Background: Offspring of parents with a mental disorder are at high risk of developing a mental disorder and experiencing other adverse outcomes, highlighting the need for preventive interventions. However, it remains uncertain to what extent these interventions are effective in reducing offspring’s risk of developing mental disorders and other important outcomes. The main objective of this systematic review will be to assess the effects of preventive interventions versus any control intervention for parents with a mental disorder on offspring outcomes.

Methods/design: A systematic review with meta-analysis will be performed and reported as recommended by Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA), bias will be assessed with the Cochrane Risk of Bias tool-version 2 (ROB2), an eight-step procedure will be used to assess if the thresholds for clinical significance are crossed, trial sequential analysis will be conducted to control for random errors, and the certainty of the evidence will be assessed with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. To identify relevant trials, we will search for published trials in several electronic databases from their inception to the present. We will also search for unpublished trials and grey literature. Two review authors will independently screen the articles, extract data, and perform a risk of bias assessment. We will include any published or unpublished randomized clinical trial comparing a psychological preventive intervention versus any control intervention for parents with any mental disorder. The primary outcomes, which will be assessed in the offspring only, will be quality of life and incidence of a mental disorder. Secondary outcomes will include internalizing symptoms, externalizing symptoms, serious adverse events, out-of-home placement, and absence from school or daycare. Exploratory outcomes include trauma, socioemotional development, and language development.

Discussion: There is an urgent need for a comprehensive, updated systematic review of the beneficial and harmful effects of preventive interventions for children with parents with a mental disorder. The findings of this systematic review are expected to provide evidence-based information for policymakers, clinicians, and researchers to help them make informed decisions about the most effective interventions and guide future research for this highly prevalent population