Seasonal affective disorder (SAD) is a type of depression that's related to changes in seasons — SAD begins and ends at about the same times every year. If you're like most people with SAD, your symptoms start in the fall and continue into the winter months, sapping your energy and making you feel moody. Less often, SAD causes depression in the spring or early summer. Treatment for SAD may include light therapy (phototherapy), medications and psychotherapy. Don't brush off that yearly feeling as simply a case of the "winter blues" or a seasonal funk that you have to tough out on your own. Take steps to keep your mood and motivation steady throughout the year. Symptoms In most cases, seasonal affective disorder symptoms appear during late fall or early winter and go away during the sunnier days of spring and summer. Less commonly, people with the opposite pattern have symptoms that begin in spring or summer. In either case, symptoms may start out mild and become more severe as the season progresses. Signs and symptoms of SAD may include: Feeling depressed most of the day, nearly every day Losing interest in activities you once enjoyed Having low energy Having problems with sleeping Experiencing changes in your appetite or weight Feeling sluggish or agitated Having difficulty concentrating Feeling hopeless, worthless or guilty Having frequent thoughts of death or suicide Fall and winter SAD Symptoms specific to winter-onset SAD, sometimes called winter depression, may include: Oversleeping Appetite changes, especially a craving for foods high in carbohydrates Weight gain Tiredness or low energy Spring and summer SAD Symptoms specific to summer-onset seasonal affective disorder, sometimes called summer depression, may include: Trouble sleeping (insomnia) Poor appetite Weight loss Agitation or anxiety Seasonal changes in bipolar disorder In some people with bipolar disorder, spring and summer can bring on symptoms of mania or a less intense form of mania (hypomania), and fall and winter can be a time of depression. When to see a doctor It's normal to have some days when you feel down. But if you feel down for days at a time and you can't get motivated to do activities you normally enjoy, see your doctor. This is especially important if your sleep patterns and appetite have changed, you turn to alcohol for comfort or relaxation, or you feel hopeless or think about suicide.

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