Seasonal affective disorder - Introduction

Seasonal Affective Disorder (SAD) is a type of depression that has a seasonal pattern. It is characterised by episodes of depression that recur at the same time each year.

SAD is sometimes known as 'winter depression' because the symptoms are more apparent during the winter.

As with other kinds of depression, two of the main symptoms of SAD are a low mood and a loss of interest in ordinary things. Other symptoms of SAD include:

• being less active
• putting on weight
• sleeping more

SAD affects people mostly in the winter

As SAD most commonly happens in winter, the symptoms are worse in the winter months. SAD sometimes affects people in the summer, although this is rare.

The symptoms of SAD often start as the days begin to get shorter in the autumn. They are worst during December, January, and February. For most people with SAD, the symptoms start to improve by spring time, then disappear.

How common is SAD?

In the UK, it is thought that SAD affects around 7% of people. It tends to affect mainly younger people, especially those in their twenties. Depression in general affects twice as many women as men. This figure is likely to be the same for SAD.

Outlook

Like any type of depression, SAD can be a difficult condition to live with. Symptoms can make you feel tired, stressed and unhappy. However, a number of treatments and medications are available, including:

• light therapy: treatment with bright light
• talking therapies: such as cognitive behavioural therapy (CBT)
• antidepressants: medication to treat depression