Insomnia as a Public Health Issue: Sociomedical Determinants in the Adult Population of Serbia

Background/Objectives: Insomnia is a prevalent sleep disorder with substantial public health implications, yet epidemiological data from Serbia remain limited. This study aimed to assess the prevalence of clinically significant insomnia symptoms in the adult population of Serbia and to examine associated sociodemographic, comorbidity, psychosocial, and lifestyle factors. Materials and methods: A cross-sectional study was conducted from September 2023 to September 2025, including 2577 adults aged 18-89 years across Serbia. Insomnia symptom severity was measured using the Insomnia Severity Index (ISI), with scores ≥ 15 indicating clinically significant insomnia symptoms. Sociodemographic, comorbidity, psychosocial, and lifestyle factors were assessed via self-reported questionnaires. Multivariable logistic regression with LASSO variable selection was used to identify factors independently associated with clinically significant insomnia symptoms. Results: The prevalence of clinically significant insomnia symptoms (ISI ≥ 15) was 10.9%. Independent factors associated with clinically significant insomnia symptoms included being single (OR = 1.54) or divorced (OR = 1.75), lower educational attainment (OR = 0.71 per level increase), being retired (OR = 1.83) or a student (OR = 1.66), dermatological comorbidities (OR = 2.99), use of anxiolytic medications (OR = 2.44), exposure to stressful life events (OR = 1.88), engagement in late-night activities (OR = 1.37), consumption of coffee/tea (OR = 2.22), energy drink consumption (OR = 1.52), and late-night eating habits (OR = 1.27). Conclusions: Clinically significant insomnia symptoms among adults in Serbia are influenced by a complex interplay of sociodemographic, comorbidity, psychosocial, and lifestyle factors. These findings underscore the need for integrated approaches that address both medical and modifiable behavioral determinants in the prevention and management of insomnia symptoms.