Evaluation of the Clinical and Organizational Impact of the Digital Medical Device Dalia in the Management of Depression

Worldwide, depression is a disease that affects 3.8% of the population, i.e., about 280 million people [1]. INSERM specifies that major depressive disorder affects all ages of life and concerns about 15 to 20% of the general population [2]. In France, 12.5% of people aged 18-85 years had a history of major depressive episode (MDE) during the past 12 months in 2021 [3]. In 2017, the prevalence of MDE during the past 12 months was 8.2% among the employed French active population [4].

The diagnosis of MDE is clinical. The symptoms of an MDE must persist for at least 2 weeks, and each of them at a certain degree of severity, almost every day. These symptoms must represent a change compared to the patient's usual functioning (professional, social, family) and cause significant distress. Among the main symptoms: depressed mood, loss of interest, dejection, loss of energy, increased fatigability [5]. Standardized assessment tools are diagnostic aids, notably the Patient Health Questionnaire-9 (PHQ-9), the Montgomery-Åsberg Depression Rating Scale (MADRS), the Beck Depression Inventory-II (BDI-II), the Hospital Anxiety and Depression Scale (HADS), and the Hamilton Depression Rating Scale (HDRS) [5].

A first depressive episode may be isolated and resolve spontaneously within six to nine months without specific treatment. However, in most cases, drug treatment is necessary. As a rule, after 8 weeks of a well-conducted drug treatment, one third of patients show complete remission of symptoms, one third show partial remission, and one third do not respond to treatment [2]. One of the main clinical aspects of depression is its recurrent nature. The risk of having another depressive episode gradually increases after each decompensation. Thus, after a first decompensation, more than 50% of individuals will develop a second depressive episode. After two episodes, the relapse rate increases to 70%, and beyond three episodes, to 90% [6].

Due to its consequences at the individual and societal level, depression is a major public health issue, generating high costs related to absenteeism but also to the overall management of affected individuals [7-9]. Indeed, depression impairs the daily functioning, social and professional relationships of affected individuals, and is associated with suicidal behaviors that are very frequent in these individuals. In France, mental health is now a priority, with health insurance expenditures exceeding 23 billion euros in 2023 [8,9]. When including indirect costs, total expenditures related to psychiatric illnesses could exceed 163 billion euros, with depressive and anxiety disorders being among the main causes of years of life lost due to disability [10].

Based on data from the literature, during a major depressive episode, several physical and physiological parameters (heart rate, physical activity, oxygen saturation, and body temperature) are disrupted [13-23]. Continuous monitoring of these parameters would make it possible to better characterize depressive patients and to detect early relapse/recurrence. Early detection of the risk of relapse and recurrence of MDEs could allow for early management.