Grant: Travel Awards - Institute Community Support

Insomnia is a prevalent sleep disorder in the general population that produces negative effects on personal health (increased risk of psychological and medical problems) and society (greater health-care costs). The risk of insomnia is higher in individuals with at least one family member also suffering from insomnia than individuals with a family member not suffering from insomnia. To show that insomnia may be explained by genetics, researchers must first show evidence of "familial aggregation", that is, show that insomnia tends to "run" in families more than what would be expected by chance. This study aimed to examine if familial aggregation of insomnia is greater in biological relatives of individuals with and without insomnia. To see if there were any environmental influences on insomnia, spouses of individuals with and without insomnia also participated in the study. Biological relatives (n=371) and spouses (n=138) completed a survey on the type, severity, and frequency of sleep disturbances to determine if they had or did not have insomnia. Results indicated that biological relatives of individuals with insomnia had a significantly higher risk of also having insomnia than biological relatives of individuals without insomnia, regardless of age and sex. The increased risk of insomnia was particularly higher in siblings of individuals with insomnia than siblings of individuals without insomnia. The risk of insomnia was high in spouses of individuals with insomnia than spouses of individuals without insomnia, but not statistically different. Overall, findings show evidence of strong familial aggregation of insomnia. These results have important implications, as they may be used to better understand insomnia risk factors and to help design more effective treatment and prevention programs for "at-risk" people (if related to someone with insomnia). More research is needed to better understand the relative contribution of genetic and environmental factors in insomnia.