There are no medical tests for diagnosing autism. An accurate diagnosis must be based on observation of the individual’s communication, behaviour, and developmental levels. However, because many of the behaviours associated with autism are shared by other disorders, various medical tests may be ordered to rule out or identify other possible causes of the symptoms being exhibited.

autism word display on tablet

The characteristic behaviours of autism spectrum disorders may or may not be apparent in infancy (18 to 24 months), but usually become obvious during early childhood (24 months to 6 years). While there is no one behavioural or communications test that can detect autism, several screening instruments have been developed that are now used in diagnosing autism. When autism is suspected, your child will need to be referred to someone who specializes in diagnosing autism spectrum disorders. This may be a developmental pediatrician, a psychiatrist or psychologist. Other professionals may be included who are better able to observe and test your child in specific areas.


This multidisciplinary assessment team may include some or all of the following professionals. They may also be involved in treatment programs.

Developmental pediatrician – Treats health problems of children with developmental
delays or handicaps.

Child psychiatrist – A medical doctor who may be involved in the initial diagnosis can
prescribe medication and provide help with behaviour/emotional adjustments and social

Clinical psychologist – Specializes in understanding the nature and impact of
developmental disabilities, including autism spectrum disorders. May perform
psychological and assessment tests, and may help with behaviour modification and
social-skills training.

Occupational therapist – Focuses on practical, self-help skills that will aid in daily living,
such as dressing and eating; may work on sensory processing, coordination of
movement, and fine motor skills.

Physical therapist – Helps improve the use of bones, muscles, joints, and nerves to
develop muscle strength, coordination, and motor skills.

Speech/language therapist – Involved in the improvement of communication skills,
including speech and language.

Social Worker – May provide counselling services or act as case manager, helping toarrange services.