How Are Children with ASD Diagnosed?
- Autism can often be diagnosed in children as young as toddlers, but sometimes it takes longer to begin recognizing signs
- Diagnosing autism in children must be done by a doctor or licensed therapist trained in recognizing the signs of autism in toddlers, children, and adolescents
- Early intervention is important for helping your newly diagnosed child reach their full potential, whether you choose ABA therapy or other methods
Many parents say they “just knew” their child was on the spectrum. Others may recognize challenging behaviors in their children but not realize they are early signs of autism. Each individual with autism is unique, and no two people on the spectrum are exactly alike. However, there are some specific signs that a person may have autism.

Early Signs of Autism
In many cases, early signs of autism are evident by as young as 6 months of age. Other children may seem to be developing normally until they are a little older and then regress in their language or social development. Some of the earliest signs of autism in toddlers can include:
By 6 Months of Age
- Doesn’t or rarely makes eye contact
- Doesn’t or rarely smiles
By 9 Months of Age
- Doesn’t make eye contact or engage in smiling and other expressions
- Has limited vocal expression, such as babbling or mimicking
By 12 Months of Age
- Doesn’t respond to name
- Doesn’t babble or attempt speech
- Doesn’t make gestures such as waving or pointing
By 16 to 18 Months of Age
- Has few or no words
By two years of age
- Has no or few two-word phrases, aside from copying or mimicking
Diagnosing Autism in Older Children and Teens
In some cases, diagnosing autism in children under the age of two is not possible. Sometimes language and social skills begin to develop, but regress or stop as the child gets older. In other cases, parents may not recognize the signs of autism in toddlers, or the signs may not appear until later. For this reason, the AAP has begun to recommend that all children be screened for autism at their well-child visits. Not all doctors may be aware of this change, so ask your doctor if you have any concerns about your child’s development.
Early signs of autism in children older than two years include:
- Loss of speech or eye contact when previously acquired
- Preference for being alone
- Avoidance or inability to make eye contact
- Limited areas of interest
- Delayed speech development
- Repetition of words or phrases
- Repetitive movements such as spinning, bouncing, or hand flapping
- Resistance to even minor changes in routine
- Unusually strong reactions to stimuli such as smells or sounds
- Inability to understand or empathize with the feelings of others
Diagnosing Autism in Children
Autism cannot always be diagnosed based on signs alone. There may be alternative reasons for any of these signs or symptoms, such as hearing loss or another neurological or developmental disorder, such as ADHD or ODD. Children from a traumatic background may also have symptoms that mimic ASD.
Children often have more than one developmental disorder at the same time. This is called co-morbidity, and each disorder may require its own therapies and treatments.
Some of the ways doctors and therapists work with families to secure an autism diagnosis in children include:
Ruling out Medical Disorders
Hearing and eyesight should be evaluated to ensure there are no sensory issues causing your child’s behaviors. In rare cases, a medical condition could also be to blame.
Take the M-CHAT-R Screening Questionnaire
This is a questionnaire you can take to determine if your child has common early signs of autism. It is not enough to secure a diagnosis, but it will let you know if a discussion with your doctor is warranted.
Get Further Analysis
Once alternative options have been ruled out, your doctor may decide to proceed with further behavioral and developmental testing. This will include observing your child’s social and developmental skills and gathering thorough information from you and other family members on your child’s behaviors at home.

What to do After the Diagnosis
If all testing shows that your child is on the autism spectrum, you may have many questions about how to help him reach his full potential. While autism can present challenges, it doesn’t mean your child can’t have a full and meaningful life. Getting your child into therapy will help them learn skills they will need to achieve their goals in school and in their social interactions. Excel Together’s therapists can help you develop a therapeutic plan personalized to your child. Contact us today to get started.