BACKGROUND AND AIMS: Cannabis use is highly prevalent among young adults with first-episode psychosis (FEP) and is associated with poorer clinical and functional outcomes. Mobile health interventions may help address structural barriers to delivering cannabis-focused psychosocial interventions within early intervention services (EIS), yet little is known about how such tools are experienced and integrated into routine care. This study explored young adults with FEP and clinician experiences of two cannabis-focused mobile interventions, iCanChange (iCC) and Cannabis Harm-reducing App to Manage Practices Safely (CHAMPS), with a particular focus on implementation within EIS.

DESIGN: Qualitative exploratory study using semi-structured individual interviews. Data were analysed using a reflexive thematic approach informed by the integrated Promoting Action on Research Implementation in Health Services (i-PARIHS) framework.

SETTING: Six EIS programs in Canada (five in Quebec and one in Nova Scotia).

PARTICIPANTS: Twenty-eight young adults aged 18-35 years with FEP who participated in the intervention arms of the iCC or CHAMPS pilot randomized controlled trials, and 17 EIS clinicians from multiple professional backgrounds.

MEASUREMENTS: Semi-structured interviews explored experiences of app use, perceived benefits and challenges, contextual influences, clinician involvement and factors affecting engagement and integration within EIS. Themes were mapped to the i-PARIHS domains of innovation, recipients, context and facilitation.

FINDINGS: Participants generally perceived both mobile interventions as acceptable, relevant and well aligned with the daily realities of young adults with FEP. The apps' accessibility, flexibility and non-judgmental approach supported self-reflection, autonomy and increased awareness of cannabis use. However, engagement was shaped by individual motivation, psychosis-related symptoms, competing life and treatment priorities and, for some, app-related challenges, including content-related concerns and technical issues that interfered with use. Clinician involvement was widely viewed as beneficial for sustaining engagement and supporting reflection, yet was inconsistently implemented due to time constraints, limited familiarity with app content and uncertainty regarding clinicians' roles.

CONCLUSIONS: Cannabis-focused mobile interventions appear to be acceptable and relevant complements to standard early intervention service care for psychosis. Their successful implementation depends not only on usability, but also on active facilitation, clear clinician role definitions and adaptive integration strategies that align with real-world constraints within early intervention services.