Supplementary Material for: Breaking the Intergenerational Cycle of Abuse – a Randomized Controlled Prevention Trial in Parents with Serious Mental Illness

Introduction: Although children of parents with mental illness (MI) are at increased risk of adverse childhood experiences and parental maltreatment, prevention trials targeting parents with MI are scarce. In addition, meta-analyses highlight significant methodological shortcomings in the current research. Trial design: To investigate real-world efficacy of a 12-hours mentalization-based parenting counselling program (MB-PC) compared to a psychoeducation workshop (SCC+) as supplements to standard clinical care (SCC). Methods: This large-scale, cluster-randomized, open-label (partially observer-blind), active-controlled bicentre superiority trial was conducted at German psychiatric hospitals. It included 252 patients undergoing psychiatric treatment for various serious MIs. MB-PC subsumed five individual sessions including video feedback, five group sessions that guided parents to better understand and respond to their child’s mental states, and two sessions of social counselling, all provided by an interprofessional hospital team of non-psychothera¬pists. Results: Patients in the MB-PC arm reported improved parenting practices – measured by the Alabama Parenting Questionnaire (APQ) total score as primary outcome – at post-intervention compared to those from the SSC+ arm (effect size (ES) = 0.43, 95% CI (0.13, 0.73), p=0.004), but group difference decreased at 3-months follow-up (ES = 0.25, 95% CI (-0.04, 0.53), p=0.085). All secondary outcomes were in favour of the MB-PC intervention, such as parental stress, child abuse potential, and child emotional well-being. Conclusion: Implementing a mentalisation-based parenting programme in routine psychiatric hospital care may represent an important step forward in reducing the risk of child maltreatment and neglect among offspring of parents affected by severe mental disorders.