A pilot study on amygdala volumetric changes among young adults with childhood maltreatment histories after a mindfulness intervention.

The amygdala morphometry is highly sensitive to stress and is implicated in various psychopathologies that are common among individuals with childhood maltreatment histories. This pilot study investigated bilateral amygdala volumetric changes among 15 young adults with childhood maltreatment histories undergoing an eight-week mindfulness intervention compared to 19 matched participants in a waitlist control group. Results indicated significant cross-individual variability in amygdala volumetric changes after the intervention, which resulted in no significant group by time interaction effect. Degree and direction of changes in right amygdala volume correlated with baseline volumes, with larger than average right amygdala showing an increase in volume and smaller amygdala a decrease. Increasing right amygdala volume was also associated with higher intervention compliance, and a greater increase in self-compassion. Increasing left amygdala volume was associated with more reduction in perceived stress, rejection sensitivity and interpersonal distress. Findings from the present study highlight the importance of investigating individual variability and its contributing factors in future studies on neural responses of mindfulness interventions, as well as the distinct responses of the left and right amygdala.