Common Illness with an Estimated Prevalence of 10%-15%, and a Median Duration of 4 Years,

PRIMARY INSOMNIA, MEETING DSM-IV CRITERIA, IS A COMMON ILLNESS WITH AN ESTIMATED PREVALENCE OF 10%-15%, AND A MEDIAN DURATION OF 4 YEARS, with more than one-third of patients reporting chronicity in excess of 10 years.1-3 Cross-sectional studies, utilizing varying definitions, have found the complaint of insomnia to be associated with impaired quality of life and reduced productivity and functioning,4 increased healthcare utilization,4,5 increased risk of accidental injury,6,7 and substantial overall economic cost estimated at well over $20 billion in the United States alone.8 Chronic symptoms of insomnia appear to be associated with an increased risk of coronary events,9,10,11 reduced immune function,12,13 as well as a significantly increased risk of developing major depression.14 Whether effective treatment reduces these health risks has not yet been tested. The etiology of chronic insomnia is uncertain, though it is likely to be multifactorial. Transient insomnia may be initially triggered by medical stressors (e.g., pain or illness), psychological stressors (e.g., marital or work stress), or disruptive environmental conditions (e.g., shift work, noisy or uncomfortable sleep setting).15,16,17 In some individuals (the precise proportion is uncertain due to lack of longitudinal studies), transient insomnia persists and may evolve into a chronic illness.18 Treatment recommendations for chronic insomnia typically include sleep hygiene training and pharmacologic or nonpharmacologic interventions,19 though a review recently noted that the benefits of sleep hygiene in chronic insomnia are not yet supported by data from controlled treatment research.20 Recognition of the extent to which insomnia is a chronic and/or recurring illness has led some investigators to call for a systematic program of longitudinal clinical trials research, modeled on the past 20 years of treatment research in depression.21 Only a small handful of double-blind, placebo-controlled trials have been reported which evaluate the efficacy of hypnotics beyond 2 months of nightly treatment.22,23 Additionally, a few double-blind, placebo-controlled trials have studied the long-term (>2 months) efficacy of non-nightly (as needed) treatment for insomnia.24 Overall, the results of these studies have been positive; but given the extensive long-term use of hypnotics, a recent NIH Consensus Conference noted the need for additional long-term treatment studies.25 Long-Term Nightly Treatment with Indiplon in Adults with Primary Insomnia: Results of a Double-Blind, Placebo-Controlled, 3-Month Study Martin B. Scharf, PhD1; Jed Black, MD2; Steven Hull, MD3; Rick Landin, PhD4; Robert Farber, PhD4