There was a longstanding belief that pre-pubescent children were too developmentally and cognitively immature to experience the core aspects of depression. In the mid-1980s research studies disputed those claims. By the late ‘80s, it was widely accepted that children ages six and older could experience clinical depression. Subsequently, treatment studies looked at various forms of psychotherapy and psychopharmacology for that age group. Recent studies, including ours at Washington University, have extended that story down to age three.