Signs of Autism in 18 Month Old: Key Red Flags to Watch

At 18 months, signs of autism may include limited or no use of single words, lack of pointing or other gestures to share interest, reduced eye contact, not responding to their name, and repetitive behaviors like hand flapping or spinning objects. While every child develops differently, these behaviors warrant a discussion with your pediatrician and possibly a developmental evaluation.

Social and Communication Red Flags at 18 Months

By 18 months, most toddlers are actively engaging with others, using gestures, and beginning to speak. A child with autism may show differences in these areas. According to the CDC, signs include avoiding or not keeping eye contact, not responding to their name by 9 months, and not showing facial expressions like happy, sad, or angry. The University of New Mexico's Autism Programs notes that diminished babbling, especially back-and-forth babbling that looks like the baby is "talking" to another person, is a red flag. Additionally, little or no joint attention—where the child and another person share interest in an object or event—is a key indicator. Joint attention typically emerges around 9 months and should be well established by 18 months.

Other communication signs include no single words by 16 months, infrequent use of gestures like pointing by 14 months, and limited shared enjoyment such as showing objects or engaging in back-and-forth activities like waving or reaching by 12 months. Some children may repeat words or phrases over and over (echolalia) or have an abnormal tone of voice that is flat, robotic, or sing-song.

Behavioral and Play Differences

Children with autism may engage in repetitive behaviors and have unusual play patterns. They might line up toys, spin objects, or focus on parts of objects, such as spinning the wheels of a car rather than making it go. They may not be interested in functional play like making cars go "vroom" or pretending to eat toy food. Instead, they may play with toys the same way over and over and become upset if others try to join in.

Repetitive movements such as hand or finger posturing, flapping, or spinning are also common. Some children may seek out or avoid certain textures, sounds, or movements, and they may have visual differences like fixating on objects or looking at things in odd ways. Getting excessively upset by minor changes on a regular basis is another potential sign.

Regression and Loss of Skills

Some children with autism appear to develop typically until around 18 months and then lose skills or regress. This regression can include loss of previously acquired speech, babbling, or social skills. Autism Speaks highlights that loss of previously acquired speech, babbling, or social skills is a sign of autism at any age. If you notice your child losing skills they once had, it is important to seek an evaluation promptly.

When to Seek an Evaluation

If you notice any of these signs, do not take a "wait and see" approach. Early intervention can make a significant difference. The University of New Mexico emphasizes that there is no time for the "wait and see" approach when there are concerns about a child's development, and there is no harm in screening or seeking a referral. Talk to your pediatrician about your concerns and request a developmental screening. You can also contact your state's early intervention program for a free evaluation. In the US, you can find your local program through the CDC's "Learn the Signs. Act Early." initiative.

Remember that none of these signs alone indicate autism, and many children without autism may show some of these behaviors. However, if you have concerns, it is always best to seek professional guidance.

What Parents Can Do

Keep track of your child's developmental milestones and bring up any concerns at well-child visits. The CDC offers milestone checklists for ages 2 months to 5 years. If your child is not meeting milestones, ask for an evaluation. Early intervention services, such as speech therapy, occupational therapy, and behavioral therapy, can help your child develop important skills.

For more detailed information, visit the CDC's signs and symptoms page or the University of New Mexico's early indicators page.