Seasonal affective disorder (SAD)

The most common symptom of seasonal affective disorder (SAD) is depression that happens in the winter and goes away in the summer.

Seasonal affective disorder (SAD) is thought to be linked to reduced daylight in winter, and changes to brain chemicals and sleeping patterns.

Treatments for seasonal affective disorder (SAD) include antidepressants, talking therapies and light therapy.

You can help seasonal affective disorder (SAD) symptoms by going outside every day, exercising, and having a good sleep routine.

The main symptom of seasonal affective disorder (SAD) is depression that happens in the winter and goes away in the summer.

Some people have depression symptoms in summer instead, but this is less common.

Symptoms of seasonal affective disorder include:

• low mood
• a lack of interest in things you usually enjoy
• feeling guilty, hopeless or worthless
• feeling restless or irritable
• difficulty concentrating
• being more hungry and eating more than usual
• being more tired and sleeping more than usual
• thoughts of suicide or self-harm

Some people also have a period of feeling more energetic than usual at the start of spring or summer.

• you think you might have seasonal affective disorder (SAD)
• you’ve been diagnosed with seasonal affective disorder and treatment is not helping

It’s not known exactly what causes seasonal affective disorder (SAD), but it’s thought to be linked to reduced levels of daylight in winter.

This may cause changes to brain chemicals like melatonin and serotonin that affect your mood and your sleeping patterns (circadian rhythm).

If you see a GP about seasonal affective disorder (SAD) symptoms, they’ll usually ask about your moods and how they change over time. You may also be asked to fill in a questionnaire about your symptoms.

You may be diagnosed with seasonal affective disorder if you’ve had depression symptoms at a particular time of year for 2 years or longer.

Seasonal affective disorder can be difficult to deal with, but treatment can help manage your symptoms.

Treatments for seasonal affective disorder include:

• antidepressants
• talking therapies, such as cognitive behavioural therapy (CBT)
• light therapy

Many people need treatment every winter to stop symptoms from coming back.

Light therapy

Light therapy involves using a bright light, sometimes called a SAD lamp or light box, to simulate daylight in winter.

It’s not usually available on the NHS as there’s not enough evidence to tell whether it’s effective. But many people find it helps their symptoms.

Speak to a GP before trying light therapy. It might not be suitable if you have certain eye conditions or are taking some medicines that increase your sensitivity to light.

If you buy a light box or SAD lamp, make sure it's bright enough (10,000 lux is standard), UV-free and has a UKCA or CE mark. Follow the manufacturer’s instructions for using your light.

There are things you can do to help your seasonal affective disorder (SAD) symptoms.

• get as much natural daylight as you can – try to go outside in the daytime every day

• get regular exercise

• stay in contact with friends and family

• keep up with your usual activities

• try to go to bed and wake up at the same time every day

• do not drink too much alcohol or use illegal drugs

• do not use electronic devices, such as smartphones, right before going to bed

If you have seasonal affective disorder (SAD), you can get support from your GP. They'll also be able to give you information about local support services you may find helpful.

There are also national and local charities, such as Mind and Rethink Mental Illness, that can offer information and support.

Online or local support groups

There are charities that offer online or local support groups for anyone affected by seasonal affective disorder.

• How to find a support group (Mind)

Support for family, friends and carers

If you care for someone who has seasonal affective disorder, you can get advice and support from charities.

• How to help someone with seasonal affective disorder (Mind)
• Caring for someone else's mental health (Rethink Mental Illness)

More information and advice

You can read more information and advice about seasonal affective disorder on charity websites.

• Seasonal affective disorder (Mind)
• Mental health advice and information service (Rethink Mental Illness)