In light of different challenges associated with the COVID-19 pandemic, university students are considered a particularly vulnerable population to mental health and study engagement issues. The first years at university represent a crucial period for students and are associated with an increase in mental health problems, particularly in healthcare studies. This study aimed (1) to document the current levels of mental health and study engagement among healthcare students in Tunisia, and (2) to investigate the relationships between emotional regulation, optimism, study engagement and common mental health problems (stress, anxiety and depression) among this population. A cross-sectional, electronic survey-based research design was used to draw a sample of 366 health care students from a University in Tunisia. Participants mostly reported mild (34.7%) or moderate (44.3%) levels of depression, moderate (44.7%) or severe (33.6%) levels of anxiety, average (50.8%) or mild (33.8%) levels of stress, and high levels of study engagement (>85%). Through structural equation modelling, the results showed that emotional regulation negatively affected stress, anxiety, and depression. Optimism partially mediated the relationship between emotional regulation, anxiety and depression and fully mediated the relationship between emotional regulation and study engagement. The findings indicated a high prevalence of psychological distress among healthcare university students in Tunisia, and specific protective factors that may be targeted to reduce mental health problems.

BACKGROUND Digital mental health interventions (DMHIs) are increasingly proposed to address rising mental health problems among university students, yet their effectiveness is persistently constrained by low and heterogeneous engagement. Conventional metrics such as initiation and module completion rates fail to capture how students actually experience, appropriate, and integrate these tools into their daily lives, and may mask meaningful differences between delivery formats. OBJECTIVE This study aimed to characterize the lived experience and mechanisms of engagement with ETUCARE, an 8-week DMHI for university students in France, and to examine how online-only and hybrid delivery formats (combining digital modules with face-to-face workshops) shape distinct engagement pathways and configurations. METHODS A qualitative-led convergent mixed-methods design was used. Semi-structured interviews with students from both conditions (N=23) were analyzed using reflexive thematic analysis (Braun & Clarke) to document engagement mechanisms, facilitators, and barriers. To corroborate and extend these findings, latent profile analysis (LPA) was conducted on a subsample of participants with detailed engagement data (N=97), integrating behavioral indicators derived from platform logs and experiential indicators (perceived quality, enjoyment, usefulness). Associations between delivery format and profile membership were examined using the R3STEP procedure, and ANOVAs compared conditions on composite engagement scores. Findings were integrated using a joint display. RESULTS Qualitative analysis identified six themes characterising how students engaged with ETUCARE. Online engagement was driven by self-regulated autonomy, flexible and selective use of a modular toolbox, and intermittent catch-up rhythms. Hybrid engagement was socially scaffolded, supported by psychological safety, group bonding, and facilitator guidance, but frequently burdened by the reframing of digital tasks as obligatory homework, workload underestimation, and compounded usability frictions. LPA corroborated these experiential patterns by identifying four distinct engagement profiles: engaged and satisfied (53.6%), engaged but dissatisfied (16.5%), low engagement (16.5%), and minimal engagement (13.4%). Hybrid participants had significantly higher odds of belonging to the low engagement profile rather than the engaged and satisfied profile (OR=3.51, 95% CI 1.07–11.52, P=.038), and showed significantly lower behavioral (ω²=.067) and experiential (ω²=.064) engagement than online-only participants. CONCLUSIONS Engagement with ETUCARE was multidimensional and heterogeneous, shaped by distinct mechanisms across delivery formats. Hybrid delivery did not automatically enhance digital engagement and, under specific conditions, constrained it by transforming autonomous self-care into perceived obligation. These findings challenge prevailing assumptions about blended DMHIs and support mechanism-informed, qualitatively grounded approaches to measuring and optimizing engagement in youth digital mental health programs. CLINICALTRIAL Not applicable. The study was approved by the Ethics Committee of Nantes University (IRB No. IORG0011023, Ref. 06042023-2).