Negative Ions May Offer Unexpected MH Benefit

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 ionization.

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 the public.

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 not.

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 rooms.”

Subjects were assessed for depressive symptoms at the start of, during, and end of treatment. Outcomes for the five treatment groups were compared.