Seasonal Affective Disorder (SAD)

What is Seasonal Affective Disorder (SAD)

Seasonal affective (or mood) disorder (SAD) is a type of depression with a seasonal pattern, occurring at the same time each year, most commonly in winter. Mild forms of SAD are commonly called ‘winter blues.’

The symptoms of SAD can vary from person to person, and are similar to those in other types of depression. Common symptoms include:

• Difficulty waking up in the morning
• Decreased energy/lethargy craving for sweet and starchy foods (carbohydrates) leading to weight gain
• Increased appetite
• Increased sleep
• Difficulty concentrating
• Decreased in interest in sex (libido)
• Withdrawal from family and friends
• Depression, anxiety and irritability

How Common is Seasonal Affective Disorder?

It is thought that 3-6% of people in the UK are thought to experience SAD. It is thought that perhaps as many as 12-13% of people, experience “winter blues”. SAD is less common in countries near to the equator where the hours of sunlight are more constant and bright throughout the year. It is reported that SAD affects four times as many women as men and usually first begins between the ages of 20 to 30, although it can develop at any age.

What Causes Seasonal Affective Disorder? 

The exact cause of SAD isn’t fully understood. The amount of sunlight affects the number of nerve messages, which you send from the eyes to certain parts of the brain. The activity of nerve messages caused by sunlight affects the level of brain chemicals (such as serotonin) and hormones (such as melatonin). These chemicals and hormones affect your mood.  With less sunlight during the winter months, changes in the balance of these chemicals and hormones may trigger depression.