Epidemiology of Insomnia: Prevalence and Risk Factors

Insomnia is among the most prevalent health complaints, with approximately 10 to 15% of the general population suffering regularly from it and about 25 to 35% presenting transient or occasional insomnia (Ancoli-Israel & Roth, 1999; Ohayon, 2002; Morin et al., 2006; Doghramji, 2006; LeBlanc et al., 2009). However, many questions remain unanswered with regard to our understanding of insomnia and prevalence estimates vary because of inconsistent definitions and diagnostic criteria. In addition, the use of baseline and followup assessments to establish incidence and remission rates can be problematic because of the wide spectrum of insomnia duration (e.g., a positive finding of insomnia at baseline and 1year follow-up may reflect unremitting chronic insomnia or 2 episodes of transient insomnia) (Roth, 2001; Young, 2005).