An observational analysis of behavior in depressed preschoolers: further validation of early-onset depression.

OBJECTIVE: To investigate whether higher levels of negative and lower levels of positive behaviors could be observed in a sample of depressed preschoolers. Support for the validity of preschool depression is now available; however, objective evidence of negative behaviors among depressed preschoolers is needed.

METHOD: A structured observational parent-child interaction task was conducted. The behaviors of 152 preschoolers (ages 3.0-5.6) in three study groups (depressed, disruptive, and healthy) were examined with further analyses of depressed subgroups based on severity and comorbidity.

RESULTS: Anhedonically depressed preschoolers emerged as demonstrating less enthusiasm, more avoidance, more noncompliance, and having a more negative overall experience than healthy controls. This more severe and proposed melancholic anhedonic subgroup also displayed less enthusiasm than nonanhedonically depressed preschoolers. Furthermore, the "pure" anhedonic depressed preschoolers without disruptive comorbidity emerged as the only depressed subgroup that was significantly distinguishable from healthy preschoolers.

CONCLUSIONS: Findings provide the first objective evidence of more negative and fewer positive behaviors among depressed preschoolers. Notably, the finding that anhedonically depressed preschoolers demonstrated significantly less enthusiasm than those with nonanhedonic depression provides the first objective evidence of the manifestation of anhedonia, a key sign of preschool depression. The implications of the finding that the "pure" anhedonic depressed subgroup without disruptive comorbidity was most distinguishable from comparison groups are explored.