For some, it seems that anxiety about or obsession with death makes them want to reread the books or rewatch the "Harry Potter" films, said Lance Garmon, an assistant professor at Salisbury University in Maryland in the US.
"For people who do dwell on death, the series could serve as a coping mechanism," Garmon said.
Researchers studied more than 400 college students. Participants were asked to identified how many times they had read each of the books and watched each of the movies in the "Harry Potter" series.
They were then asked a series of questions about why they read or watched both, as well as about how prominently death featured in their daily thoughts.
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People in the study who had read the books at least nine times or watched the movies at least 30 times were considered to have high exposure to the series, 'Live Science' reported.
The high-exposure group reported higher death awareness. For example, they ruminated on death or were anxious about the thought of death - compared with the low-exposure group.
People who said they do it as a way to cope or form their own identity were most likely to have higher levels of death awareness, compared with people who read or watched primarily for entertainment, Garmon said.