FALMOUTH – The winter months drag Ken Hess down.

Hess struggles with depression year-round, but finds his mood plummeting even further as the days shorten. The former insurance salesman recalls that he would spend much of January in bed.

Hess suffers from seasonal affective disorder. An estimated 4 percent to 6 percent of the population is afflicted with wintertime depression marked by fatigue, changes in sleep patterns, craving for carbohydrates, weight gain and difficulty making decisions. Another 10 percent have milder symptoms.

For years, light therapy has been the most common treatment for SAD, but a University of Maine psychologist is trying to find out whether conventional therapies widely used for depression also will work for SAD.

Professor Sandra Sigmon says researchers and therapists generally approach SAD from a biological perspective, assuming that a lack of sunlight is the root of the problem and look for treatments based on that.

But Sigmon wants to know how psychological techniques called cognitive and behavioral therapies can be applied to SAD.

Cognitive therapy aims to break people out of a spiral of negative thoughts that build upon each other.

“If you say to yourself, ‘It’s cold, it’s dark. Oh my God, I hate this so much,’ then you really are going to start feeling worse,” Sigmon said.

“So what you have to say to yourself is ‘OK, what is it I can do realistically about the cold? What can I do realistically about this winter weather?'”

Once people become aware that they’re dwelling on negative thoughts, they can try to break the cycle and come up with more productive ones. People who aren’t caught up in negative thinking improve their mood, Sigmon said.

In behavioral therapy, people are encouraged to improve their mood through action.

People with SAD may feel so down that they withdraw from activities they normally like. Just as negative thinking feeds on itself, the lack of activity worsens their mood, causing a downward spiral of worsening depression.

People who seek therapy sometimes “contract” with their therapists to engage in activities that will help them break out of that pattern, Sigmon said.

“You’ll start enjoying yourself just a little bit more,” she said. “But you have to keep doing the things that you typically like to do.”

Norman E. Rosenthal, the psychiatrist who first defined SAD in the 1980s, believes research such as Sigmon’s can help people understand the disorder, but he still believes light therapy is the best course of treatment.

“These are interesting questions,” said Rosenthal, author of “Winter Blues” and a clinical professor at Georgetown University Medical School.

“I am very impressed with the value of both cognitive and behavioral intervention. So, I think this would be a useful addition to our knowledge base,” he said.

Efforts to adapt cognitive and behavioral therapies to SAD have yielded some promising results, Sigmon said.

In one study, two groups of volunteers received either cognitive or behavioral therapy but not light therapy.

Subjects who underwent those therapies were less depressed than those in another group who didn’t.

The improvements were comparable to those other researchers have observed with light therapy, Sigmon said.

In another study, Sigmon hypothesizes that cognitive and behavioral therapies may have long-term benefits, unlike light therapy that must be done each winter.

“These are life skills, they’re not exactly the ones we learn in elementary school but you can learn then and apply them to other situations,” she said.

It’s too soon to tell whether that’s the case with SAD.

Sigmon said this pilot study needs further follow-up

with more subjects for a longer time.

In Falmouth, 140 miles away from the Orono campus, Hess is seeking relief through light therapy.

He has a light box outfitted with full-spectrum fluorescent bulbs set up in the living room of his Falmouth home.

He sits in front of it for a couple of hours each day and tries to keep his mood up in other ways – including meditation and attending a support group – while he waits for spring.

“I’m not as bad as I know I can be,” he said.

Ken Hess is president of the Maine chapter of the National Depressive and Manic-Depressive Association, which meets at 7 p.m. Mondays in Portland at Maine Medical Center’s Dana Center. More information is available at http:///www.ndmda.org.