No School Toilets, Poorer Mental Health: Study Links Sanitation Gaps to Girls’ Distress in India

The absence of a basic amenity that many readers will never have thought twice about—a toilet at school—may be quietly shaping the psychological well-being of millions of adolescent girls in northern India. A new study published in Humanities and Social Sciences Communications examines the relationship between school toilet availability and mental health outcomes among adolescent and young adult girls in Uttar Pradesh and Bihar, two of India’s most populous states. Drawing on an unusually rich longitudinal dataset, the research finds that girls attending schools without toilet facilities score significantly worse on measures of mental health, even after accounting for a wide range of sociodemographic characteristics. But the study also delivers a more nuanced and arguably more important message: the statistical fingerprints of the association suggest that missing sanitation operates less as a direct psychological insult and more as a visible marker of deeper educational and social disadvantage.

The research, conducted by Pintu Paul of the Tata Institute of Social Sciences in Hyderabad, exploits two waves of the Understanding the Lives of Adolescents and Young Adults survey, known as UDAYA, a large-scale longitudinal study carried out in Uttar Pradesh and Bihar. The analytical sample pooled across the two survey waves comprised 12,924 girls aged between 10 and 23 years. Because the same girls were followed over time, the data allow researchers to distinguish between two very different kinds of statistical explanations: differences between girls who attend schools with and without toilets, and changes within the same girl as her school sanitation circumstances shift between survey waves. This distinction, central to modern causal inference in observational social science, turns out to be the crux of the entire study.

The mental health outcomes were captured through poor mental health scores, and the author applied a battery of regression techniques to interrogate the association from multiple angles. Pooled ordinary least squares models, which treat all observations as a single dataset, showed that girls in schools lacking toilet facilities had significantly higher poor mental health scores. Between-effects models, which focus on stable differences between individuals, and mixed-effects models, which combine within- and between-person information, produced the same pattern. Across these specifications, the association survived adjustment for sociodemographic characteristics, indicating that the link between absent sanitation and poorer mental health is not simply an artifact of poverty, age, or family background—at least as far as the measured covariates can capture those constructs.

Then comes the twist. When the author estimated an individual fixed-effects model—a specification that effectively compares each girl with herself across the two survey waves, sweeping out all time-invariant personal and household characteristics—the significant association disappeared. In other words, girls whose school sanitation situation changed over time did not show corresponding changes in their mental health scores. The fixed-effects result suggests that the observed relationship is driven primarily by differences between girls rather than by within-individual changes in school toilet availability. Statistically, this is a crucial diagnostic: it implies that the girls attending toilet-less schools are, on average, different in ways that both their schooling circumstances and their mental health reflect, rather than the toilets themselves exerting a direct, dynamic effect on any individual girl’s psychological state.

What kind of differences might these be? The author’s interpretation, offered in the study’s conclusions, is that the absence of school toilet facilities functions as a marker of broader educational and social disadvantage. A school without toilets is rarely a school that is otherwise well resourced; it signals underinvestment in infrastructure, weaker institutional support, and communities whose educational environments are stretched thin. Girls attending such schools may also come from households and neighborhoods facing compounding disadvantages that the regression covariates only partially capture. The toilet, in this reading, is not the poison but the symptom—a readily observable indicator that a girl’s learning environment, and the social context surrounding it, is failing her in multiple ways at once.

The subgroup analyses add texture to the headline finding. The association between missing school toilets and poorer mental health was more pronounced among girls residing in urban areas, among girls from Uttar Pradesh as opposed to Bihar, and among married girls, particularly those married early. The pattern was especially evident during the second survey wave. These heterogeneities hint at how context conditions the experience of inadequate sanitation. Urban schools, for instance, might be expected to meet basic infrastructure standards, making their absence particularly telling; married girls, meanwhile, may face layered constraints on mobility, privacy, and autonomy that make deficient school environments more consequential. The study reports these subgroup patterns as descriptive evidence, and they underscore that a one-size-fits-all sanitation intervention is unlikely to reach all girls equally.

Robustness was tested through sensitivity analyses based on a balanced panel—restricting the sample to girls observed in both survey waves—which reproduced the pattern seen in the main findings. This matters because longitudinal surveys inevitably lose participants between waves, and attrition can distort estimates if those who drop out differ systematically from those who remain. The consistency of results across the balanced panel strengthens confidence that the reported associations are not artifacts of sample composition. Together, the convergence of pooled, between-effects, and mixed-effects estimates, the null fixed-effects result, and the stable sensitivity checks form a coherent statistical picture that is more informative than any single coefficient could be.

The study also looked beyond mental health to two downstream outcomes in girls’ lives: continued school enrolment and subsequent marriage. Supplementary findings demonstrated that access to school toilet facilities was associated with higher odds of continued school enrolment, reinforcing a substantial body of evidence linking sex-specific sanitation to girls’ educational persistence. The mechanism is intuitive—adolescent girls managing menstruation without private, functional facilities face practical and dignity-related barriers to attending school, and many respond by staying home or leaving altogether. By contrast, no significant association was observed between school toilet access and subsequent marriage once sociodemographic characteristics were adjusted for, suggesting that the pathway from sanitation to marriage timing, if it exists, is entangled with the same background factors that drive both.

For policymakers, the implications cut in two directions simultaneously. On one hand, the persistent association between toilet-less schools and poorer mental health, alongside the enrolment findings, argues for prioritizing school sanitation as part of any serious effort to improve girls’ educational participation and psychological well-being. Toilets are cheap relative to most educational interventions, and their absence is a solvable engineering problem. On the other hand, the fixed-effects results caution against expecting sanitation alone to transform mental health outcomes. If missing toilets are a marker of broader disadvantage, then installing them in isolation, without addressing the surrounding deficits in school infrastructure, staffing, and supportive learning environments, may yield disappointing returns. The author’s conclusion is accordingly measured: strengthening school sanitation should be prioritized alongside broader investments in school infrastructure and supportive learning environments.

The study also carries methodological lessons for the growing field of research on water, sanitation, and adolescent health. Much of the literature in this area rests on cross-sectional data, where the direction of causality is hopelessly entangled and confounding is rampant. By deploying longitudinal data and explicitly comparing between-person and within-person estimates, this study models a standard of transparency that other researchers would do well to emulate—and it demonstrates that the answer to a seemingly simple question can be genuinely two-sided. The association is real and policy-relevant, yet its causal interpretation demands humility. For the 12,924 girls of Uttar Pradesh and Bihar whose experiences underpin these findings, the message is ultimately one of visibility: the state of a school toilet block, mundane as it seems, is legible in the statistical record of their minds, and attending to it means attending to the whole architecture of disadvantage in which it stands.

Subject of Research: The association between school toilet availability and mental health outcomes among adolescent and young adult girls in Uttar Pradesh and Bihar, India

Article Title: Inadequate school sanitation and mental health outcomes among adolescent and young adult girls in Uttar Pradesh and Bihar, India

Article References: Paul, P. (2026). Inadequate school sanitation and mental health outcomes among adolescent and young adult girls in Uttar Pradesh and Bihar, India. Humanities and Social Sciences Communications. https://doi.org/10.1057/s41599-026-09323-0

Image Credits: AI Generated

DOI: 10.1057/s41599-026-09323-0

Keywords: school sanitation, adolescent mental health, girls' education, Uttar Pradesh, Bihar, UDAYA survey, longitudinal study, fixed-effects models, school toilets, India, educational disadvantage, public health