Light Therapy (SAD) | Health Articles

"The days are growing rapidly shorter and the nights, only too noticeably longer... It is this discouraging veil of blackness, falling over the sparkling whiteness of earlier nights, which sends a vein of despair running through our souls." (Dr Frederick Cook, 19th century Polar explorer and travel writer.) There can't be many of us who don't, to some degree, feel a bit lower in the winter than in the summer. Whether it is just a dislike of the dark winter mornings or if you feel the need to hibernate under your duvet for six months to escape the gloom and depression.

Seasonal Affective Disorder, or SAD, is the medical term used to describe those of us who are affected most by the dark winter months. According to recent research (1998) in Britain about 1 million adults suffer from SAD. However 5 million people, nearly 20% of adults, have milder symptoms – usually referred to as 'winter blues'. These milder symptoms include disrupted sleep patterns and over-eating. When these symptoms disrupt your life or become difficult to cope with it is termed SAD.

Typical SAD symptoms include:

Depression - despair, misery, guilt, anxiety, normal tasks become frustratingly difficult
Sleep problems - oversleeping but not refreshed, cannot get out of bed, needing a nap in the afternoon
Overeating - carbohydrate craving leading to overweight
Family problems - avoiding company, irritability, loss of libido, loss of feeling
Lethargy - too tired to cope, everything an effort
Physical symptoms - often joint pain or stomach problems, lowered resistance to infection
Behavioural problems - especially in young people

The symptoms tend to start from around the beginning of September each year, lasting until April but is at their worst from December to February - the darkest months.

What causes SAD?

SAD is caused by lack of bright light in winter. It is not psychosomatic or imaginary. It is recognised by the medical profession and the World Health Organisation. When bright light enters our eyes it causes chemical reactions to occur which control our daily rhythms. For example, at daybreak, bright light suppresses the production of melatonin - a substance that makes us drowsy. But the lack of bright light on dull days can hinder this natural waking up process. Exposure to bright light also increases the production of serotonin, a neurotransmitter that carries signals between the nerves in the brain. Low levels of serotonin are known to be a cause of depression and indeed this maps well onto what people say: tasks which are easy when you are well become frustratingly difficult when you are depressed.

What treatment is there for SAD?

The best, but not always the most practicable, option is getting away as much as possible in the winter and seeking the sun – whether it is a skiing trip or a winter-sun holiday – anywhere with bright light. The treatment of choice in NHS SAD specialist clinics is the use of bright lights, which, in most cases, is done by using a light box (or 'bright light'). After all, if the problem is caused by a lack of light it makes sense to get more light by other means (to address the problem at source).

Lightboxes are effective in up to 85% of cases of SAD. Various bright light devices are available for treating SAD. Light boxes are the most commonly used. They come in a range of styles so that the user can choose one to suit their lifestyle. There are also light visors, worn like a sun-visor. Basically, the brighter the light, the less time it takes to use, from as little as 20 minutes for the brightest lights to around 90 minutes for the less bright lights. It is recommended that SAD sufferers seek support from their doctor, but this is not essential before trying a light box. Another way to relieve symptoms of SAD is to use a dawn simulator or 'bodyclock' which works by using your body's natural response to sunrise to help synchronise your sleep/wake pattern.

A bodyclock looks like a bedside light with a built in alarm clock: each morning the light comes on very slowly (imitating sunrise) at the time you choose, so, by the time you open your eyes your body has already, subconsciously, being responding to increased light levels around you, so you wake-up feeling refreshed. There's none of the startling 'beep beep beep' which normally rouses you from deep sleep. Scientific research has found that dawn simulators can alleviate symptoms of SAD, and even if you don't suffer from SAD they can improve your mood and energy levels. Contrary to some beliefs the light need not be a special daylight matching or 'full spectrum' type and simply changing the lamps in a room to these special types will not produce sufficient light to help people with SAD.