Seasonal Affective Disorder (SAD)
SAD is a type of depression with a particular pattern – it starts in the autumn or winter and stops in the spring and summer, regularly each year. For this reason it is sometimes called “recurrent winter depression”.
The exact cause of SAD is not fully understood, but it is thought to be linked to reduced exposure to sunlight during the shorter days of the year.
To find out more about SAD visit the NHS Choices page on SAD