School-based targeted prevention for children with mild intellectual disabilities or borderline intellectual functioning and behaviour problems: A pilot implementation study

Background: We examined the implementation and potential effectiveness of a school-based targeted prevention programme addressing behaviour problems, adapted for children with mild intellectual disabilities or borderline intellectual functioning. Method: Thirteen children participated. The intervention was implemented in schools. We examined intervention dosage, reach, responsiveness, satisfaction, and comprehension, using questionnaires completed by children and trainers. We assessed child- and teacher-reported behaviour problems before and after the intervention. Results: Trainers selected both children who did and did not meet the intervention eligibility criteria, suggesting problems in intervention reach. Intervention dosage, responsiveness, satisfaction, and comprehension were satisfactory. There were group-level behaviour problem decreases (i.e., Cohen's d). Individual-level behaviour problem changes (i.e., Reliable Change Indices) showed large heterogeneity and little reliable change. Conclusions: The results provide initial evidence that the intervention has potential for successful implementation in schools, but the current evidence for intervention effectiveness is inconclusive.