Bipolar disorder prevalence: a systematic review and meta-analysis of the literature. [Rev Bras Psiquiatr. 2015

Clemente AS

Dell’Aglio Jr JC

Goodwin FK

Insel T

Kapczinski F

Malhi GS

Merikangas KR

Parker GB

Rafael Tabarés-Seisdedos

Vicent Balanzá-Martínez

Yutzy SH

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Brazilian Journal of Psychiatry

The prevalence of bipolar disorders in the general population: a growing trending topic?

Balanzá Martínez, Vicent

Tabarés Seisdedos, Rafael

Repositori d'Objectes Digitals per a l'Ensenyament la Recerca i la Cultura

EDITORIALThe prevalence of bipolar disorders in the generalpopulation: a growing trending topic?Vicent Balanza´-Martı´nez,1,2,3,4 Rafael Tabare´s-Seisdedos2,3,51Teaching Unit of Psychiatry, La Fe University and Polytechnic Hospital, Valencia, Spain. 2Department of Medicine, University of Valencia,Valencia, Spain. 3Centro de Investigacio´n Biome´dica en Red de Salud Mental (CIBERSAM), Madrid, Spain. 4International Society forNutritional Psychiatry Research (ISNPR), International Society for Nutritional Psychiatry Research (ISNPR), Spain. 5Fundacio´n para laInvestigacio´n del Hospital Clı´nico de la Comunidad Valenciana (INCLIVA), Valencia, Spain.In the current issue of Revista Brasileira de Psiquiatria,Clemente et al.1 report the first meta-analysis of theprevalence of bipolar disorder (BD) from population-based studies. Strengths of the manuscript include theuse of suitable methods of analysis, reporting both annualand lifetime prevalence rates, and providing separatedata for bipolar subtypes I and II. The latter is relevantbecause type II is not simply a milder or minor form of BD.This publication is of considerable interest, firstlybecause it confirms that the frequency of BD in thegeneral population is low and closer to the conservativeestimates of 1-2%, as suggested by historical data.2,3 It isworth pointing out that these might be underestimatesbecause, compared to longitudinal studies, data frompopulation-based cross-sectional studies may underesti-mate the real prevalence of BD.4More importantly, the authors found an increase inprevalence estimates over recent decades, in parallel withchanging DSM diagnostic criteria. Lifetime prevalence ofBD type I has virtually doubled with each edition fromDSM-III to DSM-IV. The increase in type II is onlymarginally significant, although the number of studies isalso lower. This is quite surprising, since the only relevantchange in the bipolar section of the DSM over the lastthree decades was the appearance of BD type II in DSM-III-R, whereas criteria for type I have remained essentiallythe same. In a conservative explanation, the authorsattribute the increase in type I to the use of differentinstruments, whereas growth in type II frequency wouldbe the result of changing DSM criteria.However, this meta-analysis leaves some key ques-tions ‘‘blowing in the wind.’’ For instance, how much ofthis growth is real or artifactual? In other words, is it theresult of increased awareness by clinicians, more accuratenosologies, broadening of diagnostic criteria, or just anothervogue? Recently, there has been much controversy aboutan epidemic of BD, and psychiatry is facing risks forboth bipolar ‘‘overdiagnosis’’ and ‘‘underdiagnosis.’’ Theresults of this paper will surely fuel the debate. Interestingly,if one assumes that a genuine increase in bipolar frequencyhas taken place, it would be relatively independent ofthe gradual expansion of the bipolar phenotype, fromthe narrowly-defined ‘‘classic’’ manic-depressive illness(BD type I) to the broadly-defined ‘‘full bipolar spectrum.’’The latter may present with higher rates, but is more difficultto capture; therefore, its prevalence has been lessexamined in community samples.Another fascinating issue is why increased prevalencein non-clinical samples is more obvious in BD type I. Onecould expect a similar, or even greater, trend for BDtype II. Some reflections about hypomania, which liesbetween the narrow and broad bipolar phenotypes, meritfurther discussion. Recognition of mania is straightfor-ward, with exceptionally high concordance rates amongclinicians. However, an accurate diagnosis of hypomaniais usually difficult in clinical practice – even more so incommunity surveys! On the one hand, patients certainlydo not label hypomania as abnormal. On the other hand,the successive DSM editions have refined the diagnosticcriteria for hypomania, but its definition remains con-troversial. Hypomania has not gone through Robins andGuze’s gold-standard criteria to establish the validity andreliability of major mental disorders.3 Indeed, its dissec-tion from mania does not rely on quantity or quality ofsymptoms, which are identical, with the exception ofpsychotic features. Rather, it is based on the somewhatarbitrary, non-symptom criteria of minimum duration of7 days, need for hospitalization, and marked functionalimpairment in the case of mania.5 Moreover, markedimpairment is not clearly operationalized in DSM.6 All ofthis likely leads to underestimation of the true prevalenceof BD type II, especially in the general population. Asmentioned by the authors, its prevalence is greater inclinical samples. That also seems to be the case amongadolescents, an age group in which lifetime prevalencerates of hypomania can reach 3-4% in prospectivecommunity samples.7 This question must await furtherinquiry, because the present systematic review focusedonly on adult samples. Future meta-analyses should alsoreveal whether the inclusion of studies using the ICDdiagnostic system would modify the present findings.Certainly, establishing the prevalence of bipolar andother psychiatric disorders is a complex endeavor.Differences in settings (general population, primary carevs. psychiatric clinics), types of prevalence estimatesCorrespondence: Vicent Balanza´-Martı´nez, Departament de Medicina,Facultat de Medicina, Avda Blasco Ibaa˜ez, 15, 46010, Valencia,Spain.E-mail: Vicente.Balanza@uv.esRevista Brasileira de Psiquiatria. 2015;37:91–92Associac¸a˜o Brasileira de Psiquiatriadoi:10.1590/1516-4446-2015-3701(e.g., point, 12-month, lifetime), assessment instruments,and changing diagnostic criteria may affect prevalencerates and comparisons of studies. These factors maylikely account for much of the discrepancy in the literatureregarding BD prevalence. However, defining the bound-aries of the phenotype is unique to BD and represents amajor source of this variability, as mentioned above.BD is among the leading causes of disability worldwide.Robust and reliable prevalence estimates, such as thosefrom the present meta-analysis, represent a relevantaddition to the epidemiology of this disorder and haveclinical, socioeconomic, and policy-making implications.For instance, they may help inform planning of health careand services. People with BD deserve more effectivetreatments, and advancing a better definition, ideallybased on a better understanding of BD neurobiology, is akey step.6 Clearly, there is substantial room for improve-ment of our current diagnostic systems. In this regard,recent proposals, such as clinical staging systems8 andResearch Domain Criteria,9 will hopefully move the fieldforward and improve clinical outcomes.AcknowledgementsThe authors would like to acknowledge the support of theSpanish Ministry of Economy and Competitiveness, Insti-tuto de Salud Carlos III (ISCIII), and Centro de Investiga-cio´n Biome´dica en Red de Salud Mental (CIBERSAM).This work was sponsored by a grant from Fundacio´npara el Fomento de la Investigacio´n Sanitaria y Biome´dicade la Comunitat Valenciana (FISABIO; UGP-14-184) and anational grant that belongs to the Spanish Plan Nacional deI+D+I 2013-2016 (PI14/00894) and is co-funded by theISCIII-Subdireccio´n General de Evaluacio´n y el FondoEuropeo de Desarrollo Regional (FEDER).DisclosureThe authors report no conflicts of interest.References1 Clemente AS, Diniz BS, Nicolato R, Kapczinski FP, Soares JC, FirmoJO, et al. Bipolar disorder prevalence: a systematic review and meta-analysis of the literature. Rev Bras Psiquiatr. 2015;37:155-61.2 Goodwin FK, Jamison KR. Manic-depressive illness: bipolar dis-orders and recurrent depression. 2nd edition. New York: OxfordUniversity Press; 2007.3 Yutzy SH, Woofter CR, Abbott CC, Melhem IM, Parish BS. Theincreasing frequency of mania and bipolar disorder: causes andpotential negative impacts. J Nerv Ment Dis. 2012;200:380-7.4 Dell’Aglio JC Jr, Basso LA, Argimon IIL, Arteche A. Systematic reviewof the prevalence of bipolar disorder and bipolar spectrum disordersin population-based studies. Trends Psychiatry Psychother. 2013;35:99-105.5 Parker GB, Graham RK. An evaluation of the DSM-5 rules definingmania and hypomania with identical symptom criteria. J Affect Disord.2015;170:91-4.6 Malhi GS, Berk M. Diagnosing bipolar disorder: defining thresholdsand setting boundaries. Aust N Z J Psychiatry. 2014;48:500-4.7 Merikangas KR, Lamers F. The ‘true’ prevalence of bipolar II disorder.Curr Opin Psychiatry. 2012;25:19-23.8 Kapczinski F, Magalha˜es PV, Balanza´-Martinez V, Dias VV, Frangou S,Gama CS, et al. Staging systems in bipolar disorder: an InternationalSociety for Bipolar Disorders Task Force Report. Acta Psychiatr Scand.2014;130:354-63.9 Insel T, Cuthbert B, Garvey M, Heinssen R, Pine DS, Quinn K, et al.Research domain criteria (RDoC): toward a new classificationframework for research on mental disorders. Am J Psychiatry. 2010;167:748-51.Rev Bras Psiquiatr. 2015;37(2)92 V Balanza´-Martı´nez & R Tabare´s-Seisdedos

The prevalence of bipolar disorders in the general population - a growing trending topic?

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The prevalence of bipolar disorders in the general population - a growing trending topic?

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