Impact of Smoking on Circadian Typology, Sleep Habits and Mental Health of Japanese Students Aged 18 - 30 Years

Many studies have shown that smoking can be related to worse sleep quality. However, as the impact of smoking, double view points on mental health and chronotype have been shortened. An integrated questionnaire including the diurnal type scale constructed by Torsvall & ?kerstedt, and questions on smoking was administered to 1376 students attending university and mental training schools (693 women and 683 men), 19.9 years on average in 2010-2013. Only 4.1% of the participants were smokers and they tended to be more evening-typed than non-smokers (p = 0.061). Smokers had significantly more difficulty falling asleep (p = 0.003) and more frequently lacked emotional control (p = 0.001) than non smokers. Smoking, being evening-type and having poor mental health may all be correlated in students attending Japanese university and medical training schools.