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has been cited by the following article:

• TITLE: The Relationship between a Night Usage of Mobile Phone and Sleep Habit and the Circadian Typology of Japanese Students Aged 18 - 30 yrs

  AUTHORS: Takahiro Kawada, Tetsuro Kataoka, Fujiko Tsuji, Miyo Nakade, Milada Krejci, Teruki Noji, Hitomi Takeuchi, Tetsuo Harada

  KEYWORDS: Night Usage, Smart Phone, Sleep Habits, Circadian Typology, Mental Health, Japanese Students Aged 18 - 30 Years

  JOURNAL NAME: Psychology, Vol.8 No.6, April 30, 2017

  ABSTRACT: This study tries to investigate the current relationship between the habit to use mobile phone and the diurnal type scale and sleep habit in Japanese students. An integrated questionnaire was administered to 555 students aged 18 - 30 years old attending university and medical training schools for physical therapists and medical nurses (average age: 19.8 ± 1.6 years) in 2015. Integrated questionnaire included questions on sleep habits, the circadian typology, mental health (out of emotion-control, anger, irritation, depression), meal habits, the diurnal type scale (Torsvall & ?kerstedt, 1980). Most of all students have their own mobile phones and 96% of their phones are “smart phones”. Two hundreds and twenty four students of 531 ones used their phones within 30 min per one usage, whereas 180 students used it 5 - 6 hours per one. There have been significantly no differences in the diurnal type scale scores due to the durations of usage per one usage. Students who put their own mobile phones near to their body during night sleep occupied 461 of 543 students, and they were much more evening-typed than those who put their mobile phones at places far from bed in the same room (p