Paediatric bipolar disorder and its controversy.

Objectives: Paediatric bipolar disorder - bipolar disorder occurring in prepubertal children - is a diagnosis subject to considerable controversy. Whilst historically considered to be very rare, proponents since the 1990s have argued that mania can present differently in children and, as such, is much more common than previously thought. Such proposals raise questions about the validity of proposed phenotypes and potential risks of iatrogenic harm.

Methods: I critically examine the construct of paediatric bipolar disorder using Robins and Guze's (1970, American Journal of Psychiatry126, 983-987) influential criteria for the validity of a psychiatric diagnosis. I review, in turn, evidence relating to its clinical description, delimitation from other conditions, follow-up studies, family studies, laboratory studies, and treatment response.

Results: Across domains, existing research highlights significant challenges establishing the diagnosis. This includes significant heterogeneity in operationalising criteria for children; variable or poor inter-rater reliability; difficulty distinguishing paediatric bipolar disorder from other conditions; large differences in rates of diagnosis between the United States of America and other countries; limited evidence of continuity with adult forms; and a lack of evidence for proposed paediatric phenotypes in children at genetic high-risk of the condition. Laboratory and treatment studies are limited, but also do not provide support for the construct.

Conclusions: Evidence for the more widespread existence of paediatric bipolar disorder and its various proposed phenotypes remains weak. The ongoing popularity of the diagnosis, most evident in America, may reflect social pressures and broader limitations in psychiatric nosology. The uncertainty around the diagnosis highlights the need for careful longitudinal assessment of children potentially affected.