Wearable Bracelet Tracks Bipolar Mood Swings

Author: European College of Neuropsychopharmacology
Published: 8 Oct 2023 - Updated: 19 Jul 2026
Publication Type: Experimental Study

Table of Contents:
Synopsis - Definition - Overview - FAQs - Insights, Updates - Related Content

Synopsis

This research reports early findings from a study in which Barcelona-based psychiatrists, working with a data scientist in Edinburgh, used the Empatica E4 wearable bracelet to continuously measure physiological biomarkers in people with bipolar disorder. The team recruited 38 patients and 19 healthy controls, each wearing the device for around 48 hours, and found that electrodermal activity - the skin's electrical conductivity - dropped significantly during depressive phases and shifted measurably as a person moved between manic and depressive states. Because bipolar mood swings are currently diagnosed mostly through subjective interviews and questionnaires, and because only about 30 to 40 percent of treated individuals respond as expected to their first medication, an objective physiological signal could support faster, more personalized treatment and help flag risks such as suicide or unsafe driving. The work matters for patients, clinicians, and caregivers, particularly those in remote areas with limited access to mental health facilities, though the authors stress it is an exploratory observational study presented at the 36th ECNP Congress that will need larger samples and machine learning analysis before clinical use.*

At a Glance

• 1 - Between 1 and 2 percent of Europeans live with bipolar disorder, which works out to over 700,000 people. That is roughly the population of a city the size of Glasgow or Washington DC.
• 2 - The commercially available Empatica E4 bracelet measures several physiological changes, but the researchers focused mainly on tiny electrical shifts in the wearer's skin. Each participant wore it for about 48 hours.
• 3 - An independent commentator noted that earlier wearable studies tracking motor behavior could not tell anxious restlessness in depression apart from the early hyperactivity of a manic switch. Skin conductance may capture these subtle differences more reliably.

Topic Definition

Electrodermal Activity

Electrodermal Activity, sometimes called skin conductance or galvanic skin response, refers to the way the electrical properties of the skin change as the body's sweat glands respond to signals from the nervous system. When a person becomes stressed, aroused, or emotionally activated, the sympathetic nervous system subtly alters how well the skin conducts a tiny electrical current, and sensitive devices can pick up these shifts in real time. Because this response happens automatically and is not under conscious control, it offers an objective window into a person's physiological state that does not depend on what they say or how they feel in the moment. In the context of bipolar disorder, researchers are interested in it because skin electrical activity appears to differ between manic, depressive, and stable moods, making it a candidate marker for tracking mood changes as they unfold. Wearable sensors worn on the wrist now make it practical to collect this data continuously outside a clinic, which is what draws attention to its potential in mental health monitoring.

Overview

Researchers have announced preliminary results of using wearable technology to measure electrical impulses in the skin and other physiological biomarkers which might be associated with mood changes in bipolar disorder. The work is at an early stage, but they hope that they will be able to build on these patterns to detect mood swings in bipolar disorder sufferers, so helping in diagnosis and potentially offering more rapid and personalized treatments.

Bipolar disorder (formerly called manic-depressive illness or manic depression) is a mental illness that causes swings in a person's mood, energy, activity levels, and concentration. These shifts can make it difficult to carry out day-to-day tasks and can make interactions with other people difficult. The degree of mood swing can vary from person to person, from feeling manic (very "up") to feeling depressed. At present, these mood swings are mostly diagnosed subjectively, through interview with doctors or by questionnaires. This takes time, and requires an immediate medical presence.

Now a group of Barcelona-based psychiatrists, in collaboration with data scientist in Edinburgh, have used a research grade wearable device to continuously collect several physiological biomarkers during the diverse phases and episodes of bipolar disorder. Among the collected physiological biomarkers is electrodermal activity which uses changes in the skin's electrical conductivity to indicate the level of stress through the reactivity of the nervous system. This is a potential immediate indicator of whether someone is in a manic, depressive or in a normal mood state.

They recruited 38 patients with bipolar disorder, and 19 healthy controls, all from the Barcelona area.

Researcher Diego Hidalgo-Mazzei said;

"Each participant was fitted with a commercially available Empatica E4 bracelet, which they were asked to wear for around 48 hours. This can measure a variety of physiological changes, but we were most interested in measuring small electrophysiological changes in the skin of the wearer. We found that bipolar disorder patients in their depressed phase had on average a significantly lower skin electrical activity than the rest of the bipolar group or the healthy control group. We also found that as an individual moved from manic to depressive state (or vice versa), this was detectable by a change in skin surface electrical activity."

"It is important for the patient and doctor to know how and when these mood fluctuations take place. It is important also to highlight that the treatment is different for manic or depressive states. This can help with a prompt diagnosis and early personalized treatment, but it can also help in preventing adverse outcomes, for example in alerting to an increased risk of suicide, or of mood swings which may lead to dangers with activities such as driving. It is also easier to treat patients if we know if they are in a manic phase or a depressed phase. Until now, these mood swings have mostly been diagnosed subjectively, through interview with doctors or by questionnaires, and this had led to real difficulties. Arriving at the correct drug is difficult, with only around 30 to 40% of treated individuals having the expected response. We hope that the additional information these systems can provide will give us greater certainty in treating patients."

"We are still some way from that though. This is an exploratory observational study, so we need to look at a larger sample and use machine learning to analyze all the biomarkers collected by the wearers to confirm the findings to determine patterns which might indicate a specific episode. This may not be ideal for every bipolar disorder sufferer, in every circumstance, but a potential pattern may help in the future the people hardest hit by the mood changes which affect their lives".

According to a 2019 study between 1% and 2% of Europeans suffer from bipolar disorder (exact numbers are difficult to obtain), meaning that over 700,000 suffer in Europe. That's equivalent to a city the size of Frankfurt, Washington DC, or Glasgow.

Commenting, Professor Paolo Ossola (of the University of Parma, Italy) said:

"In this seminal study, Dr Hidalgo and collaborators have laid the foundation for a new approach to diagnosing and treating bipolar disorders. Bipolar disorder is defined by the occurrence of episodes (either manic or depressive) interspersed with periods of wellbeing known as euthymia. To date, the course of the illness is entirely unpredictable, and the occurrence of new episodes relies solely on their early recognition at a subjective level through early-warning symptoms."

"Having a physiological biomarker that extends beyond the subjective level would enable more timely intervention. More importantly, the fact that it originates from a wearable device could assist individuals who, due to geographical reasons, lack easy access to clinical facilities."

"The shift from the subjective to the biological level could also promote understanding of the underlying mechanistic dynamics of mood swings. Previous attempts, based on the study of motor behavior using wearable devices, failed to differentiate, for example, the restlessness caused by anxiety in a depressive episode from the initial hyperactivation associated with a manic switch. A more finely tuned biomarker, such as skin conductance, could capture these subtle changes and thus determine whether a treatment is effective and the reasons behind it."

"As the authors note, this is just a preliminary exploratory study, but their encouraging results could pave the way for future research aimed at unravelling clinical puzzles in the diagnosis and treatment of bipolar disorder."

"The exciting collaboration between doctors and data scientists is significantly accelerating the development of this new branch of precision psychiatry. I eagerly anticipate the much-needed transition from 'bench to bedside' with these technologies becoming available in community-based mental health settings".

This is an independent comment, Professor Ossola was not involved in this work.

About:

This work is presented at the 36th ECNP Congress, which takes place in Barcelona and online on 7-10 October 2023. With more than 6,000 participants the ECNP Congress is Europe's leading platform for the latest research in disease-related neuroscience.

This project was funded by the ISCIII (FIS PI21/00340, TIMEBASE Study), co-funded by the European Union, as well as a Baszucki Brain Research Fund grant from the Milken Institute.

Frequently Asked Questions

NOTE: Researched FAQs by Disabled World (DW)

What is the Empatica E4 bracelet used for?

The Empatica E4 is a research grade wearable device that measures several physiological signals from the wrist, including skin electrical activity, heart rate, and temperature. It is widely used in medical and behavioral research to collect continuous data outside a clinical setting.

Can a wearable device diagnose bipolar disorder on its own?

No, current wearable technology cannot diagnose bipolar disorder by itself. It may provide supporting physiological data to assist clinicians, but formal diagnosis still relies on professional medical evaluation and clinical criteria.

Is electrodermal activity monitoring safe and non-invasive?

Yes, measuring electrodermal activity is completely non-invasive and painless, using only surface sensors that rest against the skin. The device does not deliver any harmful current and simply reads the skin's natural electrical changes.

How is bipolar disorder currently treated?

Bipolar disorder is typically managed with mood stabilizing medications, sometimes combined with antipsychotics or antidepressants, alongside psychotherapy and lifestyle support. Treatment differs depending on whether a person is in a manic or depressive phase.

Why is it hard to find the right medication for bipolar disorder?

Individual responses to bipolar medications vary widely, and only about a third to less than half of patients respond as expected to their first treatment. Finding an effective drug often involves trial, adjustment, and close monitoring over time.

Could this kind of wearable help people in rural or remote areas?

Yes, one of the noted advantages is that a wearable device could support individuals who lack easy access to clinical facilities. Continuous remote monitoring may help bridge gaps in mental health care for geographically isolated patients.

What is euthymia in bipolar disorder?

Euthymia refers to the periods of relative stability and wellbeing that occur between manic and depressive episodes. During euthymia a person's mood is neither elevated nor depressed, though the timing of the next episode remains unpredictable.

Insights, Analysis, and Developments

Editorial Note: What gives this study its weight is the pairing of clinicians with data scientists, a collaboration that is quietly reshaping what some now call precision psychiatry, where treatment is guided by measurable biological signals rather than recollection alone. The project drew funding from Spain's ISCIII, the European Union, and a Baszucki Brain Research Fund grant from the Milken Institute, and its independent reviewer described it as laying the foundation for a genuinely new approach to a condition whose course has long been unpredictable. For the many people whose lives are upended by episodes that arrive without warning, the promise here is not a finished product but a plausible path toward tools that could one day reach community mental health settings and the patients hardest hit by mood changes.*

Attribution/Source(s): This quality-reviewed publication was selected for publishing by the editors of Disabled World (DW) due to its relevance to the disability community. Originally authored by European College of Neuropsychopharmacology and published on 8 Oct 2023, this content may have been edited for style, clarity, or brevity.

* Editorial additions by Ian C. Langtree.