Seasonal affective disorder (SAD), also called "winter depression," is a depression disorder that is influenced by the changing daylight amount of the seasons. Negative feelings are most significant during the fall and winter months when the number of sunlight hours has decreased. Symptoms include a change in appetite (frequently resulting in weight gain), loss of energy and an increasing feeling of irritability. SAD also unfavorably affects the individual's ability to react socially and to concentrate on details. Affected people frequently report a disruption in sleep patterns that results in oversleeping during daytime hours.
Definition of Negative Ionization
Negative ions are negatively charged air molecules that occur naturally and are thought to impact the level of serotonin in the brain. Summer air has significantly more negatively charged ions than winter air. Negative ions can be produced through mechanical generation in laboratories and treatment facilities.
Causes
The causes of SAD are disputed, but all theories are based on diminished winter light. Some scientists maintain that the limited amount of light in winter months impacts some individuals. Other studies state that the quality of light, not its quantity, is the trigger for SAD. Winter light is less intense than summer sun and does not provide the necessary elements for some patients. One group of scientists speculates that the body's internal clock is set by morning sunlight and that this is disrupted by the dark early mornings in winter. There is no major scientific consensus as to any one cause.
Impact
The number of individuals impacted by SAD varies greatly, but statistics show that from 10 to 65 million people have symptoms at some point in life. SAD affects slightly more women than men. The vast majority of cases are in individuals under the age of 40, but a few of these occur in children and teens as well. Most cases are located in the American Pacific Northwest, Alaska and states in the northern Midwest and East.
Light Treatment
Recognition of SAD and development of treatments began in the 1980s with the introduction of light therapy. A major study conducted at the Rush-Presbyterian St. Luke's Medical Center in Chicago in the late 1990s found that when groups experiencing symptoms of SAD were exposed to light therapy, more than 50 percent recovered after only a month of treatments. Light treatment varied in each study, but one researcher used 10,000 lux exposure provided through fluorescent lights (using an ultraviolet filter) with the subject placed in a light box for a minimum of a half hour. Some studies used 3,000 lux for at least one hour, sometimes two or three hours.
Negative Ionization Therapy
Studies at Columbia University Medical Center, under pioneer researcher Dr. Michael Terman, director of the Center for Light Treatment and Biological Rhythms and director of the Clinical Chronobiology Program at New York State Psychiatric Institute, used both low- and high-density ion generators to create 10,000 to 2,700,000 ions per cubic centimeter with significant effects on more than half of the test subjects and no negative results. The high-density generators, creating an ion-charged environment just prior to waking up each day, produced greater results than the low-density machines. The final study summary reported that the results were comparable to traditional light treatment therapy. Many of the ion studies combined the treatment with simulated dawn and dawn pulse therapy.
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