BAGHDAD—According to members of his squad, 22-year-old Army Pfc. Casey Schreiner, who has been stationed in Iraq's Sunni Triangle for nearly a year and a half, is nearing completion of his psychological withdrawal from the war that constantly surrounds him. "The timetable for his exit certainly isn't optimal—we still need him to stay with us," said Cpl. Chris Oswald, adding that Schreiner began pulling out mentally little by little as members of his platoon were killed by roadside bombings, sniper shootings, and various personnel carrier and helicopter crashes. "At this rate, I think he'll be completely gone by spring." U.S. and coalition commander in Iraq Lt. Gen. David Petraeus said Schreiner is just one of thousands of troops who have experienced a phased cerebral withdrawal, adding that throughout the next year an estimated 20,000 more are expected to stage a retreat from reality.