Abstract
IMPORTANCE: Many studies have demonstrated an association between early-life adversity (ELA) and executive functioning in children and adolescents. However, the aggregate magnitude of this association is unknown in the context of threat and deprivation types of adversity and various executive functioning domains. OBJECTIVE: To test the hypothesis that experiences of deprivation are more strongly associated with reduced executive functioning compared with experiences of threat during childhood and adolescence. DATA SOURCES: Embase, ERIC, MEDLINE, and PsycInfo databases were searched from inception to December 31, 2020. Both forward and reverse snowball citation searches were performed to identify additional articles. STUDY SELECTION: Articles were selected for inclusion if they (1) had a child and/or adolescent sample, (2) included measures of ELA, (3) measured executive functioning, (4) evaluated the association between adversity and executive functioning, (5) were published in a peer-reviewed journal, and (6) were published in the English language. No temporal or geographic limits were set. A 2-reviewer, blinded screening process was conducted. DATA EXTRACTION AND SYNTHESIS: PRISMA guidelines were used to guide data extraction and article diagnostics (for heterogeneity, small study bias, and p-hacking). Article quality was assessed, and data extraction was performed by multiple independent observers. A 3-level meta-analytic model with a restricted maximum likelihood method was used. Moderator analyses were conducted to explore heterogeneity. MAIN OUTCOMES AND MEASURES: Primary outcomes included measures of the 3 domains of executive functioning: cognitive flexibility, inhibitory control, and working memory. RESULTS: A total of 91 articles were included, representing 82 unique cohorts and 31 188 unique individuals. Deprivation, compared with threat, was associated with significantly lower inhibitory control (F1,90 = 5.69; P = .02) and working memory (F1,54 = 5.78; P = .02). No significant difference was observed for cognitive flexibility (F1,36 = 2.38; P = .12). The pooled effect size of the association of inhibitory control with deprivation was stronger (Hedges g = -0.43; 95% CI, -0.57 to -0.29) compared with threat (Hedges g = -0.27; 95% CI, -0.46 to -0.08). The pooled effect size of the association of working memory with deprivation was stronger (Hedges g = -0.54; 95% CI, -0.75 to -0.33) compared with threat (Hedges g = -0.28; 95% CI, -0.51 to -0.05). CONCLUSIONS AND RELEVANCE: Experiences of both threat and deprivation in childhood and adolescence were associated with reduced executive functioning, but the association was stronger for exposure to deprivation. Efforts to address the consequences of ELA for development should consider the associations between specific dimensions of adversity and specific developmental outcomes.