Brief modular anxiety intervention for primary care: Hybrid I pilot randomized controlled trial of feasibility, acceptability, effectiveness, and implementation potential.

Background: Anxiety is highly prevalent, but undertreated, in primary care. Brief, non-pharmacological interventions are needed. Modular Anxiety Skills Training (MAST), a cognitive-behavioral anxiety intervention, was developed for primary care and tailored for a Veteran sample (MAST-V). The purpose of this mixed methods pilot study was to evaluate MAST-V's feasibility, acceptability, and implementation potential, and preliminarily examine its effectiveness compared to Primary Care Behavioral Health (PCBH) usual care.

Methods: This hybrid I randomized controlled trial (conducted 2019-2021) assigned 35 primary care patients (M = 47, 17 % female, 27 % racial/ethnic minority) with clinically significant anxiety symptoms to receive MAST-V or PCBH usual care. Participants completed validated measures of anxiety symptoms and functional impairment at 0, 4, 8, 12, and 16 weeks.

Results: Participants attended more sessions in MAST-V than usual care. After necessary adjustments to reduce session duration, MAST-V will likely fit within PCBH practice parameters. Participants in both conditions valued treatment, but treatment satisfaction, credibility, and therapeutic alliance were higher for MAST-V. Study therapists achieved high treatment fidelity and rated MAST-V as highly feasible, acceptable, and appropriate for PCBH. They identified ways to address potential barriers to implementation. MAST-V was more effective than usual care in reducing anxiety symptoms and impairment.

Limitations: This was a small pilot study at a single site using study therapists. Results should be considered preliminary until replicated in a full-scale clinical trial.

Conclusions: This brief modular anxiety intervention, which was designed with implementation in mind, may help to address the anxiety treatment gap in primary care.