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Reduced Working Memory Mediates the Link between Early Institutional Rearing and Symptoms of ADHD at 12 Years

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ABSTRACT

Children who are raised in institutions show severe delays across multiple domains of development and high levels of psychopathology, including attention deficit/hyperactivity disorder (ADHD). Low performance in executive functions (EFs) are also common in institutionally reared children and often do not remediate following improvements in the caregiving environment. ADHD symptomatology also remains elevated even after children are removed from institutional care and placed in families. We investigate whether poor EF is a mechanism explaining elevated rates of ADHD in children reared in institutional settings in the Bucharest Early Intervention Project (BEIP). In the current study, we examine the potentially mediating role of poor EF in the association between institutionalization and symptoms of ADHD at age 12 years. A total of 107 children were assessed with the Cambridge Neuropsychological Test Automated Battery (CANTAB) on working memory, set-shifting and planning. We also obtained concurrent teacher reports on their levels of ADHD symptoms (inattention and impulsivity separately). Institutionalization strongly predicted elevations in symptoms of inattention and impulsivity at age 12 years (ps < 0.01). Indices of working memory and planning were also associated with ADHD after controlling for potential confounders (ps < 0.03). Mediation analyses revealed that poor working memory performance mediated the link between exposure to early institutionalization and higher scores of both inattention and impulsivity. These results replicate and extend the findings that we reported in the BEIP sample at age 8 years. Together, they suggest that compromised working memory is a key mechanism that continues to explain the strikingly high levels of ADHD in late childhood among children institutionalized in early life. Interventions targeting working memory may help to prevent ADHD among children exposed to institutional care.

No MeSH data available.


Related in: MedlinePlus

Full mediation models linking exposure to institutionalization to inattention and impulsivity through working memory.
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Figure 1: Full mediation models linking exposure to institutionalization to inattention and impulsivity through working memory.

Mentions: In our final sets of analyses we tested our main hypotheses; namely that poor EF performance explained the link between exposure to institutionalization and elevated ADHD symptoms. To do that, we tested two mediation models, one for each of the two dependent variables, in which we included the institutionalization status as the predictor, EF indices as mediators and birth weight and gender as covariates. For each model, we tested separately whether the indirect effect of institutionalization on ADHD symptoms through working memory and planning was statistically significant. These findings are presented jointly in Figure 1.


Reduced Working Memory Mediates the Link between Early Institutional Rearing and Symptoms of ADHD at 12 Years
Full mediation models linking exposure to institutionalization to inattention and impulsivity through working memory.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5121247&req=5

Figure 1: Full mediation models linking exposure to institutionalization to inattention and impulsivity through working memory.
Mentions: In our final sets of analyses we tested our main hypotheses; namely that poor EF performance explained the link between exposure to institutionalization and elevated ADHD symptoms. To do that, we tested two mediation models, one for each of the two dependent variables, in which we included the institutionalization status as the predictor, EF indices as mediators and birth weight and gender as covariates. For each model, we tested separately whether the indirect effect of institutionalization on ADHD symptoms through working memory and planning was statistically significant. These findings are presented jointly in Figure 1.

View Article: PubMed Central - PubMed

ABSTRACT

Children who are raised in institutions show severe delays across multiple domains of development and high levels of psychopathology, including attention deficit/hyperactivity disorder (ADHD). Low performance in executive functions (EFs) are also common in institutionally reared children and often do not remediate following improvements in the caregiving environment. ADHD symptomatology also remains elevated even after children are removed from institutional care and placed in families. We investigate whether poor EF is a mechanism explaining elevated rates of ADHD in children reared in institutional settings in the Bucharest Early Intervention Project (BEIP). In the current study, we examine the potentially mediating role of poor EF in the association between institutionalization and symptoms of ADHD at age 12 years. A total of 107 children were assessed with the Cambridge Neuropsychological Test Automated Battery (CANTAB) on working memory, set-shifting and planning. We also obtained concurrent teacher reports on their levels of ADHD symptoms (inattention and impulsivity separately). Institutionalization strongly predicted elevations in symptoms of inattention and impulsivity at age 12 years (ps < 0.01). Indices of working memory and planning were also associated with ADHD after controlling for potential confounders (ps < 0.03). Mediation analyses revealed that poor working memory performance mediated the link between exposure to early institutionalization and higher scores of both inattention and impulsivity. These results replicate and extend the findings that we reported in the BEIP sample at age 8 years. Together, they suggest that compromised working memory is a key mechanism that continues to explain the strikingly high levels of ADHD in late childhood among children institutionalized in early life. Interventions targeting working memory may help to prevent ADHD among children exposed to institutional care.

No MeSH data available.


Related in: MedlinePlus