Preschool-Onset Major Depressive Disorder is Characterized by Electrocortical Deficits in Processing Pleasant Emotional Pictures.

Reductions in positive affect are a salient feature of preschool-onset major depressive disorder. Yet, little is known about the psychophysiological correlates of this blunted positive affect and whether reduced physiological responding to pleasant stimuli may differentiate depressed and healthy young children. 120 four-to-seven year old children with current depression and 63 psychiatrically healthy 4-to-7 year old children completed a simple picture-viewing task of pleasant and neutral pictures while event-related potentials (ERPs) were recorded. The early-childhood version of the Kiddie Schedule for Affective Disorders and Depression was used to establish psychiatric diagnoses. A one-way ANCOVA was used to test for group differences in response to pleasant and neutral pictures. Young children with depression showed a reduced response to pleasant vs. neutral pictures (LPP), after controlling for children's age (F(1,180) = 4.15, p = 0.04, η2 = 0.02). The LPP for the children with preschool-onset depression (M = 0.99, SE = 0.65) was significantly smaller than the LPP in the healthy group of young children (M = 3.27, SE = 0.90). This difference did not vary as a function of depression or anhedonia severity within the group with depression or the healthy children. Similar to older children and adolescents with depression, young children with depression display reductions in responsivity to pleasant stimuli as indexed by the LPP. These findings extend prior findings indicating a blunted response to pleasant stimuli in preschool- onset depression. Given the greater neuroplasticity of emotional response and regulation, these findings suggest clinical attention to emotional response to pleasure is an important target in preschool-onset depression. Clinical trial registration information: A Randomized Control Trial of PCIT-ED for Preschool Depression; http://clinicaltrials.gov/;NCT02076425.