Several countries have seen recent increases in the prevalence of mental disorders. Has this contributed to reduced fertility? A Norwegian register-based analysis shows negative associations between mental disorders and birth rates, but, according to Øystein Kravdal, Martin Flatø and Fartein A. Torvik, the increasing prevalence of these disorders has likely not contributed much to the country’s sharp fertility decline since 2009.
Background
There are good reasons to expect that health problems may lead to lower fertility. Individuals who are exhausted because of health problems or who struggle with daily functioning may not want as many children as others, and those with particularly severe conditions may be less likely to enter partnerships. Additionally, some mental or physical diseases or the treatments for them may reduce fecundity. However, there are also mechanisms that could lead to a relatively large number of children, or quite early childbearing, among individuals with health issues. For example, to the extent that health problems make schooling more difficult, this could increase fertility, especially among women. So far, demographers who study high-income countries have taken little interest in the possible importance of health as a fertility determinant.
Most women and men of reproductive age are in good health, but some suffer, for example, from chronic physical diseases with a severe impact on their lives, and in recent decades there have been indications of a quite sharp rise in depression, anxiety and other mental disorders among teenagers and young adults in many high-income countries (Krokstad et al. 2022; Zhou et al. 2025). Has this increase contributed negatively to fertility? This question is especially relevant for the Nordic countries, where fertility was higher than in most other rich countries for many years but has declined more markedly since 2009 (Eurostat 2025).
Associations between mental disorders and fertility in Norway
In a recent analysis (Kravdal, Flatø and Torvik 2025), we used data from Norwegian registers for the years 2008-2018 to estimate whether individuals who had consulted a general practitioner or a specialist for a mental disorder in a certain year were less likely to have a child two years later than individuals who had not consulted. We found that women with depression had reduced first-, second- and third-birth rates (Table 1). According to a simulation where the calendar year was set to 2018, these lower birth rates correspond to a reduction in completed fertility from 1.60 births per woman (close to Norway’s total fertility rate in 2018) among those without any of the mental disorders under study, to 1.34 among those who – hypothetically – have depression throughout their reproductive period (Table 1, column 4). Depression is even more strongly linked to lower fertility among men: the corresponding numbers for them are 1.41 and 0.90.
The associations between anxiety and fertility were of similar magnitude, while fertility was even lower among individuals with bipolar disorder, eating disorder or personality disorder. The simulated completed fertility was lowest among women and men with schizophrenia: 0.36 and 0.16, respectively. However, to the extent that individuals with mental disorders enter parenthood, many of the estimates suggested that they did so at a relatively early age.
It is important to note that these observed associations reflect the effects of mental disorders on fertility – through a variety of causal pathways – but may also be a result of individual and societal characteristics that influence not only the probability of developing a mental disorder but also fertility. We carried out additional analyses controlling for partnership, education and income. These factors may be joint determinants of mental health and fertility, and may also mediate the causal effects of mental disorders on fertility. Additionally, we controlled for unobserved characteristics shared by siblings, by comparing siblings with and without mental disorders. These steps made the associations between mental disorders and fertility weaker, but many of them were still significant. The remaining associations may partly reflect causal effects of mental disorder on fertility, operating through factors other than the above-mentioned control variables. For example, women and men with mental health problems may fear that raising a child will be too burdensome, and therefore not want a child, or another child. However, the remaining associations may also be linked to characteristics unique to one sibling, such as experiences early in life, that have implications for both mental health and fertility. It is hard to imagine a statistical analysis that is entirely free from this kind of confounding.
The contribution to the national total fertility rate
In our paper (Kravdal, Flatø and Torvik 2025), we also showed that Norwegian fertility would have been higher in 2008-2018 in a hypothetical scenario without mental disorders, but not by much: only 0.05 extra children per woman, (depression and anxiety, the most prevalent conditions, are the main drivers of reduced fertility in our simulation). In other words, if we disregard the fact that the causal effects of mental disorders on fertility are likely smaller than the estimated associations, and if we assume hypothetically that the prevalence of the disorders increases from zero to the overall level observed in 2008-2018, fertility will be reduced by 0.05. Clearly, the increase in the actual prevalence from 2009 up to now is different from this, partly because the data do not capture all cases of mental disorders, and especially not the least severe. Everything considered, it is hard to believe that the rise in mental disorders has contributed more than modestly to the half-a-child reduction of the total fertility rate in Norway since 2009.
Conclusion
The apparent increase in mental disorders is undoubtedly a challenge. Poor health reduces people’s wellbeing, partly because of its adverse effects on their education and income, which in turn have implications for society. Our analysis of Norwegian data shows that individuals with mental disorders also have fewer children than others, although the increasing prevalence of these problems is unlikely to have influenced the recent fertility decline in any significant way. In settings with less generous welfare policies, mental health may be more strongly linked to birth rates. All in all, this suggests that mental disorders probably deserve more attention from a demographic perspective than they have received thus far.
References
Eurostat (2025). Fertility statistics. Fertility statistics – Statistics Explained – Eurostat
Kravdal, Ø., Flatø, M. & Torvik, F.A. (2025). Fertility among Norwegian women and men with mental disorders. European Journal of Population, online first
Krokstad, S., Weiss, D.A., Krokstad, M.A., Rangul, V., Kvaløy, K., Ingul, J.M., Bjerkeset, O., Twenge, J. & Sund, E.R. (2022). Divergent decennial trends in mental health according to age reveal poorer mental health for young people: repeated cross-sectional population-based surveys from the HUNT Study, Norway. BMJ Open, 12(5), e057654.
Zhou, W., Hei, B., Liu, Z., Liu, Y., Ding, Z., & Li, M. (2025). Global temporal trends in depression incidence among women of childbearing age: A 30-year analysis and projections to 2030. Social Science & Medicine, 372, 118005.