Posts tagged anxiety

ScienceDaily (May 15, 2012) — A novel mechanism for anxiety behaviors, including a previously unrecognized inhibitory brain signal, may inspire new strategies for treating psychiatric disorders, University of Chicago researchers report.

By testing the controversial role of a gene called Glo1 in anxiety, scientists uncovered a new inhibitory factor in the brain: the metabolic by-product methylglyoxal. The system offers a tantalizing new target for drugs designed to treat conditions such as anxiety disorder, epilepsy, and sleep disorders.

The study, published in the Journal of Clinical Investigation, found that animals with multiple copies of the Glo1 gene were more likely to exhibit anxiety-like behavior in laboratory tests. Further experiments showed that Glo1 increased anxiety-like behavior by lowering levels of methylglyoxal (MG). Conversely, inhibiting Glo1 or raising MG levels reduced anxiety behaviors.

"Animals transgenic for Glo1 had different levels of anxiety-like behavior, and more copies made them more anxious," said Abraham Palmer, PhD, assistant professor of human genetics at the University of Chicago Medicine and senior author of the study. "We showed that Glo1 was causally related to anxiety-like behavior, rather than merely correlated."

In 2005, a comparison of different mouse strains found a link between anxiety-like behaviors and Glo1, the gene encoding the metabolic enzyme glyoxylase 1. However, subsequent studies questioned the link, and the lack of an obvious connection between glyoxylase 1 and brain function or behavior made some scientists skeptical.

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May 14, 2012

What goes bump in the night? In many U.S. households: people. That’s according to new Stanford University School of Medicine research, which found that about 3.6 percent of U.S. adults are prone to sleepwalking. The work also showed an association between nocturnal wanderings and certain psychiatric disorders, such as depression and anxiety.

The study, the researchers noted, “underscores the fact that sleepwalking is much more prevalent in adults than previously appreciated.”

Maurice Ohayon, MD, DSc, PhD, professor of psychiatry and behavioral sciences, is the lead author of the paper, which will appear in the May 15 issue of Neurology, the medical journal of the American Academy of Neurology.

Sleepwalking is a disorder “of arousal from non-REM sleep.” While wandering around at night can be harmless and is often played for laughs — anyone remember the Simpsons episode where Homer began wandering around and doing silly things in his sleep? — sleepwalking can have serious consequences. Episodes can result in injuries to the wanderer or others and lead to impaired psychosocial functioning.

It is thought that medication use and certain psychological and psychiatric conditions can trigger sleepwalking, but the exact causes are unknown. Also unclear to experts in the field is the prevalence.

"Apart from a study we did 10 years ago in the European general population, where we reported a prevalence of 2 percent of sleepwalking," the researchers wrote in their paper, "there are nearly no data regarding the prevalence of nocturnal wanderings in the adult general population. In the United States, the only prevalence rate was published 30 years ago."

For this study, the first to use a large, representative sample of the U.S. general population to demonstrate the number of sleepwalkers, the researchers also aimed to evaluate the importance of medication use and mental disorders associated with sleepwalking. Ohayon and his colleagues secured a sample of 19,136 individuals from 15 states and then used phone surveys to gather information on participants’ mental health, medical history and medication use.

Participants were asked specific questions related to sleepwalking, including frequency of episodes during sleep, duration of the sleep disorder and any inappropriate or potentially dangerous behaviors during sleep. Those who didn’t report any episodes in the last year were asked if they had sleepwalked during their childhood. Participants were also queried about whether there was a family history of sleepwalking and whether they had other parasomnia symptoms, such as sleep terrors and violent behaviors during sleep.

The researchers determined that as many as 3.6 percent of the sample reported at least one episode of sleepwalking in the previous year, with 1 percent saying they had two or more episodes in a month. Because of the number of respondents who reported having episodes during childhood or adolescence, lifetime prevalence of sleepwalking was found to be 29.2 percent.

The study also showed that people with depression were 3.5 times more likely to sleepwalk than those without, and people with alcohol abuse/dependence or obsessive-compulsive disorder were also significantly more likely to have sleepwalking episodes. In addition, individuals taking SSRI antidepressants were three times more likely to sleepwalk twice a month or more than those who didn’t.

"There is no doubt an association between nocturnal wanderings and certain conditions, but we don’t know the direction of the causality," said Ohayon. "Are the medical conditions provoking sleepwalking, or is it vice versa? Or perhaps it’s the treatment that is responsible."

Although more research is needed, the work could help raise awareness of this association among primary care physicians. “We’re not expecting them to diagnose sleepwalking, but they might detect symptoms that could be indices of sleepwalking,” said Ohayon.

Among the researchers’ other findings:

• The duration of sleepwalking was mostly chronic, with just over 80 percent of those who have sleepwalked reporting they’ve done so for more than five years.
• Sleepwalking was not associated with gender and seemed to decrease with age.
• Nearly one-third of individuals with nocturnal wandering had a family history of the disorder.
• People using over-the-counter sleeping pills had a higher likelihood of reporting sleepwalking episodes at least two times per month. (Indeed, a sleeping pill was the trigger for Homer Simpson’s middle-of-the-night shenanigans.)

D. Le’ger, MD, PhD, from the Universite Paris Descartes in France, was senior author of the study. Researchers from the University of Minnesota Medical School, the Hopital Gui-de-Chauliac in Montpellier, France, and Duke University School of Medicine were also involved.

Provided by Stanford University Medical Center

Source: medicalxpress.com