http://www.sfgate.com/cgi-bin/article.cgi?f=/n/a/2007/12/14/national/a000711S88.DTLA survey of 120 students at St. Lawrence University, a small liberal arts college in northern New York, found that students who have never pulled an all-nighter have average GPAs of 3.2, compared to 2.95 for those who have. The study, by assistant professor of psychology Pamela Thacher, is to be included in the January issue of Behavioral Sleep Medicine.
A second study by Thacher, a clinical psychologist, had "extremely similar" results showing lower grades among the sleep skippers.