Key Points Question What is the agreement between prospective and retrospective measures of childhood maltreatment? Findings This systematic review and meta-analysis of 16 unique studies and 25 471 unique participants found poor agreement between prospective and retrospective measures of childhood maltreatment, with Cohen κ = 0.19. On average, 52% of individuals with prospective observations of childhood maltreatment did not retrospectively report it, and likewise, 56% of individuals retrospectively reporting childhood maltreatment did not have concordant prospective observations. Meaning Because findings from this meta-analysis demonstrated that prospective and retrospective measures of childhood maltreatment identify largely different groups of individuals, the 2 measures cannot be used interchangeably to study the associated health outcomes and risk mechanisms.

Both prospective informant-reports and retrospective self-reports may be used to measure childhood maltreatment, though both methods entail potential limitations such as underestimation and memory biases. The validity and utility of standard measures of childhood maltreatment requires clarification in order to inform the design of future studies investigating the mental health consequences of maltreatment. The present study assessed agreement between prospective informant-reports and retrospective self-reports of childhood maltreatment, as well as the comparative utility of both reports for predicting a range of psychiatric problems at age 18. Data were obtained from the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally-representative birth cohort of 2232 children followed to 18 years of age (with 93% retention). Childhood maltreatment was assessed in two ways: (i) prospective informant-reports from caregivers, researchers, and clinicians when children were aged 5, 7, 10 and 12; and (ii) retrospective self-reports of maltreatment experiences occurring up to age 12, obtained at age 18 using the Childhood Trauma Questionnaire. Participants were privately interviewed at age 18 concerning several psychiatric problems including depression, anxiety, self-injury, alcohol/cannabis dependence, and conduct disorder. There was only slight to fair agreement between prospective and retrospective reports of childhood maltreatment (all Kappa's ≤ 0.31). Both prospective and retrospective reports of maltreatment were associated with age-18 psychiatric problems, though the strongest associations were found when maltreatment was retrospectively self-reported. These findings indicate that prospective and retrospective reports of childhood maltreatment capture largely non-overlapping groups of individuals. Young adults who recall being maltreated have a particularly elevated risk for psychopathology.

Childhood trauma is a key risk factor for psychopathology. However, little is known about how exposure to childhood trauma is translated into biological risk for psychopathology. Observational human studies and experimental animal models suggest that childhood exposure to stress can trigger an enduring systemic inflammatory response not unlike the bodily response to physical injury. In turn, these "hidden wounds" of childhood trauma can affect brain development, key behavioral domains (e.g., cognition, positive valence systems, negative valence systems), reactivity to subsequent stressors, and, ultimately, risk for psychopathology. Further research is needed to better characterize the inflammatory links between childhood trauma and psychopathology. Detecting and healing these hidden wounds may help prevent and treat psychopathology emerging after childhood trauma.

Background Childhood maltreatment is associated with poor mental and physical health. However, the mechanisms of gene-environment correlations and the potential causal effects of childhood maltreatment on health are unknown. Using genetics, we aimed to delineate the sources of gene-environment correlation for childhood maltreatment and the causal relationship between childhood maltreatment and health. MethodsWe did a genome-wide association study meta-analysis of childhood maltreatment using data from the UK Biobank (n=143 473), Psychiatric Genomics Consortium (n=26 290), Avon Longitudinal Study of Parents and Children (n=8346), Adolescent Brain Cognitive Development Study (n=5400), and Generation R (n=1905). We included individuals who had phenotypic and genetic data available. We investigated single nucleotide polymorphism heritability and genetic correlations among different subtypes, operationalisations, and reports of childhood maltreatment. Family-based and population-based polygenic score analyses were done to elucidate gene-environment correlation mechanisms. We used genetic correlation and Mendelian randomisation analyses to identify shared genetics and test causal relationships between childhood maltreatment and mental and physical health conditions.Findings Our meta-analysis of genome-wide association studies (N=185 414) identified 14 independent loci associated with childhood maltreatment (13 novel). We identified high genetic overlap (genetic correlations 0•24-1•00) among different maltreatment operationalisations, subtypes, and reporting methods. Within-family analyses provided some support for active and reactive gene-environment correlation but did not show the absence of passive geneenvironment correlation. Robust Mendelian randomisation suggested a potential causal role of childhood maltreatment in depression (unidirectional), as well as both schizophrenia and ADHD (bidirectional), but not in physical health conditions (coronary artery disease, type 2 diabetes) or inflammation (C-reactive protein concentration).Interpretation Childhood maltreatment has a heritable component, with substantial genetic correlations among different operationalisations, subtypes, and retrospective and prospective reports of childhood maltreatment. Familybased analyses point to a role of active and reactive gene-environment correlation, with equivocal support for passive correlation. Mendelian randomisation supports a (primarily bidirectional) causal role of childhood maltreatment on mental health, but not on physical health conditions. Our study identifies research avenues to inform the prevention of childhood maltreatment and its long-term effects.