Seasonal sadness possibly genetic

Some people who suffer Seasonal Affective Disorder may also have a genetic mutation that may, in part, bring on wintry depression, a study by a University of Virginia researcher has found.

The study tested 220 people and found that seven of the 130 diagnosed as having SAD also had two mutated copies of a photopigment gene in the eye called melanopsin. There were people in the study with one mutated copy of the gene, but they fell into categories of people with and without SAD.

While people with the double mutations were in the SAD group, researchers don’t yet know what the correlation means.

“People have referred to it as feeling like you want to hibernate,” Iggy Provencio, a biology professor at UVa who conducted the study, said of SAD.

For many people with SAD, the “gold standard” treatment is “bright-light therapy” that bathes the affected with artificial light for up to several hours each day, Provencio said.

But that treatment works for only 50 percent of patients, said Kathryn Roecklein, an assistant professor at the University of Pittsburgh who also worked on the study.

Knowing that, researchers would like to test patients with the double-mutation to see if they are less sensitive to light than others with SAD and thus need higher doses of light therapy — or if light therapy is even the best treatment.

Researchers also said a lack of light may not be the only thing to trigger depression among SAD patients. Other factors can include lack of exercise during the winter months and a person’s attitude about the weather, Roecklein said.

She also said studies have shown where a person lives can play a factor, noting that diagnoses of SAD are about 10 times greater in Maine than in Florida.

Roecklein said she is seeking another grant to repeat the recent SAD study, which was conducted with grant money from the National Institutes of Health.