Trustees of Dartmouth College

The goal of this clinical trial is to evaluate a smartphone based just-in-time adaptive intervention (JITAI) tool to deliver somatic behavioral recommendations for anxiety management among youth. The main questions it aims to answer are:
* Is the JITAI tool acceptable among the adolescent study population?
* Is the JITAI tool feasible to deliver to the adolescent study population?
* Does the study support preliminary efficacy of the JITAI tool among the adolescent study population?
The tool will be pilot-tested among a sample of 50 rural adolescents experiencing elevated anxiety levels who will be randomly assigned to the JITAI tool or a waitlist control, for a treatment period of 3 months.
Participants will be asked to:
* Use the smartphone based JITAI tool which will deliver somatic behavioral recommendations intended to manage anxiety levels for a treatment period of 3 months
* Respond to the tool's prompts on a daily basis and follow the delivered behavioral recommendations
* Complete anxiety and interoception assessments at study start, study end (3 months), and one-month follow-up
* Complete usability and user experience instruments at study end (3 months)

In this experiment, the investigators study the brain pathways underlying several promising context interventions that enhance the strength of placebo effects. Specifically, the investigators examine the separate and joint effects of two of the most powerful context interventions: Social modeling-observing someone else being effectively treated-and prior treatment success or failure experiences. Participants will be randomized into 4 groups (Social modeling: observed success vs. observed failure and Conditioning: experienced success vs. experienced failure). The objectives are to investigate the placebo effect on pain relief and aversive image stimuli between and within-subjects. Each group will undergo a behavioral induction phase, fMRI placebo test phase, and an identical 3-month follow up fMRI placebo test phase. Follow-up assessment will provide some of the first evidence on predictors of the durability of placebo and context interventions.

This study examines the effects of placebo suggestions tailored to match or mismatch individual participants' motivational styles-an issue of person-situation 'fit' with important effects in public health settings, but which has been ignored in past research.