f you're going overseas for work, London is said to be a plum assignment. Joseph Kennedy brought his family to London in 1938, when he was named ambassador to England by President Franklin D. Roosevelt. The Kennedys are said to have had a wonderful time here despite World War II. I suppose I should consider myself and my family lucky; I was called to London six months ago to help launch another health-related Internet company and brought my wife and three children with me. We all thought it would be a great adventure -- the kids would be exposed to a new culture, and my wife and I could enjoy the sophisticated city of London as residents, not tourists. Certain aspects of being overseas do make London seem like the choice assignment it is purported to be. But those positive aspects do not include the famously bad English weather.

Since my arrival six months ago, it has rained nearly every day. The standing joke in my office is, If you don't like the weather in London, just wait 15 minutes. On a typical day, the sky is overcast, it rains, and it's sunny for brief periods. On the evening weather report, the forecaster measures the amount of sunshine in hours per day: "We had 1.2 hours of sunshine today" or "We've experienced a cumulative total of 0.8 hours of sunshine since dawn."

Don't get me wrong, London is a fantastic city. But coming here from Austin, Texas, where the sun bakes the entire state nearly every day, I am convinced this dark English weather is getting me down. This summer it rained for weeks at a time and was cloudy with intermittent sunshine, and according to the British, Mother Nature was being rather generous. They kept warning me, "Wait till the winter, when it doesn't get light till 8 a.m. and gets dark by 3 p.m."

My family and I aren't exactly strangers to depressing weather. Before moving to Texas, we lived in New England, where the winters are normally dark and long. With the short days and the icy cold of Connecticut, we all felt pretty down for a few months -- especially when all three of our children had colds at the same time.

Clearly, where you live is a key factor in determining whether or not you get SAD. Those living in New England are more likely to suffer from SAD than people living in Texas, simply due to the decreased amount of light.

To pick our spirits up during those dark days, my wife and invested in specially designed light boxes for our kitchen, where we spent the majority of our time. After just a few short days of morning light therapy, the entire family seemed happier. We're not the only ones who benefited from increased light in our day; several medical studies show that daily exposure to the brilliant light generated by specialized phototherapy units provides marked relief from winter depression. Doctors call this form of depression or moodiness seasonal affective disorder. The cause is very simple: lack of natural light.

Seasonal affective disorder, or SAD, is an extreme form of the winter blues that actually results in clinical depression. It is estimated that 11 million Americans suffer from the condition in the winter and that 25 million others have a milder form of the winter blues. Women are more likely to develop SAD than men are. The condition typically starts in September or October and can last until April. People who have this type of winter depression actually experience a shift in their circadian rhythm (i.e., their "biological clock") because waking up in darkness causes negative shifts in people's sleep/wake cycle. Decreased daylight causes people to feel sleepy and withdrawn. SAD results when the brain's pineal gland increases production of the sleep-inducing hormone melatonin in the darker winter months, resulting in sleepiness, apathy, fatigue, and depression.

Studies show that people with mild SAD benefit from using household fluorescent or incandescent bulbs for 30 minutes to 2 hours of "light therapy" every morning in the winter. By reducing melatonin production, light therapy alleviates symptoms of depression. But research also shows that most extreme sufferers of SAD require exposure to much brighter light. Therapeutic levels are at least five times higher (as measured in lux, the unit that measures light intensity) than that provided by ordinary lamps and ceiling fixtures in the home or office. Average domestic or office lighting emits an intensity of 200-500 lux; the minimum dose necessary to treat severe SAD is 2,500 lux. To put this in perspective, on a bright summer day the sun can emit a whopping 100,000 lux. Special light boxes are commercially available that can provide a high intensity of light -- between 2,500 and 10,000 lux -- and filter out ultraviolet waves.

Clearly, where you live is a key factor in determining whether or not you get SAD. Those living in New England are more likely to suffer from SAD than people living in Texas, simply due to the decreased amount of light.

Unfortunately, we didn't bring our special light boxes to England, and I already regret it. Julie keeps saying she is trying to "hibernate the winter away" by staying in bed longer in the mornings and going to bed earlier. She says she thinks she must have been a bear in a previous life. Trudging through the bleak and rainy London weather, she is often uncharacteristically blue and withdrawn. But if the sun shines through the clouds even for even a brief moment, it brings an instant smile to her face. My response to winter darkness has been to eat more, particularly potato chips, and to stay indoors. Our kids are often moody and throw more temper tantrums than usual in the winter. We try every day to be more British in our approach to the weather -- stiff upper lip and all. Until we master that, we're importing some light boxes from the United States.

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