StudiCare Mindfulness - Randomized controlled trial to evaluate an unguided as well as a "guidance on demand" version of an internet-based mindfulness intervention for students

INTERVENTION: Intervention 1: unguided intervention group with immediate access to an internet‐based mindfulness intervention developed according to the principles of Acceptance and Commitment Therapy as well as stress management (e. g. interoception, dealing with stressful thoughts, values and goals); consisting of seven modules that are supposed to be worked through on a weekly basis as well as two booster sessions 4 and 12 weeks after completion of the last (seventh) module; additionally the possibility to book a SMS coach with tips and reminders for the time of the intervention Intervention 2: "guidance on demand" intervention group that also receives immediate access to the same intervention as the unguided intervention group; additionally, participants of this group have the possibility to contact their e‐coach in case of questions or for feedback concerning their finished modules at any time Intervention 3: waitlist control group; access to same internet‐based training as unguided intervention group after waiting period of 6 months CONDITION: no health condition, preventive; low to moderate mindfulness PRIMARY OUTCOME: Mindfulness according to the Freiburg Mindfulness Inventory; data collection before (t0), 8 weeks after (t1) and 6 months after (Follow‐Up, FU) randomisation; additional intermediate assessment for mediation analysis after 4 weeks SECONDARY OUTCOME: Depression (PHQ‐9), anxiety (GAD‐7),, stress (PSS‐4), wellbeing (WHO‐5), self‐efficacy (SWE), presenteeism (SPS), cognitive fusion (CFQ‐D), intervention satisfaction (CSQ‐8), adherence (number of completed modules) and acceptance (self‐developed questionnaire), credebility/expectancy (CEQ), risks and side effects (modifed version of INEP); data collection before (t0), 8 weeks after (t1) and 6 months after (Follow‐Up, FU) randomisation; additional intermediate assessment of anxiety, stress, depression, self‐efficacy and cognitive fusion for mediation analysis after 4 weeks INCLUSION CRITERIA: moderate to low mindfulness (Freiburg Mindfulness inventory 37 or lower); at least 18 Jears old; enrolled as a college/university student