By CARLA K. JOHNSON, ASSOCIATED PRESS

As winter is coming and daylight hours are getting shorterPeople prone to seasonal depression may feel it in their body and brain.

“It’s a feeling of panic, fear, anxiety and dread all at the same time,” said Germaine Pataki, 63, of Saskatoon, Saskatchewan.

She is one of millions of people suffering from seasonal affective disorder, or SAD. Her coping strategies include yoga, walking and antidepressant medication. She is also part of a Facebook group for people with SAD.

“I try to focus on helping others,” Pataki said. “It gives me purpose.”

People with SAD typically have episodes of depression that begin in the fall and subside in the spring or summer. The return to standard time, which is happening this weekend, can be a trigger for SAD. A milder form, subsyndromal SAD, is recognized by medical experts, and there is also a summer variety of seasonal depression, although less is known about it.

In 1984, a team led by Dr. Norman Rosenthal, then a researcher at the National Institutes of Health, first described SAD and coined the term. “I believe because it’s easy to remember, the acronym stuck,” he said.

What causes seasonal affective disorder?

Scientists are learning how specialized cells in our eyes transform the blue part of the light spectrum into neural signals that affect mood and alertness.

Sunlight is loaded with blue light, so when cells absorb it, the alertness centers of our brain are activated and we feel more awake and perhaps even happier.

Researcher Kathryn Roecklein of the University of Pittsburgh tested people with and without SAD to see how their eyes reacted to blue light. As a group, people with SAD were less sensitive to blue light than others, especially during the winter months. This suggests a cause of winter depression.

“In winter, when light levels drop, this, combined with lower sensitivity, may be too low for healthy functioning, leading to depression,” Roecklein said.

Miriam Cherry, 50, of Larchmont, New York, said she spent the summer planning how she would deal with her winter depression. “It’s like clockwork,” Cherry said. “The sunlight is weak. The day ends at 4:45 p.m., and suddenly my mood is horrible.

Is light therapy useful?

Many people with SAD respond to light therapy, said Dr. Paul Desan of the Winter Depression Research Clinic at Yale University.

“The first thing to try is light,” Desan said. “When we expose patients to bright light for about half an hour each morning, the majority of patients improve significantly. We don’t even need medicine.

The therapy involves devices that emit light about 20 times brighter than regular indoor light.

Research supports using light of around 10,000 lux, a measure of brightness. You should use it for 30 minutes every morning, according to research. Desan said it can help not only people with SAD, but also those with less severe winter problems.

Specialty lights cost between $70 and $400. Some products marketed for SAD are too weak to do much good, Desan said.

Yale tested products and offers a list of recommendationsand the nonprofit Center for Environmental Therapeutics has a consumer guide when selecting a light.

If your doctor has diagnosed you with SAD, check with your insurance company to see if the cost of a light might be covered, Desan suggested.

What about talk therapy or medication?

Antidepressants constitute a first-line treatment for SAD, along with light therapy. Doctors also recommend maintaining a regular sleep schedule and walking outside, even on cloudy days.