Let the sun shine in! Or maybe not. Treatment options for seasonal
affective disorder seem to be expanding—from antidepressants or
bright-light therapy to exposure to a simulated dawn or negative air
One of the pioneers in this area is Michael Terman, Ph.D., director of the
Center for Light Treatment and Biological Rhythms at Columbia University
Medical Center and director of the Clinical Chronobiology Program at New York
State Psychiatric Institute. A few years ago, Terman and several coworkers
obtained preliminary evidence that a simulated dawn could reduce the symptoms
of seasonal affective disorder. They then obtained evidence that high-density
negative air ionization could have the same effect.
"We were seeking a plausible placebo control for light
therapy—which, by definition, cannot be administered blind,"
Terman told Psychiatric News. "There is an old pop literature
on the mood-enhancing effects of negative air ions—think Niagara
Falls—and the deleterious effect on mood when the balance [of ions]
leans positive [as is the case] in dry, heated environments and indoor spaces
with central air conditioning."
With this in mind, a friend suggested that a disconnected electronic
ionizer would work as well as a placebo because subjects would believe the
method to be effective, yet could not directly sense the presence or absence
of air ions. However, Michael Terman and his group decided to use real
negative ions as a placebo instead. Much to their surprise, they found that
high-density—but not low-density—negative air ionization can
counter the symptoms of seasonal affective disorder.
In the past six years or so, Terman, along with Jiuan Su Terman, Ph.D., his
wife and a research scientist in his Clinical Chronobiology Program, have been
comparing the therapeutic values of negative air ionization and dawn
simulation to those of a well-established treatment for seasonal affective
disorder, bright-light exposure, as well as to the therapeutic value of
another possible treatment for the malady, a pulse of dawn light. The
nonprofit Center for Environmental Therapeutics, of which Michael Terman is
president of the board, sells both light boxes and negative ion generators to
Results from this investigation, published in the December 2006
American Journal of Psychiatry, suggested that high-density negative
air ionization, dawn simulation, and a dawn pulse are as effective as
bright-light exposure, but that low-density negative air ionization is
In the study, 99 adults with the winter seasonal pattern of major
depressive disorder or of bipolar II disorder were split into five treatment
groups and treated daily over a three-week period. The treatment conditions
were exposure to bright light for half an hour after awakening, a simulated
sunrise at wake-up time, a pulse of dawn light for 13 minutes before wakeup
time, negative air ions for 93 minutes before wake-up time at a low flow rate
with an inconsequential effect on air circulation, and negative air ions for
93 minutes before wake-up time at a high flow rate—or what Michael
Terman called "an `industrial strength' flow rate, such as used in clean
Subjects were assessed for depressive symptoms at the start of, during, and
end of treatment. Outcomes for the five treatment groups were compared.
The proportion of subjects who achieved a depression score reduction of 50
percent or more by the end of the study was statistically comparable for the
bright light group, the dawn simulation group, the dawn pulse group, and the
high-density ion group, but not for the low-density ion group (see chart).
Thus, dawn simulation, high-density negative ionization, and dawn pulse
appeared to be comparable to bright light in treating seasonal affective
disorder, but low-density negative ionization was not.
Nonetheless, "Despite the superiority of the dawn pulse over
low-density ions and lack of difference from other active treatments,"
there was a distinct group of nonresponders in the dawn-pulse group. Thus, the
Termans are reluctant to endorse dawn pulse as a treatment option for seasonal
In contrast, both dawn simulation and high-density negative ionization are
comparable to bright light in treating seasonal affective disorder, they
believe, and the choice of one therapy over the other "may depend on
convenience and ease of compliance."
For example, automated exposure to a simulated dawn or to negative air ions"
during sleep has an advantage over post-awakening bright light
therapy," Michael Terman explained.
"On the other hand, dawn presentation in the bedroom can disturb a
sleep partner with a later wake-up time, whereas bright light therapy can be
administered privately in a separate room. Negative air ionization during
sleep appears to be the most innocuous alternative; thus far, we have received
no reports of disturbance in bed partners."
"The Termans have been pioneers in the use of light therapies in the
treatment of seasonal affective disorder," David Avery, M.D., a
professor of psychiatry at the University of Washington and a seasonal
affective disorder expert, told Psychiatric News. "[They]
developed the idea of using dawn simulation to treat seasonal affective
disorder in the late 1980s and now have conducted a very well-designed study
that further supports the efficacy of a dawn signal compared to a control
condition.... The efficacy of the negative air ionization is intriguing and
"The Termans are well known for their careful and rigorously
conducted clinical studies," Raymond Lam, M.D., a professor of
psychiatry at the University of British Columbia and a seasonal affective
disorder authority, added. "This is an important study that carefully
assessed the therapeutic effects of dawn simulation, bright light, and
high-density negative ions against a credible placebo condition (low-density
negative ions) in patients with seasonal affective disorder. Although the
sample size was quite small—about 20 patients per condition—they
were able to show significant antidepressant effects of the active conditions
over the three weeks of treatment.
"There has, regretfully, been less [commercial] interest than
expected in these new noninvasive biological treatments," Lam also
commented. The reason, he indicated, is because there is no huge profit to be
made from them as from, say, psychotropic medications.
The investigation was funded by the National Institutes of Health.
"Controlled Trial of Naturalistic Dawn Simulation and Negative
Air Ionization for Seasonal Affective Disorder" is posted at<http://ajp.psychiatryonline.org/cgi/content/full/163/12/2126>.▪