The moderating role of co-occurring attention-deficit hyperactivity disorder in social skills group training for autistic children and adolescents

Social skills group training is frequently used to support autistic children and adolescents in coping with everyday social demands and expectations. Meta-analytic studies suggest small to medium effect sizes. Effect moderators must be better understood to inform implementation and allow optimization of intervention protocols. Using data from two pragmatic randomized trials (<i>N</i> = 241) of the KONTAKT™ social skills group training program as an add-on to standard care in clinical settings, we aimed to explore the moderating role of co-occurring attention-deficit hyperactivity disorder in children (7-12 years) and adolescents (13-18 years). Two distinct response criteria were defined based on the parent-rated Social Responsiveness Scale: reliable improvement (⩾25 points) and clinically relevant improvement (⩾10 points). Moderator analyses indicated that the intervention effect was moderated by co-occurring attention-deficit hyperactivity disorder and age group. Logistic regressions stratified by co-occurring attention-deficit hyperactivity disorder showed significant effects among those without attention-deficit hyperactivity disorder (<i>n</i> = 63), both in terms of reliable improvement (odds ratio: 11.85, <i>p</i> = 0.002) and clinically relevant improvement (odds ratio: 10.00, <i>p</i> = 0.001). In contrast, no significant effects were observed in those with co-occurring attention-deficit hyperactivity disorder (<i>n</i> = 178). Explorative analyses further stratified by age suggested significant effects in adolescents, but not children, with co-occurring attention-deficit hyperactivity disorder. The findings preliminarily suggest that autistic children with attention-deficit hyperactivity disorder may need other or additional support.Lay abstractSocial skills group training can help some autistic children and adolescents improve their social life. Still, the positive effects may be less clear for those who also have attention-deficit hyperactivity disorder. We used data from two previous projects evaluating the effects of a social skills group training program called KONTAKT™ as an addition to the common healthcare provided. Our study included 241 children (8-12 years) and adolescents (13-18 years). To determine whether the participants had improved their social skills, we used ratings provided by the parents before and after the training and 3 months later. We then explored if KONTAKT led to improvement for autistic children and adolescents with and without attention-deficit hyperactivity disorder. Autistic children and adolescents often struggle to understand others and express themselves in everyday social situations. These challenges can create barriers to well-being and future life chances. Social skills group training can improve social skills in some autistic youths, but not all will benefit equally from the training. It is therefore important to better understand whether some groups need more support or other forms of assistance. Many autistic children and adolescents also have attention-deficit hyperactivity disorder, which can make the training of social skills more complicated. We found that both children and adolescents can benefit from KONTAKT. Still, preadolescent autistic children with attention-deficit hyperactivity disorder did not seem to improve as a result of the training. Based on these findings, it is important to find additional strategies to support this specific group of autistic children in handling social situations.