Dr. Kathleen Pajer, a recent addition to Dalhousie’s Department of Psychiatry, has brought more than a love of the East Coast to the Dalhousie and Halifax medical communities. The new head of Dal’s Division of Child and Adolescent Psychiatry has arrived with groundbreaking research linking genetic markers with depression.
Dr. Pajer is currently celebrating the success of a pilot study that was the first blood test to diagnose major depression in teens. She worked with Dr. Eva Redei (Northwestern University) and blood analyst Brian Andrus to identify a specific set of genetic markers that can diagnose depression and identify subtypes of the disorder.
“You have a much better chance of helping people live better lives, long-term, when you intervene when they’re kids,” says Dr. Pajer, explaining that “70 per cent of serious adult mental illness begins before the age of 14.”
Dr. Pajer says her interest in pursuing the pilot study began when she worked at Nationwide Children’s hospital of Ohio State University (the same institute that funded her and Dr. Redei’s research). There, she had looked at the biomarkers of stress-response-system function in girls with conduct disorders, depression, or anxiety disorders.
“What I learned from the girls who were depressed there is what got me interested in diagnostic biomarkers for early onset depression.”
A perfect partnership
The study with Dr. Redei and Mr. Andrus collected data from 28 teens between the ages of 15 and 19 years old. Fourteen control subjects were matched by sex and race with 14 subjects who were patients of Dr. Pajer and her colleagues, having been diagnosed with major depression but who had not yet received clinical treatment.
Dr. Redei had already done decades of research, identifying 26 genetic blood markers by running tests with rats. Dr. Pajer (now also chief of the IWK Health Centre’s Department of Psychiatry and senior physician in the centre’s Mental Health and Addictions program) first bumped into Dr. Redei during lunch at an international meeting for the Society of Neuroscience.
“She was looking for humans to test out rat models, and I was looking for a way to better diagnose depression,” says Dr. Pajer.
The two researchers have now spent five years working together, starting their pilot study in 2009 and realizing the implications of their results when they analysed the combined data last fall.
Exciting results
The ability to differentiate between major depression and major depression combined with anxiety disorder was a pleasant surprise for the collaborators.
“It was more exciting than finding that genes differ between depressed and non-depressed subjects,” says Dr. Pajer, adding that this discovery has the potential to help physicians develop more specific treatments for patients with depression.
The ability to diagnose depression by examining patients’ genes does not mean that depression is passed on genetically, but that a body’s interactions with its environment can cause a panel of genes to be turned on or off in a particular pattern.
“We’re not looking at DNA. We’re looking at gene expression,” says Dr. Pajer.
Despite the excitement, Dr. Pajer emphasizes that the research, which has already generated extensive international media attention, is a pilot study.
“It’s not ready for prime time yet,” she says.
The next step will be a study that includes 350-400 participants—half with depression and half without. A larger group of patients will allow the doctors to test the biomarker they found and run more than the initial 26 genes.
This next study, which will be conducted in Halifax, will determine whether Dr. Pajer’s and Dr. Redei’s findings can be used in clinical practice.
Healing depression stigmas
Dr. Pajer believes that a blood test that can diagnose major depression in adolescents will help reduce the stigma that surrounds mental illnesses and encourage patients to seek treatment by emphasizing that they have a medical condition.
“A lot of people still feel that having depression is a sign that you’re weak, but if there was a physical, objective change that we could determine, we might be able to move depression to disease status [in their minds].”
It would also mean that doctors would no longer have to rely soley on interpreting patients’ accounts of symptoms. That said, Dr. Pajer stresses that the test would not be a substitute for psychiatric interviews but “enhance clinical evaluation” instead.
Dr. Pajer’s other projects include a forthcoming study of stress-response-system function in pregnant women. With the results, she hopes to be able to improve fetus brain development and reduce severe behavioural disorders.