Although empirical evidence has confirmed the causal relationship between childhood maltreatment and depression, findings are inconsistent on the magnitude of the effect of age of exposure to childhood maltreatment on psychological development. This systematic review with meta-analysis aims to comprehensively synthesize the literature on the relationship between exposure age of maltreatment and depression and to quantitatively compare the magnitude of effect sizes across exposure age groups. Electronic databases and grey literature up to April 6th, 2022, were searched for English-language studies. Studies were included if they: 1) provided the information on exposure age; and 2) provided statistical indicators to examine the relationship between childhood maltreatment and depression. Fifty-eight articles met eligibility criteria and were included in meta-analyses. Subgroup analyses were conducted based on subtypes of maltreatment and measurements of depression. Any kind of maltreatment (correlation coefficient [r] = 0.17, 95% CI = 0.15-0.18), physical abuse (r =0.13, 95% CI = 0.10-0.15), sexual abuse (r = 0.18, 95% CI = 0.15-0.21), emotional abuse (r = 0.17, 95% CI=0.11-0.23), and neglect (r = 0.08, 95% CI=0.06-0.11) were associated with an increased risk of depression. Significant differential effects of maltreatment in depression were found across age groups of exposure to maltreatment (Q = 34.81, p < 0.001). Age of exposure in middle childhood (6-13 years) had the highest risk of depression, followed by late childhood (12-19 years) and early childhood (0-6 years). Implications of the findings provide robust evidence to support targeting victimized children of all ages and paying closer attention to those in middle childhood to effectively reduce the risk of depression.
Keywords: age at maltreatment; childhood maltreatment; depression; depressive symptom; psychopathology; sensitivity period.