A Second and Third Look at FIRST: Testing Adaptations of A Principle-Guided Youth Psychotherapy.

We examined the acceptability, integrity, and symptom trajectories associated with FIRST, a principle-guided treatment for youth internalizing and externalizing problems designed to support efficient uptake and implementation. We conducted two open trials of an adapted FIRST, focusing on uptake and implementation by novice trainees in a university-affiliated clinic, limiting treatment duration to six sessions, and benchmarking findings against a 2017 FIRST trial with community therapists. In Study 1, trainees received a two-day training and weekly two-hour supervision ( = 22 youths, ages 7-17, 50% female, 54.54% Caucasian, 4.55% Latinx). In Study 2, trainees received a one-day training and weekly one-hour supervision, delivering the six-session FIRST in a predetermined sequence ( = 26 youths, ages 11-17, 42.31% female, 65.38% Caucasian, 7.69% Latinx). In Study 3, the original study therapists - now practitioners - evaluated FIRST's effectiveness and implementation difficulty, and reported their own post-study FIRST use.: Acceptability (treatment completion, session attendance, caregiver participation) and integrity (adherence, competence) were comparable across Study 1, Study 2 and the 2017 trial. Improvement effect sizes across ten outcome measures were in the large range in all three trials: ES = 1.10 in the 2017 trial, 0.83 in Study 1, and 0.81 in Study 2. Study 3 showed high effectiveness ratings, low difficulty ratings, and continued use of FIRST by a majority of clinicians. Across two open trials and a follow-up survey, FIRST showed evidence of acceptability and integrity, with youth symptom reduction comparable to that in prior research.