RESUMEN
Group programs are key for targeting social skills (SS) for children with developmental disorders and/or mental illness. Despite promising evidence regarding efficacy of group treatments, there are several limitations to current research regarding generalizability and effectiveness across diagnoses. This randomized control trial assessed whether the Secret Agent Society (SAS) group program was superior to treatment as usual (TAU) in improving social-emotional functioning for children with Attention Deficit-Hyperactivity Disorder (ADHD), Autism Spectrum Disorder (ASD), and/or anxiety. Eighty-nine youth (8-12) with ADHD, ASD, and/or an anxiety disorder receiving treatment at hospital-based outpatient clinics were randomized to receive SAS (n = 47) or TAU (n = 42) over a three-month period, at which point TAU participants were offered the SAS intervention. Parent report showed significant improvement in Emotion Regulation (ER) and Social Skills (SS) for youth in SAS vs. TAU (Fs ≥ 6.79, ps ≤ 01). Gains for the SAS condition were maintained at 6-months. Intent-to-treat analysis of teacher report indicated youth in SAS had positive gains in SS (F = 0.41, p = 0.475) and ER (F = 0.99, p = 0.322), though not significantly better than youth in TAU. Clinically reliable improvement rates were significantly higher for SAS participants than TAU for parent and teacher reported SS and ER. Improvements were significant for youth with single and comorbid diagnoses. Results suggest that SAS was superior to TAU in improving SS and ER for youth aged 8-12 with ADHD, ASD, and/or anxiety. Gains maintained in the medium-term. Trial registration number NCT02574273, registered 10/12/2015.