Insomnia Among Adolescents in Northern Peru: Associations with Psychosocial, Health-Related, and Educational Factors in a Cross-Sectional Study Across Five Schools

Background/Objectives: Insomnia is common among adolescents and is associated with emotional, behavioral, and academic difficulties. Although high rates have been reported globally, evidence in Latin America—particularly in Peru—remains limited and heterogeneous. Many previous studies relied on small samples, descriptive designs, omitted key psychosocial variables, or were conducted during early pandemic waves, despite the rise in sleep disturbances following COVID-19 restrictions. This study aimed to estimate the prevalence of insomnia and identify associated factors among adolescents in northern Peru. Methods: An analytical cross-sectional study was conducted using secondary data from students attending five schools in Lambayeque, Peru. Insomnia was assessed using the Insomnia Severity Index (ISI). Sociodemographic, psychosocial, behavioral, and health-related variables—including self-esteem, family dysfunction, eating disorders, acne severity, mental health help-seeking, and digital behavior—were evaluated. Generalized linear models estimated prevalence ratios (PRs) and 95% confidence intervals (CIs). Results: Among 1313 adolescents (54.3% male; mean age 14.6 years), the prevalence of insomnia was 38.9% (95% CI: 36.1–41.5). In adjusted analyses, insomnia was associated with urban residence, non-Catholic religion, seeking mental health support, high social media use, internet use of 6–10 h/day, low self-esteem, eating disorders, greater acne severity, and experiencing the death of a family member due to COVID-19. Conclusions: Nearly four in ten adolescents reported insomnia, influenced by sociodemographic, psychosocial, and lifestyle-related factors. These findings provide updated post-pandemic evidence for the Peruvian context and highlight the multifactorial nature of adolescent insomnia. Further research is needed to clarify causal pathways and understand the long-term mental health implications of large-scale stressors such as the COVID-19 pandemic.