(CBS) — If you think it’s been overcast for a very long time, it’s not just you.

We have now had five consecutive days of 100 percent cloud cover.  And 11 of the past 15 days have been completely overcast, says AccuWeather Meteorologist Bob Larson.

“This time of year, on average, is the cloudiest time of year,” he tells WBBM’s Steve Miller. “ This is a little excessive, though.”

Rush University Medical Center Psychiatrist Dr. Robert Shulman says his staff and his patients are talking about the lethargy that comes when the sun doesn’t appear.

He says Seasonal Affective Disorder, or SAD, is something that psychiatrists have been talking about for decades.

“A 1933 issue of the Psychiatric Quarterly,” Shulman says. “I was looking for another paper but I came across something that said, ‘Light Therapy.’ Can you imagine what light therapy was in 1933? It was the psychiatrist in New York City putting his patient on the train for South Florida for two weeks at the end of December.”

Shulman says SAD is a kind of depression that’s really a kind of human hibernation.

The remedy: “You give yourself a dose of a full-spectrum light at a certain intensity early in the morning and sometimes toward the end-of-the-day period. So, just when it starts to get dark, you give another dose sometimes.

“And basically what you’re doing is tricking the brain into thinking that it’s midsummer.”

Dr. Shulman says turning on all the lights at home is not enough. He says it takes a light box — a full-spectrum light with 10,000 lux.

By the way, the forecast is mostly cloudy for at least the next few days.