Several studies in recent years have suggested that people with panic disorder are more likely to attempt suicide than patients with other psychiatric conditions. One explanation was that panic disorder, when combined with clinical depression, made people more prone to suicide.
The study appears in a recent issue of the journal Behaviour Research and Therapy.
But the new study suggests that there are other anxiety-related factors that play an important role in whether patients with panic disorder consider suicide, said Brad Schmidt, an associate professor of psychology at Ohio State University.
"Depression is a very significant predictor of whether or not a patient with panic disorder will engage in some kind of suicide behavior," Schmidt said. "But depression alone doesn't account for it all."
The researchers found four mental health factors, aside from depression, that may predict suicidal behavior in a person with panic disorder. They include a patient's overall level of anxiety; fear of panic attacks; sensitivity to and avoidance of certain unpleasant physical sensations, such as heart palpitations; and phrenophobia, or the fear of losing one's mind. In this study, suicidal behavior was defined as either thinking about or attempting suicide.
"There are specific components of anxiety that contribute to suicidal behavior, even though these factors are less substantial than depression," said Schmidt, a study co-author and also the director of the anxiety and stress disorders clinic at Ohio State.
Panic disorder is a psychiatric condition defined by sudden, unprovoked attacks of fear and panic.
The researchers asked 146 subjects with panic disorder to take a variety of tests in order to assess the extent of each patient's disorder. These tests included evaluations for depression, current thoughts of suicide, medical history and panic-related symptoms, such as the frequency of panic attacks, phobias, and the intensity of anxiety symptoms.
Nineteen percent of the patients in the study were diagnosed with major depression. Of these, 43 percent reported current suicidal thoughts, compared to 10 percent of patients without a diagnosis of major depression.
Also, suicidal thoughts were more prevalent among patients diagnosed with agoraphobia - the fear of open areas and public places. More than half of the subjects (59 percent) were diagnosed with agoraphobia, and one in four of those reported thoughts of suicide, compared to 6 percent of the patients who were not agoraphobic.
The researchers found that suicidal ideation - thinking about committing suicide - was related to more than just depression alone. The perceived severity of an anxiety disorder may increase a patient's level of distress, in turn, increasing the chances that he or she will engage in suicidal behavior.
"Additional anxiety problems play an important role in the relationship between panic disorder and actual suicide attempts," Schmidt said. He and his colleagues found that a history of suicide attempts was associated with higher levels of anticipatory anxiety - or fear of panic attacks - and a tendency to be particularly sensitive to physical sensations that the patient deemed unpleasant.
They also found that the higher the overall level of anxiety, the more likely a person was to consider suicide.
Although additional anxiety factors may worsen a patient's state of mind, depression is still an important link between panic disorder and thoughts of suicide.
"While depression leaves patients at risk for the development of suicidal thoughts, the relationship between panic disorder and suicide is greatly reduced when depression is out of the picture," Schmidt said.
This study was supported by a grant from the U.S. Department of Defense.
Schmidt co-authored the study with Kelly Woolaway-Bickel, a graduate student in psychology at Ohio State, and Mark Bates, of the Uniformed Services University of the Health Sciences in Bethesda, Md.
Contact: Brad Schmidt; 614-292-2687; Schmidt.283@osu.edu
Written by Holly Wagner, 614-292-8310; Wagner.235@osu.edu