Autism Spectrum Disorder: Overview and Facts

Autism spectrum disorder (ASD) is a developmental disorder that can be hard to identify and understand. Start here.

Autism Spectrum Disorder (ASD) is a complex neurobiological disorder that is characterized by difficulty communicating verbally and relating socially to others, alongside a need to engage in repetitive behaviors or language. Some common early symptoms that parents often notice in a child are delayed speech, restricted interests, not responding to his or her name, and avoiding eye contact.

Who’s at Risk?

Researchers don’t understand what causes ASD, but there appears to be a strong genetic component. Children with a sibling or cousin with autism are more likely to develop the condition. The condition occurs in all ethnic, age, and socioeconomic groups. It is diagnosed in boys four times more often than it is in girls.

What Causes ASD?

Research studies have definitively shown that childhood vaccinations do not cause the condition.

However, the exact cause of ASD remains unknown. Most physicians agree it is a result of abnormalities in brain structure or function, observed when comparing the MRIs of children with autism to those of neurotypical children1. A number of theories are being researched, including hereditary risk, the impact of genetics, and other medical problems.

Some studies have shown that children with an older sibling with ASD are at a higher risk for an ASD diagnosis2. Other research suggests that certain environmental conditions, such as iron deficiency during pregnancy and breast feeding3 or maternal infections/medication during the pre- and perinatal phase4 have a deep impact on the occurrence of ASD. Another study suggests specific gene mutations could influence the development of ASD5.

The “Magical World Theory” proposes that people with ASD struggle to put into context the events they experience or observe6. In other words, they cannot determine what happened before an event to cause it, or make predictions about what might occur as a result. These researchers posit that this deficiency taxes the brain, making it constantly overwhelmed with analyzing a seemingly chaotic environment. Because of this ceaseless need for observation and problem solving, people with ASD experience heightened anxiety due to endless uncertainty and hypersensitivity. They believe that the autistic brain cannot become “used to” certain touches, facial expressions, sights, and sounds in the same way a neurotypical brain can. It cannot prioritize the stimuli, and thus is constantly hypervigilant, and overly sensitive to too-tight clothing or too-loud sounds.

Some people with ASD experience only mild challenges. For others, symptoms interfere with everyday life. ASD occurs on a continuum of severity. It is not like pregnancy, where one either does or does not have the characteristics. ASD is a condition in which people do not learn social skills within typical developmental milestones7. This can present as limited interaction with children and adults around them, difficulty interpreting facial expressions or tone of voice, or limited language. Children with ASD may have delayed language skills, be completely nonverbal, or have unusual conversation habits like repeating phrases. Others will speak at length in an advanced vocabulary about a favorite topic, but have limited skills with taking turns in conversations. Repetitive behaviors can range from a movement like hand-flapping, made over and over, to becoming preoccupied with having objects in a certain order or a strict routine.

Other behaviors often occur with autism – like emotional outbursts or self-injurious behaviors like head banging or hair pulling. These could appear as self-soothing mechanisms when people with ASD are overwhelmed, or be an obsessive tic. Their cause is unknown, and these behaviors are not always present with an ASD diagnosis. Treatment tailored to severity of symptoms can help alleviate difficulties and make it easier for people with ASD to learn social skills, communicate, and control repetitive behaviors.

The condition commonly co-occurs with other medical conditions including: ADHD, gastrointestinal (GI) disorders, anxiety, fragile X syndrome, sleep dysfunction, pica and seizure disorders like epilepsy. Often, symptoms overlap with other conditions, making ASD tricky to diagnose. Learn more about symptoms and evaluations.

1“About Autism - Causes.” ADDitude Magazine. (2015). Web. (

2Janice Rodden. “New Study: Vaccines Don’t Cause Autism.” Autism Society. (2015). Web. (

3Devon Frye. “Prenatal Iron Intake Linked to Autism.” ADDitude Magazine. (2014). Web. (

4Wayne Kalyn. “Prenatal Iron Intake Linked to Autism.” ADDitude Magazine. (2014). Web. (

5Janice Rodden. “New Link Found Between Gene Mutation, Working Memory, and Autism.” ADDitude Magazine. (2015). Web. (

6Janice Rodden. “Living in an Unpredictable World: Researching the Root of Autism.” ADDitude Magazine. (2014). Web. (

7Mark Bertin. “Autism and ADHD: The Complete Playbook for Social Challenges.” ADDitude Magazine. (2015). Web. (

TAGS: Comorbid Conditions with ADD

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