The hallmarks of childhood abuse and neglect: A systematic review

Background: Studies on the impacts of child maltreatment (CM) have been conducted in diverse areas. Mechanistic understanding of the complex interplay between factors is lacking. Hallmarking is an approach which identifies common factors across studies and highlights the most robust findings. Objectives: In a review of systematic reviews and meta-analyses, we addressed the following questions: 1) What are the hallmarks associated with exposure to CM across the bio-ecological spectrum? 2) What is the strength of evidence to support each hallmark? 3) What are the gaps that future research should address? Methods: A comprehensive literature search was carried out to find relevant systematic reviews or meta-analyses. 269 articles were read in full and 178 articles, encompassing more than 6000 original papers, were included in the final synthesis. All reviews were independently rated for quality by at least 2 reviewers using AMSTAR-2. Results: Of 178 review articles, 6 were rated as high quality (all meta-analyses) and 46 were rated as medium quality. Most were from high income countries. Conclusions: Based on the most commonly reported high-quality research findings we propose that the hallmarks of exposure to child maltreatment are: Increased risk of psychopathology; Increased risk of obesity; Increased risk of high- risk sexual behaviours, Increased risk of smoking; and Increased risk of child maltreatment in children with disabilities. Research gaps include a lack of focus on complexity and resilience. Little can be concluded about directions of causality or mechanisms. Adequately powered prospective studies are required to move the field forward.