About 18% of children in industrialized countries suffer from anxiety. We designed a mobile neurofeedback app, called Mind-Full, based on existing design guidelines. Our goal was for young children in lower socio-economic status schools to improve their ability to self-regulate anxiety by using Mind-Full. In this paper we report on quantitative outcomes from a sixteen-week field evaluation with 20 young children (aged 5 to 8). Our methodological contribution includes using a control group, validated measures of anxiety and stress, and assessing transfer and maintenance. Results from teacher and parent behavioral surveys indicated gains in children's ability to self-regulate anxiety at school and home; a decrease in anxious behaviors at home; and cortisol tests showed variable improvement in physiological stress levels. We contribute to HCI for mental health with evidence that it is viable to use a mobile app in lower socio-economic status schools to improve children's mental health.

Millions of children have challenges with anxiety that negatively impact their development, education and well-being. To address this challenge, we developed version 2.0 of Mind-Full, a wearable, mobile neurofeedback system, designed to teach young children to learn to self-regulate anxiety. We present a mixed methods evaluation of a seven week long intervention in schools. We report on a subset of outcome measures related to 10 children's anxiety and stress in the classroom and describe mediating socio-technological processes that may have impacted outcomes. Findings showed improvement in children's ability to self-regulate anxiety and reduced cortisol levels for some children. Qualitative findings suggested that children who made multimodal connections during system mediated learning and had teacher support for learning transfer responded well to the intervention. We suggest that framing mental health app design as a distributed, adaptive, socio-technological system enables designers to better meet individual's unique and changing mental health needs.