The New York Times, July 18, 1993:

The blues are more commonplace in winter, and behaviorists have found that deprivation of sunlight in the winter months can cause a form of depression labeled season affective disorder.

But more recently a condition that is believed to be caused by prolonged exposure to high heat and humidity has been described by researchers at the clinical psychobiology branch of the National Institute of Mental Health.

The "summer blues" causes sufferers to become lethargic and have difficulty functioning at work and home... The problem is not a result of exposure to too much sunlight on long summer days, said Dr. Normal E. Rosenthal, a researcher at the mental health institute, but probably has to do with irregularities in areas of the brain, most notably the hypothalamus, that help regulate body temperature.

Just as the winter malady can be cleared up with exposure to artificial sunlight, the summer blues can be chased away if individuals cool down by remaining in air-conditioned environments or spending summers in colder climates, he said.

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