Engaging the child-parent relationship to treat early trauma: The challenge and promise of scaling with fidelity.

There is an urgent imperative to scale up access to effective, family-focused mental health services for trauma-exposed infants, toddlers, and preschoolers, who represent the most vulnerable and most underserved sector of the clinical child population. This article describes the process of scaling child-parent psychotherapy, an evidence-based treatment currently used in 39 U.S. states and six countries, as an example of the promise and challenge of large-scale implementation of relationship-based treatments.