Seasonal Affective Disorder (SAD)
Last Updated on Tuesday, 09 March 2010 21:24
In Seasonal Affective Disorder (SAD) episodes of depression occur in the winter and autumn. This is thought to be caused by a reduction in sunlight. While many people experience SAD as a mild â€˜blueâ€™ feeling, others have disabling symptoms. Treatment aims to lift the mood and to relieve depression. Light therapy is the main treatment for SAD and has good results, but exercise, vitamin D and psychological therapies can also help.
Seasonal Affective Disorder Overview
Many functions of the body, such as body temperature and the secration of hormones into the bloodstream , follow an approximate 24 hour cycle â€“ known as a circadian rythm. The organs, tissues and cells of the body seem to respond to the slow environmental cycle of day and night. This response is co-ordinated by a biological clock in a part of the brain called the hypothalamus, which links the nervous system and the endocrine system of hormones. Like the conductor of an orchestra, the hypothalamus , together with the pituitary gland to which it is connected synchronise the physiological and biochemistry of the body.
There are two general categories of SAD: one that starts in the winter and one that starts in the autumn.
Melatonin is thought to be a key hormone involved in the development of SAD because of its importance in the regulation of sleep. The pineal gland in the brain produces melatonin mostly at night when there is no daylight and the body is asleep. The blood level of melatonin reaches itâ€™s peak in the middle of the night but melatonin is almost undetectable during the day.
When the melatonin cycle and the sleep cycle are out of synch, an imbalance in the hypothalamus may result and the symptoms of depression associated with SAD may develop.
This asynchronomy and imbalance is thought to be due to fewer hours of daylight and a lack of sunshine in the autumn and winter months. When longer days arrive in spring, some people with SAD experience a short-lived period of high levels of activity. For others symptoms of SAD disappear gradually with spring.
Symptoms of Seasonal Affective Disorder
- Feelings of sadness and apathy
- Fatigue and lethargy
- Sleep problems, often over sleeping but also disturbed sleep and early waking.
- Overeating with a craving for sweet foods and carbohydrates leading to weight gain
- Loss of self esteem
- Tension and irritability
- Decreased sex drive
Treatment for Seasonal Affective Disorder
Your doctor will ask you carefully about the history of your symptoms to exclude other psychological causes or an underlying physical cause.
Bright Light Therapy
There is fairly good evidence to support treating SAD with a course of bright light therapy (phototherapy) given on a daily basis, usually early in the morning. The individual is exposed to fluorescent light from a light box with a similar spectrum to daylight. It is thought that the light needs to be at least 2,500 lux. Each treatment usually lasts for around 30-60 minutes. Light therapy may be helpful in treating both mild and severe SAD.
Selective serotonin re-uptake inhibitors (SSRIâ€™s) such as fluoxetine, may help to relieve depressive symptoms.
Depression is the primary symptom of SAD, and may be helped by various approaches. There is evidence to suggest that some people with SAD have low thyroid function, so taking steps to maintain a health thyroid may prove useful.
Vitamin D supplements may be useful to improve mood in people with SAD. It has been suggested that the seasonal effects of SAD may be due to changing levels of vitamin D3, a nutrient made by the action of sunlight on the skin, and that this can improve mood through the brain chemical serotonin. In one study subjects were given 400IU, 800IU or no vitamin D3 for five days during the late winter. Results showed that the vitamin significantly enhanced positive mood. In another study, 30 days of treatment with vitamin D completely resolved depression in a group of people with SAD. If you have SAD taking 400-800IU of vitamin D3 may help.
It is well known that exercise can usually improve mild to moderate symptoms of depression. A study found that both exercise and light therapy helped in relieving the depression symptoms of SAD. However, light therapy was found to be more effective, suggesting that SAD is not quite the same as mild clinical depression.
While the main method of treating SAD is by using light therapy and medications, promising research has suggested that including talking therapies may be beneficial. For example interpersonal therapy has helped patients cope with feelings of isolation or alienation that accompany SAD. Cognitive therapy has also shown promising results.
There is also potentially promising results for a combination of therapies for people who do not respond to light therapy alone.