Panic Disorder Blood Test May Aid Treatment

Sept. 21, 2007 — -- Harriet Brown, 49, has struggled with panic disorder her entire life.

"I remember going out to lunch with colleagues," she said. "On one level I was fine. On another level, I was absolutely freaking out. I had sweaty palms. It was like play life. That's what it's been like for me, having to carry on when I feel horrible inside."

Although Brown began suffering from panic disorder at the age of 8, she was not diagnosed until she was in her early 20s.

"It was a huge relief to be diagnosed with something that had a name," she said. "Until my 20s, I thought I was crazy or that something was wrong with me. I went through a lot of it's all in your head stuff from doctors that really was not helpful."

Soon after her diagnosis, Brown relied mostly on therapy but now prefers medication.

"For me [panic disorder] is not about anything," Brown said."I spent time in therapy trying to figure out what it was. I understood a lot of things about my family, but it didn't stop the panic attacks. For example, you can have PD crossing a bridge. You can think crossing the bridge is the problem, but it's not. I think it's a biological mechanism that goes haywire," she said.

Testing Genes for Panic Disorder

Dr. Robert Philibert is developing a blood test that can help people like Brown who live with panic disorder.

The test, which measures the gene expression in lymphocytes in a person's blood, would enable doctors to determine whether a patient has the condition.

"Panic disorder will no longer be a purely descriptive diagnosis, but as with cystic fibrosis, Down syndrome and other conditions, a diagnosis based on genetic information," explained Philibert, a professor of psychiatry at the University of Iowa College of Medicine.

Philibert warned, however, that the test is only predictive and very costly.

"We're offering a test that won't be cheap by any standards -- anywhere between $200 to $1,000 to the patient or insurance companies," he said. "The ideal person for the test is someone for whom a difference in the course of treatment is worth the cost of the test."

For some patients, the test will allow a better diagnosis of the disorder.

"For example, if a patient has chest flutters, it could be panic disorder or ventricular tachycardia," he said. "Ventricular tachycardia is not panic disorder, and it can kill you. If in this case, the test came back negative, then [the patient] would need further testing."

Dr. Charles Glatt, assistant professor of psychiatry at Weil Cornell Medical College, agreed.

"A blood based test would be really valuable," Glatt said. "Although the DSM [Diagnostic and Statistical Manual of Mental Disorders] has helped a great deal in terms of standardizing diagnoses, they're still very subjective. That's why [we] want to get to the biology."

Changing Attitudes

Philibert insisted that panic disorder is grave and warrants greater attention from the medical community.

"A lot of these people develop agoraphobia and are holed up in their house, or drink to lower anxiety and develop alcoholism," he said. "People say, 'Panic disorder? Just get over it.' Yeah, right.

"People do the best they can, but we're just people. Not Greek deities -- who, by the way, had their own faults."

He is also convinced that the test could help improve the medical community's attitude toward panic disorder by giving it a biological basis.

"They think it's a character weakness," he said. "It's no different from obesity or diabetes. There are things you can do to decrease it, but if you're gonna get it, you're gonna get it. There's nothing you can do about it.

According to Philibert, 10 million people suffer from panic disorder. "It doesn't mean we're gonna vote you off the island," he said. "If it makes their day better, great. In the end, that's what it's about."

A Genetic Report Card?

Dr. Beverly Yashar, assistant professor of human genetics at the University of Michigan, said that Philibert's test represents a recent shift in the medical community.

She noted that researchers are moving away from Mendelian genetics in which the belief is a change in one gene causes a disease, to genomic medicine in which changes in multiple genes are viewed as the cause of a disease. Multiple gene changes mean a higher susceptibility for developing a disease. It is also widely accepted that environment affects someone's susceptibility to a disease.

According to Yashar, the new trend in general diagnostics could lead to well-defined genetic signatures for everyone.

"Ultimately, this would be a way of developing a genomic signature, and it's that signature that becomes a potential diagnostic tool," she said.

However, Yashar is reluctant to refer to gene profiling tests as report cards.

"Report cards are a great idea," she said. "I wouldn't call it a report card because that's set in stone. I would rather call it a genetic signature."

The prospect of report cards or genetic signatures for everyone continues to raise troubling ethical questions and cause grave concern.

"There's a lot of concern in the genetic community," Yashar said. "Not everybody wants, nor is it appropriate to have that type of knowledge, because you might [get the disease] but not be sure."

She used the example of Huntington's disease to further illustrate her viewpoint. Though there exists a genetic test for the deadly condition, there is no cure.

"People with that family history don't get the test because there is nothing they can do about it," she said. "Many people choose not to have that info. Some people do, some don't. They may not want to know for a disease with no cure."

Glatt warned that another danger of report cards is overestimating the value of genetic test results.

"Genetic testing will have a limited predictive value, at least for behavioral disorders," he said. "The risk is [in attributing] a very powerful meaning to it, even for people who know the predictive power of genetic tests is very small."

But Glatt cautioned that overestimating the value of these tests could potentially lead to people being denied insurance or employment simply because they show a genetic risk for a disease.

The Business of Gene Profiling

According to company and industry estimates, molecular and genetic testing is a $2.2 billion industry.

"The clearest indication of the potential financial gain in this type of genetic testing is the increase in DTS -- direct to consumer genetic testing," Yashar said.

She remarked that private companies are now offering genetic tests to consumers without a physician even being involved. This trend benefits those who live in communities that are medically underserved.

Nonetheless, removing the physician from the equation is very dangerous.

"Now [they're] removing the physician and geneticist all together," she said. "Can the public interpret this test appropriately? That's where my concern is."

As the genetic testing business continues to flourish, Yashar said the discussion about its ethical implications must continue within the medical and genetic community.

Philibert, too, is aware of the potential misuse of the blood test he is developing and other future genetic testing.

"Science is like a hammer," he said. "You can build a house or break a window. We certainly intend for this finding to help people manage their disease, and when possible, to prevent it from affecting their lives."