Heart rate abnormalities in sleep, new biomarker of depression

Canadian researchers say they may have found an objective way to tell if someone is suffering from depression by measuring heart rate abnormalities during sleep.

A sleep researcher at the Royal Ottawa Institute of Mental Health Research, professor Rebecca Robillard, said "I was surprised to see the accuracy of this," according to the Canadian CTV News.

One of the problems with diagnosing depression accurately is that it is often subjective. Patients report symptoms such as lethargy and low mood, but doctors have no reliable way to confirm it with an objective test or biomarker, she added.

The researcher noted that the study compared sleep tests conducted on 664 people with diagnosed depression who had sought treatment for sleep disorders. The results were compared with sleep studies done on some 529 people who did not have diagnosed depression.

The data on heart rates during the various stages of sleep was fed to a computer with Artificial Intelligence (AI) programming to spot and learn from differences in the rates and their variation during sleep, she also pointed out.

The study found the AI program detected depression accurately in 79.9 per cent of patients. That is almost double the 47 per cent rate of detection by physicians.

"Our preliminary findings in a follow-up study show that there are marked heart rate abnormalities in people with depression, especially during sleep", said Robillard, adding that study also shows these abnormalities seem to be worse during sleep than while people are awake.