Effects of early life stress on cognitive and affective function: an integrated review of human literature

Abstract

Rationale: The investigation of putative effects of early life stress (ELS) in humans on later behavior and neurobiology is a fast developing field. While epidemiological and neurobiological studies paint a somber picture of negative outcomes, relatively little attention has been devoted to integrating the breadth of findings concerning possible cognitive and emotional deficits associated with ELS. Emerging findings from longitudinal studies examining developmental trajectories of the brain in healthy samples may provide a new framework to understand mechanisms underlying ELS sequelae.

Objective: The goal of this review was twofold. The first was to summarize findings from longitudinal data on normative brain development. The second was to utilize this framework of normative brain development to interpret changes in developmental trajectories associated with deficits in cognitive and affective function following ELS.

Results: Five principles of normative brain development were identified and used to discuss behavioral and neural sequelae of ELS. Early adversity was found to be associated with deficits in a range of cognitive (cognitive performance, memory, and executive functioning) and affective (reward processing, processing of social and affective stimuli, and emotion regulation) functions.

Conclusion: Three general conclusions emerge: (1) higher-order, complex cognitive and affective functions associated with brain regions undergoing protracted postnatal development are particularly vulnerable to the deleterious effects of ELS; (2) the amygdala is particularly sensitive to early ELS; and (3) several deficits, particularly those in the affective domain, appear to persist years after ELS has ceased and may increase risk for later psychopathology.

Fig. 1

Affective and neural dysfunction during a monetary incentive delay task in a longitudinal sample of young adults (mean age: 24.58, SD: 0.88) exposed to childhood adversities. Eight of the maltreated participants have been studied since infancy (mean age at enrollment: 8.88 months), and five have been studied since young adulthood (mean age at enrollment: 20.60 years). Relative to healthy controls (n = 31), maltreated individuals (n = 13) reported reduced positive affect (a) and were characterized by reduced activation in the left pallidus and left putamen during the anticipation of a potential reward (monetary gains) (b–d). Highlighting the specificity of these findings, groups did not differ in their affective ratings or neural responses while anticipating a potential loss (monetary penalty) or no-incentive outcome (no monetary changes) (for all variables, the Group × Condition interaction was significant.) Functional MRI signals were extracted from structurally defined basal ganglia regions, including the putamen and pallidus (see panel b)