Seasonal Affective Disorder (SAD) in winter is a widely-known phenomenon. There is less sunlight during winter days, which affects the serotonin ("happy" hormones) produced in response to light striking our pineal gland, causing depression and listlessness. But not many people are aware that SAD has a summer equivalent as well. Studies performed on people in countries near the equator have found that their populations often suffer from SAD in the summer months. But what can be its cause?For some people, the seasonal change to summer can cause depression, agitation and irritability. Although it is thought to affect only 1% of the population, it is a real phenomenon nevertheless. Not everyone is happy with hot temperatures, and many people suffer through the increased heat and humidity. It becomes more difficult to sleep, many suffer a loss of appetite and/or just don't want to cook in hot, steamy weather. They may exercise less because of the heat and spend hours in an air-conditioned living room watching TV because it's too hot to do anything else. We are also very much creatures of habit, and any change to our daily routine and circadian rhythms (which are responsible for the sleep-wake cycle) can upset our balance. In summer the kids are home, families often go to sleep and wake up at different times and have a whole new daily routine. In the midst of all that, many Americans and Europeans choose to take their annual vacation during these months, which further upsets their regular schedules (as pleasant as that interruption usually is). Your habits of sleep, work and meals can change radically in the summer months. Then there's the issue of body image. In the cooler months, those of us who do not still maintain the body of an active 20-year-old can cover up our various bumps and bulges in loose sweaters. Not so in the summer. Even a modest bathing suit at the beach reveals more than many of us would like. And many people starve themselves in an effort to get their "bikini body" back for their two-week holiday by the sea, adding to the stress their body must endure. Finally, the financial strain that a summer vacation puts on the budget can also take its toll. In addition, many working parents have to pay for childcare in the summer, or have to fork out a significant sum for camp, so summer is not always the best time for a family financially, increasing stress and rates of summer depression. And for families who can't afford either childcare option, three solid months of having the kids at home all day can drive even the most patient parent up a wall. To combat summer depression, there are a number of things you can do. First, be sure you give yourself sufficient sleep and exercise. It's tempting to stay up later than usual in the summer months, but remember that 7 to 8 hours of sleep a night are necessary in order to function at your best. If it's too hot to exercise, try exercising late at night or early in the morning before things heat up. You can also join an air-conditioned gym for a couple of months until things cool down. Eat a sensible, balanced diet high in fruits and vegetables, which help to keep you hydrated while providing important nutrients. Don't try to lose a bunch of weight all at once. Planning ahead is your best option, as you can put away a little money every month toward your summer holiday and can also gradually lose any excess weight before beach season without putting stress on your body. Finally, plan to do something fun. Call a friend to come over and join you to share a movie in your air-conditioned house or go out for exotic cocktails with your partner. The good news is that summer depression can be prevented or managed with a just little advance planning. Those who suffer from summer SAD often find that the symptoms disappear with the return of fall and a more "normal" lifestyle rhythm. However, if you find that your depression continues well after the seasons begins to turn, it may be a good idea to consult your physician.