How does a developmental perspective inform us about the early natural history of bipolar disorder?

Objective: The focus of this paper is to explore how a developmental perspective can advance understanding of the clinical trajectory into bipolar disorder (BD) and clarify controversies regarding the diagnosis in youth. Method: In this selective review, we focus on findings from longitudinal studies of general population and high-risk pediatric cohorts in order to inform our understanding of the development of BD in youth. Also highlighted are related aspects of the debate about the diagnosis in young children and a discussion of the implications of the findings for advancing early detection and intervention clinical and research efforts. Results: Evidence overwhelmingly suggests that BD typically onsets in adolescence and early adulthood, with the depressive polarity of the illness dominating the early course. Non-specific childhood antecedents have been noted in some high-risk individuals. However, in youth without a confirmed familial risk of BD, manic-like symptoms have little prognostic significance for BD and not uncommonly form part of the normative adolescent experience. Over-emphasis of symptoms and reliance on parent report alone, alongside the relative neglect of the child's developmental stage and risk profile, contributes to the over diagnosis in young children and under recognition of BD early in the clinical course. Conclusions: Longitudinal population and high-risk studies over development have made major contributions to our understanding of the early natural history of BD in youth. Implications call for a different diagnostic approach to facilitate accurate identification of youth in the early clinical stages of psychiatric disorders and to differentiate between the emerging illness trajectories and transient normative symptoms in childhood and adolescence.