Bipolar disorder is a serious psychiatric disease that affects approximately 2% of the world’s population and is characterized by episodes of mania and depression alternating with periods of stability. Despite advances in research, there are still no objective biomarkers that allow the evolution of the disease to be monitored and treatments to be adapted in a personalized way. Now, a study published in the Journal of Affective Disorders presents a promising new approach: measuring skin temperature with wearable devices.
Previous studies showed that in cases of depression there is a dysregulation of body temperature control, which can manifest itself, among other things, in a skin temperature higher than in people without depressive symptoms. Although there are several hypotheses as to why this phenomenon occurs, there is no conclusive explanation.
In the present study, led by Clàudia Valenzuela-Pascual, Diego Hidalgo-Mazzei and Eduard Vieta, from the IDIBAPS Bipolar and Depressive Disorders research group, 104 people with bipolar disorder were monitored for two consecutive days whilst they were going about their normal lives. The participants wore a smartwatch that recorded their skin temperature, and the researchers compared the circadian patters of this parameter between four groups: patients in depressive, manic, or euthymic states, and healthy controls. Moreover, patients in the depressive or manic groups repeated the procedure once they had stabilized.
The results show that skin temperature during daytime hours is significantly higher in patients who are in a manic episode, compared to those who are stable or a depressive phase. This increase in temperature disappears when the manic episode ends and the person returns to symptomatic remission. This suggests that skin temperature, measured non-invasively and continuously during daily life, could objectively characterize the patient’s psychopathological state in bipolar disorder.
According to the authors, this discovery could have an impact in clinical practice: “Currently, the follow-up of bipolar disorder is based on clinical interviews and subjective questionnaires. The availability of an objective parameter such as the temperature of the skin that is sensitive to psychopathological states can help to detect changes in state early and adjust treatment before they become more serious. Above all, we believe that its potential lies in its combination with other biomarkers such as heart rate or physical activity,” explains Valenzuela-Pascual, first author of the study.
Hidalgo-Mazzei, co-author of the study, comments that, “the research reveals the potential of wearable devices to bring us closer to continuous and personalized patient monitoring.” Despite the promising results, more studies are needed to validate the use of skin temperature as a biomarker in daily clinical practice, alone or in combination with other biomarkers, and to explore whether it can help predict relapse or improve adherence to treatment.
The study involved the participation of the University of Cádiz, the Pere Mata Institute, and Basurto University Hospital in the recruitment of patients, and was made possible thanks to funding from the Carlos III Health Institute (project FIS PI21/00340), the Milken Institute (Baszucki Brain Research Fund grant) and the Spanish Government’s Ministry of Science, Innovation and Universities, which supported the research project and the PhD of the first author of the article.
Study reference:
Clàudia Valenzuela-Pascual, Rocío G. Lamberti, Ariadna Mas, Roger Borràs, Gerard Anmella, Filippo Corponi, Vincenzo Oliva, Michele De Prisco, Marta Korniyenko, Marina Garriga, Meritxell González-Campos, Marc Valentí, Isabella Pacchiarotti, Antoni Benabarre, Iria Grande, Anna Bastidas, Isabel Agasi, Cristina Romero-Lopez-Alberca, Cecilia Muñoz-Doña, Ana Catalan, Allan H. Young, Michael Berk, Eduard Vieta, Diego Hidalgo-Mazzei, State-dependent skin temperature increase during manic episodes of bipolar disorder, Journal of Affective Disorders, Volume 389, 2025. https://doi.org/10.1016/j.jad.2025.119643.
