What is autism?

Autism spectrum disorder (ASD) is a developmental condition that affects how a child communicates, behaves and interacts with others. It can involve difficulties with social skills, communication or behavior, and in some cases, may be linked to intellectual disability.

Although about one in 31 children is diagnosed with autism, each child may experience it differently. For instance, some children may have social challenges but be gifted learners. Others may need more support with learning and communication. Symptoms often appear in childhood. Learn more about early signs and symptoms of autism.

What causes autism?

Autism occurs in the brain, but the exact cause is unknown.

Patricia Evans, M.D., Ph.D., Pediatric Neurologist at Children's Health and Co-Director of the UT Southwestern and Children’s Health℠ Center for Autism Care, says that research shows that there are many different causes which are responsible for autistic behaviors.

Most physicians and researchers believe these causes affect both the cerebellum and the frontal lobe of the brain sometime before a child is born until about 2 years of age. The frontal lobe of the brain is located just behind the forehead. The cerebellum is in the back of the brain and supplies important information that the frontal lobe needs to have well-developed functioning for things such as attention, impulse control, fine motor control and mood regulation. Its function helps shape behaviors, learning, personality and movements.

Most physicians and researchers believe these causes affect both the cerebellum and the frontal lobe of the brain sometime before a child is born until about 2 years of age. The frontal lobe of the brain is located just behind the forehead. The cerebellum is at the back of the brain and supplies important information that the frontal lobe needs to have well-developed functioning for things such as attention, impulse control, fine motor control and mood regulation. Its function helps shape behaviors, learning, personality and movements.

“Lots of things may cause autistic behaviors: Fragile X genes, in-utero exposure to alcohol or drugs, trauma during pregnancy or even serious illnesses during the first few years of life, such as meningitis,” says Dr. Evans. “Anything which potentially alters the cerebellumor frontal lobe pathways during these particular crucial first three years of life may cause autistic behaviors.”

Some children may also be more likely to have autism due to their genetics.

You may have heard concerns that taking acetaminophen (Tylenol) during pregnancy could cause autism. Research has not shown a cause-and-effect relationship. Acetaminophen is still considered the safest over-the-counter option for pain relief in pregnancy. Learn more about what the research shows, and talk with your doctor if you have questions.

Levels of autism

Beginning in 2013, psychiatrists and psychologists use the fifth edition of Diagnostic and Statistical Manual of Mental Disorders (DSM-5) to diagnose autism. These new diagnoses don’t use previous names for autism like Asperger’s Syndrome or Pervasive Developmental Disorder. These terms are out-of-date.

Instead, medical professionals now use levels to describe autism:

• Level 3 means children require very substantial support for severe communication and behavior problems

• Level 2 means children need substantial support for inflexible behaviors or trouble communicating

• Level 1 means children need support for mild social or communication difficulties

The term social communication disorder was also developed to describe people with very mild social or communication problems or autism-like symptoms.

Dr. Evans encourages any parent who is concerned their child may have autism to talk with their pediatrician. Early diagnosis and treatment can help children reach their full potential.

Learn more

The Center for Autism Care is an interdisciplinary program offering comprehensive patient care and translational medicine for individuals with autism and related neurodevelopmental disorders. Learn more about our program and services.