Got a Case of the Winter Blues?

During the winter months, you may chalk up sluggish, sad feelings to the winter blues — known as seasonal affective disorder (SAD), a type of depression that recurs every fall and abates with spring. But SAD affects only about 5 percent of us — so before you decide to just tough it out until the sun returns, be sure one of these other conditions isn't to blame for your downshift in mood.

Obstructive sleep apnea
How it causes the blahs: For most of us, the soft tissue in the back of the throat stays open while you sleep just as it does when you're awake. But for patients with sleep apnea, this tissue collapses during sleep, blocking the airway. Your brain then sends the emergency message "You're suffocating!" so you awaken just enough to start breathing again. This is why your bedmate may notice snorts and pauses in breath during the night. Apnea causes restless sleep at night and intense fatigue and irritability during the day, so it's often misdiagnosed as depression.
The fix: Your doctor may first recommend lifestyle changes — such as quitting smoking, losing weight, and staying off your back while you sleep — to ease breathing. Other treatments include CPAP therapy (a machine blows air through your airway, forcing it to stay open during sleep so you'll continue breathing) or surgery to remove tonsils, adenoids, and/or the uvula (soft tissue in the back of your throat) to open space in your airway.

Folate deficiency
How it causes the blahs: Folate helps your body make brain chemicals like serotonin, the feel-good chemical. And not having enough serotonin increases your risk of such depressive symptoms as decreased energy, appetite, and concentration, says Eve Wood, M.D., author of 10 Steps to Take Charge of Your Emotional Life.
The fix: While foods such as dark leafy greens contain some folate, your body absorbs the vitamin more efficiently in supplement form, says Wood. Most multivitamins contain 400 mcg (the recommended dose to prevent birth defects), but Wood suggests that women suffering from even mild depressive symptoms take double that amount.