More cats, happier country? Study of 93 nations finds a feline link to well-being

Several studies have found that owning a cat reduces loneliness and stress while improving mood.

At the same time, concerns have persisted that cats — the definitive host of Toxoplasma gondii, a parasite transmissible to humans — may affect mental health.

Now, an analysis of 93 countries finds that nations with more cats per capita tend to score higher on happiness, while those with higher rates of recent Toxoplasma gondii infection tend to score lower.

Counterintuitively, countries with more cats actually showed lower rates of recent infection.

The findings were published in volume 21, issue 9 of the international journal PLOS One by Javier Borráz-León of Mexico's National Institute of Psychiatry and Dario Maestripieri of the University of Chicago. Rather than conducting new surveys, the research team compiled publicly available national statistics and analyzed correlations among cat populations, Toxoplasma gondii infection rates, and happiness scores across 93 countries.

The research team gathered national happiness scores for 2022–2024 based on the World Happiness Report, along with data on cat populations, GDP per capita, income levels, and healthcare spending as a share of GDP.

Cat numbers were converted to a per-10,000-population figure; the average across the 93 countries was 989 cats per 10,000 people.

The analysis found a correlation coefficient of 0.62 between the per-capita cat population and happiness scores.

A correlation coefficient expresses how closely two values move together on a scale of -1 to 1, with values closer to 1 indicating that when one is larger, the other tends to be as well.

However, the factor most strongly tied to happiness scores was economic standing. The correlation coefficient between happiness scores and GDP per capita was 0.80, and with income levels it was 0.78.

Cat populations were also strongly correlated with GDP per capita (0.79) and income levels (0.77), meaning that countries with more cats were generally wealthier.

Toxoplasma gondii is a single-celled parasite that infects nearly all warm-blooded animals, including humans. It spreads to people through cat feces or undercooked meat.

An estimated 10 to 30 percent of adults worldwide are infected, though most healthy individuals show no symptoms.

Some studies have linked chronic infection to schizophrenia, depression, and anxiety disorders.

When the research team compared infection rates with happiness scores, countries with higher rates of recent infection scored lower on happiness, with a correlation coefficient of -0.54.

Contrary to expectations, countries with more cats showed lower rates of recent infection.

The research team said that in wealthier countries, cats are kept primarily indoors, fed commercial food, and given regular veterinary care, reducing opportunities for transmission.

In low- and middle-income countries, cats are more often allowed to roam freely, which may increase the risk of infection, the team said.

However, the researchers noted that the results reflect statistical associations at the national level and do not demonstrate causation.

In the paper, the team stressed that "these results should not be used to infer individual-level effects or risks related to cat ownership, happiness, or Toxoplasma gondii infection."

The researchers said the higher happiness scores in countries with more cats may reflect favorable attitudes toward pets, higher real incomes, and better living conditions.

They also noted a limitation: happiness scores already incorporate GDP per capita, creating an overlap with economic indicators.

DOI: 10.1371/journal.pone.0357911

J.I. Borráz-León, M.J. Rantala, I. Krams, & D. Maestripieri, Wealth, health, cats and Toxoplasma gondii: An ecological correlational study of subjective well-being across 93 countries, PLoS One 21 (2026) e0357911.