Seasonal affective disorder (SAD) is a cyclic, seasonal condition, meaning signs and symptoms are present only during a particular season of the year and then go away. Most of the time, signs and symptoms of seasonal affective disorder typically appear during the winter and recede in the spring and summer.

“If you have SAD, winter’s short days and long nights may induce feelings of depression, loss of energy, social withdrawal, increased sleep, overeating, weight gain, irritability, headaches, and difficulty concentrating and processing information,” said Dr. Ashok Seshadri M.D., consultant psychiatrist, Mayo Clinic Health System in Austin and Albert Lea.

What causes seasonal affective disorder is unclear, but heredity, age and your body’s chemical makeup all seem to play a role. So can the availability of sunlight. Researchers suspect that reduced sunlight may disrupt the circadian rhythms that regulate your body’s internal clock, which lets you know when it’s time to sleep and when it’s time to wake up. This disruption may cause depression or exacerbate a preexisting depressive condition.

“Although there’s no cure for SAD, there are treatments to help you successfully manage the condition,” Seshadri said. “Light therapy is the main treatment for many people with winter depression. In light therapy, you sit a few feet from a special light box so that you’re exposed to bright light within the first hour of waking up each day. Your doctor may prescribe an antidepressant in combination with light therapy or as an alternative if light therapy isn’t working.”

Seshadri recommends some things that you can do on your own to cope with seasonal depression:

• Increase the amount of light in your home.
• Get outside.
• Exercise regularly.
•  Find ways to relax.
• Take a trip to a sunny, warm location, but stay on the same sleep schedule if the trip is under seven days long.
• Avoid nighttime use of computer, tablet or phone, especially when in bed.
• Although some people attempt to use tanning beds, there does not seem to be the same benefit as simple bright light in the range of 10,000 lux for kids under 9 and 10,000 lux for adults.

“Most people experience some days when they feel down. But if you feel down for days at a time and this happens during the same time each year, see your doctor. This is particularly important if you notice that your sleep patterns and appetite have changed,” Seshadri said.