The Classification of Autism Spectrum Disorder

Autism

Unlock the classification of Autism Spectrum Disorder, its impact, and the importance of early diagnosis.

Steven Zauderer

June 27, 2024

9 min read

min read

Understanding Autism Spectrum Disorder

Autism Spectrum Disorder, often referred to as ASD, is a complex developmental condition that entails a broad range of conditions characterized by challenges with social skills, repetitive behaviors, speech, and nonverbal communication.

Definition and Overview of ASD

Autism, or autism spectrum disorder (ASD), is a condition that causes a child's brain to function differently. It is not a mental illness but a developmental disorder that can manifest in various ways, affecting communication, social skills, and behaviors. People with autism may struggle with communication and social skills to varying degrees [1].

ASD can be associated with intellectual impairment, language impairment, known medical or genetic conditions, environmental factors, and other neurodevelopmental, mental, or behavioral disorders.

ASD includes social, communication, and behavioral challenges that can vary in severity from mild to severe, or somewhere in between. Early diagnosis is crucial for starting treatment sooner [3].

The Historical Context of Autism

Before the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) introduced the term "autism spectrum disorders" (ASD), there were five independent subtypes of autism: autistic disorder, Asperger's disorder, childhood disintegrative disorder, pervasive developmental disorder not otherwise specified, and Rett syndrome. These subtypes were merged into a single diagnosis of ASD due to their overlapping symptoms and the recognition of autism as a spectrum disorder [4].

Previously, experts categorized different types of autism including autistic disorder, Asperger’s syndrome, and pervasive developmental disorder not otherwise specified (PDD-NOS). However, they are now all referred to as "autism spectrum disorders".

In the context of the classification of autism spectrum disorder, it's crucial to understand that the term 'spectrum' in ASD refers to the wide range of symptoms and severity. The classification of ASD helps professionals better understand and diagnose autism, thereby guiding the development of effective treatment plans and interventions.

The Classification of Autism

Understanding the classification of autism spectrum disorder (ASD) is crucial for accurately diagnosing and supporting those living with the condition. The classification has evolved over time, with significant changes introduced in the shift from the DSM-IV to the DSM-5 diagnostic manuals.

From DSM-IV to DSM-5

The transition from the DSM-IV to DSM-5 brought substantial changes to the classification of ASD. As per the DSM-5 guidelines, individuals with a well-established DSM-IV diagnosis of autistic disorder, Asperger’s disorder, or pervasive developmental disorder not otherwise specified should now be given the diagnosis of autism spectrum disorder.

This shift to a single umbrella diagnosis of ASD represents an effort to more accurately reflect the diversity and complexity of the experiences of individuals with autism.

The Three Levels of ASD

According to the DSM-5, ASD is divided into three levels based on how much support an individual requires in their daily life and how incompatible their autistic traits are with neurotypical expectations [5].

Level	Description	Support Required
1	Difficulties with communication, reading social cues, transitioning between activities, social anxiety, and burnout from long-term masking.	Requires Support
2	Difficulty engaging in accepted social behaviors, displays repetitive behaviors such as stimming for self-regulation, struggles with shifting focus and changing activities.	Requires Substantial Support
3	Significant difficulties expressing themselves verbally and non-verbally, engages in repetitive behaviors, struggles with daily tasks and social interactions. High risk for neglect and discrimination.	Requires Very Substantial Support

Individuals with Level 1 ASD may experience challenges in communicating with neurotypical individuals, reading social cues, and transitioning between activities. They may also experience social anxiety and burnout from long-term masking.

Level 2 ASD individuals require substantial support. They often find it difficult to engage in accepted social behaviors and may display repetitive behaviors such as stimming for self-regulation. They might struggle with shifting focus and changing activities.

Level 3 ASD represents individuals who require very substantial support. They may have significant difficulties in expressing themselves both verbally and non-verbally and may engage in repetitive behaviors. These individuals often struggle with daily tasks and social interactions and are at a higher risk for neglect and discrimination.

The severity of ASD is based on social communication impairments and restricted, repetitive patterns of behavior.

By understanding the classification of ASD, professionals, caretakers, and individuals living with autism can better navigate the complexities of the disorder, leading to more personalized and effective support.

Autism and Developmental Delays

Understanding the connection between developmental delays and autism is a crucial component of the broader discussion on the classification of autism spectrum disorder (ASD). It is essential to recognize the signs of developmental delays and understand when they might point towards a more significant issue, such as autism.

Recognizing Developmental Delays

Approximately 10-15% of preschool-aged children experience some form of delay in their development, indicating that developmental delays are more common than perceived. However, minor delays are usually not alarming, but significant delays or delays in multiple areas might signify something bigger, such as autism [1].

Some common signs of developmental delays include:

Delayed speech
Difficulty with transitions
Repetitive behaviors
Impaired social interactions

It is essential to understand these signs and seek professional evaluation for early intervention if they persist.

The Connection to Autism

Autism, or autism spectrum disorder (ASD), is a condition that affects the functioning of a child's brain. It is a developmental disorder, not a mental illness, that can manifest in various ways, affecting communication, social skills, and behaviors [1]. People with autism may struggle with communication and social skills to varying degrees.

While these signs may also arise from developmental delays, they are typically more severe in children with autism. Moreover, autism spectrum disorder can be associated with intellectual impairment, language impairment, known medical or genetic conditions, environmental factors, and other neurodevelopmental, mental, or behavioral disorders.

Parents are advised to recognize the differences between developmental delays and autism, knowing when delays in their children's development are normal and when they might indicate a developmental disorder. Early intervention upon diagnosis of autism or other developmental disorders can significantly enhance a child's development. Understanding this connection is an integral part of comprehending the classification of autism spectrum disorder.

Autism Diagnostic Criteria

In understanding the classification of autism spectrum disorder (ASD), it is essential to consider the diagnostic criteria. These criteria focus on core symptoms of ASD and the presence of co-occurring conditions.

Core Symptoms of ASD

The DSM-5, released in May 2013, defines autism spectrum disorder as a central diagnosis given to a continuum of complex conditions. Signs and symptoms that were attributed to subtypes under previous classifications are now considered part of a continuum of Autistic traits and characteristics with differing severity levels.

ASD can be detected through screening in children as young as 12 months old, with early detection being crucial for timely interventions and support. Not all signs across various areas of development are necessary for a diagnosis of autism spectrum disorder [6].

An ASD diagnosis is based on a combination of factors and specifies the level of support a person may require. Diagnostic specialists may use standardized tests along with their clinical judgment.

Co-occurring Conditions and Autism

Individuals may be diagnosed with 2 or more conditions if signs and symptoms meet the diagnostic criteria for additional co-occurring conditions. Autism severity is currently defined and measured based exclusively on the severity levels of the two core symptom domains: social-communication and restricted or repetitive patterns of behaviors and interests. However, autistic individuals often face challenges such as intellectual disability, limited expressive and/or receptive language, and anxiety disorders.

The combined effect of different aspects of autism on a person's life is not formally designated. A comprehensive approach that considers both core symptoms and other challenges, as well as individual factors such as daily living skills, specific support needs, and environmental resources, would enhance the evaluation of disability in autistic individuals. Evaluating autism severity based solely on the presentation of core symptoms does not provide a complete understanding of the impact of autism on a person's real-life functioning. Co-occurring conditions and environmental factors play a significant role in how autism manifests in a person's life and can greatly impact everyday functioning and well-being.

In conclusion, a multidimensional approach to autism could provide a more comprehensive system for the classification of impairment, providing a better understanding of the challenges and strengths of autistic individuals.

The Importance of Early Diagnosis

Diagnosing Autism Spectrum Disorder (ASD) as early as possible is critical in the child's overall development and treatment. The sooner the diagnosis, the earlier the intervention services can start, which can significantly enhance the child's life quality and potential. This section focuses on the early signs of autism and the screening process.

Early Signs of Autism

Research has found that ASD can sometimes be detected at 18 months or younger. By age 2, a diagnosis by an experienced professional can be considered very reliable. However, many children do not receive a final diagnosis until much older, delaying the onset of helpful treatment services [8].

It is crucial to note that ASD's signs and symptoms can vary significantly among children, but they often involve difficulties with social interaction, communication, and repetitive behaviors. Early signs may include lack of eye contact, delayed speech, difficulty understanding others' feelings, and repetitive behaviors such as rocking or spinning. Parents and caregivers should also be aware of any developmental delays, as these can often be a precursor to ASD.

The Screening Process

The American Academy of Pediatrics (AAP) recommends that all children be screened for developmental delays and disabilities during regular well-child doctor visits. This is particularly important for children at high risk for developmental problems due to factors like preterm birth or low birth weight. Moreover, all children should specifically be screened for ASD during regular well-child doctor visits, especially those at high risk for ASD or exhibiting symptoms.

Parents are reliable sources of information about their children's development. Evidence-based screening tools that incorporate parent reports can facilitate structured communication between parents and providers, increasing parent awareness and observations of child development. Some screening tools are time- and cost-efficient, with the time for administering a screening tool ranging approximately from 2 to 15 minutes and the cost of materials and administration per visit ranging from $1.19 to $4.60 [8].

Diagnostic tools for assessing ASD in young children rely on parents' or caregivers' descriptions of the child's development and a professional's observation of the child's behavior. Specialists such as neurodevelopmental pediatricians, developmental-behavioral pediatricians, child neurologists, geneticists, and early intervention programs can provide further assessment and diagnosis when needed.

The screening process is a crucial step in the classification of autism spectrum disorder. It provides a pathway towards a better understanding of ASD, allowing for early intervention and improved outcomes for children diagnosed with this condition.

Autism Severity and Real-Life Impact

Understanding the classification of autism spectrum disorder goes beyond recognizing the core symptoms. It also encompasses the severity of the disorder and how it impacts daily life. This includes the multidimensional approach to autism and the concept of 'profound autism.'

The Multidimensional Approach

Autism severity is currently defined and measured based exclusively on the severity levels of the two core symptom domains: social-communication and restricted or repetitive patterns of behaviors and interests. However, individuals with autism are often diagnosed with other medical, developmental, and psychological co-occurring conditions that can significantly impact their day-to-day lives. These challenges may include intellectual disability, limited expressive and/or receptive language, and anxiety disorders.

Evaluating autism severity based solely on the presentation of core symptoms does not provide a complete understanding of the impact of autism on a person's real-life functioning. Co-occurring conditions and environmental factors play a significant role in how autism manifests in a person's life and can greatly impact everyday functioning and well-being. A multidimensional approach that takes into account these factors would provide a more comprehensive understanding of the challenges and strengths of autistic individuals.

Autism severity can change over time for a substantial number of individuals, with some decreasing in severity and others increasing. Factors such as cognitive abilities, language skills, environmental resources, and co-occurring conditions can influence changes in severity over time.

The Concept of 'Profound Autism'

The term "profound autism" has been proposed to describe a subgroup of individuals with high core symptom severity, co-occurring intellectual disability, and little or no language, who require extensive long-term care. This term acknowledges the additional challenges faced by individuals with autism beyond the core symptoms and emphasizes the need for individualized support and care. It's important to note, however, that not all individuals with autism fit into this subgroup, and there is a wide range of abilities and challenges within the autism spectrum.

The understanding of autism and its impact on an individual's life should be viewed from a multidimensional perspective, considering not just the core symptoms but also the co-occurring conditions and how they interact with environmental factors. The classification of autism spectrum disorder, therefore, requires a comprehensive approach that considers each individual's unique experiences and needs.