An examination of sleep quality in middle school students in the context of smartphone addiction and morningness-eveningness preference

This study aimed to examine middle school students' sleep quality based on age, gender, smartphone use, and morningness-eveningness preference. An explanatory sequential mixed methods design was used. The sample included 672 students (368 girls, 304 boys), selected via purposive sampling. Qualitative data were also gathered from 70 of these students. Findings showed that smartphone addiction and morningness-eveningness preference significantly predicted sleep quality. Findings showed that smartphone addiction and morningness-eveningness preference significantly predicted sleep quality. Evening-type (E-type) students, whether addicted to smartphones or not, had lower sleep quality than neither-type (N-type) and morning-type (M-type) students. Among M-type students, smartphone addiction did not significantly affect sleep quality. However, for N-type and E-type students, addiction led to notable differences in sleep quality. M-type individuals used smartphones more before going to bed, while E-type individuals used smartphones more in bed. Statements indicated that smartphone-addicted E-type students (SPA E-types) were more exposed to room and screen light than non-addicted E-types (NSPA E-types). NSPA M-types, in contrast, displayed healthier sleep habits. Students also reported high screen exposure and frequent breakfast skipping, especially outside the NSPA M-type group. Overall, both smartphone addiction and eveningness are associated with poor sleep quality. This situation may negatively affect the development and health of individuals, especially in this age group. SPA E-type students, who are most negatively affected, can be informed about improving their sleep quality by following healthy sleep hygiene practices, such as adhering to regular sleep and wake-up times and reducing smartphone use before bed and in bed.