Psychological and Demographic Predictors of Insomnia Severity: Evidence from a Community Sample in Ecuador

(1) Background: Insomnia is one of the most prevalent sleep disorders worldwide and a growing public health concern, yet the combined contribution of psychological and demographic factors remains understudied in Latin America. This study aimed to examine how perceived stress, generalized anxiety, and sociodemographic variables predict insomnia severity in Ecuadorian adults. (2) Methods: A community sample of 698 participants (31.7% men; M = 25.6 years, SD = 10.4) completed an online survey during nationwide electricity blackouts in 2024. Measures included the Insomnia Severity Index (ISI), the Perceived Stress Scale (PSS-10), the Generalized Anxiety Disorder Scale (GAD-7), and a demographic questionnaire. Hierarchical linear regressions were conducted to evaluate the relative contribution of predictors. (3) Results: Demographic variables (age, sex, employment status, and socioeconomic level) were not significant predictors of insomnia severity (R² = 0.007). Perceived stress strongly predicted insomnia (ΔR² = 0.207, <i>p</i> < 0.001), and generalized anxiety added further explanatory power (ΔR² = 0.074, <i>p</i> < 0.001), with both factors contributing independently (β ≈ 1.96 and β ≈ 2.67). Interaction effects with socioeconomic status were non-significant. (4) Conclusions: Psychological factors explained nearly one-third of the variance in insomnia severity, underscoring the importance of stress and anxiety as core predictors and supporting the need for integrated psychological interventions to improve sleep health in Ecuador.