Susan Jeffrey

May 09, 2012

May 9, 2012 (Philadelphia, Pennsylvania) — A new study suggests that treating sleep disorders, and sleep apnea in particular, is associated with improvement over baseline in symptoms of comorbid psychiatric disorders.

"There is a strong need for prospective studies" to further define this relationship, Umesh Vyas, MD, chair of the Department of Psychiatry and medical director of the Sleep Disorders Center in the Mayo Clinic Health System in Mankato, Minnesota, told a press conference here.

The results were presented at the American Psychiatric Association's (APA's) 2012 Annual Meeting.

Dr. Abid Malik

In a separate report, Abid Malik, MD, medical director of the Adult Unit A and of the Sleep Disorder Center at South Seminole Hospital of Orlando Health and assistant professor of psychiatry at the University of Central Florida College of Medicine, in Orlando, reviewed the literature on sleep parameters, in this case, rapid eye movement (REM) sleep latency, in patients with anxiety disorders to see whether this may provide a biological biomarker, as has been shown previously with major depression.

Chicken or Egg?

In his report, Dr. Vyas pointed out that sleep is an essentially physiological need, critical for physical, mental, and emotional well-being. Sleep disorders are often comorbid with psychiatric conditions such as depression, but the directionality of the relationship is not clear.

Dr. Vyas said he feels the relationship between sleep and psychiatric disorders is probably bidirectional, such that sleep disorders can exacerbate psychiatric issues and vice versa. For example, he said, the literature shows that around 40% of patients with psychiatric disorders have comorbid insomnia, hypersomnia, as well as documented changes in sleep architecture.

The current study was a retrospective, observational chart review that aimed to investigate the impact of the treatment of sleep disorders on the outcome of psychiatric disorders. Electronic records from the sleep disorders clinic at the Milwaukee Veterans Affairs Medical Center from October to December 2007 were included. All charts were reviewed at 6, 12, and 24 months after the start of treatment for a sleep disorder.

These patients received a baseline psychiatric status score of 0 regardless of the severity of the disorder or the nature of the condition. Change in status at each subsequent time point was scored on a Likert scale: +2 (marked improvement), +1 (mild improvement), 0 (no change), -1 (mild worsening), or -2 (marked worsening).

Change in average score for psychiatric disorders was compared individually at each time point to baseline using the signed rank test. Compliance with sleep disorder treatment was also compared between patients with and without psychiatric disorders using Fisher's exact test. Difference in score changes at each time point to baseline was compared for specific psychiatric disorders using Wilcoxon test.

A total of 117 patients were included. Of these, 97.6% were men — not surprising, given that this is a population of veterans, the vast majority of whom were between 40 and 80 years of age.

The most common sleep disorder diagnosis was sleep apnea, Dr. Vyas said. Comorbid psychiatric disorders were present in 54 patients (46.2%).

Between baseline and 24 months, Dr. Vyas found that psychiatric status significantly improved compared with baseline at all time points. The change in average score from baseline was + 0.45 at 6 months, + 0.56 at 12 months, and + 0.79 at 24 months (P < .0001).

There was no difference in the compliance rate with sleep disorder treatment regardless of whether a psychiatric disorder was present, he said.

No significant improvement was seen for individual psychiatric conditions; however, most of the patients had multiple psychiatric diagnoses, making the number of patients in each group smaller and potentially resulting in a loss of statistical power to detect such a difference, he noted.

He pointed to several limitations of his study, including the fact that all charts were reviewed by 1 reviewer (himself), raising the possibility of personal bias, and the use of a Likert scale, which has its own limitations, including a tendency for scores to cluster around the center.

Marker for Anxiety?

In a separate article, Dr. Malik investigated the hypothesis that sleep derangement, specifically REM sleep abnormalities, might be a potential biomarker for the presence of underlying anxiety disorders.

Interest in finding biological biomarkers for psychiatric illnesses has been longstanding, Dr. Malik noted, but the search for such biomarkers has not been particularly successful.

There are a number of similarities between depression and anxiety disorder when it comes to treatment, he said. Fluoxetine, sertraline, and venlafaxine, for example, are all approved by the US Food and Drug Administration for major depressive disorder, but they are also approved for obsessive-compulsive disorder (OCD), panic disorder, and other conditions.

"That made us think that if the same medication is effective in depression and anxiety disorder, is there a shared, common pathophysiological pathway that might underlie both anxiety and depressive disorder?" Dr. Malik said.

A metaanalysis published in 2011 suggested that increased REM density and shortened slow-wave sleep may represent a biological biomarker for major depressive disorder, he said. In this study, Dr. Malik conducted a literature review of studies that have investigated sleep parameters in patients with anxiety disorders.

Although such studies are few, in OCD, he found 5 that had control populations. None of these studies were done specifically to look at biological biomarkers, but he was able to extrapolate the data, "which has its own limitations," he noted. "But we can see there's a trend, that patients with OCD seem to have increased REM latency, which means they go into REM sleep sooner than control subjects."

For generalized anxiety disorder (GAD), there were only 3 eligible studies, and they showed mixed results, some indicating increased REM latency and others decreased latency in patients with GAD. Similarly, in panic disorder, the signal was mixed in the studies reviewed with regard to REM sleep latency.

In summary, he said, "most of the studies are not done with this purpose in mind, and some of the studies are small, so there is some limitation, but at least it gives us some trends."

In addition, this study looked only at REM latency, but other aspects of sleep may be of interest, including total time in REM sleep and any fragmentation in REM sleep. "Now that we have a more uniform way of scoring sleep stages, it will be easier to compare studies."

Future studies are needed to look more closely at these relationships, he concluded.

Sleep Critical

Jeffrey Borenstein, MD, medical director of Holliswood Hospital in New York City and chair of the APA Council on Communications, moderated the press conference here.

Commenting on these studies, he said that it is important to understand that in a number of psychiatric conditions, the disorder itself includes an element of sleep disturbance. "Often the complaint, the issue that brings a person to treatment, is a sleep issue, so we as psychiatrists have to be very sensitive to that and be proactive to help with that," Dr. Borenstein said.

"The other side of the coin is there are stressors that can increase the risk of developing a psychiatric condition, and poor sleep is one of the stressors. So it's really important, and I'm pleased that of the 7 presentations today, 2 of them were focused on sleep, because it is such an important issue."

Dr. Vyas, Dr. Malik, and Dr. Borenstein have disclosed no relevant financial relationships.

The American Psychiatric Association's 2012 Annual Meeting. Abstract #NR8-35, NR4-10. Presented May 6 and May 8, 2012.

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