What are the causes of autism?

Nov 14, 2025 Source: Cainiu Health

Dr. Zhang Baohua

Introduction

The causes of autism include genetic factors, abnormal neural development, environmental factors, immune system dysfunction, and adverse prenatal influences. The underlying mechanisms are complex and typically involve the interaction of multiple factors. If a child exhibits abnormalities in social communication or repetitive behaviors, prompt medical evaluation is recommended. Autism shows a clear tendency for familial clustering.

Autism spectrum disorder (ASD) has multiple potential causes, including genetic factors, abnormal neurodevelopment, environmental influences, immune dysfunction, and adverse prenatal conditions. Its pathogenesis is complex and typically results from the combined effects of various factors. If a child shows signs of impaired social communication, repetitive behaviors, or other atypical behaviors, prompt medical evaluation is recommended.

1. Genetic factors: Autism shows a clear familial clustering pattern, with relatives of affected individuals having a higher risk than the general population. Multiple gene mutations may interact to affect brain development and neural signaling, making genetics a key contributing factor.

2. Abnormal neurodevelopment: Differences in brain structure and function are observed, such as immature development in regions like the frontal and temporal lobes, and imbalances in neurotransmitter levels. These disruptions hinder the development of core abilities in social interaction, cognition, and communication.

3. Environmental factors: Early exposure to pollutants or heavy metals, or prolonged lack of social interaction during development, may increase the risk of autism. However, environmental factors usually trigger symptoms only in combination with genetic predispositions.

4. Immune dysfunction: Some individuals exhibit immune system abnormalities, such as autoantibodies attacking nerve cells or inflammatory immune responses that interfere with normal brain development and disrupt the formation and function of neural circuits.

5. Adverse prenatal influences: Maternal infections, medication use, malnutrition, or emotional stress during pregnancy may impair fetal brain development and increase the likelihood of autism in offspring, with particularly heightened risk during the first trimester.

To support individuals with autism, it is important to create a structured living environment, provide consistent opportunities for social interaction, implement individualized training programs to enhance communication and adaptive skills, and maintain balanced nutrition and emotional stability—key elements in promoting gradual functional improvement.

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What are the symptoms of autism?

Autism symptoms primarily manifest in areas such as social communication, behavior, and interests, typically including difficulties in social interaction, delayed or abnormal language development, repetitive and stereotyped behaviors, restricted range of interests, and sensory processing abnormalities. Patients often struggle to form emotional connections with others, avoid eye contact, fail to respond to being called, and rarely initiate social interactions spontaneously.

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What are the harms of autism in children?

The harms of autism in children are mainly reflected in restricted development across multiple areas such as social skills, language, and cognition. Common issues include impaired social communication, delayed or disordered language development, lagging cognitive function, weak self-care abilities, and frequent emotional and behavioral problems. Affected children often struggle to understand others' facial expressions and the meaning of language, and are unable to initiate or sustain social interactions.