ObjectivesTo assess the feasibility of the Toolkit for Optimal Recovery after Concussion (TOR-C), the first mind-body program aiming to prevent persistent concussion symptoms among young adults with anxiety, and an active control (Health Enhancement after Concussion; HE-C). We also tested preliminary improvements in outcome measures and putative mechanistic targets. DesignSingle-blind, 2-arm, randomized controlled trial.Setting: Academic medical center in the US Northeast. ParticipantsFifty young adults (ages 18-35) with a recent concussion (3-10 weeks prior) and anxiety (≥5 on the GAD7 questionnaire). InterventionsBoth interventions consisted of four 45-minute 1:1 sessions with a clinician over Zoom. TOR-C (n=25) taught mind-body, cognitive-behavioral, and return-to-activity skills. HE-C (n=25) taught health education (e.g., sleep, nutrition) without skills. Main Outcome MeasuresPrimary: feasibility outcomes (e.g., recruitment, credibility, expectancy, acceptability, safety, feasibility of assessments, fidelity, satisfaction, TOR-C homework adherence) with a-priori-set benchmarks. Secondary: intervention outcomes were concussion symptoms (PCSS), physical function (WHODAS), anxiety (GAD7/HAD-A), depression (HADS-D) and pain (NRS). TOR-C mechanistic targets were pain catastrophizing (PCS), mindfulness (CAMS-R), fear avoidance (FAB-TBI), limiting behavior and all-or-nothing behavior (BRIQ). ResultsBoth interventions met all feasibility benchmarks and were associated with significant improvements in outcomes (concussion symptoms, physical function, anxiety, depression and pain; d=0.44-1.21) and TOR-C mechanistic targets (pain catastrophizing, mindfulness, fear-avoidance, and limiting behavior; Cohen's d=0.41-1.24). Improvements in all-or-nothing behavior were only significant in TOR-C (d=0.52). Improvements in all mechanistic targets except all-or-nothing behavior following TOR-C were significantly associated with improvements in at least one outcome. ConclusionFindings provide strong support for the feasibility of TOR-C and HE-C, and preliminary evidence for improvements in mechanistic targets and outcomes. Findings inform a future fully-powered RCT testing efficacy of TOR-C vs. HE-C.