Prolonged institutional rearing is associated with atypically large amygdala volume and difficulties in emotion regulation

Abstract

Early adversity, for example poor caregiving, can have profound effects on emotional development. Orphanage rearing, even in the best circumstances, lies outside of the bounds of a species-typical caregiving environment. The long-term effects of this early adversity on the neurobiological development associated with socio-emotional behaviors are not well understood. Seventy-eight children, who include those who have experienced orphanage care and a comparison group, were assessed. Magnetic resonance imaging (MRI) was used to measure volumes of whole brain and limbic structures (e.g. amygdala, hippocampus). Emotion regulation was assessed with an emotional go-nogo paradigm, and anxiety and internalizing behaviors were assessed using the Screen for Child Anxiety Related Emotional Disorders, the Child Behavior Checklist, and a structured clinical interview. Late adoption was associated with larger corrected amygdala volumes, poorer emotion regulation, and increased anxiety. Although more than 50% of the children who experienced orphanage rearing met criteria for a psychiatric disorder, with a third having an anxiety disorder, the group differences observed in amygdala volume were not driven by the presence of an anxiety disorder. The findings are consistent with previous reports describing negative effects of prolonged orphanage care on emotional behavior and with animal models that show long-term changes in the amygdala and emotional behavior following early postnatal stress. These changes in limbic circuitry may underlie residual emotional and social problems experienced by children who have been internationally adopted.

Figure 1

Temporal layout of one block where subjects were instructed to only press a button for the neutral faces and withhold pressing to other expressions. In this example, neutral faces are the target stimuli and faces with negative valence are the distracter stimuli.

Figure 2

Morphometric segmentation across groups. A) Anatomical segmentation of the amygdala (in aqua) from neighboring structures. B) Adjusted volumes by group. Children who had been adopted out of the orphanage at older ages (> 15 months old) had larger amygdale volumes than early-adopted children (< 15 months old) and comparison children, who did not differ from each other.

Figure 3

Age of adoption and amygdala volume. The older children were when adopted out of the orphanage, the larger their amygdala volume. This association exists even when the child adopted at 60 months old is removed from the analysis.

Figure 4

Reaction time for emotional faces as targets and distracter stimuli by group. PI children had relatively slower reaction times for neutral faces in the presence of distracter faces with positively valence and relatively faster reaction times for neutral faces in the presence of distracter faces with negative valence.

Figure 5

Sensitivity on the face go-nogo by group. Late adopted PI children made more errors during blocks that contained negatively valenced faces than the comparison children, but showed no group difference in responses to positive valence.

Figure 6

Amygdala volume association with internalizing behavior and anxiety. Larger amygdala volumes were associated with A) higher ratings of internalizing behaviors as measured by the CBCL and B) number of anxiety symptoms as measured by the SCARED inventory.