According to the Mental Health Foundation, 1 in 15 people in the UK are affected by seasonal affective disorder (SAD) between the months of September and April1. Although it can affect people all over the world, it’s extremely rare for those who live within 30 degrees of the equator to suffer from SAD due to the long daylight hours1. The onset of SAD is estimated to happen between the ages of 18 and 30 and is four times more common in women than it is in men2.
Although some individuals suffering from SAD experience only mild symptoms, it can be debilitating for others, with their work and personal lives being heavily affected.
The specific cause of SAD is unknown. However, the Mayo Clinic suggests that the following factors may play a part3:
- Circadian rhythm (your body clock). The decrease in sunlight during the winter may cause disruption to your body’s internal clock
- Serotonin levels. Serotonin is a brain chemical that affects mood. Reduced sunlight during the winter months may cause a drop in serotonin.
- Melatonin levels. Melatonin plays a role in sleep patterns and mood, and may be disrupted by a change of season.
Dr Wendy Li, Psychological Health Lead Clinician at AXA PPP healthcare, answers some frequently asked questions related to seasonal affective disorder.
What is seasonal affective disorder?
Seasonal affective disorder (SAD) is a type of depression that comes and goes in a seasonal pattern. This can also be known as ‘winter depression’ because symptoms can be more apparent during the winter months. However, an individual can experience SAD symptoms during the summer and feel better during the winter.
What are the symptoms of seasonal affective disorder?
Symptoms can include:
- Persistent low mood
- Loss of pleasure or interest in everyday activities
- Feeling irritable
- Feelings of despair
- Feelings of guilt or worthlessness
- Feeling low on energy and sleepy during the day or sleeping longer than normal
- Craving carbohydrates which may lead to weight gain