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Two decades of research into SAD and its treatments: A Retrospective
It is no coincidence that I should have been involved in the modern
description and rediscovery of seasonal affective disorder (SAD)
as I am rather seasonal myself -- much more productive and energetic
in summer than in winter. This became apparent when I emigrated
from the mild climate of Johannesburg, South Africa, just south
of the Tropic of Capricorn, to the northeastern US where the long
summer days were a source of endless delight and the short, dark
winter days brought a dreariness of spirit that was alien and mysterious.
Herbert E. Kern was a 63-year-old engineer who had observed in
himself regular seasonal emotional cycles, which he believed might
be related to seasonal variations in environmental light. He learned
of the finding by Alfred J. Lewy and colleagues at the National
Institute of Mental Health that nocturnal secretion of melatonin
by the pineal gland in humans could be suppressed by bright environmental
light. The group had also pioneered the role of biological rhythms
in cyclical mood disorders under the aegis of Thomas A. Wehr and
the then-Branch Chief Frederick K. Goodwin.
In the winter of l980-1981, we admitted Kern to our unit and treated
his depression with bright light. It worked. It was one of those
rare moments in clinical research. Our follow-up study to confirm
our success led to the original description of Seasonal Affective
Disorder and light therapy in 1984, which became a Citation Classic."
The existence of SAD has been recognized at many centers around
the world. A version of our original criteria was included in DSM-III-R,
the standard US manual of psychiatric diagnoses. The basic clinical
profile of SD remains essentially unchanged: depressions are characterized
mainly by overeating, oversleeping, and weight gain, as well as
more typical depressive symptoms. Women comprise 59 percent to 94
percent of clinical samples. The prevalence of SAD in the adult
US population has been estimated at between 1.4 percent (in Florida)
and 9.7 percent (in New Hampshire). The milder, subsyndromal SAD,
which also responds to light therapy, is even more widespread.
Studies have been directed towards improving the efficacy and convenience
of light delivery and understanding the importance of intensity,
timing, spectrum, and route of administration to the antidepressant
effect. A Society for Light Therapy and Biological Rhythms has been
established. The scope of light treatment is expanding to encompass
problems of circadian rhythms, such as jet lag and certain sleep
disorders, and possibly other psychiatric disorders as well.
In the past few years pharmaceutical companies have joined in the
effort to find new angles for treating and preventing SAD. This
is an extremely welcome development because it highlights SAD as
a condition worth studying and treating. In addition, many patients
with SAD do not respond to light therapy alone, while others would
benefit by having more treatment options.
When we began our work over 20 years ago, many of our colleagues
considered it strange and eccentric. It has been gratifying to see
it enter the scientific and clinical mainstream, a realization made
concrete this past year by an award from the Anna-Monika Foundation
for depression research to Wehr and myself. An equally important
acknowledgment comes in the form of the many reports from individuals
who have benefitted from having their SAD diagnosed and successfully
treated. Despite the accomplishments of the field, we still do not
understand the fundamental biological abnormalities in SAD or how
light works. Perhaps the next decade of research will provide answers
to these questions.
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