docotor's notepad with words sleep apnea written on it

The results of a new study show that 52 percent of male military veterans with bipolar disorder and post-traumatic stress disorder experience sleep apnea. About 58 percent of those with major depressive disorders and PTSD have the sleep condition.

Male military veterans who have a combination of post-traumatic stress disorder (PTSD) and mood disorders are more likely to experience sleep apnea, according to a recent study involving a researcher at The University of Texas at Dallas.

The study was published online recently in the journal The Primary Care Companion for CNS Disorders.

“It is already known that there is a higher incidence of sleep apnea in patients with major depression or PTSD, but there seems to be an even higher bump in apnea when they go together,” said Dr. William Katz, professor of communication disorders in the School of Behavioral and Brain Sciences.

“There’s something synergistic about having PTSD and these mood disorders that correlates with higher sleep apnea,” he said.

Katz worked on the study with lead author Dr. Bettina Fehr of the VA North Texas Health Care System in Dallas and assistant professor of psychiatry at UT Southwestern Medical Center. The researchers analyzed the health records of 413 male and female veterans who visited a psychiatry outpatient clinic over a four-month period. A majority of the patients were men.

After the veterans were screened with a questionnaire about obstructive sleep apnea, their diagnoses were confirmed with a sleep study. The incidence of sleep apnea was then associated with the patients’ psychiatric conditions.

Katz outdoors

Dr. William Katz

Results showed a high prevalence of sleep apnea in the male patients, ranging from 17 percent for those with bipolar disorder (BD) to 38 percent for those with major depressive disorders (MDD). Since mood disorders such as MDD or BD often co-occur with PTSD, the rates of sleep apnea in these individuals also were examined. The results revealed rates as high as 52 percent for men with BD and PTSD, and 58 percent for those with MDD and PTSD.

Katz said the research provides the first evidence of a statistically higher incidence of sleep apnea in male veterans who have both BD and PTSD, or both MDD and PTSD, compared with men diagnosed with only one of the disorders. Because the number of women in the study was small, the researchers could not detect meaningful differences between diagnostic groups.

Katz said the connection between sleep apnea and the disorders in the male veterans is not clear.

“Correlation is not causation, so it’s a bit difficult to know which way it goes,” Katz said. “It could be that individuals with PTSD have horrible nightmares, which break up their sleep. It could also go the other way, where having sleep apnea kind of wakes you up and then leads to more PTSD symptoms.”

He said other factors contributing to apnea can include medications and obesity since many psychiatric medications can lead to weight gain. However, weight was not associated with the differences found between groups with or without sleep apnea in this study.

Katz said that while there were limitations to the study, the results highlight the importance of screening patients for sleep apnea, especially when they have been diagnosed with a combination of mood disorders and PTSD.