Parental Differential Treatment of Siblings and Child Psychopathology: A Network Meta-analysis

To determine the associations between parental differential treatment (PDT) and various psychopathological symptoms in children and its mechanisms, this systematic review integrated 26 studies spanning more than three decades, involving 37,025 participants. A network meta-analysis was employed to calculate correlations between absolute and relative PDT and specific symptoms (including anxiety, depression, aggression, and rule-breaking behavior), as well as broad-band symptoms (including internalizing and externalizing behavior) in children. Meta-analytic structural equation modelling was used to examine the mediating effect between PDT and psychopathology. Results indicated that a greater amount of PDT in the family (absolute PDT) was significantly associated with depression (r = 0.14, 95% CI [0.06, 0.22]), internalizing behavior (r = 0.14, 95% CI [0.06, 0.22]), aggression (r = 0.11, 95% CI [0.03, 0.19]), rule-breaking behavior (r = 0.21, 95% CI [0.08, 0.33]) and externalizing behavior (r = 0.13, 95% CI [0.04, 0.21]). Compared to favored siblings, disfavored children (relative PDT) displayed more anxiety (r = 0.11, 95% CI [0.01, 0.21]), depression (r = 0.10, 95% CI [0.00, 0.18]), internalizing behavior (r = 0.12, 95% CI [0.01, 0.23]), aggression (r = 0.12, 95% CI [0.02, 0.21]) and externalizing behavior (r = 0.20, 95% CI [0.10, 0.29]). Children who received less favoritism were at higher risk for psychopathology in cultures with higher levels of individualism. Furthermore, the sibling relationship factor mediated the association between absolute PDT and child psychopathology. These findings highlight that PDT may be a risk factor for both specific and broad-band symptoms of psychopathology and offer insights into its potential mechanisms.