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Seasonal affective disorder (SAD)

7-minute read

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Key facts

  • Seasonal affective disorder is a type of depression that comes at certain times of the year, usually in winter.
  • Seasonal affective disorder is very rare in Australia.
  • Symptoms can include lack of energy, overeating and sleeping too much.
  • It is thought to be caused by the changes in light exposure in different seasons.
  • Treatment includes antidepressant medicines, light therapy, vitamin D and counselling.

What is seasonal affective disorder?

Seasonal affective disorder is a type of depression that comes and goes according to the season. People with seasonal affective disorder experience symptoms of depression or mania at roughly the same time each year.

Seasonal affective disorder usually develops in autumn and winter and then disappears in spring and summer. In some people, the symptoms develop in spring and early summer.

What are the symptoms of seasonal affective disorder?

Symptoms of seasonal affective disorder in winter include:

Symptoms of seasonal affective disorder in summer include:

Symptoms usually start out mild and get worse as the season progresses. When the season changes, people normally become well again.

People with a mental health disorder might find that their symptoms change at different times of the year. For example, some people with depression or bipolar disorder find that their symptoms of depression get worse in different seasons.

CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.

What causes seasonal affective disorder?

The cause of seasonal affective disorder is not clear. It is thought to be caused by changes in light exposure, which lead to changes to the body’s circadian rhythms (its 'body clock'). At different times of the year, the body produces different amounts of melatonin and serotonin, which affect mood.

You are at higher risk of having seasonal affective disorder if you:

When should I see my doctor?

Seasonal affective disorder is very rare in Australia. If you have symptoms that don’t go away and are affecting your everyday life, it’s important to see a doctor. They can help you build a mental health care plan and refer you to a mental health professional if needed.

ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.

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How is seasonal affective disorder diagnosed?

Seasonal affective disorder can be difficult to diagnose, as it can be confused with other mental health conditions. You may not be diagnosed until you have experienced the same symptoms during winter for at least 2 years.

Your doctor ask questions about how you feel and how long you have been feeling that way. Your doctor may refer you for tests to rule out medical conditions that could be causing your symptoms.

How is seasonal affective disorder treated?

The first step of treating seasonal affective disorder is to talk to a doctor or a mental health professional.

Once you are diagnosed, treatment options can include:

It’s a good idea to make your house as light as possible during autumn and winter, and to sit close to windows as often as you can.

Getting outside as much as possible and exercising regularly can also help lift your mood and reduce symptoms of seasonal affective disorder.

Resources and support

There are Australian organisations that offer help and resources for people with depression.

If you need to speak with someone, you can call theses helplines for general mental health support.

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