EEG can identify major depression or bipolar disorder
A new study at Loyola University has concluded that a simple electrocardiogram that takes all of 15 minutes may help a doctor decide whether a patient has major depressive disorder or bipolar disorder. Because of the frequent misdiagnosis of both bipolar disorder and major depression, the study is believed to help distinguish between the two. Because the symptoms of major depression and the depressive phase of bipolar disorder are similar it is frequently hard to distinguish between the two. However, the treatments are very different.

When an individual has bipolar disorder they have experienced at some point in time at least one manic episode, which is an emotional high. Mania is not a normal characteristic of major depressive disorder and so, the treatments are significantly different. With bipolar disorder, when in the depressive phase an individual may be given an antidepressant along with a medication to stabilize the mood or sometimes an antipsychotic medication to prevent the patient from switching to a manic phase. A doctor misdiagnosing the bipolar disorder may attempt to treat the depression without treating the mania and prescribe an antidepressant without the mood stabilizing medication.
Heart Rate Variability: Depression and Bipolar Disorder
The Loyola study found that heart rate variability measured by an EEG or an electrocardiogram was able to identify whether individuals had bipolar disorder or major depression. The measure of heart rate variability is able to identify if there is a variation in the time interval between heartbeats.
Published in the World Journal of Biological Psychiatry senior author Angelos Halaras M.D., Ph.D. and professor in Loyola’s Department of Psychiatry and Behavioral and Neural Sciences and medical director of the adult psychiatry unit stated that “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.”
Major depression is by far one of the most common mental health disorders with some estimates as high as 8% to 10% of the population having it at any one period in time. While bipolar disorder may be a little less prevalent, estimates are as high as 50 million people suffering from bipolar disorder worldwide. Both can be very severe and debilitating.
All of the subjects in the research study underwent electrocardiograms at the initiation of the study, rested comfortably for 15 minutes while a EEG was attached to their chest. EEG data was then collected for the next 15 minutes and the data was then converted by a special software package developed by the study’s co-author Stephen W Porges, Ph.D. of Indiana University’s Kinsey Institute.
Researchers then computed what is known to cardiologists as respiratory sinus arrhythmia (RSA) while measuring the heart rate variability. Researchers found that at the beginning of the study a baseline was set in which individuals with major depression had much higher RSA than subjects with bipolar disorder.
Researchers also found that subjects with bipolar disorder also had higher blood levels of inflammation that individuals with major depressive disorder. Inflammation is believed to be increased when the immune system experiences heightened stress as may be experienced by an individual with bipolar disorder.
Article adapted by Paul Susic Ph.D. Licensed Psychologist from ScienceDaily Dated November 21, 2017: Simple electrocardiogram can determine whether a patient has major depression or bipolar disorder, study finds
Journal Reference:
Brandon Hage, Briana Britton, David Daniels, Keri Heilman, Stephen W. Porges, Angelos Halaris. Low cardiac vagal tone index by heart rate variability differentiates bipolar from major depression. The World Journal of Biological Psychiatry, 2017; 1 DOI: 10.1080/15622975.2017.1376113