RESUMEN
BACKGROUND: Smartphone apps may help to prevent the transition from minor to severe mental health problems. We compared a free self-help smartphone app (COGITO; www.uke.de/cogito_app) against a wait-list condition for the improvement of self-esteem and depression. METHODS: The Rosenberg Self-Esteem Scale represented the primary outcome in this controlled trial. The final sample (n = 213) was randomly assigned to either the app or to the control condition. RESULTS: The app condition significantly improved the primary outcome relative to controls for all analyses. Satisfaction of completers was high. The present results warrant independent replication; the retention rate needs to be increased to allow solid inferences about acceptance. CONCLUSIONS: The present study demonstrates that the COGITO app may represent an effective self-help tool for psychological problems.