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Rates of pediatric bipolar disorder not increasing in the US
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Results from a large, updated meta-analysis published in Journal of Clinical Psychiatry confirmed that the rates of bipolar spectrum disorders among youth were not higher in the United States than in other Western countries, nor were the rates increasing over time.
Although a previous meta-analysis came to the same conclusion, researchers were unable to examine possible moderators related to location or culture due to the small number of studies included, according to Anna Van Meter, PhD, assistant professor, Center for Psychiatric Neuroscience, The Feinstein Institute for Medical Research, Northwell Health, and colleagues.
“In the time since the original meta-analysis was published, the number of epidemiologic studies of [pediatric bipolar disorder] has increased by 50% and the number of youth represented has tripled,” they wrote.
The researchers updated a 2011 meta-analysis of pediatric bipolar disorder prevalence to improve understanding of factors that affect prevalence. In 2018, they searched relevant literature using clinical databases and reviewed studies that included a youth epidemiologic sample, number of youth with bipolar spectrum disorders reported and prevalence rates for youth separated from prevalence for adults aged older than 21 years.
Eight new articles were included. These eight studies plus the 11 included in the previous meta-analysis tripled the sample size to 56,103 participants — 1,383 of whom had bipolar disorder. Seven studies were from the U.S. and 12 were from South America, Central America or Europe.
Analysis revealed that the weighted average prevalence of pediatric bipolar spectrum disorders was 3.9% (95% CI, 2.6-5.8) with significant heterogeneity across studies (Q = 759.82; df = 32; P < .0005). Although the prevalence rate was greater than that reported in the previous meta-analysis, the CIs overlapped (1.8% previous weighted average; 95% CI, 1.1-3), according to the findings. Newer studies were tied to lower prevalence rates (P < .0001).
“The results of this meta-analysis — that the prevalence of bipolar disorder among youth in the community is similar across western countries, and that the prevalence is not increasing over time — help to dispel myths that bipolar disorder among youth is a phenomenon unique to the United States and that bipolar disorder is becoming more common,” Van Meter told Healio Psychiatry.
The rate of pediatric bipolar I disorder was 0.6% (95% CI, 0.3–1.2), with heterogeneous rates (Q = 154.27; df = 13; P < .0001). The rate of bipolar I disorder was lower in this updated meta-analysis than in the 2011 analysis (1.2%); however, six of the eight new studies reported bipolar I separately. Van Meter and colleagues recommended that the rates of pediatric bipolar I should be considered in a developmental context.
In addition, the researchers found that use of broad bipolar criteria (P < .0001), older minimum age (P = .005) and lifetime prevalence (P = .002) were predictors of higher bipolar spectrum disorder prevalence.
“Importantly, the results are consistent with multiple retrospective studies of adults with bipolar disorder that the onset of bipolar symptoms is usually in adolescence,” Van Meter said. “The data suggest increasing risk with age (from childhood to adolescence), but there are few studies of prepubescent youth, a gap we hope future epidemiological studies will fill, in addition to surveying youth from non-Western countries.” – by Savannah Demko
Disclosure: Van Meter reports funding from the American Psychological Foundation. Please see the study for all other authors’ relevant financial disclosures.