Previous research has suggested that genetic factors are involved in insomnia, but little was known about the specific risk genes for the sleep disorder. In a study of more than 113,000 people, Danielle Posthuma at the Vrije University Medical Center in Amsterdam and her colleagues compared the genomes of people who reported that they struggle to fall asleep or stay asleep at night with those of people who never or only sometimes experience such problems. The team found five genes and one section of the genome that were associated with insomnia. The gene with the strongest association, MEIS1, has previously been linked to restless legs syndrome. The analysis also revealed strong genetic correlations between insomnia and anxiety, neuroticism and depression.

The findings could help researchers to uncover the molecular mechanisms behind insomnia.