While the earliest signs of autism spectrum disorder often appear during the first year of a child’s life (studies show that one third to half of parents of children with ASD noticed symptoms before their child turned one), not all children with autism are diagnosed this early.
Some don’t show symptoms until they’re toddlers and, because autism disorder is a spectrum, some early signs can be difficult to spot, even for attentive parents and pediatricians. Still other children may seem to develop normally until around 18 to 24 months, when they stop gaining new skills or even lose skills they once had.
Whether a child is diagnosed with autism spectrum disorder as an infant or the condition is caught later, nearly 80-90 percent of parents of children with ASD report noticing symptoms by their child’s second birthday, which emphasizes the importance of being aware of common signs of autism in toddlers.
Communication-related signs of autism in toddlers
Usually, by a toddler’s first birthday, they have mastered some very basic forms of communication and interaction with others, like making eye contact, mimicking the words and actions of their caregivers, and using simple gestures to express emotions (like clapping when happy) or sentiments (like waving “bye”). This may not be the case for children with ASD.
It’s important to remember that the language and communication skills of people with autism spectrum disorder vary widely. According to the CDC, about 40% of children with ASD do not talk at all and about 25-30 percent of children with ASD have some words at 12 to 18 months of age and then lose them.
Some specific communication-related signs of autism in toddlers include:
Not babbling or cooing by 12 months
Not gesturing (movements like pointing and waving) to show interest in objects by 14 months
Not developing the ability to speak in single words by 16 months
Not moving on to two-word phrases by 24 months
Avoiding eye contact with others
Losing language skills at any age
Behavioral signs of autism in toddlers
Children with autism spectrum disorder will frequently develop repetitive actions and motions as a form of self-stimulation or “stimming.” They may also struggle with sensory issues (over- or under-sensitivities to sounds, lights, touch, tastes, smells, pain and other stimuli), which often present as toddlers.
Some specific behavioral signs of autism in toddlers include:
“Stimming” activities like flapping their hands, rocking their body, or spinning in circles
Obsessive interest in or fixation on objects
Unusual reactions to the way things sound, smell, taste, look, or feel
Staring at lights or spinning objects
Ritualistic behaviors like lining toys up obsessively or repeating patterns of behavior
Playing with toys the same way every time
Having strong negative reactions (for toddlers especially, often in the form of temper tantrums) to change
Exhibiting either a lack of fear or more fear than is appropriate in a given situation
Social signs of autism in toddlers
Toddlers who are developing normally will typically engage in simple social games like peek-a-boo, but for a child with autism spectrum disorder, even basic social interactions and games may be difficult or uninteresting.
Some specific social signs of autism in toddlers include:
Not engaging in "make-believe" or pretend play by 18 months
Expressing a strong desire to be left alone and not engage in play or socialization with others
Not understanding jokes, sarcasm, or teasing
Losing social skills at any age