Insomnia is an extremely common symptom both de novo and in the contex
t of other medical and psychiatric disorders. The impact of insomnia i
s often ignored both by the individual and by society in terms of its
clinical and socioeconomic ramifications. Insomnia is therefore under-
appreciated and almost certainly under-treated, thus making it a serio
us health concern. It is estimated that more than 60 million Americans
suffer from insomnia annually, and this figure is expected to grow to
100 million by the middle of the 21st century. Whether it be difficul
ty initiating or maintaining sleep, the disruption of nocturnal sleep
will invariably impact on daytime activities and often results in dayt
ime fatigue, performance deficits (including memory and other cognitiv
e deficits), an increase in the number of sick days taken by an indivi
dual and accidents (some catastrophic). This review examines the costs
directly related to insomnia in various sectors of healthcare, the in
direct costs associated with accidents, sick days and decreased work p
roductivity, and related costs resulting from insomnia but which meet
neither the criteria of direct nor indirect cost categories. The total
direct, indirect and related costs of insomnia are conservatively est
imated at $US30 to 35 billion annually in the US (1994 dollars). Econo
mic gains can be made by treating patients on an outpatient basis in s
leep centres.