Diagnosing ASD in Young Children

Diagnosing ASD

Doctors diagnose ASD by looking at a child’s behavior and development. Young children with ASD can usually be reliably diagnosed by age two.

Older children and adolescents should be evaluated for ASD when a parent or teacher raises concerns based on watching the child socialize, communicate, and play.

Diagnosing ASD in adults is not easy. In adults, some ASD symptoms can overlap with symptoms of other mental health disorders, such as schizophrenia or attention deficit hyperactivity disorder (ADHD). However, getting a correct diagnosis of ASD as an adult can help a person understand past difficulties, identify his or her strengths, and obtain the right kind of help.

Diagnosis in young children is often a two-stage process:

Stage 1: General Developmental Screening During Well-Child Checkups

Every child should receive well-child check-ups with a pediatrician or an early childhood health care provider. The Centers for Disease Control and Prevention (CDC) recommends specific ASD screening be done at the 18- and 24-month visits.

Earlier screening might be needed if a child is at high risk for ASD or developmental problems. Those at high risk include children who:

  • Have a sister, brother, or other family member with ASD
  • Have some ASD behaviors
  • Were born premature, or early, and at a low birth weight.

Parents’ experiences and concerns are very important in the screening process for young children. Sometimes the doctor will ask parents questions about the child’s behaviors and combine this information with his or her observations of the child. Read more about screening instruments on the CDC website.

Children who show some developmental problems during this screening process will be referred for another stage of evaluation.

Stage 2: Additional Evaluation

This evaluation is with a team of doctors and other health professionals with a wide range of specialties who are experienced in diagnosing ASD. This team may include:

  • A developmental pediatrician—a doctor who has special training in child development
  • A child psychologist and/or child psychiatrist—a doctor who knows about brain development and behavior
  • A speech-language pathologist—a health professional who has special training in communication difficulties.

The evaluation may assess:

  • Cognitive level or thinking skills
  • Language abilities
  • Age-appropriate skills needed to complete daily activities independently, such as eating, dressing, and toileting.

Because ASD is a complex disorder that sometimes occurs along with other illnesses or learning disorders, the comprehensive evaluation may include:

  • Blood tests
  • Hearing test

The outcome of the evaluation will result in recommendations to help plan for treatment.

The National Institute of Mental Health was the primary source of this information.