Individual Participant Data Meta-analysis: Impact of Conduct Problem Severity, Comorbid...

Area of Science:

• Child and Adolescent Psychology
• Clinical Psychology
• Developmental Psychology

Background:

• Established parenting programs for conduct problems may not serve families with complex mental health needs.
• Families with severe conduct issues, comorbid attention-deficit/hyperactivity disorder (ADHD), emotional problems, or maternal depression are often underrepresented in trials.
• The Incredible Years program is a widely used parenting intervention.

Purpose of the Study:

• To investigate if children with more severe conduct problems or complex mental health issues benefit less from the Incredible Years parenting program.
• To examine the impact of comorbid ADHD, emotional problems, and maternal depression on intervention effectiveness.
• To conduct an individual participant data meta-analysis of randomized trials in Europe.

Main Methods:

• Individual participant data meta-analysis of 13 randomized trials in Europe.
• Involved 1,696 families with children aged 2-11 years.
• Moderator analysis within a multilevel model was used to assess intervention effects based on child and maternal characteristics.

Main Results:

• The Incredible Years program significantly reduced children's conduct problems (Cohen's d = -0.35).
• Children with more severe conduct problems showed greater benefits from the intervention.
• Comorbid ADHD and emotional problems did not diminish intervention effects; maternal depression was associated with greater child improvements.

Conclusions:

• Children with more severe conduct problems benefit more from the Incredible Years program.
• The program's effectiveness is not reduced by comorbid ADHD or emotional problems.
• Maternal depression is linked to greater reductions in children's conduct problems, contrary to expectations.