professional to review your treatment plan

Doctors & specialists

If you have symptoms and believe you might have SAD, make an appointment to see your doctor. Prepare in advance for your appointment and be aware of the questions they may ask you. These include:

  • What are your symptoms?

  • When did you first notice your symptoms?

  • Do your symptoms occur occasionally or all the time?

  • Does anything make your symptoms better?

  • Does anything make your symptoms worse?

  • How do your symptoms affect your daily life?

  • What other physical and/or emotional conditions do you have?

  • What is your family medical history?

  • Do you smoke, use drugs, or drink alcohol?

  • What medications are you currently taking?

Give your doctor as much information as possible to help them make a diagnosis and create an effective treatment plan. They will work with you collaboratively to identify your early warning signs, triggers, and typical symptom patterns.

Your doctor may refer you to a psychiatrist who can diagnose SAD and prescribe medications to treat it, such as antidepressants. Your doctor or psychiatrist may refer you to a therapist for treatments like CBT.

When to see a doctor

If you struggle with SAD symptoms every year, don't wait until fall arrives to talk to your doctor. Getting support early is beneficial, and you will have time to come up with a personalized treatment plan and address your symptoms before they begin.

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