The 10/90 divide in mental health research: trends over a 10-year period

Summary A search (precision value 94%, recall value 93%) ofthe ISI Web of Science database (1992-2001) revealed that mentalhealth publications accounted for 3-4% of the health literature.A 10/90 divide in internationally accessible mental healthliterature was evident and remained undiminished through 10years as low- and middle-income countries (n=152) contributedonly 6%, high-income countries (n=54) 94%, and 14 leading high-incomecountries (with more than 1% contribution for majority of years under consideration) contributed 90% of internationally accessiblemental health research. Steps should be taken to improve theresearch infrastructure and capacity to conduct and disseminatemental health research in general, and on a priority basisin low- and middle-income countries.

INTRODUCTION

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INTRODUCTION

Health research plays a major role in advancing science andin providing solutions for health problems. Imbalances in healthresearch output in terms of populations and disease burdenaddressed have been noted (Horton, 2003; Canadian Medical Association Journal, 2004;Rochon et al, 2004; Paraje et al, 2005) and aptly labelled ‘Western medical journals andthe 10/90 problem’ (Canadian Medical Association Journal, 2004).In comparison with the burden imposed by mental disorders(13% of global burden of diseases), mental health is an underresearchedhealth area. In a study on global significance of health researchby Rochon et al (2004), only 2.44% of clinical trials on 25leading contributors to global burden of diseases targeted mental disorders. Geographical disproportions have also been recordedand commented upon in mental health research; only about 6%(or less) of publications are from low- and middle-income countries (Patel & Sumathipala, 2001; Parker & Parker, 2002; Saxena et al, 2004; Tyrer, 2005). Here we examine mentalhealth literature within internationally accessible health literature for geographical distribution over a 10-year period.

METHOD

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METHOD

The 4061 health-related journals indexed in the ISI Web of Sciencedatabase (1992-2001) were searched for all publications onmental health, mental disorders and services for mental health.The ISI database does not exhaustively list internationallyaccessible literature but its listing of institutional affiliationof all authors, a feature that is not offered by other databases(including Medline), which list the affiliation of only one author, makes it uniquely suited for assessment of geographicalcontribution to publications.

The list of keywords included global terms such as behaviour,psychology, psychiatry, psychosocial, mental health, mentaldisorders, mental development, intellectual disability; specificterms such as organic brain syndrome, dementia, drug abuse,psychosis, schizophrenia; and service-related terms such asmental healthcare, psychiatric hospital, psychiatric services,halfway home, residential psychiatric care, and community mentalhealth. (Complete list available from authors on request.)The final set of keywords was selected by an iterative processthat yielded a precision value of 94% and recall value of 93%(precision: proportion of relevant articles among those retrieved;recall: proportion of articles in a random sample of mentalhealth journals that were retrieved by the search strategy).

The countries of origin for each publication were determinedby the fractional counting method (assigning an equal fractionof each publication to all listed countries).

RESULTS

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RESULTS

Out of 3 288 252 health-related publications available in theISI database (1992-2001), only 117 449 (3.57%) were relatedto mental health. There was very low variability in the proportionof mental health to health-related publications across the10-year period (2.95%-3.86%).

All high-income countries (see World Bank (2003) criteria),with 15% of the world's population, contributed 94%; low- andmiddle-income countries, with more than 85% of the world'spopulation, contributed 6% to internationally accessible mentalhealth literature (Table 1). The USA and UK, with 5.6% ofthe world's population, contributed more than 50%; 14 leading high-income countries (with more than 1% contribution for themajority of years under consideration), including the USA andUK, with 12.9% of the world's population (<7% of all countries)contributed 90% (see data supplement to the online versionof this paper). Fifty-one countries (more than a quarter) amongthose listed as member states of the World Health Organization(WHO) were virtually unrepresented (<0.001% of internationallyaccessible mental health publications in any year) in the database(data not shown). Some of the unrepresented countries are mid-sizedcountries with populations above 5 million (e.g. Chad, Guinea,Haiti, Honduras, Lao People's Democratic Republic, Rwanda andSomalia). The contribution from the USA decreased from 49% to43% over the 10-year time period.

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Table 1 Percentage of world production of mental health publications (total n=117449) according to World Bank income groups

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Data supplement 1 Percentage of world production of mental health publications (total n=117449): breakdown of contributions by countries contributing more than 1% of the literature

DISCUSSION

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DISCUSSION

Mental health research publications form a much smaller fractionof health research publications in comparison with the relativeburden of mental illness (Rochon et al, 2004; present study).Currently priorities for health research are established bya combination of explicit and implicit means. Priorities maybe affected by the personal scientific interests of researchers,the priorities of those who serve as reviewers for grants andthe philanthropic interests of those who privately fund research,the availability of researchers or institutions that specialisein a subject area, government policy, stakeholder lobbying and media interest, and the profit potential of the research (Jorm et al, 2002).Mental health research has obviously receivedlow priority, as exemplified by the fact that the NationalHealth and Medical Research Council (NHMRC) of Australia spentonly 8.9% of its funds on mental health research compared with the 19.1% contribution of mental disorders to disease burdenin Australia (Jorm et al, 2002). Similarly, the scientificinterests of editors, reviewers, researchers and readers (subscribers),and overall context of publishing could also play a role inthe underrepresentation of mental health publications in general health journals. A widespread acceptance of mental health asan issue deserving attention, a perception that mental healthresearch can be scientific and advocacy for mental health researchare needed to improve the current situation. Some noteworthyefforts have been made in this direction. The World HealthReport 2001 (WHO, 2001) and a report of the Surgeon General(US Department of Health & Human Services, 1999) have calledfor greater support for mental health research.

It is evident that the 10/90 divide in health research output (Canadian Medical Association Journal, 2004; Paraje et al, 2005) also holds true for the mental health field. A very limited amount (6%) of internationally accessible mental health literatureemanates from low- and middle-income countries. The very slightincrease observed in the production of middle-income countriesis negated by the decrease in the already low production oflow-income countries.

Earlier studies of a limited number of publications in termsof journals (<10) and time periods covered (2 years) reportedsimilar findings (Patel & Sumathipala, 2001; Parker & Parker, 2002).Limited access to information, lack of adviceon research design and statistics, difficulty in writing ina foreign language, overall material, financial, policy andinfrastructural constraints, and limited appreciation by editorialoffices of the research needs of, and realities in, low- and middle-income countries may constitute barriers that impedepublication of mental health research from these countriesin widely accessible journals (Bulletin of the World Health Organization, 2004).

The fact that the proportional decrease in the contributionof the USA was balanced by an increase in mental health publicationsfrom other high-income countries suggests that the 10/90 divideis not going away and that active efforts are required to improvethe mental health research situation in low- and middle-incomecountries. The results of this study highlight the need to improvethe research infrastructure and capacity to conduct and disseminate mental health research in general, and in particular in low-and middle-income countries. The WHO has called for a substantialincrease in investment in mental health research capacity,particularly in low- and middle-income countries (WHO, 2003).A joint statement issued recently by editors of scientificjournals publishing mental health research and the WHO summarisedthe existing unsatisfactory state regarding publication ofmental health research and offered some steps to correct theseimbalances (Bulletin of the World Health Organization, 2004).The present study confirms that the 10/90 divide in mentalhealth research has remained undiminished over 10 years; hencethe urgent need to implement the steps suggested by the joint statement.

ACKNOWLEDGMENTS

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ACKNOWLEDGMENTS

We thank Professor Grant Lewison, Department of InformationScience, City University, London for serving as a scientificadvisor during finalisation of the search strategy for thisproject.

REFERENCES

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