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Sun and Mood

What makes you feel good during a winter getaway may be more complex than a vacation from the rat race.

According to David LaPorte, sunlight suppresses melatonin, a hormone produced by the brain. LaPorte teaches Clinical Neuropsychology in IUP’s Clinical Psychology doctoral program.

“If you want to go to sleep, take some melatonin,” LaPorte said.

David LaPorte

David LaPorte [Photo: Keith Boyer]

According to LaPorte, people are more alert and active in the summer, and it’s directly related to the amount of available sunlight.

“If, in the middle of July, you go to the northern part of Sweden, it will be light until eleven o’clock at night, and people will be walking around all bright eyed and bushy tailed. They aren’t sleepy, because their melatonin is being suppressed,” he said. “Conversely, in the shorter months of the year in the latitudes where we are, melatonin doesn’t get suppressed and people get tired.”

As a clinician, LaPorte says the cause often presents as a mood disturbance, but more commonly, in winter months, people are lethargic—they want to sleep more, they eat more carbohydrates, and they tend to gain weight during that time. He suggested that people who visit sunnier climates in the winter tend to feel good because of the sun, but, upon return to darker climates at higher latitudes, they also return to feeling sluggish and depressed.

“It’s almost a leftover hibernation response,” he said. “Think about animals that hibernate and don’t do anything at all during that time. That’s sort of leftover in us, as human beings.”

Too much sunlight isn’t always a good thing, however. LaPorte said, generally, there are more violent crimes committed during the summer.

“During the winter, we have a buildup of melatonin and a lack of energy. In the summer, we have a lot more energy. The opposite of depression is mania,” LaPorte said. “When people are manic, they have large amounts of energy, and, because they don’t get as much sleep, they become irritable and violent.

When you look at when people are most violent over the summer, it’s not when it’s the hottest or the most humid. It’s when the most sunlight is available.”