Dundee Association for Mental Health

Seasonal Affective Disorder (SAD) is a type of winter depression that affects nearly a third of people, but the problem can often go undiagnosed.  For a small number of people it can be seriously debilitating, preventing them from functioning normally, for others, estimated at around 20% of SAD sufferers, it is mild but causes discomfort, this is often referred to as the ‘winter blues’. The symptoms tend to start from around September each year, lasting until April, but are at their worst in the darkest months such as December, January and February.

People with SAD experience seasonal changes of mood and behaviour.  The most common one being depression. Others symptoms associated with SAD may include experiencing problems sleeping, feeling lethargic, overeating, increased anxiety, loss of libido, social problems (being irritable and not wanting to go outside or see anyone) and finding it hard to concentrate, therefore some severe sufferers find it hard to hold down a job during this season.

The exact cause of SAD is still unclear although some theories suggest it may be caused by a biochemical imbalance in the hypothalamus due to the shortening of daylight hours and the lack of sunshine.

SAD can begin at any age and can affect men, woman and children although the most common age of onset is between 18 and 30 years.  It occurs throughout the northern and southern hemisphere but it is extremely rare in those living within 30 degrees of the equator, where daylight hours are long, constant and extremely bright.

Many people make their own diagnosis of SAD and treat themselves, but it can be a good idea to talk to your GP about your symptoms and how you are dealing with it and there are a few treatments that can be used to help combat the problems of SAD.  These include:

Light Therapy

Light Therapy has been shown to be effective in up to 85% of diagnosed cases.  Light Therapy involves exposure for up to four hours per day of very bright light, at least ten times the intensity of ordinary domestic light. 

Ordinary light bulbs and fittings are not strong enough.  Average domestic lighting emits an intensity of 200-500 lux but the minimum dose necessary to treat SAD is 2500 lux.  The intensity of a bright summer day can be 100,000 lux!

Light treatment should be used daily in winter starting early Autumn when the first symptoms start to appear.  It consists of sitting two to three feet away from a specially designed light box, usually on a table, allowing the light to shine directly through the eyes.  The user can continue to carry on with normal activity such as reading, working, eating while sitting directly in front of the box.  It is not necessary to stare at the light although it has been proven safe to do so.  The light treatment is usually effective within three to four days and the effect continues provided it is used every day.  Some light boxes emit higher intensity of light, up to 10,000 lux, which can cut treatment down to half an hour a day.  Light boxes are not available on the NHS and have to be bought from special retailers; they are no VAT exempt and start at less than £100.  The SAD Association recommends you try out the light boxes before trying as several companies offer a free home trial or hire scheme and the SAD Association also has a number of boxes for short term hire (see their website -the address is at the end of this information sheet) for more details.

Antidepressant Drugs

In severe cases of SAD, SSRI antidepressants increase the activity of serotonin, have proved successful, they can be combined with light treatment.

Talking Treatments

Talking treatments such as counselling, psychotherapy or cognitive behavioural therapy can be extremely useful in helping people to cope with symptoms.  They can also help to uncover other factors that may be contributing to your problem, and can help you do something about them.

Self Help

Try and make the most of the daylight we have in winter months for example going outdoors when it is bright, sit near windows where there is natural light.  Look after yourself by eat healthily, regular mild exercise can also help to improve your mood and try various relaxing techniques to try and help you relax.   Even going away on holiday to sunnier climates in the winter months can help as can some complementary therapies.

Support groups can be a valuable source of support as they can be therapeutic; you can share your feelings and experiences and talk to other people in the same situation as yourself.