Long-Term Social Skills Group Training in Children and Adolescents with Autism Spectrum Disorder Indicates a Dose-Response Relationship: A Randomized Controlled Trial

Background: Social skills group training (SSGT) is widely used for intellectually able children and adolescents with autism spectrum disorder (ASD). Previous studies indicate small to moderate effects on social communication capacities. Objectives: We hypothesized that an extended training program would result in larger effects. Methods: This randomized controlled trial compared 24 weekly sessions of the SSGT program KONTAKT with standard care alone. The SSGT combined a previously evaluated 12 session version of KONTAKT with 12 additional sessions designed to facilitate generalization of acquired skills to real-world settings. A total of 50 participants with ASD (15 females; 35 males) aged 8-17 years were included. The study was conducted at two child and adolescent psychiatry outpatient units in Sweden. The primary outcome was the Social Responsiveness Scale -2 (SRS-2) rated by parents and blinded teachers. Secondary outcomes included parent- and teacher-rated adaptive behaviors, trainer-rated global functioning and clinical severity, and self-reported child and caregiver stress. Assessments were made at baseline, post-treatment, and at 3-months follow-up. Results: Parent-rated SRS-2 scores indicated large effects post-treatment (-19.2; 95% CI, -29.9 to -8.5; p < .001, effect size [ES] = 0.76), which were maintained at follow-up (-20.7; 95% CI, -31.7 to -9.7; p < .0001, ES = 0.82). Conclusions: These estimates indicate substantially larger improvement than previously reported for shorter SSGT. However, the effects on teacher-rated SRS-2 and most secondary outcomes did not reach statistical significance. These preliminary results indicate a dose-response relationship, and imply that service providers can reach better results by optimizing the length of SSGT.