This investigation used data from a National Institute of Mental Health–funded Validation of Preschool Depression Study. The Preschool Depression Study is an ongoing, multi-method, multi-informant (parents, children, and teachers), longitudinal investigation of 306 preschoolers. Comprehensive assessments were conducted at 3 annual waves in the Early Emotional Development Program at the Washington University School of Medicine in St Louis, St Louis, Missouri. From May 2003 to March 2005, children aged 3 to 5.11 years were recruited from pediatricians’ offices, daycare centers, and preschools in the St Louis metropolitan area using the Preschool Feelings Checklist (PFC).34 Approximately 6000 PFCs were distributed to recruitment sites and 1474 PFCs (25%) were returned to the Early Emotional Development Program. Caregivers who endorsed no items on the PFC; 2 or more internalizing items; and/or 2 or more externalizing items (n = 899) were contacted by telephone for further screening. Excluded were children with chronic medical illnesses, neurological problems, pervasive developmental disorders, or language and/or cognitive delays as well as those outside of the study age range. Of the 416 eligible caregiver-child dyads, 306 agreed to participate and presented for baseline assessment; details have been published previously.24 (link) It is important to note that the recruitment techniques used in this study were designed to oversample for preschoolers with or at risk of depression. Therefore, the recruitment numbers provided cannot be used to estimate the prevalence rates of preschool MDD in the general population.