Depression in Infancy

In this article we reviewed the uniqueness of the clinical entity of depression in infancy and the evolution of the awareness that infants can be significantly depressed. Research in recent neurobiologic studies has found biologic correlates of depression in high-risk infants, which, in turn, impacts the brain development. Several clinical vignettes have been described to illustrate the various clinical presentations of depression in infants who are exposed to different types of depressogenic environmental situations. Issues about diagnosis of depression in infancy and diagnostic criteria, based on the diagnostic classification for mental health disorders in infancy, were reviewed. Many questions remain unanswered, such as whether depression can be endogenous in infants or is always reactive to adverse environmental factors, such as maternal psychiatric illness, unresolved grief, severe psychosocial deprivation, chronic pain, and life-threatening illness. The issue of discontinuity versus continuity of depression from infancy to older ages must be studied in well-designed longitudinal studies while comparing different modalities of treatment.