Research Spotlight: The warning signs of sudden panic

panic disorder

Research Spotlight: The warning signs of sudden panic

Panic attacks that seem to strike out of the blue are not without warning after all, says SMU psychologist Alicia Meuret.

In a rare study in which patients were monitored around the clock as they conducted their daily activities, portable recorders captured changes in respiration, heart rate and other bodily functions. The researchers discovered that waves of significant physiological instability occurred for at least 60 minutes before patients became aware of an impending panic attack, says Meuret, associate professor of psychology and lead researcher on the study.

The new findings suggest sufferers of panic attacks may be highly sensitive to – but unaware of – an accumulating pattern of subtle physiological instabilities that occur before an attack, Meuret said. (By definition, the majority of the 13 symptoms of panic attack are physiological: shortness of breath, heart racing, dizziness, chest pain, sweating, hot flashes, trembling, choking, nausea and numbness.) Monitoring data also showed patients were hyperventilating on a chronic basis.

“Most patients obviously feel that there must be something going on physically,” Meuret says. “They worry they’re having a heart attack, suffocating or going to pass out. Our data doesn’t indicate there’s something inherently wrong with them physically, neither when they are at rest nor during panic. The fluctuations that we discovered are not extreme; they are subtle. But they seem to build up and may result in a notion that something catastrophic is going on.”

Notably, the researchers found that patients’ carbon dioxide (C02) levels were in an abnormally low range, indicating the patients were chronically hyperventilating. These levels rose significantly shortly before panic onset and correlated with reports of anxiety, fear of dying and chest pain.

“It has been speculated, but never verified with data recordings in daily life, that increases in CO2 cause feelings of suffocation and can be panic triggers,” Meuret says.

Meuret and her colleagues discovered these patterns using change-point analysis, a statistical method that searches for points when changes occur in a “process” over time.

“This analysis allowed us to search through patients’ physiological data recorded in the hour before the onset of their panic attacks to determine if there were points at which the signals changed significantly,” says SMU Associate Professor of Psychology David Rosenfield, lead statistician on the project.

The study is significant not only for panic disorder, but also for other medical problems where symptoms and events have seemingly “out-of-the blue” onsets, such as seizures, strokes and even manic episodes.

In a multidisciplinary collaboration, other authors on the study were psychologist Thomas Ritz, SMU Department of Psychology; psychologist Frank H. Wilhelm, University of Salzburg, Austria; electrical engineer Enlu Zhou, University of Illinois at Urbana-Champaign; and psychologist Ansgar Conrad and psychiatrist Walton T. Roth, both of Stanford University.

Meuret discusses their work in an SMU Research video. Click the YouTube screen at right to watch, or click this link to see the video on panic disorder research in a new window.

Written by Margaret Allen

> Read more at the SMU Research blog
> Visit SMU’s Stress, Anxiety & Chronic Disease Research Program website

August 23, 2011|Research|

Research Spotlight: Reduced anxiety may be a breath away

A new treatment program teaches people who suffer from panic disorder how to reduce the terrorizing symptoms by normalizing their breathing.

The method has proved better than traditional cognitive therapy at reducing both symptoms of panic and hyperventilation, according to a new study.

The biological-behavioral treatment program is called Capnometry-Assisted Respiratory Training, or CART, said SMU assistant professor of psychology and panic disorder expert Alicia Meuret.

CART helps patients learn to breathe in such a way as to reverse hyperventilation, a highly uncomfortable state where the blood stream operates with abnormally low levels of carbon dioxide, said Meuret, one of the researchers conducting the study. Hyperventilation results from excessively deep or rapid breathing and is common in patients with panic disorders.

“We found that with CART it’s the therapeutic change in carbon dioxide that changes the panic symptoms – and not vice versa,” Meuret said.

During the treatment, patients undergo simple breathing exercises twice a day. A portable capnometer device supplies feedback during the exercises on a patient’s CO2 levels. The goal of these exercises is to reduce chronic and acute hyperventilation and associated physical symptoms. This is achieved by breathing slower but most importantly more shallowly. Contrary to lay belief, taking deep breaths actually worsens hyperventilation and symptoms.

“Most panic-disorder patients report they are terrified of physical symptoms such as shortness of breath or dizziness,” Meuret said. “In our study, cognitive therapy didn’t change respiratory physiology, but CART did effectively reduce hyperventilation. CART was proved an effective and powerful treatment that reduces the panic by means of normalizing respiratory physiology.”

The findings, “Respiratory and cognitive mediators of treatment change in panic disorder: Evidence for intervention specificity,” appeared in the Journal of Consulting and Clinical Psychology. Meuret, who developed CART, is co-director of the the Stress, Anxiety and Chronic Disease Research Program in the Department of Psychology of SMU’s Dedman College. The Beth & Russell Siegelman Foundation funded the research.

The study pitted CART against a conventional cognitive therapy treatment, or CT. Traditional CT teaches patients techniques aimed at helping them change and reverse catastrophic thoughts in order to reduce fear and panic.

In the CART-CT study, 41 patients were assigned to complete either a CART or CT treatment program for panic disorder and agoraphobia, a fear of being trapped with no means of escape or help.

Both treatment programs were equally effective in reducing symptoms, said Meuret. But CART was the only treatment to physiologically alter panic symptoms by actively reversing hyperventilation in the patients. Cognitive therapy didn’t change the respiratory physiology, said Meuret.

he researchers plan to branch out with their studies on CART by taking the program into the community, particularly to ethnic minorities. They believe CART is a more universally understood treatment due to its physical exercises – as opposed to cognitive therapy’s more intellectual methods – and therefore more accessible to a broader range of people with varying levels of education and different cultural backgrounds. Ongoing studies will test the efficacy of CART in patients with asthma and fear of blood.

Co-authors of the study at SMU were David Rosenfield, associate professor of psychology, and psychology graduate students Anke Seidel and Lavanya Bhaskara. Stefan G. Hofmann, psychology professor at Boston University, was also an author on the paper.

Written by Austin Reed

> Read more from the SMU Research blog
> Watch a video demonstration of CART techniques through the SMU YouTube channel video

January 26, 2011|Research|
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