Screening & Diagnosis


understanding autism

Autism Spectrum


What is Autism Spectrum Disorder (ASD)?

Autism Spectrum Disorder (ASD), referred to as Autism, is a complex, lifelong developmental condition that typically appears during early childhood and can impact a person’s social skills, communication, relationships, and self-regulation. The Autism experience is different for everyone. It is defined by a certain set of behaviors and is often referred to as a “spectrum condition” that affects people differently and to varying degrees.

While there is no known single cause of Autism, early diagnosis helps a person receive resources to support the choices and opportunities needed to live fully.

Signs & Characteristics

Autism impacts an individual throughout their lifespan. However, research shows that early diagnosis can improve their quality of life. The behaviors of Autism may be apparent in infancy, but they usually become clearer during early childhood. As part of a regular health visit, your child’s doctor should perform developmental screenings focused on Autism. This screening is recommended at ages 18 and 24 months for all children.

Your doctor will encourage you to ask specific questions about your child’s developmental progress. The National Institute of Child Health and Human Development (NICHD) developed a detailed list of behaviors, listed in four categories: communication, social behavior, stereotyped behavior, and other behavior. Additionally, the Centers for Disease Control and Prevention (CDC) developed a list of Signs and Symptoms, which can be found here.

Social Behavior

  • Prefers solitary or parallel play rather than engaging in associative or cooperative play with other children
  • Preference for predictable, structured play over spontaneous or make-believe play
  • May not respond to name being called
  • Struggles to make eye contact to communicate interests and/or needs
Communication and autism

Stereotyped Behavior

  • Extremely distressed by changes, including new foods or changes in schedule or routine
  • Strong, persistent interest in a specific topic, part of a toy, or item
other behavior
social behavior


  • Develops speech later than typical or not at all (nonspeaking)
  • Repetition in language or movement, such as repeating the same word or sounds, hand flapping, or any repeated movement
  • Atypical nonverbal communication, including avoiding eye contact, giving few facial expressions, or having a monotone voice
stereotyped behavior

Other Behavior

  • These characteristics vary widely and do not necessarily mean your child is autistic. However, if your child is showing these behaviors, a screening is encouraged. Many families start by voicing their concerns with their child’s primary physician, with referrals being made to a specialist for further evaluation. For more information, visit our Screening & Diagnosis page

Causes & Factors

There is no known single cause for Autism, but it is generally accepted that differences in brain structure or function cause it. Brain scans show differences in the shape and structure of the brain in Autistic people compared to neurotypical development. Researchers do not know the exact cause of Autism but are investigating several theories, including the links among heredity, genetics, and medical problems.

In many families, there appears to be a pattern of Autism or related disabilities, further supporting the theory that the disorder has a genetic basis.

While no one gene has been identified as causing Autism, researchers are searching for irregular segments of genetic code that people with Autism may have inherited. It also appears that some people are born with a susceptibility to Autism, but researchers have not yet identified a single “trigger” that causes Autism to develop.

Other researchers are investigating the possibility that under certain conditions, a cluster of genes may affect brain development, resulting in Autism. Still, other researchers are investigating complications during pregnancy or delivery and environmental factors such as viral infections, metabolic imbalances, and chemical exposure.

Understanding autism

Genetic Vulnerability

Autism tends to occur more frequently than expected among individuals who have certain medical conditions, including fragile X syndrome (FXS), tuberous sclerosis, congenital rubella syndrome (CRS), and untreated phenylketonuria (PKU). Some harmful substances ingested during pregnancy also have been associated with an increased likelihood of Autism.

  • As of 2023, the CDC reports that in the United States, 1 in 36 children have Autism; in California, the number is 1 in 22.
  • People with Autism come from all racial, ethnic, and socioeconomic groups.
  • ASD is about 4 times more common among boys than among girls.
  • Autism greatly varies from person to person (no two people with autism are alike). Services for children and adults with Autism must be carefully individualized.
  • Self-advocacy is an important skill that is especially important for autistic individuals. In order to be a great self-advocate, people first must know what their strengths are as well as what accommodations serve them the best. With that knowledge, they can be their own best advocate with family, school, or community.
  • Parents who have a child with ASD have a 2%–18% chance of having a second child who is also affected (CDC 2015).

Autism is characterized in the American Psychiatric Association’s Diagnostic and Statistical Manual (DSM-V), which is used by clinicians to diagnose Autism by: Persistent differences in communication, interpersonal relationships, and social interaction across different environments. What this can look like:

  • Being nonverbal, nonspeaking, or having atypical speech patterns, having trouble understanding nonverbal communication, difficulty making and keeping friends, difficulty maintaining typical back-and-forth conversational style.

Restricted and repetitive behavior, patterns, activities and interests. What this can look like:

  • Repeating sounds or phrases (echolalia), repetitive movements, preference for sameness and difficulty with transition or routine, rigid or highly restricted and intense interests, extreme sensitivity to, or significantly lower sensitivity to, sensory stimuli.

Neurodiversity addresses the concept that humans are not neurologically ‘one size fits all’. This means that it recognizes everyone’s unique abilities and considers neurological differences, like autism and ADHD, to be the result of variations in the human genome. It is the idea to see a neurological difference as unique ways of thinking and experiencing the world.

Although neurodiversity primarily refers to autism, there are also conversations around neurodiversity and Tourette’s syndrome, ADHD, epilepsy, dyslexia, and bipolar disorder.

The term was coined by an Australian sociologist, Judy Singer, who had autism herself, in the 1990s. It was popularized by American journalist Howard Blume.

There can be controversy within the autism community around this term. The Autism Society Inland Empire believes that:

  • ALL autistic people should receive more equal treatment.
  • ALL people with autism have gifts and talents.
  • Society should allow for autistic differences and create more equal opportunities.

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