Bipolar or Depression? Heart Test May Help Tell the Difference

A simple 15-minute electrocardiogram (ECG or EKG) can help determine whether a patient has major depression or bipolar disorder, according to a new study by researchers with Loyola Medicine in Chicago.

The findings, published in the World Journal of Biological Psychiatry, show that heart rate variability (variations in the time intervals between heartbeats) can help differentiate between the two disorders.

Bipolar disorder is commonly misdiagnosed as major depression, which can be detrimental to the patient, since treatment plans for the disorders are very different. In bipolar disorder — with its emotional, manic highs, and severe depression¬†— treatment involves an antidepressant along with a safeguard such as a mood stabilizer or antipsychotic drug to prevent a switch to a manic episode.

A physician who misdiagnoses bipolar disorder as major depression could inadvertently trigger a manic episode by prescribing an antidepressant without a safeguard mood stabilizing drug.

“Having a noninvasive, easy-to-use, and affordable test to differentiate between major depression and bipolar disorder would be a major breakthrough in both psychiatric and primary care practices,” said senior author Angelos Halaris, M.D., Ph.D., professor of psychiatry and behavioral neurosciences and medical director of adult psychiatry.

For the study, the researchers enrolled 64 adults with major depression and 37 adults with bipolar disorder. Each participant rested comfortably on an exam table while a three-lead electrocardiogram was attached to the chest. After the patient rested for 15 minutes, the electrocardiographic data were collected for 15 minutes.

Then researchers converted the electrocardiographic data into the components of heart rate variability using a special software package. These data were further corrected with specialized software programs developed by study co-author Stephen W. Porges, Ph.D., of Indiana University’s Kinsey Institute.

In measuring heart rate variability, researchers calculated what is known to cardiologists as respiratory sinus arrhythmia (RSA). At the beginning of the study, patients with major depression had significantly higher RSA than those with bipolar disorder.

In addition, patients with bipolar disorder had higher blood levels of inflammation biomarkers than those with major depression. Inflammation occurs when the immune system revs up in response to a stressful condition.

Major depression is among the most common and severe health problems in the world. At least eight to 10 percent of the U.S. population suffers from major depression at any given time. While less common, bipolar disorder is also a significant mental health problem, affecting an estimated 50 million people worldwide.

Source: Loyola University Health System