Title: Systematic review of the neural correlates of mindfulness training in adolescents

Introduction: Mental health disorders are a significant public health concern for adolescents in the U.S. According to a mental health surveillance report about children in the U.S. from

2013-2019, 36.7% of high school students aged 14-18 years had experienced persistent feelings of sadness or hopelessness during the past year, and approximately one fourth of adolescents aged 12-17 years reported receiving mental health services in the past year (Bitsko et al., 2022). One promising treatment in this population is mindfulness training. Mindfulness is the practice of non-elaborative observation, acknowledgement, and acceptance of one’s bodily sensations, thoughts, feelings, and environment from moment to moment (Hoffman, 2017). This cognitive skill has been leveraged to create mindfulness-based interventions (MBI), standardized forms of mindfulness training shown to be effective in the treatment of anxious and depressive symptoms in adolescents (Dunning et al., 2019; Chi et al., 2018). Although there is evidence elucidating the measurable effects of mindfulness training on brain structure and function in adults, there has been no summary that examines the neural correlates of MBIs within a solely adolescent population. Developing an adolescent-specific neural model of the effects of mindfulness can help us better understand the mechanisms of symptom improvement in the setting of mindfulness training and subsequently design more targeted treatments for specific symptom profiles.

Aims: In this paper, we systematically review the adolescent literature to investigate how MBIs alter neural structure and function in adolescence. We synthesize and compare our findings with existing adult models and propose our own adolescent model of how mindfulness and mindfulness training induce neural changes in the brain.

Project design/methods: A search was conducted to identify studies investigating the neuroimaging correlates of mindfulness-based interventions in adolescents. Several electronic databases were searched, including Pubmed, Google Scholar, and Psycinfo. The key search terms were: “magnetic resonance,” “fMRI,” “adolescence,” “youth,” “mindfulness,” “meditation,” “mindfulness-based intervention,” and “mindfulness training.” Following PRISMA guidelines, the articles were independently screened by two reviewers against defined inclusion and exclusion criteria, initially based on title and abstract reviews, followed by full-text reviews. Data from reports was collected by both reviewers and tabulated in an excel sheet. To narratively synthesize the studies, we developed an initial description of the results of included studies, grouped conceptually similar findings, identified patterns across them in terms of both the direction and size of the effects reported, and created a theoretical model that links multiple pieces of evidence to highlight key concepts or issues relevant to the review question.

Results/Product: A total of 15 studies were included for synthesis in this review (Figure 1) with 482 total participants to assess the neural effects of mindfulness interventions in adolescents. All studies use MRI data to demonstrate relative changes in brain regions and networks either