Sleep disorders are common, with chronic sleep conditions affecting up to 20% of the population.1 Insomnia is the most common of these disorders, having chronic effects on approximately 10–15% of the population.1-3 However, prevalence data for sleep disorders vary between sources, due to differences in the diagnostic criteria used, and the timeframe examined.
Ohayon (2002) concluded that when insomnia is measured based on the definition outlined in DSM-IV, approximately 33% of the general population would display at least one of the symptoms, falling to 9–15% when the definition includes daytime consequences.4
A recent international survey of sleep problems in the general population provided information from >10,000 individuals aged ≥15 years.5 The prevalence of sleeping problems varied with geographic location – of those individuals surveyed, 56% in the US, 31% in Western Europe, and 23% in Japan, reported difficulty with sleeping.5 Most individuals considered that their sleep problems had an impact on their daily functioning.5
The prevalence of sleep disorders generally increases with age, and a US epidemiological study of 9,000 people revealed that 29% of older adults (aged 65 years or over) have some difficulty in falling asleep or staying asleep.6 The prevalence of chronic insomnia is highest (20%) in adults aged 65 years or over,7 and approximately 67% of all insomnia prescriptions, in the Major 5 EU countries and the US, are dispensed to elderly patients (>65 years).8 One of the key reasons for a high prevalence of insomnia in the elderly is their susceptibility to other illnesses such as Alzheimer’s disease, Parkinson’s disease, arthritis, and depression – all of which have a tendency to lead to residual insomnia.
References:
1. Kandel ER, Schwartz JH, Jessell TM. Principles of neural science.© The McGraw-Hill Companies Inc, 2000.
2. Mendelson WB, Roth T, Cassella J, et al. The treatment of chronic insomnia: drug indications, chronic use and abuse liability. Summary of a 2001 New Clinical Drug Evaluation Unit meeting symposium. Sleep Med Rev 2004; 8 (1): 7–17.
3. Sateia MJ, Nowell PD. Insomnia. Lancet 2004; 364 (9449): 1959–1973.
4. Ohayon MM. Epidemiology of insomnia: what we know and what we still need to learn. Sleep Med Rev 2002; 6 (2): 97–111.
5. Léger D, Poursain B, Neubauer D, Uchiyama M. An international survey of sleeping problems in the general population. Curr Med Res Opin 2008; 24 (1): 307–317.
6. Foley DJ, Monjan AA, Brown SL, et al. Sleep complaints among elderly persons: an epidemiologic study of three communities. Sleep 1995; 18 (6): 425–432.
7. Ancoli-Israel S, Roth T. Characteristics of insomnia in the United States: results of the 1991 National Sleep Foundation Survey. I. Sleep 1999; 22 (Suppl 2): S347–S353.
8. IMS Prescribing Insight, 2006.