What is Seasonal Affective Disorder?

Credit: ITV News

As the Channel Islands enter the winter months, the amount of sunlight we see is decreasing as the sun starts to set earlier.

One thing islanders may experience due to the decreasing light is Seasonal Affective Disorder (SAD).

It is also known as "winter depression" because the symptoms are usually more apparent and more severe during the winter.

To help islanders, St John Ambulance have set up a loneliness helpline 'Caring Caller' to help those who may be lonely or socially isolated this winter.

But what is Seasonal Affective Disorder?


Symptoms of Seasonal Affective Disorder include:

  • a persistent low mood

  • a loss of pleasure or interest in normal everyday activities

  • irritability

  • feelings of despair, guilt and worthlessness

  • feeling lethargic (lacking in energy) and sleepy during the day

  • sleeping for longer than normal and finding it hard to get up in the morning

  • craving carbohydrates and gaining weight


The exact cause of SAD is not fully understood, but it is often linked to reduced exposure to sunlight during the shorter autumn and winter days.

It is thought that a lack of sunlight might stop the hypothalamus in the brain working properly.

This affects the production of melatonin, the production of serotonin and the body's internal clock.

How does Seasonal Affective Disorder impact the body?

What is the hypothalamus and what does it do?

The hypothalamus is an area of the brain that controls mood and appetite. It directly influences the autonomic nervous system and manages hormones.

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What is melatonin and what does it do?

Melatonin is a hormone that occurs naturally in your body.

It helps control your sleep patterns.

Melatonin is a hormone that makes you feel sleepy, so people with SAD may produce it in higher than normal levels.

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What is serotonin and what does it do?

Serotonin is a neurotransmitter, which means it is a chemical that carries signals between nerve cells in the brain.

It is thought to have a good influence on mood, emotion and sleep. 

Sunlight can boost the levels of serotonin in the body.

A lack of sunlight may lead to lower serotonin levels, which is linked to feelings of depression.

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How can I cope with Seasonal Affective Disorder?

  • Try to get as much natural light as possible

  • Make your home and office light and airy

  • You may find it helpful to use light therapy to help you wake up in the morning

  • Sit near a window in the office if possible

  • Take regular exercise, especially outdoors

  • Eat a healthy and balanced diet


If you think you may be experiencing Seasonal Affective Disorder, people are encouraged to visit their GP if they are struggling to cope and natural strategies have not helped symptoms.