I came across an abstract in the August 25th online edition of the journal Sleep and Biological Rhythms about the relationship between nightmares and sleep time preference. Researchers administered questionnaires to 264 medical students, ages 17 to 26 years old. They assessed if the students were morning (morning lark) or evening (night owl) types, the quality of their sleep, and how frequently they experience nightmares.
The results showed that men were more likely than women to be night owls. Night owls were more likely to report poor sleep quality, daytime sleepiness, and distrubing nightmares than morning larks. The authors point out that night owls are more likely to have substance abusers, bulimia, other sleep disorders, ADHD, suicidality, and mood disorders. Also, night owls could have increased stress because of the difficulty holding down a job or attend classess if you are not able to wake up until the late morning. These factors could explain why night owls are more prone to nightmares.