Bipolar Disorder (BD) represents a prevalent and burdensome mental health disorder globally, ranking fifth largest proportion of mental disorder disability-adjusted life years (DALYs) in 2019 (Collaborators, 2022). The 2013 China Mental Health Survey reported that the 12-month prevalence of BD was 0.5 %, and the lifetime prevalence was 0.6 % (Huang et al., 2016, 2019). Nevertheless, the rate of BD patients receiving psychiatric treatment remained remarkably low, often leading to relapses, treatment delays, and repeated hospitalization (Bulteau et al., 2018). Traditional mood assessments generally entail face-to-face specialist examinations or psychological scales, which rely heavily on consistent patient adherence and regular medical visits. Therefore, an optimal approach would incorporate objective indicators and real-time assessment capabilities.

Ecological Momentary Assessment (EMA) offers a solution by enabling real-time mood fluctuation assessment through repeated sampling in natural contexts (Stone et al., 2023), which is particularly suitable for capturing real-time mood fluctuations and exploring short-term predictors and mechanisms of action (Shiffman et al., 2008). With the widespread use of smartphones and wearable devices, automated data collection, transmission, and analysis through EMA have become technically viable (Melbye et al., 2020).

Despite some studies reporting favorable adherence rates among BD patients using EMA and wearable devices (Hidalgo-Mazzei et al., 2016; Wenze and Miller, 2010), there are still multiple concerns. First, patients with mental disorders, including BD, typically exhibit poor treatment adherence and cooperation (Bulteau et al., 2018), which can impede EMA implementation. Additionally, studies have indicated that the number, frequency, and duration of patient EMA responses are restricted (Bastiaansen et al., 2018), directly affecting the quality and comprehensiveness of the data collected. Furthermore, repeated assessments of individuals experiencing persistent negative emotions may lead to perceived burdens (Bos et al., 2019). Moreover, patients with positive symptoms may have experiences triggered by the device (Myin-Germeys et al., 2018). Therefore, investigating the acceptability and usability of EMA implemented via smartphones and wearable devices among BD patients is essential. However, compared to the rapid development of this field in other countries, exploration in China is still in its nascent stages, with a lack of clinical studies on many launched applications and wearable devices. Specifically, in the Chinese context, no comprehensive studies delve into BD patients' subjective experiences with EMA.

Importantly, to effectively facilitate the clinical application of EMA, it is crucial to involve key stakeholders and address potential implementation obstacles (Grol and Grimshaw, 2003). Patients are the primary users of EMA, and psychiatrists play a crucial role in its implementation (Kaiser and Laireiter, 2018; Kroeze et al., 2017). However, few studies have examined psychiatrists' attitudes and expectations towards EMA. Therefore, there is an urgent need to explore the perceptions and recommendations of both patients and psychiatrists regarding EMA.

This study employed a qualitative research approach to explore the acceptability, usability, and recommendations of EMA based on smartphones and wearable devices for out-of-hospital self-monitoring among Chinese BD patients. The findings will provide valuable recommendations for the development of personalized self-monitoring programs for BD patients from a doctor-patient perspective, contributing to establishing an acceptable and practical methodology and promoting its clinical application.