Digital biomarkers shed light on seasonality in mood disorders

A wrist-based activity sensor worn by people with depression and those who showed evidence of a relationship between daily exposure to sunlight and physical activity over a two-week period, according to a study that Published on September 25, 2024 in Open Access Journal. PLoS Mental Health By Oleg Kovtun and Sandra Rosenthal from Vanderbilt University, US

Mood disorders are a major cause of ‘disability’ worldwide. Up to 30% of people with major depressive disorder and bipolar disorder show seasonal patterns of symptoms. This phenomenon is now recognized in official diagnostic guidelines. Little is known about the effect of day length (eg, photoperiod) and sunlight intensity (eg, solar insolation) on the seasonal patterns of major depressive disorder and bipolar disorder.

In their study, Couton and Rosenthal used a quantitative approach to examine the relationship between measures of sun exposure and objectively measured movement activity patterns to begin to understand the environmental factors involved in major depression and bipolar disorder. causing seasonal movement.

They used recordings of motor activity collected via accelerometers (which measure the rate of change of an object’s velocity over time) from 23 people with unipolar or bipolar depression and 32 people without. from pressure. Participants were recruited at the University of Bergen, Norway.

Findings revealed relationships between daytime physical activity, depression, photoperiod and solar insolation. Specifically, more depressive states were associated with lower daytime activity, whereas daytime activity increased with photoperiod and solar insolation. Additional results suggest that the effect of solar insolation on physical activity may differ between depressed individuals and those who are not.

This finding may indicate that depressed individuals exhibit an altered physiological relationship between energy balance (eg, solar insolation) and physical activity. On the other hand, it is also possible that the increase in sedentary behavior results in a reduction of time spent outdoors and does not allow depressed people to take advantage of the benefits of exposure to sunlight.

According to the authors, the study provides a generalizable strategy for understanding the complex interaction between sunlight exposure, physical activity, and depression using open-source digital tools. The ability to identify mood disorders, particularly in seasonally sensitive individuals, using passive digital biomarker data offers promise in informing the next generation of predictive, personalized diagnoses in mental health.

In particular, a digital biomarker, such as motor activity patterns derived from an accelerometer, can form the basis of an early warning system that alerts a clinician to initiate timely intervention.

Inclusion of objectively measured solar exposure markers (eg solar insolation data collected by NASA or speed-measured light exposure) can further enhance the predictive power of such tools and Based on personalized models aimed at individuals who are susceptible to mood disturbances with seasonal patterns.

Rosenthal and Kovtun add, “Individuals with seasonal mood disorders may not yet recognize the nature of their illness. One goal of our study is to encourage the development of digital tools to help clinicians and affected individuals better understand their symptoms.” The symptoms are to help with self-management.”