Washington [US], September 12 Morning India: For the first time doctors have shown that measuring changes in 24-hour heart rate can reliably indicate whether or not someone is depressed.
In practical terms, this may give clinicians an objective “early warning” of potential depression, as well as a rapid indication whether or not treatment is working, so opening the way to more rapid and responsive treatment. Presenting results of this pilot study at the ECNP virtual congress, lead researcher, Dr Carmen Schiweck (Goethe University, Frankfurt) said: “Put simply, our pilot study suggests that by just measuring your heart rate for 24 hours, we can tell with 90 per cent accuracy if a person is currently depressed or not”.
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. In part, this is because while heart rates can fluctuate quickly, depression both arrives and leaves over a longer period, with most treatments taking months to take effect. This makes it difficult to see whether or not changes in one’s depressive state might be related to heart rate.
“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 or less instantly. This allowed us to see that average resting heart rate may change quite suddenly to reflect the change in mood”, said Carmen Schiweck.
Ketamine has a history as both an anaesthetic and a party drug (a drug of abuse). However in December last year, it was licenced to treat major depression in Europe, after having been introduced in the USA a few months earlier. Traditional antidepressants can take weeks to show an effect, in contrast, ketamine is rapid-acting, with results often being seen in minutes.
As Carmen Schiweck said “We knew that something was going on 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”.
Dr Schiweck performed this work 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 who had responded to normal treatment, and 16 healthy controls. They measured their heartrates for 4 days and 3 nights, and then the volunteers with depression were given either ketamine treatment or a placebo.