Effects of parent–child interaction therapy dosage on child and parent outcomes: differentiating child‐directed interaction and parent‐directed interaction session impacts in child welfare‐involved families

Background Parent–child interaction therapy (PCIT) improves parenting and child behavior, yet little is known about how dosage of its two phases, warm relationship building focused child‐directed interaction (CDI) sessions and safe, effective discipline skills‐focused parent‐directed interaction (PDI) sessions, contributes to outcomes, particularly in child welfare‐involved families. Understanding these dose–response patterns can clarify the pathways through which PCIT produces change. Methods In a sample of 204 child welfare families with young children, we examined the dose–response relationship between each PCIT phase and key intervention outcomes of positive and negative parenting skills and disruptive child behavior problems. We also used sequential mediation models to test time‐ordered intervention dosage effects (i.e., number of CDI sessions completed and subsequent number of PDI sessions completed) on the parent and child outcomes. Results Sequential mediation models showed that the PCIT intervention exerted significant indirect effects on increased positive parenting skills and decreased negative parenting behaviors and child behavior problems through higher dosage of relationship‐enhancing CDI sessions followed by higher dosage of safe discipline‐focused PDI sessions. Further, CDI dosage interacted with PDI dosage to predict greater gains in positive parenting skills outcomes. Conclusions These results contribute new insights into the pathways through which PCIT shapes outcomes in a sample of child welfare‐involved families. Findings also highlight the significant unique contribution that limit‐setting‐oriented PDI, a relatively understudied phase of PCIT, plays in enhancing positive parenting skills and mitigating child behavior problems.