Study Sheds Light on a Potential Cause of Insomnia

In a study at Emory University, investigators have shed new light on a potential cause of insomnia, demonstrating that products of the immune system called cytokines may be the culprits. The study was published May 25, 2010 in the journal Biological Psychiatry.

Insomnia is a common sleep problem of unknown cause that occurs in about 10 percent of the population.

“Sleep disturbances are debilitating and often plague patients who have medical and psychiatric illnesses, exacerbating their conditions,” says Andrew Miller, MD, senior author and principal investigator of the study.

Miller is the William P. Timmie Professor of Psychiatry and Behavioral Sciences, Emory University School of Medicine, and director of Psychiatric Oncology, Winship Cancer Institute of Emory University.

“Our data suggests that cytokines may provide a link between disorders associated with chronic activation of the immune system, including medical and/or psychiatric illnesses and insomnia, which in turn is associated with fatigue and other problems,” says Miller.

Cytokines are fundamental signaling molecules of the immune system that allow communication of immune cells with each other as well as communication with other tissues, including the brain.

In the Emory study, participants were exposed to standardized doses of the cytokine interferon (IFN)-alpha for the treatment of hepatitis C where it activates the immune system to fight the virus.

During the three months the individuals were exposed to IFN-alpha, they showed marked deterioration of their sleep patterns. They woke up repeatedly during the night and spent much less time in the restorative, deep stages of sleep. During the day, these individuals were extremely fatigued. However, even when offered a nap, they still couldn’t sleep.

The investigators believe these findings may hold promise for novel treatments of insomnia that target the effects of cytokines on sleep. The team is currently conducting a follow-up study to determine if blocking cytokines improves sleep in depressed patients.

In addition to Miller, researchers participating in the study include Charles Raison, MD, David B. Rye, MD, Bobbi J. Woolwine, MSW, Gerald J. Vogt, PhD, Breanne M. Bautista, RN, and James R. Spivey, MD, from the Emory Departments of Psychiatry, Neurology and Digestive Diseases.

The National Institute of Mental Health funded the study. The abstract can be found at PubMed at http://www.ncbi.nlm.nih.gov/pubmed/20537611.

“Chronic interferon-alpha administration disrupts sleep continuity and depth in patients with hepatitis C: association with fatigue, motor slowing and increased evening cortisol.” Biol Psychiatry.

The Robert W. Woodruff Health Sciences Center of Emory University is an academic health science and service center focused on missions of teaching, research, health care and public service. Its components include the Emory University School of Medicine, Nell Hodgson Woodruff School of Nursing, and Rollins School of Public Health; Yerkes National Primate Research Center; Winship Cancer Institute of Emory University; and Emory Healthcare, the largest, most comprehensive health system in Georgia. Emory Healthcare includes: The Emory Clinic, Emory-Children's Center, Emory University Hospital, Emory University Hospital Midtown, Wesley Woods Center, and Emory University Orthopaedics & Spine Hospital. The Woodruff Health Sciences Center has $2.3 billion in operating expenses, 17,600 employees, 2,500 full-time and 1,500 affiliated faculty, 4,700 students and trainees, and a $5.7 billion economic impact on metro Atlanta. Learn more about Emory’s health sciences: http://emoryhealthblog.com - @emoryhealthsci (Twitter) - http://emoryhealthsciences.org