For about 5% of the population, fall and winter bring a form of severe depression called Seasonal Affective Disorder (SAD). Another 10-20% will have a milder version of SAD. The cause is simple: lack of natural sunlight. As daylight returns, symptoms diminish, disappearing by spring. According to the American Academy of Family Physicians, some people are at greater risk for developing SAD:• Females are four times more likely than males to experience SAD• SAD seldom occurs in children and teens• Older people report fewer bouts with SAD, even if they had it as young adults• People who have clinical depression or bipolar disorder may have exaggerated symptoms during fall or winterWhere you live matters, too. The farther north, the greater the risk. Washington State has seven times more SAD cases than Florida and SAD is non-existent within 30 degrees of the Equator, where the sun shines for twelve hours every day. SAD shares most of the symptoms of classic depression. No one will have all the symptoms, but the list includes:• Lack of energy, feeling sluggish• Sleepiness and sleeping longer than usual• Weight gain from inactivity and overeating• Craving carb-heavy and sugary foods• Irritability, impatience, feeling agitated• Difficulty concentrating or focusing• Feelings of hopelessness or being worthless• Wanting to stay home or avoid social situations• Attempts to self-medicate with alcohol or drugs• In extreme cases, possible thoughts of suicideOnce SAD is identified, treatment begins with phototherapy. Duplicating sunlight can provide dramatic results within as little as two days. Usually patients sit by a light therapy box or wear a special visor with therapy lights for about 30 minutes a day. Exposure to bright light seems to trigger the brain to release chemicals that are linked to mood: Serotonin and Melatonin. Within two weeks, feelings of depression are relieved. There are few side effects to light therapy, but some patients report eyestrain, fatigue, headaches, irritability, or feelings of mania. Most of the side effects can be avoided by doing light therapy in the morning.Before trying phototherapy, check with your physician to verify the diagnosis. When choosing a light therapy box or visor, buy a high-quality product to ensure safety. To make sure you’re getting an effective product, take time to learn about the options and features that are most helpful for your situation.In extreme cases, a physician may prescribe an antidepressant, either as a supplement to phototherapy or as the sole treatment. Since SAD tends to return at the same time each year, the medication is started before the known onset and extends into the late spring or summer. Antidepressants require two to four weeks before symptoms are reduced, and need to be tapered off at the end of a cycle.SAD can be a serious disorder when untreated. Thankfully, treatment is usually simple and effective. If you, your patients, or anyone you know seems to exhibit signs of depression each year, a visit to a provider can take away the dread and “SADness” of winter.