Genetics of Insomnia

Insomnia is the most prevalent sleep disorder, but surprisingly little attention has been paid to genetic risk factors until the past decade. Twin and family aggregation studies have found that 30–40% of variability in insomnia is due to genetic factors. Candidate gene studies found associations between insomnia and a range of genes involved in circadian rhythms and neurotransmitter function, but results have often failed to replicate. Rapid increases in available genome-wide association data have led to a burst of significant associations, with several replicating in multiple cohorts. The findings support substantial pleitropy with genetic risk factors for psychiatric disorder, suggesting that insomnia-specific genetic effects are unlikely to be found. There is now a need for these genetic variants to be explored in model systems to determine which are truly causal for insomnia.