This paper summarizes recent epidemiological evidence on insomnia, including its prevalence, incidence, and risk factors, as well as its course and consequences. There is now substantial evidence that insomnia is a significant public health problem. It is a highly prevalent condition, both as a symptom and a syndrome, and is often a persistent condition over time. Its persistence is associated with increased risk for mental (major depression), physical (hypertension), and occupational health problems (disability). Chronic insomnia also carries heavy economic burden, both in terms of direct healthcare costs and, more importantly, in terms of human resources loss due to the illness and lack of treatment. These findings have direct implications for community-based prevention and intervention programs and for future research including the need for: a) longitudinal, population-based studies aimed at evaluating whether we can prevent insomnia among at-risk individuals; b) clinical studies evaluating whether the morbidity associated with chronic insomnia is reversible; and c) prospective health economic evaluations of prevention programs using different dissemination technologies.
Key Points• The epidemiology of insomnia has received increased attention in the last decade and investigators have moved from a purely cross-sectional approach to a more prospective and longitudinal approach.• Progress on the epidemiology of insomnia has been hampered by important methodological shortcomings including, but not limited to, the lack of a consistent case definition and standardized assessment procedures across studies.• Additional prospective and longitudinal studies are needed to identify early precursors of insomnia and factors moderating its trajectories over time.• A better understanding of how insomnia evolves over time and what factors trigger an episode or perpetuate it over time is critical for developing effective prevention and treatment programs.
Outline• Introduction • Nature of insomnia complaints and updated diagnostic criteria • Prevalence and correlates of insomnia • Incidence and risk factors • Course of Insomnia -persistence, remission, relapse • Consequences and burden of insomnia