First it was child abuse. Then spouse abuse. Now the social pathology of the American family has expanded to include a new one: parent abuse. Kids who push around or even beat up their parents are not uncommon, according to University of Maryland psychiatrists, and the attacks sometimes go as far as attempted murder. The violence is often sparked by parental attempts at discipline, but may also be the result of the parent's doing something the child doesn't like, such as drinking too much. In one case, an 11-year-old reacted to a spanking by pushing his mother into a door, breaking her back. He then kicked her in the face as she lay on the floor. An 18-year-old held a pistol to his mother's head when she refused to give him money. Another adolescent pushed his intoxicated father down a flight of stairs, and a teenage girl twice tried to kill her parents by setting the house on fire. The key to this sort of behavior, according to the psychiatrists, who reported their findings in the current American Journal of Psychiatry, is that almost all of the parents had abdicated their authority over their children. The children, finding themselves in a vacuum that they are not mature enough to handle, become violent, said Dr. Henry T. Harbin. And "very often the parent-victims reward the violent behavior by giving in or changing their position."