This study offers a comprehensive overview of the associations between sleep quality, EDS, chronotype, and a wide range of behavioral and psychosocial factors in a large, population-based sample of Italian adolescents.
Notably, the sample included students from all high schools in the city of Savona, covering a broad cross-section of the adolescent population across multiple grades. Such comprehensive, city-wide recruitment is relatively uncommon in adolescent sleep research and adds to the strength and applicability of the findings. These characteristics make the results particularly informative for guiding local and regional health policies aimed at improving adolescent well-being.
In particular, our findings reveal that sleep disturbances are highly prevalent among adolescents, with 52% of participants classified as poor sleepers according to PSQI. Additionally, 21.6% of adolescents reported clinically relevant levels of daytime sleepiness. These data are consistent with international literature, which documents that more than half of adolescents have suboptimal sleep quality, with negative impacts on mental health, academic performance, and overall well-being22–24.
Clinically significant daytime sleepiness, poses a real risk to cognitive function, emotional regulation, and safety, including an increased likelihood of accidents and risky behaviors25,26. Moreover, daytime sleepiness and poor sleep quality are strongly associated with psychiatric disorders, such as anxiety and depression, and can predict the onset of psychiatric disorders in later years27,28.
The data suggest that the problem transcends geographical and socioeconomic boundaries and
highlight the need for targeted public health initiatives at the local and regional level to address the potential short- and long-term consequences of insufficient sleep in this vulnerable age group29,30 and to consider sleep as a key determinant of adolescent health.
The observed associations between multiple sociodemographic, behavioral, and psychological characteristics with poor sleep quality, reinforce previous research identifying adolescence as a critical period for sleep vulnerability31.
Adolescents experiencing poor sleep quality and daytime complaints were more likely to report high psychosocial stress, in line with evidence that stress-related hyperarousal can interfere with sleep onset, maintenance, and restorative function32. School-related stress emerged as a strong predictor across multiple sleep outcomes, consistent with research showing that academic pressure contributes to shorter sleep duration and reduced sleep efficiency33. Similarly, family-related stress was strongly linked to reported poor sleep, underscoring the importance of family dynamics in adolescent sleep regulation34,35. This may reflect a greater sensitivity of the adolescent brain to chronic stress, which can impair emotional regulation and lead to heightened arousal in the evening, ultimately disrupting sleep quality. Stress in the family context was also associated with an eveningness tendency. Although this specific finding has not been previously reported, it is plausible that family dynamics and parental support, by fostering better sleep quality, may positively influence sleep hygiene and, consequently, sleep timing34,35. Conversely, the evening chronotype has been linked to increased behavioral and emotional problems, which may in turn negatively affect parent–adolescent relationships36. Unexpectedly, mild school-related stress emerged as a protective factor for EDS. This suggests that moderate academic demands may enhance daytime alertness without necessarily improving nocturnal sleep parameters. These results are consistent with the concept of eustress, which may promote cognitive engagement and daytime functioning independently of sleep quality37. Interestingly, school type also showed an independent association with EDS: students attending technical or vocational schools, typically perceived as less academically demanding and more practice-oriented, were less likely to report excessive daytime sleepiness compared to their peers in traditional academic tracks. This protective association between vocational/technical school attendance and reduced daytime sleepiness is underexplored in the literature. Further studies are needed to understand how different educational structures, such as curriculum demands, daily schedules, and practical versus theoretical learning, may shape adolescent sleep patterns and alertness.Finally, positive relationships with peers were found to be associated with higher sleep quality according to the PSQI, although the literature on this topic is sparse and often contradictory38.
Digital media use emerged as a significant risk factor across multiple sleep-related outcomes. Spending more hours online during the day was associated with poor sleep quality, increased daytime sleepiness, and a preference for eveningness. This pattern may reflect the combined effects of cognitive hyperarousal, irregular daily routines, and reduced exposure to natural light39,40. Moreover, keeping the phone on at night was specifically linked to poorer sleep quality, suggesting that evening screen use and nighttime notifications may interfere with sleep onset and continuity through both psychological and physiological mechanisms41,42. These findings add to growing concerns about the impact of pervasive digital media habits on adolescent sleep health. Moreover, the temptation to use media can override the need for sleep, a recent meta-analysis reveals in adolescents a strong correlation between nighttime sleep interruptions due to smartphone ringing and incoming notifications that can interrupt sleep at any stage.
Recent theoretical models have moved beyond a unidirectional “technology impairs sleep” framework. In particular, Bauducco et al.43 proposed a bidirectional model in which poor sleep may also promote increased technology use through mechanisms such as emotion regulation and time filling before sleep. This perspective highlights that digital media habits and sleep difficulties may reinforce each other over time, underscoring the importance of addressing both behavioral and emotional processes in adolescent sleep health.
Several lifestyle-related variables were significantly associated with one or more sleep outcomes, pointing to the relevance of daily habits in shaping adolescent sleep health. Being male was associated with an increased risk of poor sleep quality. While the reasons for this gender difference remain debated, possible explanations include higher externalizing behaviors, lower sleep hygiene awareness, or a reduced propensity to report sleep problems until they become pronounced44,45.
Substance use appeared to have differentiated effects on sleep-related domains. Smoking cigarettes was associated not only with poor sleep quality, but also with a preference for eveningness. This may reflect the stimulating effects of nicotine on arousal systems, as well as behavioral patterns, such as late-night smoking, that reinforce delayed bedtimes46. Moreover, nicotine has been associated with disruption of circadian rhythm due to altered clock gene expression in animal models47,48. Similarly, frequent cannabis use was associated with an evening chronotype.
Consistently, previous literature has shown that eveningness correlates with greater impulsivity, emotional dysregulation, and a propensity for risky behaviors, which facilitate the initiation and maintenance of cannabis use in adolescence49,50. These data suggest that the evening chronotype is a relevant target for prevention and early screening interventions in public health programs aimed at adolescents.
Alcohol use, particularly binge drinking, was associated with greater daytime sleepiness in our sample. Experimental and clinical studies have shown that alcohol disrupts sleep architecture by reducing REM sleep, increasing nocturnal awakenings, and fragmenting overall sleep continuity51. Moreover, our data confirm a bidirectional relationship between alcohol consumption and eveningness, with adolescents who prefer later sleep timing more likely to engage in binge drinking, and alcohol use further reinforcing delayed sleep schedules52,53. This pattern may lead to cumulative sleep deprivation, especially during school days, ultimately resulting in increased daytime sleepiness51.
Our findings underscore the need to address adolescent sleep health as a multidimensional public health issue.
Interventions should extend beyond individual behavior change and include structural strategies such as adjusting school start times, integrating sleep education into curricula, and developing programs to promote healthier lifestyle habits, such as improved nutrition, regular physical activity, and reduced substance use, while also addressing family-wide stress management.
Programs aimed at improving sleep hygiene among adolescents, even when implemented in large-scale studies, have shown measurable benefits on various sleep and psychosocial health parameters. The most effective strategies typically include behavioral education on sleep, the promotion of regular routines, reduced use of electronic devices before bedtime, and in some cases, the integration of mindfulness techniques. Structured school-based interventions, even of short duration, have been associated with improvements in sleep quality, total sleep duration, and reductions in social jetlag, particularly when delivered by teachers and complemented by mindfulness-based activities54–56. Programs that involve adolescents actively in the design of the intervention, address specific barriers such as screen use and academic pressure, and include components targeting parents tend to be more effective and better accepted55,57. However, large-scale, structured intervention studies are still scarce in the Italian context, where most research has focused on identifying risk factors and pre-sleep habits58,59.
This study has some limitations. Its cross-sectional design does not allow for causal inference, and reliance on self-reported data may introduce recall and reporting bias. Furthermore, data were collected before the COVID-19 pandemic, which significantly affected adolescent sleep patterns60 and contributed to increased levels of stress and psychiatric symptoms61,62. For this reason, subjecting the post-pandemic generation of high school students to the same assessment tool could reveal interesting results.
Nonetheless, the use of validated instruments and the inclusion of a large, citywide sample strengthen the robustness and generalizability of the findings.
Future longitudinal and interventional studies are warranted to evaluate whether modifying sleep hygiene, screen time, and stress management behaviors can yield long-term improvements in sleep quality and daytime functioning. Developing scalable, school-based programs that incorporate sleep health into broader mental health and lifestyle promotion initiatives could help mitigate the widespread impact of sleep deprivation in this population.