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.

These days, when we try to get a fix on our wasted time, we use labels that run from the psychological (distraction, “mind-wandering” or “top-down processing deficit”) to the medical (A.D.H.D., hypoglycemia) to the ethical (laziness, poor work habits). But perhaps “acedia” is the label we need. After all, it afflicted those whose pursuits prefigured the routines of many workers in the postindustrial economy. Acedia’s sufferers were engaged in solitary, sedentary, cerebral effort toward a clear final goal — but a goal that could be reached only by crossing an open, empty field with few signposts. The empty field is the monk’s day of spiritual contemplation in a cell besieged by the demon acedia — or your afternoon in a coffee shop with tiptop Wi-Fi.

In the later Middle Ages, monks performed fewer solitary tasks, and as the historian Andrew Crislip has shown, their vulnerability to the torments of acedia diminished. But for early medieval writers, acedia’s symptoms were so prolific as to be often contradictory. For St. Benedict, the affliction took the shape of “a little black boy pulling the monk away by the hem of his garment,” while to the great fourth-century ascetic Evagrius it sometimes appeared as “demons that touch our bodies at night and like scorpions strike our limbs.” Gluttony and laziness can betoken acedia, one Desert Father, St. John Cassian, warns. However, “excesses meet” and “reluctance to eat and . . . lack of sleep put me in much greater danger.” The only real constant, during acedia’s heyday, was that it prevented monks and nuns from keeping their minds on their tasks, and their bodies in the right place. “Have you deserted your cell?” Basil the Great asks. “Then you have left continency behind you.”