RESUMO
OBJECTIVE: Parental Friendship Coaching (PFC) teaches parents to coach their children in friendship skills. This paper examines whether PFC fosters positive peer contagion processes (i.e. dyadic mutuality) and reduces negative peer contagion processes (i.e. coercive joining) within the friendships of children with attention-deficit/hyperactivity disorder (ADHD). METHOD: Participants were 134 families of children with ADHD and peer problems (age 6-11 years; 69% male; 72% white) at two Canadian sites, randomized to PFC or CARE (an active comparison intervention). Children were observed in the lab at baseline, post-treatment, and at 8-month follow-up during cooperation and competition tasks with a real-life friend. Amount and reciprocity of dyadic mutuality indicators (i.e. positive affect and positive behaviors) and coercive joining indicators (i.e. aggressive, controlling, and rule-breaking behaviors) between friends were coded. RESULTS: Across treatment conditions, children showed an increase in the amount of dyadic mutuality during cooperation and a decrease in the amount of coercive joining during competition over time. Relative to CARE, PFC induced a reduced amount of coercive joining behaviors during cooperation at post-treatment and follow-up. However, PFC led to decreases in the reciprocity of positive affect during cooperation at post-treatment and to increases in the reciprocity of coercive joining during competition at follow-up relative to CARE. Moderation analyses suggest PFC was associated with better outcomes for children with externalizing comorbidity, and for those with a stable or a best friend. CONCLUSIONS: Findings highlight the importance of transactional processes, contextual differences, externalizing comorbidities, and friendship status when assessing the efficacy of PFC.