Author
MAK Winnie W. S.; et al;
Meta-analysis of stigma and mental health.
Journal citation/publication details
Social Science and Medicine, 65(2), July 2007, pp.245-261.
Summary
The meta-analysis of data from 52 samples reported in 49 studies produces a medium correlational effect size between stigma and mental health, indicating that the association is strong enough to be observed in everyday life. No causal relationship can be inferred from the data, and no statistically significant moderating factors were discovered to explain the association.
Context
Although the importance of stigma in relation to health and social care has been long recognised, it is only relatively recently that significant attention has been paid to it by the research community. In the mental health field, health agencies have also begun to develop initiatives to combat stigma. However, empirical evidence is inconsistent on the relationship between stigma and mental health, and it is thus timely to conduct a statistical synthesis of available data.
Methods
What sources were used?
The databases PsycINFO and Medline were chosen on the grounds of their international coverage, although the preponderance of English language studies is acknowledged. The reference lists of relevant studies were also checked, and key authors contacted.
What search terms/strategies were used?
The thesaurus terms stigma and mental health were used, exploded to include subsidiary terms.
What criteria were used to decide on which studies to include?
Eligible studies were empirical, quantitative examinations of the relationship between stigma and mental health, with at least one measure of each construct. In addition, studies had to be in English and published between 1985 and January 2005.
Who decided on their relevance and quality?
The searches delivered 808 studies whose abstracts were independently checked against the inclusion criteria by four research assistants with a background in psychology. A total of 82 studies was selected, together with a further 14 identified from their reference lists. A second stage of checking excluded five duplicates, 19 studies for which full text was unobtainable, and 23 studies lacking quantitative measures for stigma and/or mental health, or inadequate statistical information for coding. Methodological quality issues such as sampling method and study design were included in the independent coding of the studies by two individuals.
How many studies were included and where were they from?
Forty-nine studies (including seven dissertations), comprising 52 independent samples and covering a range of stigmatised conditions of which mental health disorder is the most common (19 samples). Others include sexual orientation, HIV/AIDS, learning disability, physical disability, gender, race/ethnicity and employment status. The bibliographical details of the studies are available on request from the lead author, and geographical origins are not reported in the paper although the authors state that the vast majority are North American.
How were the study findings combined?
Each of the independent samples was separately coded by two unnamed individuals, with ‘satisfactory, inter-rater agreement, according to a scheme laid out in Table 2. Where necessary, authors were contacted for additional information. The statistical syntheses were conducted using the Hunter-Schmidt Meta-Analysis Programs© and included moderator analyses.
Findings of the review
Interpretation of the findings, as reported in the text and tables, requires some statistical knowledge. The authors interpret the results as showing that ‘the relation between stigma and mental health had a medium correlational effect size, which indicated that it is strong enough to be observed in everyday life.’ In addition, stigma appears to have a stronger negative impact on adjustment or growth than it does on psychological distress.
No statistically significant moderating factors were found to explain the relationship between stigma and mental health, and ‘different types of stigma on different types of people could create very different mental health outcomes.’ Important factors are the degree to which stigmatised individuals are aware of stigma and perceive it to be legitimate. ‘Only when stigmatized individuals perceive the negative acts committed by others towards them as legitimate would their mental health be adversely affected.’ In other circumstances they may feel indifference or be motivated to fight back.
Despite the lack of statistically significant moderators, ‘some interesting patterns…are worthy of attention’. The authors suggest that there is a significant ‘file drawer problem’, or a bias in favour of positive findings in the published (non-dissertation) literature, which could lead to an over-estimation of the association between stigma and psychological distress. Stronger associations were also reported by studies published in Europe and Australia than in the USA, by studies that do not focus specifically on stigma and mental health, and by those of less rigorous design. Such studies make up the bulk of those reviewed, and their relatively poor methodological quality suggests that ‘caution should be taken in interpreting these findings’.
One counter-intuitive finding is that stigma related to mental health conditions has a smaller mean correlation with mental health than stigma related to social and physical conditions. The authors suggest that this may be a result of the influence exercised by the large effect sizes observed in studies of HIV/AIDS (a third of the physical condition studies). It may also be the case that mental illness itself has ‘already taken up a great deal of variance in mental health conditions’ and that stigma is thus secondary to illness as an influence on well-being. Finally, the degree of impairment characteristic of severe psychiatric disorders may mean that affected individuals lack the cognitive insight to be aware of, and affected by, stigmatisation.
Authors' conclusions
Various limitations of the meta-analysis are discussed, including the relatively small number of studies available for moderator analyses, and the use of a wide variety of measurement approaches. The analysis is also based on bivariate correlational data so that ‘causal inference should not be drawn between stigma and mental health’.
‘Notwithstanding the limitations, the present study provided support for the importance of stigma in relation to stigmatized groups’ mental health.’
Implications for policy or practice
None are discussed although the authors conclude that efforts to combat stigma are justified as an approach to improving people’s well-being.