A Dynamic Systems Analysis of Dyadic Flexibility and Shared Affect in Preschoolers with and Without Major Depressive Disorder.

Preschool onset Major Depressive Disorder (PO-MDD) is a severe disorder often leading to chronic impairment and poor outcomes across development. Recent work suggests that the caregiver-child relationship may contribute to PO-MDD symptoms partially through disrupted caregiver-child interactions. The current study uses a dynamic systems approach to investigate whether co-regulation patterns in a dyad with a child experiencing PO-MDD differ from dyads with a child without the disorder. Preschoolers between the ages of 3-7 years-old (N = 215; M(SD) = 5.22(1.06); 35% girls; 77% white) were recruited for a randomized controlled trial of an adapted version of parent-child interaction therapy. An additional sample (N = 50; M(SD) = 5.17(.84)' 34% girls; 76% white) was recruited as a control group. Dyads completed two interactive tasks and affect was coded throughout the interaction. State Space Grids (SSG) were used to derive measures of dyadic affective flexibility (i.e., affective variability in dyadic interactions) and shared affect. PO-MDD dyads did not differ from controls in dyadic affective flexibility. However, there were significant differences in shared positive and neutral affect. PO-MDD dyads spent less time and had fewer instances of shared positive affect and spent more time and had more instances of shared neutral affect than the community control group. These comparisons survived multiple comparisons correction. There were no differences for shared negative affect. Findings suggest that children experiencing PO-MDD have differing dyadic affective experiences with their caregivers than healthy developing children, which may be a mechanism through which depressive states are reinforced and could be targeted for treatment.