The winter blues can be more than just feeling lonely during the holidays or kicking yourself for gaining 5 pounds after that perfect holiday feast.

There is a name for what afflicts people who have the blues long past the holidays, people who have it all winter long.

Seasonal affective disorder affects people who have depression through the winter months. Their depression subsides by spring, according to the National Mental Health Association.

The disorder is related to seasonal variations in light, according to the association.

As many as 500,000 people in the United States have seasonal affective disorder and another 10 percent to 20 percent of the population might experience mild seasonal affective disorder, according to the American Academy of Family Physicians.

The disorder often starts in a person’s early 20s and is more common in younger people, according to the National Mental Health Association.

The farther north of the equator, the more people there are who have the disorder, said Linda Muldoon, a senior psychologist for University Counseling and Consulting Services.

Because Minnesota receives less light than much of the rest of the country during the winter season, the state sees more cases of the disorder, she said.

Seasonal affective disorder is also more common in places like Seattle, where it rains a majority of the winter, she said.

The symptoms can be different from regular depression. These can include increased appetite, different sleep patterns and weight gain, she said.

The antidepressants used for depression also work for seasonal affective disorder, said Candy Price, a staff psychologist for Boynton Mental Health Service.

Many people also use light boxes to treat seasonal affective disorder, Price said.

A light box is a bank of white fluorescent lights on a metal reflector and a shield with a plastic screen, according to the National Mental Health Association.

People shouldn’t use the light box without the supervision of a physician, Muldoon said.

The initial investment for a light box ranges from $150 to $300, but long-term use will be less expensive than purchasing antidepressants.

People who have mood disorders can have season component aspects to their disorder, he said.

“I don’t find it useful to call it a separate disorder,” said Jacob Katzow, a psychopharmacologist and clinical professor of psychiatry at George Washington University School of Medicine.