LIGHT THERAPY & SEASONAL ADJUSTMENT DISORDER

What is S.A.D? . 

S.A.D. (Seasonal Affective Disorder) is a type of winter depression that affects an estimated half a million people every Winter between September and April, and in particular during December, January and February. It is caused by a biochemical imbalance in the hypothalamus due to the shortening of daylight hours and the lack of sunlight in winter. For many people S.A.D. is a seriously disabling illness, preventing them from functioning normally without continuous medical treatment. For others, it is a mild but debilitating condition causing discomfort but not severe suffering. We call this sub-syndromal S.A.D. or 'winter blues.'

Who Does it Affect? 

The standard figure says that around 2% of people in Northern Europe suffer badly from S.A.D., with many more (10%) putting up with milder symptoms (sub-syndromal S.A.D. or winter blues). Across the world the incidence increases with distance  from the equator, except where there is snow on the ground, when it becomes less common. More women than men are diagnosed as having S.A.D. Children and adolescents are also vulnerable. 

What are the Symptoms of S.A.D

The symptoms of S.A.D. usually recur regularly each Winter, starting between September and November and continuing until March or April. A diagnosis can be made after three or more consecutive Winters of symptoms, which include a number of the following:

• Sleep problems: Usually, the desire to oversleep and difficulty staying awake but, in some cases, disturbed sleep and early morning wakening 
• Lethargy: Feeling of fatigue and inability to carry out normal routine 
• Overeating: Craving for carbohydrates and sweet foods, usually resulting in weight gain 
• Depression: Feelings of misery, guilt and loss of self-esteem, sometimes hopelessness and despair, sometimes apathy and loss of feelings 
• Social problems: Irritability and desire to avoid social contact 
• Anxiety: Tension and inability to tolerate stress 
• Loss of libido: Decreased interest in sex and physical contact 
• Mood changes: Extremes of mood and short periods of hypomania (overactivity) in spring and autumn. 
• Weakened immune, system during the Winter, and S.A.D sufferers are more vulnerable to infections and other illnesses. 

S.A.D. symptoms disappear in Spring, either suddenly within a short period (e.g., four weeks) of hypomania or hyperactivity, or gradually, depending on the intensity of sunlight, in the Spring and early Summer. In sub-syndromal S.A.D., symptoms such as tiredness, lethargy, sleep and eating problems occur, but depression and anxiety are absent or mild. S.A.D. may begin at any age but the main age of onset is between 18 and 30 years. 

What causes S.A.D.? 

The problem stems from the lack of bright light in winter. Researchers have proved that bright light makes a difference to the brain chemistry but why some people suffer and others don't is not clear. Nerve centres in our brain controlling our daily rhythms and moods are stimulated by the amount of light entering the eyes. As night falls, the pineal gland starts to produce a substance called melatonin that tells our body clock it's night time; bright light at daybreak is the signal for the gland to stop producing this melatonin. But on dull winter days, especially indoors, not enough light is received to trigger this waking up process.

Light is also linked to serotonin  (also known as or 5HT) production, a neurotransmitter in the brain. This makes sense because a  low serotonin level is a cause  of depression and if you're depressed it can be difficult to concentrate and complete what would normally be simple tasks. Evidence has shown that serotonin levels increase with exposure to bright light - SSRI drugs such as Prozac have the same effect

Light Therapy 

Light treatment should be used daily in Winter (and during dull periods in summer) starting in early Autumn when the first symptoms appear. 

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Treatment is usually effective within three or four days and the effect continues provided it is used every day. Tinted lenses, or any device that blocks the light to the retina of the eye, should not be worn, Some light boxes emit higher intensity of light, up to 10,000 lux, which can cut treatment time down to half an hour a day. Light boxes are not available on the NHS and have to be bought from specialist retailers; they are now free of VAT and start at less than £100.

Antidepressant Drugs 

Traditional antidepressant drugs such as tricyclics are not usually helpful for S.A.D. as they exacerbate the sleepiness and lethargy that are symptoms of the illness. The non-sedative SSRI drugs such as sertraline (Lustral), paroxetine (Seroxat) and fluoxetine (Prozac) are effective in alleviating the depressive symptoms of SAD and combine well with light therapy. Other psychotropic drugs e.g. lithium, benzodiazepines have not proved widely useful in the treatment of S.A.D. Daily exposure to as much natural daylight as possible, especially at midday, should help. 

Psychotherapy 

Psychotherapy, counselling or any complementary therapy which helps the sufferer to relax, accept their illness and cope with its limitations are extremely useful.