Pre-Existing Insomnia Linked to Mental Disorders After Military Deployment
Soldiers who have troubles sleeping before their deployments may be at greater risk of developing posttraumatic stress disorder (PTSD), depression and anxiety once they return home.
A new study, published in the journal SLEEP, found that pre-existing insomnia symptoms posed almost as large of a risk for those mental disorders as combat exposure.
"Understanding environmental and behavioral risk factors associated with the onset of common major mental disorders is of great importance in a military occupational setting," lead study author Philip Gehrman, PhD, assistant professor of Psychology at the University of Pennsylvania said in a statement.
"This study is the first prospective investigation of the relationship between sleep disturbance and development of newly identified positive screens for mental disorders in a large military cohort who have been deployed in support of the recent operations in Iraq or Afghanistan," he added.
Researchers looked at self-reported data from the Millennium Cohort Study to evaluate the association of pre-deployment sleep duration and insomnia symptoms on the development of new-onset mental disorders among 15,204 service members. Researchers identified 522 people with new-onset PTSD, 151 with anxiety and 303 with depression following deployment. Researchers found that combat-related trauma and pre-deployment insomnia symptoms were significantly associated with higher odds of developing posttraumatic stress disorder, depression, and anxiety.
"One of the more interesting findings of this study is not only the degree of risk conferred by pre-deployment insomnia symptoms, but also the relative magnitude of this risk compared with combat-related trauma," Gehrman explained. "The risk conferred by insomnia symptoms was almost as strong as our measure of combat exposure in adjusted models."
The findings revealed that short sleep duration or sleeping less than six hours a night, separate from general insomnia, was associated with new-onset PTSD symptoms.
"We found that insomnia is both a symptom and a risk factor for mental illness and may present a modifiable target for intervention among military personnel," Gehrman said. "We hope that by early identification of those most vulnerable, the potential exists for the designing and testing of preventive strategies that may reduce the occurrence of PTSD, anxiety, and depression."
Researchers said the next step is to study whether routine inquiry about insomnia symptoms and early intervention could reduce subsequent mental disorders.