What is Autism?

Autism, or Autism Spectrum Disorder (ASD), is a developmental condition that affects communication, behavior, and social interactions. It is categorized as a spectrum disorder due to the wide range of symptoms and severity it presents.

The term "spectrum" reflects the diversity in challenges and strengths experienced by individuals with autism, based on the classification provided by the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM-5, 2013).

According to the Centers for Disease Control and Prevention (CDC), approximately 1 in 36 children in the United States is diagnosed with ASD, a figure that highlights its prevalence, making it more common than pediatric cancer, diabetes, and AIDS combined (CDC, 2023).

ASD occurs in people of all racial, ethnic, and socio-economic backgrounds. Furthermore, it is about four times more likely to be diagnosed in boys than girls, as reported by the CDC (2023). Symptoms can vary widely, from mild speech and language difficulties to more profound developmental challenges, including intellectual disabilities and co-occurring conditions such as cerebral palsy.

Definition of Autism

Autism, or Autism Spectrum Disorder (ASD), is a neurodevelopmental condition characterized by challenges in social interaction, communication (both verbal and non-verbal), and the presence of restricted and repetitive behaviors. According to the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM-5), these symptoms typically manifest in the first three years of life, although their onset can vary. Some children show signs from birth, while others may appear to develop typically, only to exhibit symptoms of autism between 18 and 24 months (American Psychiatric Association, 2013).

Autism was first identified in 1943 by Dr. Leo Kanner at Johns Hopkins Hospital. Around the same time, German scientist Dr. Hans Asperger described a milder variant of the condition, now known as Asperger Syndrome (Kanner, 1943; Asperger, 1944). While both were initially classified separately in the DSM-IV as distinct disorders, they are now included under the broader umbrella of Autism Spectrum Disorder in the DSM-5. Other related conditions, such as Rett Syndrome, Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS), and Childhood Disintegrative Disorder, also fall under ASD, each presenting varying degrees of challenges in communication, social skills, and repetitive behaviors (American Psychiatric Association, 2013).

Classification of Autism

DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition)

DSM-V (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition)

ICD-10 (International Classification of Diseases, 10th Edition)

Causes

While many potential causes of Autism Spectrum Disorder (ASD) have been proposed, the exact causes remain largely unknown. Current research suggests that autism is a multifactorial condition, meaning multiple factors contribute to its development.

Although the precise cause of autism is yet to be determined, researchers have identified other possible contributing factors. These include metabolic and neurological factors, prenatal or birth complications, and certain types of infections.

Genetic factors are believed to play a predominant role in the onset of autism. Studies indicate that autism has a high heritability, though it remains unclear which specific genes or combinations of genes are responsible. According to the National Institute of Neurological Disorders and Stroke (NINDS), numerous genes are likely involved, and their interaction with environmental factors is complex (NINDS, 2020).

Additionally, studies of individuals with autism have revealed abnormalities in brain structure and development, suggesting that the disorder may be linked to early brain development (Centers for Disease Control and Prevention, 2023). Despite ongoing research, no single cause of autism has been definitively established, reinforcing the idea that autism arises from a combination of genetic, biological, and environmental factors.