According to recent estimates, in 2017 971 million people worldwide suffered mental health issues (GBD 2017 Disease and Injury Incidence and Prevalence Collaborators, 2018). Among these, 264 million had depression (of which 163 million cases were major ones) and 284 million had anxiety disorders. Mental disorders may have important adverse individual effects including reduced employment and lower earnings (Ridley et al. 2020).
There has existed a substantial mental health gap in sexual orientation that may be attributed to either actual or perceived discrimination against sexual minorities. For a long time, homosexuality was considered to be a disease rather than a way of life. The World Health Organization, for example, published the International Statistical Classification of Diseases and Related Health Problems (ICD) in 1948, in which homosexuality was classified as a mental disorder. Same-sex relationships were against the law in many countries in the past, and they still are in some countries nowadays. Although the extent of discrimination against sexual minorities varies across countries and regions, there is no doubt about the existence of this type of discrimination in the labour market and other situations (Bertrand and Duflo 2017, Badgett et al. 2021).
Due to discrimination and unfair treatment, sexual minorities may have suffered more from mental health problems than heterosexuals. However, opinions about same-sex relationships have been gradually evolving. As part of structural changes in partnership formations and family institutions, countries around the world have started to accept and formalise same-sex relationships to the extent that some of them have legalised same-sex marriages. Same-sex marriage legalisation (SSML) is a typical anti-discrimination policy to remove institutional discrimination against sexual minorities by providing them with marriage equality. Our study (Chen and van Ours 2021) aims to examine whether this marital policy reform may help to mitigate mental health issues amongst sexual minorities.
Attitudes to sexual minorities
The Netherlands is highly tolerant of sexual minorities, as can be seen in Table 1, which provides an overview of attitudes towards homosexuality in European countries. Clearly, attitudes have become more favourable in all countries presented. The percentage of the population that thought “homosexuality is never justified” has dropped over time. The right-hand side of Table 1 displays a similar trend of attitudes towards sexual minorities in the first decade of this century in Europe with another survey question. In 2002, the share of the population that believed “gay men and lesbians should be free to live their life as they wish" was 80% or more in Belgium, Denmark, the Netherlands, and Sweden. In 2010, at least 90% of the population held such an opinion in Denmark, the Netherlands, and Sweden.
Table 1 Attitudes to homosexuality in European countries
Source: Kuyper et al. (2013).
Note: The numbers are from the European Value Survey 1981, 1990, 1999, 2008 (Percentage of inhabitants thinking that homosexuality is never justified) and the European Social Survey 2002, 2010 (Percentage of population who believe that gay men and lesbians should be free to live their life as they wish).
We use data from a health survey – the Permanent Life Situation Study (POLS) of Statistics Netherlands – to establish the mental health conditions of individuals. Through unique individual identification numbers, we are able to link the health survey sample to the administrative micro-data of Statistics Netherlands, in order to identify the sexual orientation of individuals.
The administrative individual micro-data cover the whole Dutch population registered from 1995 onward. There is information about personal characteristics, such as the country where the person was born, gender, immigrant status, birth year, and month. Moreover, the administrative household micro-data include detailed household information over time such as the household type, change in the household composition, and the individual position in the household. We rely on the administrative individual and household micro-data to identify sexual minority and different-sex relationships by comparing the gender(s) of the two partners in a household. Individuals that established both different-sex and same-sex relationships are included in the sexual minority group while people who did not register any relationship during the whole administrative data period are excluded in our main analysis.
POLS is a monthly repeated cross-sectional survey starting in 1997. In every wave (month), 700-1000 individuals randomly drawn from the Dutch population answered health related questions. The estimation of the baseline model is based on a sample from 1998 to 2008 to avoid the potential contamination of our parameter estimates due to the impacts of other marital polices. After the data tailoring, our sample for the baseline analysis comprises 40,586 observations – 19,069 observations for males and 21,517 for females, and 3,671 observations for sexual minorities and 36,915 for heterosexuals. Our mental health indicators on depression and anxiety, ranging from 0 (never/not at all) to 1 (very often/constantly), are rescaled to have a mean of zero and a standard deviation of one.
Figure 1 illustrates the evolution of the averages of our mental health indicators across the period 1998-2008 for our estimation sample. For individuals in different-sex relationships, both depression and anxiety exhibit mild fluctuations across years. The variations in mental health for individuals in same-sex relationships present a different pattern. Before 2001, there was a substantial gap of sexual orientation for both mental health indicators. From 2001 onward, both indicators for sexual minorities declined drastically and largely converged to those of heterosexuals.
Figure 1 Developments of depression and anxiety; annual averages 1998-2008
Mental health effects of same-sex marriage legalisation
We conduct a difference-in-differences (DiD) analysis to compare the changes in depression and anxiety after SSML for sexual minorities relative to heterosexuals. In line with Figure 1, we find that before SSML, sexual minorities suffered more serious mental health issues than heterosexuals. However, SSML significantly ameliorated their mental health status. Both depression and anxiety amongst sexual minorities declined and converged to those of heterosexual individuals.
We investigate and discuss various mechanisms including marriage, marital stability, an enriched choice basket of partnership forms, and societal attitude changes for the mental health effects of SSML. The beneficial mental health effects are present for both married and non-married sexual minorities. Thus SSML did not take effect on mental health through marriage only. Moreover, the legislation stabilised same-sex formal partnerships and enlarged the choice set of same-sex partnership forms, which may contribute to the mental health gains of sexual minorities.
We also investigate the heterogeneity of mental health effects of SSML in terms of gender, urban characteristics of the resident place, age cohort, employment status, and educational attainment. We conclude that SSML closed the sexual orientation gap of mental health more completely among women, residents in low urban regions, younger people, and college degree holders.
For a long time, sexual minorities have been discriminated against in different situations, including the right of marriage. Such institutional discrimination and unfair treatment may have harmed their mental health. Over the past couple of decades, in more and more countries, marriage has been made available to same-sex couples. This reform of marital policy may have exerted beneficial mental health effects for sexual minorities.
We study how the 2001 same-sex marriage legalisation in the Netherlands affected the mental health of sexual minorities focusing on depression and anxiety. We find a significant improvement in the mental health of sexual minorities following the legislation. We also find that marriage itself was only partially responsible for the amelioration of mental health among sexual minorities. More importantly, the legal recognition of same-sex marriage improved mental health for both male and female sexual minorities irrespective of their own marital status.
SSML substantially decreased the sexual orientation gap of mental health. As a typical anti-discrimination policy, SSML is effective in improving not only societal attitudes towards discriminated individuals (sexual minorities in the current context) but also their health and well-being. The findings of this study may suggest that anti-discrimination policies can have beneficial mental health effects for discriminated minorities in general with respect to race, religion, immigration, disability, and so forth.
Badgett, M L, C S Carpenter, and D Sanson (2021), “LGBTQ Economics”, Journal of Economic Perspectives 35(2): 141-170.
Bertrand, M, and E Duflo (2017), “Field experiments on discrimination”, in A V Banerjee and E Duflo (eds.), Handbook of Field Experiments, Volume 1, 309-393, North-Holland.
Chen, S, and J C van Ours (2021), “Mental health effects of same-sex marriage legalization”, CEPR Discussion Paper no. 15632.
Kuyper, L, J Iedema, and S Keuzenkamp (2013), “Towards Tolerance; Exploring Changes and Explaining Differences in Attitudes towards Homosexuality in Europe”, The Hague: The Netherlands Institute for Social Research (SCP).
Ridley, M, G Rao, F Schilbach, and V Patel (2020), “Poverty, depression, and anxiety: Causal evidence and mechanisms”, Science 370 (6522).