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You can only fight depression when you know it’s symptoms. So many of us get confused when it comes to understanding the difference between sadness and depression, that often this mental health condition goes untreated. Depression not only affects how a person feels and behaves, but also impairs their ability to live a fruitful life.
To live a productive life, it is important to catch depression before it gets severe. And for the first time, doctors have shown that measuring changes in 24-hour heart rate can reliably indicate whether or not someone is depressed.
These changes in the heart rate could be the early warning signs of potential depression, according to the researchers. This can also indicate whether or not the treatment is working, hence leading the way to more rapid and responsive treatment.
Lead researcher, Dr Carmen Schiweck from Goethe University, Frankfurt said: “Our pilot study suggests that by just measuring your heart rate for 24 hours, we can tell with 90% accuracy if a person is currently depressed or not.”
What do we know about heart rate variability and depression?
Scientists have known that heart rate is linked to depression, but until now they have been unable to understand exactly how one is related to the other. It is difficult to deduce because the heart rate can fluctuate quickly, whereas depression stays over a longer period. This makes it difficult to see whether or not changes in one’s depressive state might be related to heart rate.
Dr Schiweck says, “Two innovative elements in this study were the continuous registration of heart rate for several days and nights, and the use of the new antidepressant ketamine, which can lift depression more instantly. This allowed us to see that the average resting heart rate may change quite suddenly to reflect the change in mood.”
Dr Schiweck adds: “We knew that there is something to link heart rate to psychiatric disorders, but we didn’t know what it was, and whether it would have any clinical relevance. In the past researchers had shown that depressed patients had consistently higher heart rates and lower heart rate variability, but because of the time it takes to treat depression it had been difficult to follow up and relate any improvement to heart rate. But when we realized that ketamine leads to a rapid improvement in mood, we knew that we might be able to use it to understand the link between depression and heart rate”.
How did Dr Schiweck conduct the study?
Dr Schiweck carried out this study in the Mind Body Research group at KU Leuven, Belgium, with Dr Stephan Claes as the principal investigator. The team worked with a small sample of 16 patients with major depressive disorder, none of whom had responded to normal treatment, and 16 healthy people. They measured their heart rates for 4 days and 3 nights, and then the volunteers with depression were given either ketamine treatment or a placebo.
“We found that those with depression had both a higher baseline heart rate and a lower heart rate variation, as we expected. On average we saw that depressed patients had a heart rate which was roughly 10 to 15 beats per minute higher than in controls,” says Dr Schiweck.
“After treatment, we again measured the heart rates and found that both the rate and the heart rate fluctuation of the previously depressed patients had changed to be closer to those found in the controls,” adds Dr Schiweck.
What did the study find?
The most striking finding was that the scientists were able to use 24-hour heart rate as a biomarker for depression. Heart rates were measured using a wearable mini-ECG. The data was fed to an artificial intelligence programme, which was able to classify nearly all controls and patients correctly as being depressed or healthy.
“Normally heart rates are higher during the day and lower during the night. Interestingly, it seems that the drop in heart rate during the night is impaired in depression. This seems to be a way of identifying patients who are at risk to develop depression or to relapse.” said Dr Schiweck.
The team also found that patients with a higher resting heart rate responded better to the treatment with Ketamine, which may help identify which patients are likely to respond to which treatment.
“We need to remember that this is a small proof-of-concept study: six of our 16 initial patients responded to treatment with at least a 30% reduction on the Hamilton Rating Scale for depression, so we need to repeat the work with a larger, anti-depressant free sample. Our next step is to follow up depressed patients and patients who are in remission, to confirm that the changes we see can be used as an early warning system,” concluded Dr Schiweck
So till the time this study is conducted on a larger scale let’s just hope it turns out positive. This will not only help to detect the risk of depression easily but can also tell what medication is working which is a really really big step towards curing this mental illness.