Emerging research has identified specific genes that may trigger the development of sleep problems. Moreover, new findings demonstrate a genetic link between insomnia and psychiatric disorders such as depression, or physical conditions such as type II diabetes.
Dr. Murray Stein of the University of California San Diego and colleagues at the VA San Diego Healthcare System conducted genome-wide association studies (GWAS) analyzing DNA samples obtained from more than 33,000 soldiers.
Data from soldiers of European, African and Latino descent were grouped separately as part of efforts to identify the influence of specific ancestral lineages. Stein and his colleagues also compared their results with those of two recent studies that used data from the UK Biobank.
Up to 20 percent of Americans and up to 50 percent of U.S. military veterans are said to have trouble sleeping. The effects insomnia has on a person’s health can be debilitating and place a strain on the health care system.
Chronic insomnia goes hand in hand with various long-term health issues such as heart disease and type II diabetes, as well as mental illness such as post-traumatic stress disorder (PTSD) and suicide.
The study appears in the journal Molecular Psychiatry.
The new research was informed by previous studies of twins that have found various sleep-related traits, including insomnia, are heritable. Based on these findings, researchers have started to look into the specific gene variants involved.
Stein says such studies are important, given the vast range of reasons why people suffer from insomnia, and the different symptoms and varieties of sleeplessness that can be experienced.
“A better understanding of the molecular bases for insomnia will be critical for the development of new treatments,” he adds.
Overall, the study confirms that insomnia has a partially heritable basis. The researchers also found a strong genetic link between insomnia and type II diabetes. Among participants of European descent, there was additionally a genetic tie between sleeplessness and major depression.
“The genetic correlation between insomnia disorder and other psychiatric disorders, such as major depression, and physical disorders such as type II diabetes suggests a shared genetic diathesis for these commonly co-occurring phenotypes,” said Stein.
The new research supports and will strengthen similar conclusions from prior twin and genome-wide association studies.
Insomnia was linked to the occurrence of specific variants on chromosome 7. In people of European descent, there were also differences on chromosome 9. The variant on chromosome 7, for instance, is close to AUTS2, a gene that has been linked to alcohol consumption, as well as others that relate to brain development and sleep-related electric signaling.
“Several of these variants rest comfortably among locations and pathways already known to be related to sleep and circadian rhythms,” Stein said.
“Such insomnia associated loci may contribute to the genetic risk underlying a range of health conditions including psychiatric disorders and metabolic disease.”