Family studies in insomnia.
OBJECTIVE
Several predisposing factors to insomnia have been hypothesized, including a familial component; however, few studies have focused on this topic. The aim of this study is to evaluate the prevalence of insomnia among first-degree relatives of chronic insomniacs and to compare the symptoms between sporadic and familial insomnia.


METHODS
Two hundred fifty-six consecutive chronic insomniacs completed a clinical interview, psychometric questionnaires, a questionnaire on the family history of insomnia and, when indicated, a polysomnography. A control group was performed to estimate a base-rate incidence of insomnia in their families.


RESULTS
Patients with primary (n=77) and psychiatric (n=104) insomnia were definitely included. Of those with primary insomnia, 72.7% reported familial insomnia compared with 24.1% in the noninsomnia control group. Among the psychiatric insomniacs, 43.3% reported familial insomnia. The mother was the relative most frequently affected. Comparisons between the family prevalence rates of insomnia assessed by the probands and by first-degree relatives show high concordance. A tendency to a younger age at onset was observed in familial and primary insomnia.


CONCLUSIONS
This study reports a significant increase of familial aggregation of insomnia, warranting further genetic studies in primary insomnia with early age at onset.
Dauvilliers
Yves
Y
Service de Neurologie B, Hôpital Gui-de-Chauliac, 80 Avenue Augustin Fliche, Montpellier cedex 5 34295, France. ydauvilliers@yahoo.fr
Morin
Charles
C
Cervena
Katerina
K
Carlander
Bertrand
B
Touchon
Jacques
J
Besset
Alain
A
Billiard
Michel
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D020132:Anticipation, Genetic / Q000235:genetics; D002908:Chronic Disease; D005260:Female; D006580:Genetic Carrier Screening; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D017286:Polysomnography; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology / Q000235:genetics* / Q000523:psychology