Background Given the increased use of smart devices and the advantages of individual behavioral monitoring and assessment over time, wearable sensor–based mobile health apps are expected to become an important part of future (forensic) mental health care. For successful implementation in clinical practice, consideration of barriers and facilitators is of utmost importance. Objective The aim of this study was to provide insight into the perspectives of both psychiatric outpatients and therapists in a forensic setting on the use and implementation of the Sense-IT biocueing app in aggression regulation therapy. Methods A combination of qualitative methods was used. First, we assessed the perspectives of forensic outpatients on the use of the Sense-IT biocueing app using semistructured interviews. Next, 2 focus groups with forensic therapists were conducted to gain a more in-depth understanding of their perspectives on facilitators of and barriers to implementation. Results Forensic outpatients (n=21) and therapists (n=15) showed a primarily positive attitude toward the addition of the biocueing intervention to therapy, with increased interoceptive and emotional awareness as the most frequently mentioned advantage in both groups. In the semistructured interviews, patients mainly reported barriers related to technical or innovation problems (ie, connection and notification issues, perceived inaccuracy of the feedback, and limitations in the ability to personalize settings). In the focus groups with therapists, 92 facilitator and barrier codes were identified and categorized into technical or innovation level (n=13, 14%), individual therapist level (n=28, 30%), individual patient level (n=33, 36%), and environmental and organizational level (n=18, 20%). The predominant barriers were limitations in usability of the app, patients’ motivation, and both therapists’ and patients’ knowledge and skills. Integration into treatment, expertise within the therapists’ team, and provision of time and materials were identified as facilitators. Conclusions The chances of successful implementation and continued use of sensor-based mobile health interventions such as the Sense-IT biocueing app can be increased by considering the barriers and facilitators from patients’ and therapists’ perspectives. Technical or innovation-related barriers such as usability issues should be addressed first. At the therapist level, increasing integration into daily routines and enhancing affinity with the intervention are highly recommended for successful implementation. Future research is expected to be focused on further development and personalization of biocueing interventions considering what works for whom at what time in line with the trend toward personalizing treatment interventions in mental health care.

BACKGROUND Given the increased use of smart devices and the advantages of individual behavioral monitoring and assessment over time, wearable sensor-based mHealth apps are expected to become an important part of future mental healthcare. For successful implementation in clinical practice, consideration of barriers and facilitators is of utmost importance. OBJECTIVE The aim of the current study was to provide insight into the perspectives of both psychiatric outpatients and therapists in a forensic setting on the use and implementation of the Sense-IT biocueing app in aggression regulation therapy (ART). METHODS A combination of qualitative methods was used. First, we assessed the perspectives of forensic outpatients on the use of the Sense-IT biocueing app using semi-structured interviews. Next, two focus groups with forensic therapists were conducted to gain a more in-depth understanding of their perspectives on facilitators and barriers to implementation. RESULTS Forensic outpatients (N=21) and therapists (N=15) showed a primarily positive attitude toward the addition of the biocueing intervention in therapy, with increased interoceptive and emotional awareness as most frequently mentioned advantage in both groups. In the semi-structured interviews patients mainly reported barriers related to technical or innovation problems (i.e. connection and notification issues, perceived inaccuracy of the feedback, and limitations in the ability to personalize settings). In the focus groups with therapists, 92 facilitator/barrier codes were identified and categorized into technical or innovation level (n=13), individual therapist level (n=28), individual patient level (n=33), and environmental and organizational level (n=18). Predominant barriers were limitations in usability of the app, patients’ motivation, and both therapists’ and patients’ knowledge and skills. Integration in treatment, expertise within the therapists’ team, and the provision of time and materials were identified as facilitators. CONCLUSIONS The chances of successful implementation and continued use of new mHealth interventions, such as the Sense-IT biocueing app, can be increased by considering the barriers and facilitators from patients’ and therapists’ perspectives. Technical or innovation-related barriers, such as usability issues, should be addressed first. On the level of the therapists, increasing integration in daily routines and enhancing affinity with the intervention are highly recommended for successful implementation. Future research is expected to be focused on further development and personalization of biocueing interventions, considering what works for whom at what time, in line with the trend toward personalizing treatment interventions in mental healthcare. CLINICALTRIAL The study among forensic outpatients was registered in the Netherlands Trial Register (NL8206).