The Application of Audio-Visual Entrainment for the Treatment of
Seasonal Affective Disorder
By Dave Siever
Abstract: Seasonal Affective Disorder (SAD) strikes all people from all
nations, not just those near the poles of the earth as might be thought. The
treatment of SAD has traditionally involved the use of anti-depressants,
and more recently, light box therapy. Audio-Visual Entrainment (AVE)
has also been shown to be beneficial in the treatment of this genetically
based affective disorder and its related anxious/depressive/dietary conditions.
Introduction
Each year, 6% of northern populations are affected with Seasonal Affective Disorder (SAD) and another 14% have a milder form of SAD, called the winter blues. Surprisingly, SAD may occur at any time of year and in equatorial regions although the ratio of northerners with SAD as compared to those living in the tropics is about 10-1. People in the southern USA experience SAD in the summer from staying indoors where air conditioning allows them to escape the unbearable summer heat. People have also experienced SAD moving into a basement suite or an office on the north side of a building or after painting the interior of their home a darker shade of color. People have experienced SAD following the development of cataracts or after wearing sunglasses for an extended period of time and during overcast, rainy periods (Rosenthal, 1993).
The common symptoms are depression, anxiety, extreme fatigue, hypersomnia, carbohydrate cravings, and weight gain. Women through the ages of 20 to 40, their sexually reproductive years, are most susceptible (Rosenthal, 1993). The first controlled study using light therapy to treat SAD was published in 1984. SAD was officially accepted as a clinical malady in 1987 by the American Psychiatric Association and described in its then current diagnostic manual, the DSM-III-R. Since that time, a great number of studies on the topic have been completed.
Animals are more sensitive to the seasons than humans, as they go through migration, mating, molting and hibernation. For instance, hamsters can sense the difference between a 12-hour day when their gonads don’t grow versus a 12-hour and 15 minute day when their gonads begin growth. It is thought that humans aren’t as sensitive as animals because humans originated in and around Africa where solar fluctuations are much more minimal than those near the Earth’s poles (Wright, 2002).
Tick-Tock Goes the Clock
It must be understood that circadian timing has nothing to do with the sense of time lapsing
between events, nor the ability to notice differences in timing between two events, such as two
tone-bursts or other sensory stimulation. Stimulation from events initiates an attentional cortical
reset, which in turn synchronizes brain activity. More specifically, about 300 milliseconds later,
the brain generates an attentional spike known as the P300 response. This spike starts a timing loop, initiated in the substantia nigra, a part of the basal ganglia, which in turn sends a burst of the neurotransmitter dopamine to another part of the brain called the striatum. The striatum contains “spiny” cells, which oscillate at different frequencies. Over time, the differences or “beats” add up. When attention is once again initiated, the count is recorded, providing a “time stamp” for that interval, which higher levels of the brain then interpret into a sense of timing (Wright, 2002).
Copyright: Dave Siever (2013) CA. Reprinted with permission. All rights reserved.