Thacher surveyed 120 of  students at St. Lawrence University and found that students pulling all-nighters had an average GPA of 2.95, while student who had never pulled an all-nighter averaged 3.20.
Thacher’s results will be published in the January 2008 issue of Behavioral Sleep Medicine. Thatacher stated that this paper, “Establishes some preliminary data that pulling all-nighters is associated with lower GPAs (although for a few students this is not true).” [St. Lawrence University]

Another study by Thacher had similar results.

This conclusion parallels other studies that show a lack of sleep is bad for people, interfering with concentration and performance for students and workers.

Studies do show that people who study late into the night do not show this decline in performance and concentration if their circadian rhythm (relating to a 24-hour cycle) permits these night-owls to continue to learn. However, these people also do not stay up all night, only study later than most students.

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