Background: Many children with attention-deficit/hyperactivity disorder (ADHD) demonstrate impairment in social skills. However, ADHD rarely occurs in isolation, with approximately one-third of children with ADHD having one additional disorder, and another third having two or three comorbidities. Few studies have considered the global and specific patterns of social skill performance based on comorbidity status.
Method: Using a large dataset containing 1400 carefully phenotyped children with ADHD (ages 7-12; 28% girls) in the United States and Canada, we characterized social skill deficit profiles associated with the presence of internalizing comorbidity (depression and/or anxiety), externalizing comorbidity (oppositional defiant or conduct disorder), and both internalizing + externalizing comorbidities. All children had parent and teacher ratings of social skills on a consistent measure, and we took a nuanced approach that considered both global social skills and specific subdomains of skills.
Results: Parent ratings indicated main and interaction effects of each comorbidity on lower social skill performance in a varied pattern. Both comorbidities were associated with poorer global social skills, responsibility, and self-control. In addition, internalizing was associated with poorer assertion, while externalizing was associated with poorer communication, cooperation, and empathy. Interaction effects suggested that the impact of externalizing overshadowed internalizing for poor responsibility and self-control; however, internalizing comorbidity attenuated the negative association between externalizing comorbidity and empathy. On teacher ratings, only externalizing comorbidity was associated with poorer global social skills, communication, cooperation, assertion, responsibility, empathy, and self-control. In addition, girls and younger children tended to have poorer global social skills (using a gender-normed standard score), while girls and older children showed better specific social skills (using a raw, not gender-normed score).
Conclusion: Children with ADHD and these comorbidities had poorer social skills relative to children with ADHD only, as perceived by parents and teachers. There also may be different social skill profiles depending on the comorbid condition and informant. These findings may inform more personalized social skill interventions for children with ADHD.
Keywords: ADHD; comorbidity; externalizing; internalizing; social skills.