Interestingly, they also found a genetic overlap with anxiety disorders, depression and neuroticism, and low subjective wellbeing. Anke Hammerschlag, a neuroscientist and first author of the

study, said: “This is an interesting finding, because these characteristics tend to go hand in hand with insomnia.  “We now know that this is partly due to the shared genetic basis.”

Additionally, slightly more women than men tend to suffer. Professor Danielle Posthuma, of Vrije Universiteit Amsterdam, said: “We also found a difference between men and women in terms of

prevalence: in the sample we studied, including mainly people older than fifty years, 33 per cent of the women reported to suffer from insomnia. For men this was 24 per cent.”