Autism Spectrum Disorders: Types, Symptoms, and Treatments

Ian C. Langtree - Writer/Editor for Disabled World (DW)
Published: 2010/07/16 - Updated: 2025/05/31
Publication Type: Informative
Category Topic: Neurological Disorders - Academic Publications

Page Content: Synopsis - Introduction - Main - Insights, Updates

Synopsis: This information provides a comprehensive overview of Autism Spectrum Disorders (ASD), detailing the range of conditions included under the ASD umbrella—such as autistic disorder, Rett's syndrome, Asperger's syndrome, childhood disintegrative disorder, and pervasive developmental disorder not otherwise specified (PDD-NOS). It explains that ASD typically manifests in early childhood and is characterized by significant challenges in social interaction, communication, and repetitive behaviors, with varying degrees of intellectual and functional abilities.

The article highlights the complex interplay of genetic and environmental factors in ASD's development, referencing authoritative studies and epidemiological data, including findings from the Centers for Disease Control and Prevention, which estimate that about 1 in 44 children are diagnosed with ASD. It distinguishes between the different subtypes, noting unique features such as the later onset and variable symptoms of PDD-NOS, the relatively preserved language and cognitive abilities in Asperger syndrome, and the genetic underpinnings and severe physical manifestations of Rett syndrome.

Treatment and management approaches are discussed, emphasizing individualized educational and behavioral interventions to improve quality of life and independence, making this resource especially useful for families, caregivers, educators, and healthcare providers supporting people with disabilities and neurodevelopmental differences. The authority of the information is reinforced by the author’s background in disability advocacy and the inclusion of current research and clinical perspectives - Disabled World (DW).

Introduction

The autism spectrum, also called autism spectrum disorders (ASD) or autism spectrum conditions (ASC), with the word autistic sometimes replacing autism, is a spectrum of psychological conditions characterized by widespread abnormalities of social interactions and communication, as well as severely restricted interests and highly repetitive behavior. There are three main types of autism spectrum disorder, and two are rare.

• Autistic disorder
• Rett's syndrome
• Asperger's syndrome
• Childhood disintegrative disorder
• Pervasive developmental disorder, not otherwise specified (PDD-NOS)

Main Content

A study conducted by the Centers for Disease Control and Prevention (CDC) from 2009 to 2017 determined that approximately 1 in 44 children ages 3-17 are diagnosed with some form of ASD. Autism spectrum disorders affect three different areas of a child's life:

• Social interaction: Problems and difficulties include a lack of understanding and awareness of other people's emotions and feelings.
• Communication (nonverbal and verbal): Impaired language and communication skills, such as delayed language development and an inability to start conversations or participate properly.
• Repetitive behaviors or interests: Unusual thought patterns and physical behavior. This includes making repetitive physical movements, such as hand tapping or twisting. The child develops set routines of behavior, which can upset the child if the routines are broken.

Autism spectrum disorder (ASD) and schizophrenia (SCZ) have complex inheritance patterns, with multiple genetic and environmental factors influencing disease risk. Sufficient evidence has shown that genetic factors contribute substantially to the etiology of both disorders. Although ASD and SCZ are clinically distinct disorders, evidence suggests that genetic overlap exists. These disorders co-occur at a higher rate than would be expected in the general population (Chisholm et al., 2015). A large epidemiological study showed that a family history of SCZ in first-degree relatives is a risk factor for ASD (Sullivan et al., 2012).

People with autism have difficulties with communication and social interaction and display restricted repetitive patterns of interest and activity. Autism is thought to be present soon after birth, with the disorder's characteristics becoming apparent in the first three years of life.

Autism seems to be on the rise, and autism spectrum disorders affect between two and six children out of every 1,000 in the U.S. It's unclear whether the growing incidence of autism represents a real increase or just improved detection.

• Around 75% of people with autism also have intellectual disability.
• The remaining 25% may have impaired insight, social functioning, and communication skills but do not have an intellectual disability or significantly reduced cognitive ability. This is called 'higher functioning autism.'
• A small number of people with higher functioning autism may have extraordinary creative or artistic skills and abilities.

Pervasive Developmental Disorder - Not Otherwise Specified (PDD-NOS)

This diagnosis applies to most children with an autistic spectrum disorder. Children whose autism is more severe than Asperger's syndrome but not as severe as an autistic disorder are diagnosed with PDD-NOS. Autism symptoms in kids with PDD-NOS vary widely, making it hard to generalize. Overall, compared to children with other autistic spectrum disorders, children with PDD-NOS have:

• A later age of onset.
• Impaired social interaction - like all children with an autistic spectrum disorder.
• Fewer repetitive behaviors than children with Asperger's syndrome or autistic disorder.
• Better language skills than kids with autistic disorder, but not as good as those with Asperger's syndrome.

Asperger Syndrome

People with Asperger syndrome have social deficits and restricted patterns of interest and activity similar to people with autism. However, they do not have an intellectual disability, and their language and cognitive skills development appear normal, at least in the first two years of life.

Professional and practical experience indicate that people with Asperger syndrome have disordered language and specific learning difficulties.

Formal recognition and diagnosis of Asperger syndrome usually occur later than for autism. It is thought that it is probably because the person's social deficits don't become apparent until they spend time in social settings, such as kindergarten or school.

Rett Syndrome

Signs of Rett syndrome that are similar to autism.

Rett Syndrome is a childhood neurodevelopmental disorder characterized by normal early development followed by loss of purposeful use of the hands, distinctive hand movements, slowed brain and head growth, gait abnormalities, seizures, and mental retardation.

The signs of this disorder are most easily confused with those of Angelman syndrome, cerebral palsy and autism. It affects females almost exclusively. Rett syndrome is caused by mutations (structural alterations or defects) in the MECP2 (pronounced meck-pea-two) gene, which is found on the X chromosome.

Girls with Rett syndrome are prone to gastrointestinal disorders, and up to 80% have seizures. They typically have no verbal skills, and about 50% of females are not ambulatory.

Scoliosis, growth failure, and constipation can be problematic.

Rett Syndrome signs may stabilize for many decades, particularly for interaction and cognitive functions such as making choices. Anti-social behavior may change to highly social behavior.

Motor functions may slow as rigidity and dystonia appear.

Seizures may be problematic, with a wide range of severity.

Scoliosis occurs in most and may require corrective surgery. Those who remain ambulatory tend to have less progression of scoliosis.

Treatment and Management of Autism Spectrum Disorders

No single treatment is best, typically tailored to the child's needs.

Intensive sustained special education programs and behavior therapy can help children acquire self-care, social, and job skills early in life.

The main treatment goals are to lessen associated deficits and family distress and improve quality of life and functional independence.

Available approaches include applied behavior analysis (ABA), developmental models, structured teaching, speech and language therapy, social skills therapy, and occupational therapy. ABA therapy has a strong research base but may be limited by diagnostic severity and IQ.

Insights, Analysis, and Developments

Author Credentials: Ian is the founder and Editor-in-Chief of Disabled World, a leading resource for news and information on disability issues. With a global perspective shaped by years of travel and lived experience, Ian is a committed proponent of the Social Model of Disability-a transformative framework developed by disabled activists in the 1970s that emphasizes dismantling societal barriers rather than focusing solely on individual impairments. His work reflects a deep commitment to disability rights, accessibility, and social inclusion. To learn more about Ian's background, expertise, and accomplishments, visit his full biography.