THURSDAY, Oct. 29 (HealthDay News) -- As daylight hours dwindle, people with seasonal affective disorder (SAD) can often feel the onset of wintertime depression, but a new study suggests one type of remedy may work better than another at banishing the SAD blues.

Cognitive behavioral therapy specially designed to treat people with SAD is more effective at preventing recurrences of depression than either light therapy or a combination of the two, the study found.

The psychotherapy may also be a time-saver -- potentially welcome news with Daylight Saving Time coming to an end on Nov. 1.

"It's an up-front investment, three hours of therapy a week in total over six weeks, whereas light therapy is 30 minutes a day and not just for six weeks," said study author Kelly Rohan, a psychologist at the University of Vermont. "Light therapy depends on a lot of time and effort, a minimum 30 minutes in front of the fixture every day of the symptomatic months every year. I don't know how many people are willing to do that."

The study was published in a recent issue of the journal Behavior Therapy.

According to Rohan's group, this is the first published data on the long-term effects of different therapies for SAD, which is characterized by mood and energy declines between November and April, when light is in short supply in the northern hemisphere.

The treatment of choice for the disorder has traditionally been light therapy, which spurs remission in about 53 percent of cases during the winter.

Light therapy involves exposure to bright light, typically administered using a "light box" -- a set of fluorescent bulbs or tubes encased in small, portable devices made of plastic or aluminum. A plastic screen covering the bulbs blocks out potentially harmful ultraviolet rays.

But the authors of this study had also developed and tested a group cognitive-behavioral therapy (CBT) protocol geared to people with SAD.

The treatment addresses attitudes, thoughts and behaviors which contribute to SAD.

For the initial study, 69 people with SAD were randomized to receive light therapy, CBT, a combination of the two or neither (they were wait-listed).

Six weeks after treatment started, 80 percent of those receiving combination therapy were in remission vs. 50 percent for CBT and the same for light therapy. Only 20 percent of those in the control group experienced remission.

The current paper adds data collected a full year after the first treatment.

This time, 5.5 percent of those receiving the combo therapy and 7 percent of those receiving CBT alone had a SAD recurrence, vs. 36.7 percent of those treated with a light box. That represents a sharp drop in the number of people benefiting from light therapy, possibly due to the inconvenience of the method, which must be used every day.

In this study, only four people continued their light therapy into the following winter.

Individuals receiving CBT alone also had less severe depression than either of the other two groups, indicating that CBT may be the way to go.

What's puzzling is the fact that combining CBT and light therapy didn't work as well as CBT alone. "There's something about being initially treated with the combination that seems to water down the effectiveness the next winter," Rohan said.

This all seems to suggest that CBT could be the way to go.

"It's [working] from the very first symptom, which for most people is October or November through March or April. The initial time in treatment is less with CBT and it's also meant to be over and done with -- the treatment that keeps on giving," Rohan said. "Once you're finished, you don't have to be in treatment every winter for the rest of your life, whereas you are expected to get the light box out and use it for every day of fall and winter. You undergo [psychotherapy], you learn, you keep using the techniques in the future."

"I absolutely agree with this study," said Susan Zafarlotfi, clinical director of the Institute for Sleep/Wake Disorders at Hackensack University Medical Center in New Jersey. "I find CBT more effective in general for depression. Behavioral therapy is resetting a person's thoughts. In CBT, you take all of the aspects of a person's thoughts and you rewrite the dictionary in a different way."

"But don't minimize the power of light therapy," Zafarlotfi warned. "It can be useful."

Rohan is now following a larger sample of patients over two winters.

More information

There's more on SAD at the National Alliance on Mental Illness.

SOURCES: Kelly J. Rohan, Ph.D., associate professor, psychology, University of Vermont, Burlington; Susan Zafarlotfi, Ph.D., clinical director, Institute for Sleep/Wake Disorders, Hackensack University Medical Center, New Jersey; September 2009, Behavior Therapy

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