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SAD – Seasonal Affective Disorder

October 29, 2012

In Eastern medicine it has been traditional to emphasize the importance of living in alignment with cycles of daylight and the seasons. Illness is known to occur when we disregard our connection to the natural world. A great deal of modern research in the West now supports this view.

What is SAD?

SAD (Seasonal Affective Disorder) is a common form of winter depression which may be accompanied by a craving for carbohydrates (that can trigger subsequent weight gain) and fatigue, even though sufferers may often sleep for longer during winter months. These symptoms may lead to increased levels of stress, anxiety, immune dysfunction and physical pain.

SAD is generally thought to be caused by a biochemical imbalance in the brain’s hypothalamus due to the reduction of daylight hours and the lack of sunlight in winter. For many people SAD is a debilitating illness that requires ongoing medical supervision. Others simply experience discomfort and fatigue as a sub-syndromal SAD and some estimates suggest that this milder condition is extremely common. There is also a rare reverse form of SAD, known as summer SAD, where symptoms arise in the summer and disappear in winter.

SAD symptoms usually reoccur each winter, starting in autumn and continuing through till spring. The symptoms may disappear suddenly – often with a few weeks of hyperactivity – or more gradually, depending on the intensity of sunlight in the spring. In summer SAD, symptoms such as fatigue and stress may be related to excessive heat rather than light.

What Causes S.A.D ?

Genetics and age are relevant factors but there are several main theories regarding the cause of SAD which all relate to dysfunction of the hormonal system as follows:

Low serotonin levels
 – There are several neurotransmitters (brain messaging hormones) involved in SAD, but the main one is serotonin. Levels of serotonin have been found to be significantly lower in depressed people in winter.

High melatonin levels
 – During darkness the brain’s pineal gland produces the hormone melatonin which induces sleep. Light stops melatonin production so that we begin to wake up.
People with SAD have been found to produce elevated levels of melatonin in winter. When treated with bright light, melatonin levels can drop back down to normal.

Disrupted circadian rhythm (body clock)
 – The circadian rhythm is the body’s internal, biological clock and various physiological functions relate to this 24hr cycle. The suprachiasmatic nucleus (SCN) in the hypothalamus region of the brain regulates circadian rhythm by scanning for levels of daylight. SCN dysfunction can slow down the body clock, causing lethargy and depression. Bright light (in the morning or from light treatment) can ‘reset’ the body clock.

Other potential triggers
of SAD include childbirth, hysterectomy and other shifts in the hormonal system. Some postnatal depression may be SAD triggered by childbirth. Other triggers may include loss, bereavement or serious illness, all of which are common triggers of depression.

The simple reality is that we tend to spend less time in natural light, with more work being done at night. This change is obviously related to an increase in light deficiency symptoms.

Therapy ?

The most popular  non-drug therapies are bright light therapy, dawn simulation therapy and high-density negative air ion therapy. The December 2006 issue of the American Journal of Psychiatry reports clinical trials of these three methods conducted by Dr. Michael Terman, the Director of the Center for Light Treatment and Biological Rhythms at New York-Presbyterian Hospital, Columbia University Medical Center. All three methods were statistically superior to placebo.

As always I observe the connection between traditional Eastern wisdom and modern Western science.

Spencer Joseph

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