Seasonal affective disorder - SAD

Many people can experience low periods during the autumn and winter months which coincides with daylight hours becoming shorter. However, for some people, these feelings can develop into seasonal affective disorder (SAD), a type of depression that affects people due to reduced daylight.

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SAD primarily occurs during December, January and February. A milder condition which causes discomfort but not as severe suffering is known as subsyndromal SAD or 'winter blues'. SAD affects around half a million people in the UK.  Although it can happen at any stage in life, it occurs more often in people aged between 18 and 30 and is more common amongst women. Notably, it occurs throughout the northern and southern hemispheres but is extremely rare in those living within 30 degrees of the Equator, where daylight hours are long, constant and extremely bright.

What are the symptoms of seasonal affective disorder SAD-

Symptoms can vary between sufferers and are similar to those associated with other types of depression. Diagnosis is generally made after these have continued for three or more consecutive years. Typical symptoms recur every autumn and winter, with the most common including:

  • Feeling low or depressed for most of the day
  • Irritability
  • Sleep problems - requiring more than usual
  • Lethargy
  • Overeating
  • Anxiety
  • Mood swings
  • Periods of Hypomania (over activity) during spring and summer
  • Loss of Libido
  • Weakened immune system during winter

Such symptoms disappear in spring, often suddenly with a short period of hypomania or hyperactivity. Sometimes the symptoms disappear more gradually depending on the sunlight intensity. SAD can become seriously disabling, preventing some people from functioning normally and needing continuous medical treatment.

What causes seasonal affective disorder SAD?-

alcohol addiction quoteSAD is caused by a biochemical imbalance in a part of the brain called the hypothalamus which controls mood, appetite and sleep. This is thought to be induced by the shortening of daylight hours and the lack of sunlight in winter. Sufferers seem to react to the decrease in light by secreting less serotonin. This is a chemical in the brain which is found to 'lift' your mood. It is thought that people with SAD may have abnormally low levels of chemicals such as serotonin in winter and more of a hormone called melatonin, which slows down the body clock and affects sleeping patterns and your mood.

Care and management of SAD-

Medicines which suppress the secretion of melatonin have been found not to stop the symptoms of SAD, so this is clearly not the only factor. If you have a close relative with SAD, you may be more likely to develop it yourself. Treatments available for SAD include:

Light therapy-

This is an effective treatment for around eight out of ten people. It entails daily exposure to a very bright light from a specially designed light box (around 10 times brighter than normal domestic lighting). The light emitted is very similar to natural daylight and won't harm your eyes unlike ultraviolet (UV) light.  Many sufferers notice a real improvement in their symptoms in under a week.  Light therapy should be continued daily until springtime when the daylight hours begin to lengthen.

Antidepressant medicine-

Selective serotonin reuptake inhibitors (SSRI’s) are most effective as they are non-sedative i.e. sertraline (Lustral), paroxetine (Seroxat) and fluoxetine (Prozac) and can help the depressive symptoms of SAD and work well with light therapy.  If antidepressants are prescribed you should only need to take them during the autumn and winter seasons.


Cognitive behavioural therapy (CBT), psychotherapy and counselling are highly beneficial to those suffering from SAD. Other complementary therapies which help sufferers to relax, accept their illness and cope with its limitations are very useful.

CBT tackles your negative thoughts. For example, when something unfortunate happens, depressed people blame themselves, but when a positive experience happens, they tell themselves that they've just been lucky. They also assume that other people are reacting negatively to them. CBT helps people think in a more balanced way and challenges a person's assumptions about their lives. It aims to identify and change aspects of behaviour that may cause or prolong symptoms of depression.

How the Priory can help-

Priory has been helping to treat people with SAD for many years. Our committed and professional staff provide the highest standards of care, understanding and service for everyone. This service brings hope and confidence, allowing our patients to take control of their lives within a safe and secure environment.

For further details on how Priory can provide you with further assistance regarding Seasonal affective disorder - SAD, please call 0800 840 3219. For professionals looking to make a referral, please click here

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What can I do to help myself?

There are many ways you can reduce the effects of SAD.  If possible try to:

  • Get outside every day and go for a walk - especially if it's sunny
  • Try to sit next to a window when you are inside
  • Try to take regular exercise
  • Eat a well balanced diet
  • Plan ahead for the winter

Finding help

Contacting your GP is often the easiest, and should be the first, route to help and further treatment. He or she may refer you to a specialist for further assessment. This may lead to outpatient treatment or, if more serious, day or inpatient treatment.

If you're worried about talking to your GP, you can:

  • Consider writing down your concerns and questions
  • Take a friend or family member with you
  • See another doctor in the practice
  • Consider joining a new GP practice

The type of professional support offered will depend on the services that are available in your area, or the arrangements that your primary care trust (PCT) have with other health authorities or private providers. Treatment for SAD is also available privately through the Priory.

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