·When perceiving environmental uncertainty or competitive pressure, organisms weigh the pros and cons and prioritize energy for the maturation of the reproductive system (such as early menarche), leading to a reduction in resources for neurobehavioral development.

The process of urbanization has brought better education and healthcare resources, but it has also been accompanied by overcrowding, pollution, and intense social competition. For a long time, epidemiological studies have found that urban living is associated with a high risk of mental illnesses such as schizophrenia, but the underlying neurobiological mechanisms have not been fully elucidated. A recent study suggests that the intensity of urban life during childhood is closely related to early puberty in females, and this developmental "rush" may be a key factor leading to changes in brain structure and specific personality traits in adulthood.

The study was recently published online in the journal Nature Cities, and the authors are a research team from institutions such as Tianjin Medical University General Hospital. By analyzing the genetic, brain imaging, and environmental data of 2950 young women, researchers found that the age of menarche (AAM) plays a key mediating role between early urban living environment and adult brain and personality traits.

Although urbanization may facilitate access to education and healthcare, it also brings environmental and psychosocial challenges, "the authors of the paper wrote in their research." We attempt to validate the Life History Theory, which suggests that individuals may adopt strategies to accelerate reproductive maturity in stressful or competitive urban environments, but this may come at the cost of sacrificing brain development and physical growth. ”

This study employed high-precision objective measurement methods - using satellite remote sensing data (building density and nighttime lighting) to assess the degree of "urbanization exposure" of participants from birth to adolescence, combined with 3.0T magnetic resonance brain imaging data and gene polygenic risk score (PGS) to exclude interference from purely genetic factors. The research team conducted in-depth analysis on 2950 healthy young Han Chinese women from the Chinese Imaging Genetics (CHIMGEN) cohort.

Research has found that the higher the degree of urbanization in early life environments, the earlier the age of menarche for women. This physiological precocity is significantly associated with a decrease in gray matter volume in the medial prefrontal cortex (MPFC) in adulthood, which is a critical brain area for processing emotions, decision-making, and social cognition.

In statistical models, age at menarche significantly mediates the impact of urbanization on brain structure. Specifically, high stress in urban environments (such as family socioeconomic status pressure, air pollution, etc.) prompts the body to adjust resource allocation and accelerate sexual maturity, while premature exposure to sex hormones may lead to excessive synaptic pruning or developmental changes in the prefrontal cortex.

In addition to brain structure, research has also found that personality traits are influenced by this pathway. Women with higher exposure to early urbanization and earlier menarche tend to score lower on the personality dimensions of agreeableness and Reward Dependence in adulthood. This means that they may exhibit lower levels of affinity and social attachment, a personality trait typically considered a risk factor for mental health.

To validate the clinical significance of these changes, the research team conducted a meta-analysis comparing the results with brain imaging and personality data of patients with schizophrenia (SCZ) and major depression (MDD).

The results indicate that the brain regions most significantly affected by urbanization and early puberty, such as the medial prefrontal cortex, and personality traits, such as low agreeableness and low reward dependence, highly overlap with the damage patterns exhibited by patients with schizophrenia and depression.

This means that girls who grow up in urban environments may experience early puberty due to environmental stress, which may shift their brain and psychological characteristics towards susceptibility to mental illness. For example, the reduction in volume of the medial prefrontal cortex is particularly typical in patients with schizophrenia.

This study provides a detailed speculation on the biological basis of this mechanism. According to the theory of life history, when perceiving environmental uncertainty or competitive pressure, organisms weigh the pros and cons and prioritize energy for the maturation of the reproductive system (such as early menarche), leading to a reduction in resources for neurobehavioral development. In addition, high calorie diets, light pollution, and endocrine disruptors in urban environments may also accelerate this process by activating the hypothalamic pituitary gonadal axis (HPG axis).

Our research suggests that the life history theory can serve as a mechanistic framework to explain how early urban life affects women's adult brains and personality traits associated with mental disorders. "The authors state," This finding suggests that menarche age may serve as a biomarker of developmental vulnerability for identifying high-risk children and early intervention

This study not only deepens our understanding of the complex interaction between "environment brain psychology", but also provides a scientific basis for urban planning and public health policies. By improving the urban environment (such as increasing green spaces, controlling pollution, and reducing social psychological pressure), this developmental "compensatory trade-off" may be alleviated, thereby protecting the brain health of adolescents.

References:

Guo, L., Liu, F., Zhu, W. et al. Pathways from early-life urbanicity to adult neurobehavioral traits via menarche timing. Nat Cities (2025).  https://doi.org/10.1038/s44284-025-00352-5

·When perceiving environmental uncertainty or competitive pressure, organisms weigh the pros and cons and prioritize energy for the maturation of the reproductive system (such as early menarche), leading to a reduction in resources for neurobehavioral development.

The process of urbanization has brought better education and healthcare resources, but it has also been accompanied by overcrowding, pollution, and intense social competition. For a long time, epidemiological studies have found that urban living is associated with a high risk of mental illnesses such as schizophrenia, but the underlying neurobiological mechanisms have not been fully elucidated. A recent study suggests that the intensity of urban life during childhood is closely related to early puberty in females, and this developmental "rush" may be a key factor leading to changes in brain structure and specific personality traits in adulthood.

The study was recently published online in the journal Nature Cities, and the authors are a research team from institutions such as Tianjin Medical University General Hospital. By analyzing the genetic, brain imaging, and environmental data of 2950 young women, researchers found that the age of menarche (AAM) plays a key mediating role between early urban living environment and adult brain and personality traits.

Although urbanization may facilitate access to education and healthcare, it also brings environmental and psychosocial challenges, "the authors of the paper wrote in their research." We attempt to validate the Life History Theory, which suggests that individuals may adopt strategies to accelerate reproductive maturity in stressful or competitive urban environments, but this may come at the cost of sacrificing brain development and physical growth. ”

This study employed high-precision objective measurement methods - using satellite remote sensing data (building density and nighttime lighting) to assess the degree of "urbanization exposure" of participants from birth to adolescence, combined with 3.0T magnetic resonance brain imaging data and gene polygenic risk score (PGS) to exclude interference from purely genetic factors. The research team conducted in-depth analysis on 2950 healthy young Han Chinese women from the Chinese Imaging Genetics (CHIMGEN) cohort.

Research has found that the higher the degree of urbanization in early life environments, the earlier the age of menarche for women. This physiological precocity is significantly associated with a decrease in gray matter volume in the medial prefrontal cortex (MPFC) in adulthood, which is a critical brain area for processing emotions, decision-making, and social cognition.

In statistical models, age at menarche significantly mediates the impact of urbanization on brain structure. Specifically, high stress in urban environments (such as family socioeconomic status pressure, air pollution, etc.) prompts the body to adjust resource allocation and accelerate sexual maturity, while premature exposure to sex hormones may lead to excessive synaptic pruning or developmental changes in the prefrontal cortex.

In addition to brain structure, research has also found that personality traits are influenced by this pathway. Women with higher exposure to early urbanization and earlier menarche tend to score lower on the personality dimensions of agreeableness and Reward Dependence in adulthood. This means that they may exhibit lower levels of affinity and social attachment, a personality trait typically considered a risk factor for mental health.

To validate the clinical significance of these changes, the research team conducted a meta-analysis comparing the results with brain imaging and personality data of patients with schizophrenia (SCZ) and major depression (MDD).

The results indicate that the brain regions most significantly affected by urbanization and early puberty, such as the medial prefrontal cortex, and personality traits, such as low agreeableness and low reward dependence, highly overlap with the damage patterns exhibited by patients with schizophrenia and depression.

This means that girls who grow up in urban environments may experience early puberty due to environmental stress, which may shift their brain and psychological characteristics towards susceptibility to mental illness. For example, the reduction in volume of the medial prefrontal cortex is particularly typical in patients with schizophrenia.

This study provides a detailed speculation on the biological basis of this mechanism. According to the theory of life history, when perceiving environmental uncertainty or competitive pressure, organisms weigh the pros and cons and prioritize energy for the maturation of the reproductive system (such as early menarche), leading to a reduction in resources for neurobehavioral development. In addition, high calorie diets, light pollution, and endocrine disruptors in urban environments may also accelerate this process by activating the hypothalamic pituitary gonadal axis (HPG axis).

Our research suggests that the life history theory can serve as a mechanistic framework to explain how early urban life affects women's adult brains and personality traits associated with mental disorders. "The authors state," This finding suggests that menarche age may serve as a biomarker of developmental vulnerability for identifying high-risk children and early intervention

This study not only deepens our understanding of the complex interaction between "environment brain psychology", but also provides a scientific basis for urban planning and public health policies. By improving the urban environment (such as increasing green spaces, controlling pollution, and reducing social psychological pressure), this developmental "compensatory trade-off" may be alleviated, thereby protecting the brain health of adolescents.

References:

Guo, L., Liu, F., Zhu, W. et al. Pathways from early-life urbanicity to adult neurobehavioral traits via menarche timing. Nat Cities (2025).  https://doi.org/10.1038/s44284-025-00352-5