What is Seasonal Affective Disorder?

3 min read

Seasonal affective disorder is a type of depression that typically occurs during seasonal change. Usually, symptoms emerge in the autumn or winter months. In ten percent of cases, SAD can present during the spring/summer months.

SAD is thought to affect up to two million individuals in the UK and more than twelve million across Northern Europe. SAD is more prevalent in women and young adults between eighteen to thirty.

The symptoms of seasonal affective disorder

Symptoms can persist for around 4 to 5 months and include:

• Low mood

• Trouble sleeping and daytime fatique

• Loss of physical energy

• Difficulty concentrating

• Suicidal thoughts

• Changes to appetite leading to weight gain or in some cases weight loss

• Loss of interest in socialising

What causes seasonal affective disorder (SAD)?

The exact cause of SAD isn’t currently known. It is thought that several factors may contribute to the condition:

Reduced exposure to sunlight in winter and increased exposure in the spring and summer can affect the natural biological clock that regulates sleep, hormones and mood. Those suffering from SAD may be unable to regulate their natural biological clock, which is also known as the circadian rhythm.

Irregular serotonin and melatonin levels can disrupt the circadian rhythm. Serotonin affects mood and melatonin is the hormone we need to induce sleep.

Individuals with a family history of SAD and other mental health disorders, can be more susceptible to the condition.

How is seasonal affective disorder diagnosed?

Your GP will ask you questions about your difficulties and look for the following when trying to diagnose SAD.

A diagnosis of SAD requires the presence of depressive symptoms which have occurred only during a specific season for a minimum of two consecutive years.

If there have been only very minor changes to mood during a specific season, it may be that you have ‘subsyndromal’ seasonal affective disorder instead of SAD.

Can seasonal affective disorder be treated?

SAD is highly treatable and can be made more manageable with talking therapy (CBT) or anti-depressant medications. It is also thought that SAD can be helped with the following:

Vitamin D supplements; but it is unclear how effective they are for SAD until further research is done.

Light therapy; this involves using a certified light box for at least 30 minutes a day during the winter months to mimic natural daylight. There can be some side effects of this, so it is recommended that you speak with your GP first.

A dawn simulator uses a timer-activated light to replicate the sunrise, and can be used to stimulate the body’s circadian rhythm.

What else can help to reduce the symptoms of SAD?

The Seasonal Affective Disorder Association (SADA) suggest a number of ways to reduce the symptoms of SAD:

Stay active

It is thought that a 60 minute walk in the middle of the day could be as helpful as light therapy.

Get some fresh air

Being outside in natural daylight really helps: especially at midday. If you can’t get outside, sit near windows whenever you can and open them to let the fresh air energise you (if it is not too cold).

Keep warm

Being cold can maintain low mood. Studies have shown that staying warm can reduce depressive symptoms.

Layer up and aim to keep your home between 18C and 21C if possible. Warm food and drinks can help.

Eat a balanced diet

Balance your cravings for carbohydrates with plenty of fresh fruit and vegetables. Eating stodge can make us feel more sluggish and less motivated to be active.

Maintain your interests or learn a new hobby

An active mind can help us focus on living and engaging in the world around us. Learning something new can help with concentration and improve motivation.


Despite not feeling in the mood, making an effort to maintain contact with people you care about can improve how we feel.

Talk it through with a professional

Find out more about counselling and psychotherapy in Manchester, by reaching out to me today.