At one stage or another in our lives, all of us will experience difficulties falling asleep. It is a frustrating time, although while these nights might be sporadic occurrences for many of us, there are those suffer from extended periods of insomnia, leaving them with constant challenges to fall asleep or refrain from waking up throughout the night.
While the common causes of insomnia are believed to be linked to depression, stress, anxiety and other mental health issues, there has been research conducted for over a century in regards to its heritability. In this blog, Team Medexplain the research behind insomnia aggregating around families.
Since studies began back in the early sixties, there has been a growing amount of research suggesting a correlation between sufferers of insomnia and family members with similar conditions. In a recent 2015 study, conducted by Mackenzie J. Lind of the Virginia Institute for Psychiatric and Behavioural Genetics at Virginia Commonwealth University School of Medicine in Richmond, it is now estimated that the heritability of insomnia is around 59 per cent for women, and 38 per cent for men.
Locating the ‘Insomnia Genes’
Researchers started looking into the heritability of insomnia by focusing on the genes most involved in the sleeping process. Studies revolved around circadian rhythm genes and the neurotransmitters responsible for the regulation of sleep, however they found a significant shortage of reliable evidence that would suggest these candidate genes were causing insomnia on an inherited basis.
Work has since progressed with a different approach in locating candidate genes. This includes genome-wide association studies, in which vast amounts of a person’s genetic code is scanned in order to locate any particular ties to inherited traits and insomnia. Curious findings identified many possible candidate genes and genetic regions, with some even being specifically based on gender, which may explain the percentages mentioned earlier. In the largest GWAS of insomnia, in which 1,331,010 people were analysed, 956 genes across 202 locations were found with a link to insomnia.
How Stress Stills Plays a Part
Although serious revelations are emerging in modern research, the heritability of insomnia is not certain. A person is also more at risk of developing insomnia due to environmental factors, such as stress. How stress affects the brain and our sleeping behaviours isn’t completely understood, either, however there is a wealth of evidence suggesting that stressful events can change how genes are expressed in our cells, which may in turn be at the heart of insomnia.
Essentially, it is understood that insomnia does have a significant genetic relationship, however further research is needed to gain a complete understanding of this phenomenon.