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Seasonal Affective Disorder

by Wendy Morray-Jones(more info)

listed in sad, originally published in issue 17 - January 1997


It has long been known that certain diseases can be linked to the changing seasons. In the fifth century B.C. Hippocrates wrote that "Such diseases as increase in the Winter ought to cease in the Summer . . . the physician too must treat disease with the conviction that each of them is powerful in the body according to the season which is most conformable to it." Seasonal Affective Disorder is one such condition and thanks to the increasing publicity it has received in recent years, a growing number of sufferers are seeking help from GPs and other health professionals.

In the early 80s, doctors working at the National Institute for Mental Health in Bethesda, USA, were approached by Herb Kern, a research engineer, who thought that his annual cycle of depression might be caused by the shorter and duller daylight hours in Winter.

Doctors at the Institute exposed Herb to light which was equivalent to Summer sunlight, for several hours each day and by the fourth day his improvement was remarkable.

In 1984 these pioneering doctors - Rosenthal, Wehr, Mueller, Lewy et al, wrote their seminal paper "Seasonal Affective Disorder: A description of the syndrome and preliminary findings with light therapy." The lives of thousands of sufferers were about to change for the better.




Geographical incidence of S.A.D

Since S.A.D. is caused by a lack of sufficient daylight in Winter, it is rarely found in countries within thirty degrees of the Equator where the sun stays bright all year round. However, since snow is also a good reflector of light, it is not only in warmer climates that sufferers can get relief from their symptoms. For this reason many people with this condition find it helps to take a break in Winter.

A description of S.A.D.

Dr. Ian Rodin works in the mood disorders clinic at the Royal South Hants Hospital in Southampton where he diagnoses and advises on treatment for S.A.D. The clinic is run by Professor Chris Thompson, a leading researcher in this field, whose works are published internationally. The clinic cannot cope with general enquiries, but will see patients who have a G.P.'s referral. Dr. Rodin explains "Seasonal Affective Disorder is a recurrent depressive illness which starts at the same time each year. The most common and most widely published form is Winter S.A.D. in which depressive symptoms begin in Autumn and cease the following Spring, when in some patients there is a conversion from depression to mild hypomania.

"A diagnosis of S.A.D. should only be made if a depressive illness (clinical depression) has occurred at the same time of year on at least three occasions. Symptoms are similar to non-seasonal depressive illness although hypersomnia, increased appetite and weight, carbohydrate craving and fatigue with an afternoon slump in energy are particularly common in Winter S.A.D. In sub-syndromal S.A.D. some patients experience marked changes in energy, sleep and appetite without depressed mood during the Winter. These changes are observed to some extent in most people but if severe enough to produce impairment of function, the symptoms will often be relieved by phototherapy, so recognition of this condition is important. Phototherapy may be acting on the hypothalamus, an area rich in seratonin. Latest research into the condition points to a primary abnormality with seratonin function. We know that seratonin influences melatonin secretions and also that levels of seratonin vary with the seasons, being lowest in Winter."

In June this year a novel hypothesis was put forward at the annual meeting of the Society for Light Treatment and Biological Rhythms in Washington DC. Dan Oren produced slides of the chemical structures of haemoglobin and chlorophyll to demonstrate their similarities.

He suggested that since chlorophyll is very light sensitive in plants, one of the functions of haemoglobin might be to carry the message that light is available around the body.

Treatment with Phototherapy

The intensity of lights found at work or in the home measures 200-500 lux, but the minimum intensity required for phototherapy treatment of S.A.D. is 2,500 lux which is similar to that of a bright Spring day. Special lightboxes are available for treating S.A.D. and 85% of sufferers find partial or total relief from their symptoms by using one of these every day in Winter. These lightboxes are not available on the NHS but are VAT exempt owing to their medical status. Some manufacturers offer a trial period of two or three weeks - long enough for the patient to decide if this treatment works for them. Dr. Rodin advises that the duration of phototherapy required each day depends on the brightness of the lightbox used, but will be approximately two hours at 2,500 lux and one hour at 10,000 lux, though some patients may need longer. Treatment is best taken soon after waking, but when this isn't possible, it can be split between morning and early evening. It is not recommended to use a lightbox late at night when it is likely to interfere with sleep. Patients who have a predisposition to mania may experience this if excessive phototherapy is used.

Treatment with drugs

Dr. Rodin says "Antidepressants provide a useful backup when light treatment is not enough on its own, or if the patient has a preference for this medication. Specific Seratonin Re-uptake Inhibitors are most useful for the treatment of S.A.D though other groups can be tried if there is no response to these. Phototherapy and antidepressants are only used during the period the patient is suffering from depression.

When conversion to mania in the Spring is a problem then Lithium may prove useful."

More guidelines to treating S.A.D.

Treatments for S.A.D. can be layered throughout the Winter starting with daily light treatment and progressing to medication as necessary.

Assuming the patient presents in the Autumn when the symptoms are mild, a daily walk in the fresh air will help, as would aerobic exercise.

Patients can also help themselves by increasing the general lighting in their homes. When not being used for actual treatment a lightbox can be left on for background lighting.

Alice's story

"In Winter I have always found it extremely difficult to get to sleep at night though I could readily fall asleep at work as soon as I sat down.

Most days I was tired, moody, negative and depressed. I was also overweight and found it hard to concentrate.

"For the last month I have been using a lightbox for one hour every day and the effects have amazed me. I was sceptical about light treatment working for me, but after a week I had a lot more energy and felt marvellous. My sleep has also improved and I have no trouble in getting up in the morning as I have my lightbox positioned next to my bed on a time switch. This means that I wake up naturally before my alarm goes off and get half my daily treatment before going to work.

"Many people have noticed the improvement in me, without being aware that I am taking light treatment. In four weeks I have lost over a stone in weight, my skin looks healthier, and my circulation has improved - I can actually feel my feet for the first time in years! This treatment has been very liberating for me as I can now feel happier and healthier in the Winter."

Carol's Story

"Around September each year I felt tired and unable to cope with the usual stresses and strains of life. I became forgetful and unable to concentrate. Though I felt exhausted all day, every evening I would start feeling more lively around nine o' clock and be wide awake by bedtime. I felt I needed to fill myself with stodgy foods and chocolate, so I gained around a stone each Winter. I was very anxious - not at all like my Summer disposition which was cheerful and outgoing, and seemed to pick up more infections than most people in Winter.

The symptoms got worse as the Winter progressed, so I dreaded the months January and February. I was aware of the seasonal pattern but just thought of myself as a 'Summer person'.

"When Spring came I seemed to go to the other extreme, having a lot more energy than other people. I quickly lost my Winter weight and became sociable and uninhibited. I had little self-awareness and spent money on unsuitable items because my judgement was impaired. The character of Mr. Toad in the Wind In The Willows accurately described my response to Spring!

"By June I had 'levelled out' for a few brief months. I felt moderate then and it was a relief to be rid of the peaks and troughs for a while.

"One dark day in February about fifteen years ago, I used a sunbed for the first time, and after the first session I felt more cheerful and full of energy. I used the sun-bed three times a week for a month, by which time I had lost that Winter's surplus weight. People told me how well I looked and I realise now that I was receiving a partial light treatment."

Phototherapy for other conditions

Other problems associated with circadian rhythm disturbances such as jet-lag, difficulties experienced by shift-workers, and pre-menstrual syndrome, can also be successfully treated with light therapy. Lightboxes are even regularly used by NASA to manipulate the sleep/wake cycle of astronauts.

A Canadian study revealed improvements in academic achievement, attendance and growth rates in the classroom when children were treated with bright light. It also showed a reduction in tooth decay.

Another study, this time carried out at Cornell University, showed that working under very bright lighting helped to reduce perceptual fatigue. Hopefully, continuing studies may discover further benefits soon.

Where to get support or information

The Seasonal Affective Disorder Association (S.A.D.A.) is a charity which gives support to people who have S.A.D. It also advises health professionals, and monitors international developments in S.A.D. It does not receive funding so subscriptions form its only financial basis. To receive an information pack send a cheque made payable to "SADA".


Hippocrates (1923-1931) Works of Hippocrates, WHS Jones and ET Withington, eds. and trans. Harvard University Press, Cambridge, MA.
Rosenthal N et al (1984) Seasonal Affective Disorder, a description of the syndrome and preliminary findings with light therapy, Archives of General Psychiatry
Seasonal Affective Disorder Association, A compact guide to Seasonal Affective Disorder, July, 1996


SOUTHAMPTON Prof C Thompson, Dept of Psychiatry, RSH Hospital, Graham Rd, SO9 4PE
LONDON Prof S Checkley, Dean, Maudsley Hospital, Denmark Hill, London, SE58AF
STEVENAGE Dr R Tresman, Mental Health Unit, Lister Hospital, Coreys Mill Lane, SG1 4AB
N. YORKS Dr G Vincenti, Dept of Mental Health, Friarage Hospital, Northallerton, DL6 1JG
ABERDEEN Dr J Eagles, Ross Clinic, Royal Cornhill Hospital, Cornhill Rd, AB9 2ZF

Light therapy equipment

Wendy Morray-Jones, 21, Milsom Street, Bath, BA1 1DE. Tel: 01225-317429

Information Pack

SAD Association, P O Box 989, Steyning, BN44 3HG

Further reading

Rosenthal N and Blehaar M, eds (1989) Seasonal Affective Disorders and Phototherapy, Guilford, New York


  1. Florence said..

    I need help & support with my 20yr SAD affliction. I'm increasingly emotional with each winter & bad autum season. My surgery GP is not knowledgeble about where to refer me and is not much of a help to me.I could do with some infor pack of SAD clinics in the UK to push forward for a referal from my GP. Can anyone help pls?

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