Childhood Bipolar Disorder More Rare Than Previously Claimed, Study Finds

A recent reexamination of previous meta-analytic data finds that instances of “pediatric bipolar disorder” (PBD) are substantially lower than claimed. This study, published in Child and Adolescent Mental Health, highlights the numerous methodological issues behind a widely-cited meta-analysis.

“PBD [pediatric bipolar disorder] proved to be controversial because it led to many US prepubertal children with significant internalising and externalising symptoms being reconceptualised as having a severe adult mental illness requiring lifelong medication often using complex polypharmacy with drugs that have not been fully trialed for children,” the study authors write.

Until the late 1990s, the onset of mania was understood to occur almost always in late adolescence or young adulthood. In 1995, two articles were published introducing PBD and applying the bipolar diagnosis to children. This marked a “significant departure from the traditional concept of mania.”  Almost 10 years later, this was being implemented as common clinical practice, but not without considerable controversy.

“In most other nations the pre-pubertal onset of classic bipolar disorder continued to be seen as exceedingly rare.”

Parry and a team of researchers in Australia sought to expand on criticisms of a highly-cited meta-analysis published by Van Meter, Moreira, and Youngstrom in 2011 which claimed to have found data supporting PBD across 12 epidemiological surveys. This meta-analysis suggested that PBD was going underdiagnosed and undermedicated in children and in non-US countries, arguing that the prevalence of PBD was 1.8% across children and adults alike.

A previous critique found that these surveys featured information on adolescents rather than pre-pubertal children, combined parent and youth data despite disagreements, and did not include follow-up data to either validate or invalidate a bipolar spectrum disorder diagnosis.

In their reexamination of the 12 epidemiological studies, the researchers found heterogeneous methodologies employed across a number of dimensions. Consistent with the previous critique, the ages of participants reflected an adolescent, not prepubertal sample. Instruments used across surveys were inconsistent, informants ranged from either parents, children, or both, and the time frames of diagnosis ranged from a singular point in time to a 6-month, 12-month, or lifelong prevalence.

Findings also revealed divergent definitions and conceptualizations of the diagnosis in question. These variations included mania, hypomania, bipolar-I, bipolar-II, bipolar-NOS, bipolar spectrum disorder, cyclothymia or a combination of these.

“Given the heterogeneity of the 12 studies,” write the authors, “it is debatable whether they lend themselves to statistical meta-analysis.” The observed differences across findings do not support the results of the 2011 meta-analysis, and in fact, demonstrate lower rates of PBD.

“A reexamination of the studies that comprise the meta-analysis reveals that rates of bipolar-I in the United States are quite low (0.0%-1.0%) with understandably higher rates for bipolar spectrum (up to 6.7%) depending on how that is defined.”

Rates are even lower outside of the U.S., around 0.0%-0.1%, the researchers report, except in Mexico where rates of mania are estimated around 2.05%.

“The 12 studies suggest that where methodology correlated parent and child reports for agreement, and included impairment criteria, that rates of bipolar-I disorder in children and adolescents were close to zero outside the United States and only slightly higher in the United States, though rates of bipolar spectrum disorder were slightly higher.”

The marked disagreements regarding the diagnostic criteria constituting PBD are similarly evident in practice, the researchers note. For example, in one transatlantic comparison study observing practitioners diagnosing tendencies, U.S. child psychiatrists were significantly more likely to diagnose mania for three out of the four cases in contrast to British child psychiatrists who only diagnosed one case as featuring a manic episode.

The authors conclude by cautioning researchers against espousing PBD based on the findings from this meta-analysis, and from those conducted with a lack of methodological rigor.

“Articles that cite the meta-analysis need to critically examine the original studies.”

 

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Parry, P., Allison, S., & Bastiampillai, T. (2017). Measurement Issues: ‘Paediatric bipolar disorder’ rates are lower than claimed–a reexamination of the epidemiological surveys used by a meta‐analysis. Child and Adolescent Mental Health.