Abstract
Compromised respiratory sinus arrhythmia (RSA, i.e., low cardiac vagal control) frequently characterizes clinically depressed adults and also has been detected in infants of depressed mothers; however, its existence has not been established in older at-risk offspring. We investigated developmental patterns of RSA in a sample of 163 5- to 14-year-old children, who were either at high risk for depression (due to having a parent with a childhood-onset mood disorder) or low-risk for depression. We hypothesized that high-risk children have lower resting RSA than do low-risk children, which could reflect atypical developmental trajectories. Children's RSA was assessed during resting baseline periods on multiple occasions, typically 1-year apart. Linear growth modeling indicated a group by age interaction. Low-risk children (but not the high-risk children) exhibited a significantly increasing trajectory in resting RSA with age. Mood disorders in offspring did not account for the Group X Age interaction effect. Our study provides new evidence that children at high risk for depression have an atypical developmental trajectory of RSA across late childhood.