Seasonal Affective Disorder (SAD) is a type of depression that occurs at a specific time of year, usually during the winter months when daylight hours are shorter. It’s more than just the “winter blues”; SAD can significantly impact daily life and mental wellbeing.
SAD signs and symptoms
People with SAD may experience:
- Persistent low mood
- Loss of interest in everyday activities
- Irritability
- Feelings of despair, guilt, and worthlessness
- Lethargy and sleepiness during the day
- Sleeping longer than usual and finding it hard to get up in the morning
- Craving carbohydrates and gaining weight
These symptoms often begin in the autumn and continue through the winter months.
Seasonal Affective Disorder in the UK
Estimates of SAD prevalence in the UK vary. According to the Royal College of Psychiatrists, about 3 in every 100 people have significant winter depression.
Other sources suggest that around 1 in 15 people are affected each year.
Additionally, a survey conducted in 2021 found that 6.79% of respondents had been diagnosed with SAD, with a further 12.84% suspecting they may have the condition.
What causes SAD?
The precise cause of SAD is not completely understood, but it’s often linked to the reduced exposure to sunlight and vitamin D during the shorter days in autumn and winter.
The main theory – also referenced by the NHS – is that being exposed to less sunlight may stop a part of the brain (the hypothalamus) from working properly, which can impact:
- Melatonin production – melatonin is a hormone that makes you feel sleepy; in people with SAD, the body may produce it in higher-than-normal levels
- Serotonin production – serotonin is a hormone that affects your sleep, appetite and mood; a lack of sunlight may lead to lower serotonin levels, which is linked to feelings of depression
- Circadian rhythm (your body’s internal clock) – your body uses sunlight to time various important functions – for example, when you wake up, or start to feel tired later in the day – so lower light levels may interfere with your body clock and lead to symptoms of SAD
Common misconceptions
One common misconception is that SAD is simply “feeling a bit down” during the winter. In reality, it’s a recognised mental health disorder that can severely affect daily functioning.
Another misconception is that SAD only occurs in winter; however, a less common form, known as summer-pattern SAD, can occur during the summer months.
Treatment and management
The NHS recommends several approaches to manage SAD:
- Cognitive Behavioural Therapy (CBT): A type of talking therapy that helps people manage their problems by changing the way they think and behave.
- Antidepressant medication: Selective serotonin reuptake inhibitors (SSRIs) are commonly prescribed to treat SAD.
- Light therapy: Exposure to a lightbox that simulates sunlight can help alleviate symptoms, though its effectiveness is still under review.
In addition to these treatments, lifestyle measures can be beneficial:
- Maximise exposure to daylight: Spend time outdoors during daylight hours and keep indoor environments as light and airy as possible.
- Regular exercise: Physical activity can help relieve stress and anxiety, which can exacerbate SAD symptoms.
- Healthy diet: Eating a balanced diet can improve energy levels and overall wellbeing.
Managing your symptoms
If you suspect you have SAD, it’s important to speak to your GP for an accurate diagnosis and appropriate treatment plan. Early intervention can help manage symptoms effectively and improve quality of life during the challenging winter months.
