The 2-week duration criterion and severity and course of early childhood depression: Implications for nosology

Background: Although validity for DSM-IV MDD symptom criteria in preschoolers has been demonstrated, whether the 2-week duration criterion is an appropriate threshold of clinical significance at this age remains unclear. The current study aimed to begin addressing this question. Method: Three hundred and six preschoolers were recruited from community sites and followed longitudinally for 2 years. A subsample including healthy preschoolers (N = 77) and those with MDD (N = 74) were examined. The MDD group was further divided based upon meeting (DSM, N = 24) or failing to meet (< DSM, N = 50) the DSM-IV 2-week duration criterion. Groups were compared on parent and teacher report measures of symptom severity and functional impairment at baseline and 2-year follow-up. Limitations: A larger sample of depressed preschoolers and refined measures of duration are needed to replicate the current study. Results: Preschoolers with MDD differed significantly from controls on the majority of measures examined regardless of duration status and time of assessment. Further, the DSM group significantly differed from the < DSM group at baseline on measures of MDD symptom severity and impairment. No differences in the risk of a MDD diagnosis at follow-up were found on the basis of duration group status. Conclusions: DSM-IV duration criterion failed to capture all clinically affected preschoolers at baseline or confer greater predictive validity for a depression diagnosis 2 years later. Findings suggest that preschoolers meeting all DSM-IV MDD criteria except for episode duration exhibit a clinically significant form of depression and experience a 2-year MDD outcome similar to those meeting full criterion.