Background: Although the relationship between problematic social media use (PSMU) and happiness has been already explored, less is known about the mechanisms that translate PSMU into lower happiness through lifestyle habits. Therefore, the current study focuses on the association between PSMU and happiness, exploring a mediating effect of lifestyle habits (e.g., difficulties in getting to sleep and frequency of physical activity) among Italian adolescents. Methods: A total of 58,976 Italian adolescents (mean age = 13.6, SD = 1.63; age range = 10.5−16.5; 49.4% females) were included. The pattern of relationships specified by the theoretical model was examined through path analysis. Results: Difficulties in getting to sleep (β = −0.037, p < 0.001) and frequency of physical activity (β = −0.012, p < 0.001) were mediators in the relationship between PSMU and happiness. Multi-group analyses across gender and age groups (11, 13, and 15 years old) showed that the chain mediating effect of the frequency of physical activity on the difficulties in getting to sleep was not significant for females but significant for males and for all of the three age groups. Overall, females and older ages were sensitive to the whole model. Conclusion: Along with difficulties in getting to sleep and the frequency of physical activity, lifestyle habits may contribute to the association between PSMU and happiness. We also recommend that future studies focus on PSMU in females and older adolescents, as they show more general sleep problems and reduced physical activity.
Keywords: happiness; path analysis; physical activity; problematic social media use; sleep.