“StudiCare Mindfulness”: effects of an online mindfulness-based intervention on mindfulness, stress, and interoception in university students – a randomized controlled trial

BACKGROUND: University students experience elevated stress levels that increase the risk for developing mental disorders. Online mindfulness-based interventions (MBIs) represent a promising low-threshold approach to improve health-related variables. However, evidence regarding their effects on psychobiological stress markers and interoceptive abilities remains limited. METHODS: This randomized controlled trial investigated the efficacy of an 8-week guided online MBI (StudiCare Mindfulness) in university students (n = 60) compared to a waitlist control group (n = 61). Assessments were conducted at baseline (T0), after eight weeks (T1), and 6-month follow-up (T2). Primary outcome was mindfulness (Freiburg Mindfulness Inventory). Secondary outcomes included perceived stress (Perceived Stress Scale-4), psychobiological stress (hair cortisol), interoceptive accuracy (heartbeat perception task), and interoceptive sensibility (confidence ratings, Body Perception Questionnaire). Hierarchical linear models were employed for data analysis. RESULTS: Significant time × group interactions demonstrated that the intervention group significantly improved in mindfulness (β = 3.137, p = .002) and showed reductions in perceived stress (β = - 0.989, p < .001) compared to controls, with effects maintained at follow-up. No significant intervention effects were observed for psychobiological stress and interoceptive abilities. CONCLUSIONS: The guided online MBI effectively enhanced mindfulness and reduced perceived stress in university students, with sustained effects at 6-month follow-up. However, the intervention did not significantly affect psychobiological stress markers or interoceptive processing, suggesting differential sensitivity of psychological versus psychobiological stress dimensions to online MBIs. At the same time, the absence of effects on psychobiological measures should be interpreted with caution, as these outcomes may have been subject to additional uncontrolled sources of variability. TRIAL REGISTRATION: German Clinical Studies Trial Register TRN: DRKS00014701, trial registration date: 07.05.2018.