Summary:
This narrative review examined how environmental exposures across the lifespan may contribute to both neurodevelopmental disorders, such as autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), and neurodegenerative diseases including Alzheimer’s disease (AD) and Parkinson’s disease (PD). The review highlighted several environmental risk factors linked to brain health, including air pollution, heavy metals, pesticides, and industrial chemicals. Heavy metals such as lead, mercury, arsenic, and cadmium were associated with cognitive impairment, developmental delays, behavioural problems, and an increased risk of age-related neurological disease. According to this study, environmental exposures may affect the brain through shared mechanisms including oxidative stress, mitochondrial dysfunction, chronic inflammation, immune dysregulation, impaired protein clearance, and epigenetic changes. These processes can damage neurons, disrupt communication between brain cells, and increase vulnerability to both developmental and degenerative neurological conditions. The review also identified the gut-brain axis as an important pathway linking the environment to brain health. Alterations in gut microbiota may influence inflammation, immune function, and neuron signalling, potentially contributing to neurological disorders throughout life. Overall, this study concluded that environmental exposures may shape neurological health from early development through ageing. The findings support a lifespan approach where environmental factors, genetics, and gut health interact to influence the risk of both neurodevelopmental and neurodegenerative disorders. The authors suggested that reducing exposure to environmental toxins and identifying early markers of neurological injury may help support long-term brain health.
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Abstract:
Neurodevelopmental and neurodegenerative disorders are related disorders lying on a spectrum of neural dysfunction with overlapping molecular and cellular mechanisms. Early-life diseases like autism spectrum disorder and attention-deficit/hyperactivity disorder are the result of disturbed neurodevelopment, while late-onset diseases such as Alzheimer’s disease and Parkinson’s disease are defined by progressive neuronal loss and loss of function. Emerging evidence shows that environmental exposures are important, modifiable factors that affect brain health throughout the lifespan. Factors such as air pollution, heavy metals, pesticides, and endocrine-disrupting chemicals act in combination with genetic susceptibility to disrupt neurogenesis, synaptic plasticity, and neuro-immune signaling. These exposures cause persistent epigenetic modifications, oxidative stress, mitochondrial dysfunction, and chronic neuro-inflammation, linking early developmental insults to neurodegenerative processes later in life. The concepts of the exposome and the developmental origins of health and disease provide additional support for the cumulative, lifelong impact of environmental interactions. Mechanistically, the recurrent process of neuronal damage is caused by impaired proteostasis, microglial stimulation, and blood–brain barrier dysfunction. Furthermore, the gut-brain axis is a hyperactive system in which immune responses and microbial metabolites trigger neurobiological responses to external stimuli. This review integrates multidisciplinary evidence to elucidate the mechanism and emphasizes environmental risk mitigation and translational strategies to reduce disease burden and promote lifelong brain resilience.
Article Publication Date: 14/08/2026
DOI: 10.3389/fneur.2026.1867856
