Childhood Maltreatment and Mental Health Problems: A Systematic Review and Meta-Analysis of Quasi-Experimental Studies

Abstract

Objective: Childhood maltreatment is associated with mental health problems, but the extent to which this relationship is causal remains unclear. To strengthen causal inference, the authors conducted a systematic review and meta-analysis of quasi-experimental studies examining the relationship between childhood maltreatment and mental health problems.

Methods: A search of PubMed, PsycINFO, and Embase was conducted for peer-reviewed, English-language articles from database inception until January 1, 2022. Studies were included if they examined the association between childhood maltreatment and mental health problems using a quasi-experimental method (e.g., twin/sibling differences design, children of twins design, adoption design, fixed-effects design, random-intercept cross-lagged panel model, natural experiment, propensity score matching, or inverse probability weighting).

Results: Thirty-four quasi-experimental studies were identified, comprising 54,646 independent participants. Before quasi-experimental adjustment for confounding, childhood maltreatment was moderately associated with mental health problems (Cohen's d=0.56, 95% CI=0.41, 0.71). After quasi-experimental adjustment, a small association between childhood maltreatment and mental health problems remained (Cohen's d=0.31, 95% CI=0.24, 0.37). This adjusted association between childhood maltreatment and mental health was consistent across different quasi-experimental methods, and generalized across different psychiatric disorders.

Conclusions: These findings are consistent with a small, causal contribution of childhood maltreatment to mental health problems. Furthermore, the findings suggest that part of the overall risk of mental health problems in individuals exposed to maltreatment is due to wider genetic and environmental risk factors. Therefore, preventing childhood maltreatment and addressing wider psychiatric risk factors in individuals exposed to maltreatment could help to prevent psychopathology.

Keywords: Child/Adolescent Psychiatry; Environmental Risk Factors; Genetics/Genomics; Violence/Aggression.

Figure 1. Forest plot depicting the study-average effects of child maltreatment on mental health from quasi-experimental studies.

Note. MREM = multi-level random-effects meta-analysis model. For clarity of presentation, the forest plot shows 1 effect size per study (reflecting the average of all individual effect sizes obtained from each study), rather than all 150 effect sizes used to derive the pooled MREM estimate. The average effect size per study and its variance was calculated using the MAd package,(87) assuming a correlation of 0.6 between multiple within-study effect sizes. The 156 effect sizes are presented in Table S9 of the Supplement. I² for the MREM was 76.27, indicating that 76% of variation between effect sizes would remain if sampling error was eliminated.

Figure 2. Meta-analytic associations between child maltreatment and mental health problems across different quasi-experimental methods.

Note. k=number of studies (i.e., papers); n=number of participants across studies; ES=number of effect sizes. “MZ twin difference” refers to twin difference designs including only monozygotic twins, while “twin difference” refers to twin difference designs that include both monozygotic and dizygotic twins. Quasi-experimental methods used by only a single study in the meta-analysis (namely the adoption design (43), Children of Twins design (42), and random-intercept cross-lagged panel model (55)) were not included in the moderator analysis.

Figure 3. Meta-analytic associations between child maltreatment and different mental health problems

Note. k=number of studies (i.e., papers); n=number of participants across studies; ES=number of effect sizes; ADHD=attention-deficit/hyperactivity disorder. Specific mental health outcomes were grouped into categories shown in the figure. Internalising problems includes internalising symptoms, internalising behavior, emotional symptoms, and trauma symptoms; conduct problems includes conduct disorder, conduct problems, antisocial, oppositional, or aggressive behavior, arrest or incarceration; externalising problems includes externalising symptoms or behavior; personality disorder includes borderline, paranoid, schizoid, schizotypal, histrionic, narcissistic, antisocial, avoidant, obsessive-compulsive and dependent personality disorders; psychopathology broad includes total psychopathology symptoms, the p-factor, any psychopathology disorder, and total behaviour problems (on the Strengths and Difficulties Questionnaire). Outcomes assessed in only one study (bulimia (37) and substance use disorder (54)) were not included in the moderator analysis.

Figure 4. Meta-analytic associations between different types of child maltreatment and mental health problems

Note. k=number of studies (i.e., papers); n=number of participants across studies; ES=number of effect sizes. Maltreatment includes assessment of multiple subtypes of abuse and/or neglect; victimisation includes assessment of maltreatment alongside other forms of victimisation (e.g., bullying); ACEs includes assessment of maltreatment alongside other forms of adverse childhood experiences.