Just two decades ago, researchers at the National Institute of Mental Health (NIMH) first put a name to seasonal affective disorder (SAD), a mostly winter-linked form of major depression that affects about 6 percent of Americans. At the same time, the team posited SAD's potential cure: light therapy.

Since then, many studies have verified and refined the notion that light can be a potent healer for SAD sufferers, who without treatment become sluggish, sleep more, gain weight and become depressed in late fall and winter until they regain their groove in the spring. The now-standard treatment for SAD-30 minutes of 10,000-lux, diffused, white fluorescent light taken early in the morning-helps about half of SAD patients fully remit, regaining energy and positive moods. Remission rates climb to 80 percent if light therapy is tailored to a person's individual sleep-wake cycle, says Columbia University Medical Center Psychology Professor Michael Terman, PhD, who has conducted a wide variety of SAD studies.

"The meta-analyses in the area are quite conclusive: Bright light therapy, administered at the right time and in the right dose, is the most efficient, tested and safe method for treating SAD," says Terman, who also is director of New York-Presbyterian Hospital's new Center for Light Treatment and Biological Rhythms.

Building on these successes, some SAD researchers are seeking other ways to help SAD clients get better, especially those who don't respond well to bright light therapy or who stop using it over time. Several new avenues-some from biologically oriented labs and others from psychological ones-show particular promise. These include negative air-ion therapy, where people passively receive charged particles from an electronic device; cognitive-behavior therapy (CBT) tailored to seasonal issues; and combinations of those and other treatments.

In part, the range of new approaches reflects the dual nature of the disorder itself, comments Illinois Institute of Technology (IIT) Associate Professor of Psychology Michael Young, PhD, a SAD researcher and president of the Society for Light Treatment and Biological Rhythms.

"With SAD, there's a combination of psychological and biological processes at work," Young notes. "We're still working on the challenge of integrating these elements into research and practice."

The ionic man

One of the most intriguing new treatments from the biological camp is negative-ion therapy, which emerged by fortunate accident about 10 years ago, says Terman. Finding a placebo condition for light therapy was difficult, because people can clearly tell if they are in the group that receives light therapy. A colleague's husband suggested the use of a negative-ion device-touted as a mood-enhancer in the pop-psychology world-that was disconnected internally so people would believe they were getting benefits.

Terman liked this idea, but he also felt he needed to add an actual ion condition to create a truly rigorous design. His team reported their surprising results in the Archives of General Psychiatry (Vol. 55, No. 10, pages 872-882), in 1998. They compared four light conditions in 158 SAD patients, as well as high and low levels of negative ions.

"We found that patients responded to the high level but not to the low level of ions," Terman says-in fact, they did about as well as participants who received light therapy.

The air-ion generators Terman uses in his studies are small devices that operate in silence, producing a high electron flow rate that charges air particles but is undetectable to the senses. Participants receive the ions via an automatic timer either before or after they awake. To maximize exposure, they're fitted with a grounded wrist strap, and the device is placed two or three feet away from their head.

Recently, Terman and his wife and colleague, New York Psychiatric Institute psychologist Jiuan Su Terman, PhD, replicated their earlier finding. In a study of 77 SAD patients, in press at the American Journal of Psychiatry, participants who received high levels of the tiny particles responded about as well as those who received light treatment.

The Termans' research may indeed represent a breakthrough, but more work is needed to verify its usefulness, comments Yale University psychiatrist Dan Oren, MD, one of the original researchers of the psychobiology of SAD.

"It would be great to see his work independently replicated by another group," Oren says. "But to date, there is not sufficient replication or broad use to justify it as an officially accepted treatment."

And, it remains a mystery how negative ions work in the body, both Oren and Terman emphasize. Older studies suggest the serotonin system may play a part, but "we need new studies on mechanisms of action," Terman says.

Combination power

Researchers also are exploring ways to tackle SAD at cognitive and behavioral levels.

In one as-yet-unpublished study, IIT doctoral candidate Justin Enggasser and Young found that SAD clients who tended to take negative events personally and ruminate about their symptoms reported higher levels of wintertime depression than those with fewer of those tendencies.

"These findings aren't terribly surprising," says Young, "but they're the kinds of factors often overlooked with SAD because people have a strictly biological view."

University of Vermont psychologist Kelly Rohan, PhD, is working with clients who have SAD to change some of these tendencies through CBT.

Recent studies by Rohan and colleagues-one, a pilot of 23 SAD clients reported in the June 2004 Journal of Affective Disorders (Vol. 80, Nos. 2-3, pages 273-283), and the other, and an as-yet-unpublished three-year study of 61 SAD patients-find that such approaches work.

In both studies, the team compared how people fared after six weeks of standard light treatment, CBT alone or CBT plus light therapy. In the CBT conditions, the researchers challenged patients' negative thoughts about winter, and suggested behavioral changes that could enhance mood, such as building fun wintertime activities into their schedules.

Compared with a wait-list control, all three groups improved after six weeks. But at a one-year follow-up-at which point neither group had received any additional treatment, though light-therapy participants received information on how to continue using lights-the CBT-only subjects had less severe symptoms and a lower recurrence of depression than the light therapy-only group, Rohan found.

"To me, this says that people treated with CBT may have learned something in therapy that they can carry with them into the next fall and winter season," she says.

A different form of combination therapy-light therapy plus antidepressants-may also be a potent tool for treating SAD, says Oren. In fact, the literature shows that about a third of SAD patients do better when they take antidepressants along with bright light, he notes.

"When light therapy works perfectly on its own, great," says Oren. "But if it doesn't do all of the job, it can fit well with other more conventional therapies such as medications and psychological therapies."

Tori DeAngelis is a writer in Syracuse, N.Y.