Autism spectrum disorder (ASD) is a neurodevelopmental condition marked by persistent deficits in social communication and interaction alongside restrictive and repetitive behaviors or interests. ASD is sometimes accompanied by intellectual impairment.

These core symptoms manifest differently among individuals, ranging from mild to severe. The disorder's complexity extends beyond its clinical presentation, encompassing a diverse range of biological, cognitive, and sociocultural influences.

Early Signs and Diagnosis

Early indicators of ASD typically emerge within the first two years of life. Children with ASD often display limited responsiveness to social stimuli, such as reduced eye contact or lack of reaction to their name being called. Difficulties with joint attention — a shared focus between an individual and another person — are common. Repetitive behaviors, including hand-flapping, rocking, or fixation on particular objects or routines, provide additional diagnostic clues. Despite advances in diagnostic criteria, disparities persist across demographic groups, influenced by socioeconomic, ethnic, and gender biases. Girls, for instance, may exhibit subtler symptoms, complicating timely recognition.

Etiology and Contributing Factors

ASD is a multifactorial condition with a substantial genetic basis. Children whose siblings have ASD are at increased risk for the disorder. Twin studies reveal concordance rates upwards of 80% in monozygotic twins, highlighting hereditary influences. Variations in genes related to synaptic function and neural development are implicated. Environmental contributors, such as advanced parental age, prenatal exposure to certain medications or infections, and other perinatal factors, interact with genetic predispositions. Neurologically, alterations in brain connectivity, structure, and neurotransmitter systems further underlie ASD pathophysiology.

Cognitive and Sensory Processes

Psychological theories underscore deficits in cognitive processes, such as the theory of mind — the ability to attribute mental states to oneself and others — as central to ASD. Individuals with ASD may struggle to interpret others' intentions, leading to difficulties in social reciprocity. Sensory processing differences, including heightened sensitivity to sounds, lights, or textures, significantly affect daily experiences, often contributing to heightened anxiety or behavioral challenges. The social motivation approach to ASD suggests that individuals with ASD are profoundly less interested in social stimuli compared to typically developing people.

Importance of Early Intervention

Intervening early in a child's developmental trajectory is vital for optimizing outcomes. Evidence-based approaches, including applied behavior analysis (ABA), speech therapy, and occupational therapy, focus on enhancing communication, social engagement, and adaptive skills. Early interventions leverage the brain's plasticity during critical developmental windows, improving independence and quality of life for individuals with ASD.