An excerpt from a New York Times article:
For some people, however — an estimated 15 percent of the bereaved population, or more than a million people a year — grieving becomes what Dr. M. Katherine Shear, a professor of psychiatry at Columbia, calls “a loop of suffering.” And these people, Dr. Shear added, can barely function. “It takes a person away from humanity,” she said of their suffering, “and has no redemptive value.”