Seasonal affective disorder (SAD)

If your sleep patterns, appetite and mood change with the seasons, you may have a form of depression called seasonal affective disorder (SAD). You’ll usually have symptoms in the winter months (September to April) although some people experience SAD in the summer months.

SAD affects around two in every 100 adults in the UK.

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What does seasonal affective disorder feel like?

If you have SAD you may:

  • feel very low or sad
  • lose interest in your usual activities
  • find it difficult to concentrate
  • have low energy levels and feel tired a lot
  • find it difficult to wake up in the morning
  • need more sleep, and sleep more than usual
  • eat more than usual, especially craving carbohydrates, which can make you gain weight
  • lose interest in sex (loss of libido)
  • experience symptoms of anxiety
  • experience mood swings during the months you don’t usually have symptoms of SAD
  • have some physical symptoms, such as headaches, palpitations (being aware of your own heartbeat) and aches and pains

Symptoms may start as autumn sets in and daylight decreases – and disappear in the spring as the amount of daylight increases again. For some people they may start in spring and disappear in the winter months.

What makes people more likely to develop seasonal affective disorder?

It isn’t clear why some people are more prone to SAD. We do know that:

  • you may more likely to develop SAD if one of your parents, siblings or children has the condition
  • your risk of developing SAD may be related to how your body responds to changes in daylight during the autumn and winter
  • you're more likely to have SAD if you live further away from the equator where there are very few daylight hours during winter
  • people with SAD may also have a problem with their production of certain brain chemicals and hormones (serotonin and melatonin)

What treatments are available for seasonal affective disorder?

SAD is usually treated in the same way as depression.

  • Self-help – for example exercise, spending more time outside, working near natural light, relaxation and eating a balanced diet.
  • Light therapy – exposure to a bright artificial light to make up for the shortage of natural daylight.
  • Talking therapies – usually cognitive behavioural therapy (CBT).
  • Medication – see our info on antidepressants.

For more information on treatments, see our information on common treatments and support. We also have more detailed information on seasonal affective disorder.

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    • Seasonal affective disorder. PatientPlus., reviewed 12 September 2013
    • Mental health. Oxford Handbook of General Practice (online). Oxford Medicine Online., published April 2014
    • Seasonal affective disorder. BMJ Best Practice., reviewed 30 March 2015
    • Kurlansik S, Ibay A. Seasonal Affective Disorder. Am Fam Physician 2012; 86:1037–41
    • Depression treatment and management: Bright-light therapy. Medscape., reviewed 21 July 2015
    • Seasonal affective disorder. Royal College of Psychiatrists., accessed 4 November 2015
    • Depressive illness. Oxford Handbook of Psychiatry (online)., published March 2013
    • Cognitive Behavioural Therapy. Royal College of Psychiatrists., accessed 4 November 2015
    • Cognitive and Behavioural Therapies. PatientPlus., reviewed 2 April 2014
    • Gupta A, Sharma PK, Garg VK, et al. Role of serotonin in seasonal affective disorder. Eur Rev Med Pharmacol Sci 2013; 17(1): 49–55.
    • Depression in adults: recognition and management. National Institute for Health and Care Excellence (NICE), October 2009.
    • Depression. NICE Clinical Knowledge Summaries., published October 2015
  • Produced by Clare Foster, freelance health editor, and Nick Ridgman, Head of Health Content, Bupa UK, September 2017
    Next review due September 2020

    Bupa UK expert reviewers:

    • Naomi Humber, Psychology Services Manager, EAP
    • Stuart Haydock, Resilience Lead, Health Clinics
    • Sarah Deedat, Head of Behaviour Change

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