Study protocol for a randomized controlled trial testing the efficacy of Emotion Detectives In-Out: a blended version of the unified protocol for transdiagnostic treatment of emotional disorders in Portuguese children.

Background: Childhood emotional disorders (EDs; i.e., anxiety and depressive disorders) are currently a public health concern. Their high prevalence, long-term effects, and profound influence on the lives of children and families highlight the need to identify and treat these disorders as early and effectively as possible. This clinical trial will examine the efficacy of a blended version (i.e., combining face-to-face and online sessions into one treatment protocol) of the Unified Protocol for Children (the "Emotion Detectives In-Out" program). This program is a manualized cognitive-behavioral therapy for the transdiagnostic treatment of EDs in children aged 7 to 12 years that aims to reduce the intensity and frequency of strong and aversive emotional experiences by helping children learn how to confront those emotions and respond to them in more adaptive ways.

Methods: This study is designed as a multicenter equivalence randomized controlled parallel-group two-arm trial comparing the Emotion Detectives In-Out program with an evidenced-based group intervention for children with anxiety disorders (the Coping Cat program). Participants will be children aged between 7 and 12 years with an anxiety disorder or with clinically significant anxiety symptoms as well as one of their parents or a legal representative. A minimum sample size of 138 children (69 per group) is needed to test whether the efficacy of the proposed intervention is equivalent to that of the well-established Coping Cat intervention.

Discussion: We expect Emotion Detectives In-Out to be a feasible and efficacious alternative intervention for treating children's EDs by allowing for a greater increase in children's access to care. A blended format is expected to overcome common barriers to treatment (e.g., parents´ lack of time to attend regular sessions) and make the intervention more accessible to families.

Trial Registration: The clinical trial is registered at ClinicalTrials.gov (Identifier: NCT05747131, date assigned February 28, 2023).