Evaluation of the app-based prevention course "Einsamkeit reduzieren, Beziehungen stärken, Stress abbauen - Stressreduktion mit der platoniq App"

The primary purpose of this study is to evaluate the efficacy of a digital, app-based prevention intervention designed to reduce perceived stress by strengthening social support and reducing loneliness. Stress-related disorders are a major public health concern, often exacerbated by a lack of social resources. The "Stress-Buffering Hypothesis" suggests that social support protects individuals from the pathogenic effects of stressful events. The intervention is a 6-week, app-based course. It combines evidence-based methods from Cognitive Behavioral Therapy (CBT), Social Skills Training (SST), and specific Behavior Change Techniques (BCTs). The course is structured into six weekly modules addressing stress management. This study is designed as a longitudinal intervention study) with measurements at baseline (T0), post-intervention (T1, one week after end of intervention, between day 42 and day 97), and follow-up (T2, 8 weeks after T1, between day 98 and day 153). Participants are adults (18+) who are either directly affected by stress or who want to proactively strenghten their (social) ressources to prevent further stress perceiving a deficit in social support or feelings of loneliness. We hypothesize that participation in the intervention will lead to: - A significant reduction in perceived stress (Primary Outcome). - A significant increase in perceived social support. - A significant reduction in feelings of loneliness . Eligible participants are German-speaking adults (18+) with smartphone access who exhibit elevated stress (PSS-10 > 13), low social support (F-SozU K-6 < 20), or high loneliness (UCLA-9 > 18). Exclusion criteria encompass lack of consent capacity, active seeking of therapy, or acute psychological crises, suicidality, or inpatient treatment within the past month. Furthermore, individuals with severe mental disorders requiring treatment are excluded, as multimodal stress and resource management interventions are contraindicated in such cases and cannot replace professional care.