Standalone effects of focus mode and social comparison functions on problematic smartphone use among adolescents

•Effects of app-based interventions on problematic smartphone use (PSU) were tested.•In the focus-function group, participants had use limits placed on selected apps.•In the feedback-function group, a social comparison of smartphone use was provided.•Self-reported PSU was reduced after the intervention in both intervention groups.•App-recorded smartphone use frequency was reduced in both intervention groups.