HSE scientists propose using heart rate analysis to diagnose anxiety and depression

A group of scientists at HSE University have discovered how anxiety and depression can be diagnosed by analysing heart rate. It turns out that under mental stress, the heart rate of individuals with a predisposition to mental health disorders differs from that of healthy individuals, especially when performing more complex tasks. These changes in cardiovascular parameters can even be detected using a pulse oximeter or a smartwatch. The study findings have been published in Frontiers in Psychiatry. 

According to the World Health Organization, one in five adults under the age of 30 suffers from depression or an anxiety disorder. To prevent the development of mental health conditions and treat them effectively, reliable personalised diagnostic methods are needed. 

Today, many technology companies are developing mental health analysis systems based on heart rate data. Various wearable devices, such as smartwatches, bracelets, rings, and others, are used for this purpose. However, it is important not only to record changes in heart rate but also to interpret them accurately. 

Scientists at HSE University, in collaboration with the Russian Academy of Sciences Institute of Higher Nervous Activity and Neurophysiology, conducted a study to determine whether signs of depression and anxiety can be detected through changes in heart rate during cognitive tasks. They performed an experiment with 90 subjects, aged 18 to 45, some of whom had a history of anxiety and depression episodes. 

Participants completed memory and attention tasks that gradually increased in complexity: they were instructed to view images of coloured balls and compare each one with the previous one to identify colour matches. As the difficulty level increased, participants had to memorise more balls and colours. 

During the experiment, participants' heart rates were recorded using an electrocardiogram (ECG), while simultaneously photoplethysmography (PPG) was conducted to analyse heart function based on changes in blood volume in peripheral vessels. This simple, non-invasive method allows data to be read from the finger or wrist; PPG is the technology used in all wearable devices today. 

Data analysis revealed that individuals with higher levels of anxiety or depression exhibited more pronounced changes in heart rate, particularly during complex tasks. 

'When faced with a challenging task, people experience stress. They can make mistakes, which is normal and does not necessarily indicate a mental health issue. However, at a critical point of increasing complexity—when the task is still manageable but requires maximum attention—individuals with signs of mental disorders exhibit a higher average heart rate, resulting in a more pronounced and distinct pattern of heart rate variability,' explains Evgeniia Alshanskaia, Junior Research Fellow at the Institute for Cognitive Neuroscience. 

A key aspect of the experiment was the comparison of data obtained using EEG and PPG. Although EEG is traditionally regarded as a more reliable method for measuring heart rate variability, the study indicated that PPG might be a more sensitive tool for assessing depression and anxiety. The scientists attribute this to the specific characteristics of the sympathetic nervous system. 

'Under stress, noradrenaline, which is linked to attention, is activated first, followed by the activation of adrenaline, which prepares the body for action and triggers the "fight or flight" response. Our heart rate increases, and our blood pressure rises. Noradrenaline also acts on receptors that induce vasoconstriction. At this stage, changes in the pulse wave can be observed using PPG. Only afterward is adrenaline released from the adrenal glands, which amplifies and prolongs the body's stress response, causing the heart to beat faster. Subsequently, changes are observed on the ECG. This indicates that PPG is a relatively reliable method that is also more accessible, faster, and informative compared to ECG,' according to Alshanskaia.  

The study demonstrates that changes in heart rate in response to increasing cognitive load can serve as an early biomarker for anxiety and depressive disorders. Additionally, the findings from the experiment open new opportunities for developing algorithms for wearable devices and applications that can monitor a person’s psychological state in real time. Early, personalised, and non-invasive diagnosis of depressive and anxiety disorders through heart rate analysis could significantly transform the approaches to treatment and prevention of mental health conditions in the future.

The study was conducted within the framework of the Strategic Project 'Success and Self-Sustainability of the Individual in a Changing World' (Priority 2030 programme).