There isn't a medical test to determine if a person has autism spectrum disorder (ASD). Your child's doctor may order tests to rule out health problems or disabilities that have similar symptoms, but otherwise, a diagnosis is made through observation of how a child behaves and communicates, and how he or she is developing compared to other children the same age.

Each child develops at his or her own pace, and falling behind the typical milestones isn't necessarily a cause for concern. However, signs of ASD typically appear before age 3, and sometimes it can be detected as early as 18 months. If you're concerned that your son or daughter may be developing slowly or has unusual communication and social behaviour, talk to your doctor. The earlier autism spectrum disorder is diagnosed, the sooner treatment can begin and the more effective it will be. Studies show the children of preschool age who receive individualized, intensive therapy make good progress.

There are several early warning signs for ASD. Your doctor might decide more assessment is required if your child:

  • doesn't babble or coo by 12 months
  • doesn't gesture (for example, grasp, wave, or point) by 12 months
  • doesn't speak single words by 16 months
  • doesn't say 2-word phrases by 24 months
  • loses knowledge of language and social skills learned earlier

Your child's doctor might refer you to a specialist for a more detailed evaluation, including observation of your child's behaviour as well as social and language skills, and talking to you about how they've evolved. ASD symptoms vary greatly between children. It may take several months to reach a diagnosis, possibly not until age 2 or 3. Your input and that of your child's other caregivers and teachers are very important.

Doctors have screening tools to help diagnose autism spectrum disorder (the following may not identify mild ASD):

  • Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, which is the standard screening tool used in North America (published by the American Psychiatric Association)
  • Childhood Autism Rating Scale (CARS), based on behaviour
  • Autism Diagnostic Observation Schedule (ADOS-G), a structured observation tool that assesses social skills and communication
  • Autism Diagnostic Interview- Revised (ADI-R), a question-based assessment tool
  • Modified Checklist for Autism in Toddlers (M-CHAT)
  • Screening Tool for Autism in Two-Year-Olds (STAT)

Once a diagnosis is made, your child's doctor will help you decide which treatment is most appropriate. Options include medication, communication and behavioural therapies, and complementary therapies.

There are currently no medications available for ASD, but there are some that help control symptoms like hyperactivity. Behavioural and communication therapies teach skills and help with language, social, and behavioural issues. Complementary therapy can include dietary changes, nutritional supplements, art therapy, and sensory integration (reducing sensitivity to sound and light). There isn't yet evidence that these are effective, so discuss with your doctor how to incorporate them into your child's treatment.

original article by Jaclyn Law, 
with revisions by the MediResource Clinical Team