John Plotz writes for The New York Times:

By some miracle, you set aside a day to tackle that project you can’t seem to finish in the office. You close the door, boot up your laptop, open the right file and . . . five minutes later catch yourself thinking about dinner. By 10 a.m., you’re staring at the wall, even squinting at it between your fingertips. Is this day 50 hours long? Soon, you fall into a light, unsatisfying sleep and awake dizzy or with a pounding headache; all your limbs feel weighed down. At which point, most likely around noon, you commit a fatal error: leaving the room. I’ll just garden for a bit, you tell yourself, or do a little charity work. Hmmm, I wonder if my friend Gregory is around?

This probably strikes you as an extremely, even a uniquely, modern problem. Pick up an early medieval monastic text, however, and you will find extensive discussion of all the symptoms listed above, as well as a diagnosis. Acedia, also known as the “noonday demon,” appears again and again in the writings of the Desert Fathers from the fourth and fifth centuries. Wherever monks and nuns retreated into cells to labor and to meditate on matters spiritual, the illness struck.

New York Times: Their Noonday Demons, and Ours

(via Adam Gurri)

Acedia was also considered a precursor to the deadly sin of sloth.