Characteristics signs of autism spectrum disorder can be seen in children as young as

Autism spectrum disorder (ASD) can look different in different people. It’s a developmental disability that affects the way people communicate, behave, or interact with others.

Experts don’t fully understand all of the causes of autism spectrum disorder. It seems to be genetic, but things such as parental age and prescription medications taken during pregnancy may be involved.

For instance:

  • A person is more likely to be on the spectrum if a brother, sister, or parent is. But it doesn’t always run in families.
  • About 10% of kids with ASD have a form of genetic disorder such as Down syndrome and fragile X syndrome.
  • A large Danish study found a link between ASD and advanced parental age of either parent.
  • Women prescribed opioids just before pregnancy are likelier to have a child with ASD.

Some children who are on the spectrum start showing signs as young as a few months old. Others seem to have normal development for the first few months or years of their lives and then they start showing symptoms.

But up to half of parents of children with ASD noticed issues by the time their child reached 12 months, and between 80% and 90% noticed problems by 2 years. Children with ASD will have symptoms throughout their lives, but it’s possible for them to get better as they get older.

The autism spectrum is very wide. Some people might have very noticeable issues, others might not. The common thread is differences in social skills, communication, and behavior compared with people who aren’t on the spectrum.

A child with ASD has a hard time interacting with others. Problems with social skills are some of the most common signs. They might want to have close relationships but not know how.

If your child is on the spectrum, they might show some social symptoms by the time they're 8 to 10 months old, including:

  • They don't respond to their name by their first birthday.
  • Playing, sharing, or talking with other people don’t interest them.
  • They prefer to be alone.
  • They avoid or reject physical contact, including hugging.
  • They avoid eye contact.
  • When they’re upset, they don’t like to be comforted.
  • They don’t understand emotions -- their own or others’.
  • They may not stretch out their arms to be picked up or guided with walking.

About 40% of kids with autism spectrum disorders don’t talk at all, and between 25% and 30% develop some language skills during infancy but then lose them later. Some children with ASD start talking later in life.

Most have some problems with communication, including:

  • Delayed speech and language skills
  • Flat, robotic speaking voice, or singsong voice
  • Echolalia (repeating the same phrase over and over)
  • Problems with pronouns (saying “you” instead of “I,” for example)
  • Not using or rarely using common gestures (pointing or waving), and not responding to them
  • Inability to stay on topic when talking or answering questions
  • Not recognizing sarcasm or joking
  • Trouble expressing needs and emotions
  • Not getting signals from body language, tone of voice, and expressions

Children with ASD also act in ways that seem unusual or have interests that aren’t typical, including:

  • Repetitive behaviors like hand-flapping, rocking, jumping, or twirling
  • Constant moving (pacing) and “hyper” behavior
  • Fixations on certain activities or objects
  • Specific routines or rituals (and getting upset when a routine is changed, even slightly)
  • Extreme sensitivity to touch, light, and sound
  • Not taking part in “make-believe” play or imitating others’ behaviors
  • Fussy eating habits
  • Lack of coordination, clumsiness
  • Impulsiveness (acting without thinking)
  • Aggressive behavior, both with self and others
  • Short attention span

The earlier treatment for autism spectrum disorder begins, the more likely it is to be effective. That’s why knowing how to identify the signs and symptoms is so important.

Make an appointment with your child’s pediatrician if they don’t meet these specific developmental milestones, or if they meet but lose them later on:

  • Smiles by 6 months
  • Imitates facial expressions or sounds by 9 months
  • Coos or babbles by 12 months
  • Gestures (points or waves) by 14 months
  • Speaks with single words by 16 months and uses phrases of two words or more by 24 months
  • Plays pretend or “make-believe” by 18 months

  • you think your child might be autistic

You could speak to:

  • a GP
  • a health visitor (for children under 5)
  • any other health professional your child sees, such as another doctor or therapist
  • special educational needs (SENCO) staff at your child's school

Getting diagnosed can help your child get any extra support they might need.

Find out how to get diagnosed

autism

Characteristics signs of autism spectrum disorder can be seen in children as young as

What is autism?

Autism expresses itself through a spectrum of symptoms. Autism spectrum disorder (ASD) appears in infancy and early childhood, causing delays in many basic areas of development, such as learning to talk, play, and interact with others.

The signs and symptoms of autism vary widely, as do its effects. Some children with autism have only mild impairments, while others have more obstacles to overcome. However, every child on the autism spectrum has problems, at least to some degree, in the following three areas:

  • Communicating verbally and non-verbally.
  • Relating to others and the world around them.
  • Thinking and behaving flexibly.

There are different opinions among doctors, parents, and experts about what causes autism and how best to treat it. There is one fact, however, that everyone agrees on: early and intensive intervention helps. For children at risk and children who show early signs, it can make all the difference. But no matter your child’s age, don’t lose hope. Treatment can reduce the disorder’s effects and help your child thrive in life.

Melanie is a healthy one-year old, but her parents are worried about her development because she’s not doing many things that her older brother did at her age, like playing peek-a-boo and mimicking expressions and gestures. Melanie’s mom and dad try to engage her with toys, songs, and games, but nothing they do gets her interest, let alone a laugh or a smile. In fact, she rarely makes eye contact. And although her hearing has been checked and is normal, she doesn’t babble, make other baby noises, or respond when her parents call her name. Melanie needs to be checked out by a child development specialist right away.

How parents can spot the warning signs

As a parent, you’re in the best position to spot the earliest warning signs of autism. You know your child better than anyone and observe behaviors and quirks that a pediatrician, in a quick fifteen-minute visit, might not have the chance to see. Your child’s pediatrician can be a valuable partner, but don’t discount the importance of your own observations and experience. The key is to educate yourself so you know what’s typical and what’s not.

[Read: Autism Spectrum Disorders]

Monitor your child’s development. Autism involves a variety of developmental delays, so keeping a close eye on when—or if—your child is hitting the key social, emotional, and cognitive milestones is an effective way to spot the problem early on. While developmental delays don’t automatically point to autism, they may indicate a heightened risk.

Take action if you’re concerned. Every child develops at a different pace, so you don’t need to panic if your child is a little late to talk or walk. When it comes to healthy development, there’s a wide range of “typical.” But if your child is not meeting the milestones for his or her age, or you suspect a problem, share your concerns with your child’s doctor immediately. Don’t wait.

Don’t accept a wait-and-see approach. Many concerned parents are told, “Don’t worry” or “Wait and see.” But waiting is the worst thing you can do. You risk losing valuable time at an age where your child has the best chance for improvement. Furthermore, whether the delay is caused by autism or some other factor, developmentally delayed kids are unlikely to simply “grow out of” their problems. In order to develop skills in an area of delay, your child needs extra help and targeted treatment.

Trust your instincts. Ideally, your child’s doctor will take your concerns seriously and perform a thorough evaluation for autism or other developmental delays. But sometimes, even well-meaning doctors miss red flags or underestimate problems. Listen to your gut if it’s telling you something is wrong, and be persistent. Schedule a follow-up appointment with the doctor, seek a second opinion, or ask for a referral to a child development specialist.

Signs and symptoms of autism in babies and toddlers

If autism is caught in infancy, treatment can take full advantage of the young brain’s remarkable plasticity. Although autism is hard to diagnose before 24 months, symptoms often surface between 12 and 18 months. If signs are detected by 18 months of age, intensive treatment may help to rewire the brain and reverse the symptoms.

[Read: Autism Treatments, Therapies, and Interventions]

The earliest signs of autism involve the absence of typical behaviors—not the presence of atypical ones—so they can be tough to spot. In some cases, the earliest symptoms of autism are even misinterpreted as signs of a “good baby,” since the infant may seem quiet, independent, and undemanding. However, you can catch warning signs early if you know what to look for.

Some autistic infants don’t respond to cuddling, reach out to be picked up, or look at their mothers when being fed.

Early signs

Your baby or toddler doesn’t:

  • Make eye contact, such as looking at you when being fed or smiling when being smiled at.
  • Respond to their name, or to the sound of a familiar voice.
  • Follow objects visually or follow your gesture when you point things out.
  • Point or wave goodbye, or use other gestures to communicate.
  • Make noises to get your attention.
  • Initiate or respond to cuddling or reach out to be picked up.
  • Imitate your movements and facial expressions.
  • Play with other people or share interest and enjoyment.
  • Notice or care if you hurt yourself or experience discomfort.

The following delays warrant an immediate evaluation by your child’s pediatrician:

By 6 months: No big smiles or other warm, joyful expressions.

By 9 months: No back-and-forth sharing of sounds, smiles, or other facial expressions.

By 12 months: Lack of response to name.

By 12 months: No babbling or “baby talk.”

By 12 months: No back-and-forth gestures, such as pointing, showing, reaching, or waving.

By 16 months: No spoken words.

By 24 months: No meaningful two-word phrases that don’t involve imitating or repeating.

Signs and symptoms in older children

As children get older, the red flags for autism become more diverse. There are many warning signs and symptoms, but they typically revolve around impaired social skills, speech and language difficulties, non-verbal communication difficulties, and inflexible behavior.

Signs of social difficulties

  • Appears disinterested or unaware of other people or what’s going on around them.
  • Doesn’t know how to connect with others, play, or make friends.
  • Prefers not to be touched, held, or cuddled.
  • Doesn’t play “pretend” games, engage in group games, imitate others, or use toys in creative ways.
  • Has trouble understanding feelings or talking about them.
  • Doesn’t seem to hear when others talk to them.
  • Doesn’t share interests or achievements with others (drawings, toys).

Basic social interaction can be difficult for children with autism spectrum disorder. Many kids on the autism spectrum seem to prefer to live in their own world, aloof and detached from others.

Signs of speech and language difficulties

  • Speaks in an atypical tone of voice, or with an odd rhythm or pitch (e.g. ends every sentence as if asking a question).
  • Repeats the same words or phrases over and over, often without communicative intent.
  • Responds to a question by repeating it, rather than answering it.
  • Uses language incorrectly (grammatical errors, wrong words) or refers to him or herself in the third person.
  • Has difficulty communicating needs or desires.
  • Doesn’t understand simple directions, statements, or questions.
  • Takes what is said too literally (misses undertones of humor, irony, and sarcasm).

Children with autism spectrum disorder have difficulty with speech and language. Often, they start talking late.

Signs of nonverbal communication difficulties

  • Avoids eye contact.
  • Uses facial expressions that don’t match what they are saying
  • Doesn’t pick up on other people’s facial expressions, tone of voice, and gestures.
  • Makes very few gestures (such as pointing). May come across as cold or “robot-like.”
  • Reacts unusually to sights, smells, textures, and sounds. May be especially sensitive to loud noises. Can also be unresponsive to people entering/leaving, as well as efforts by others to attract the child’s attention.
  • Atypical posture, clumsiness, or eccentric ways of moving (e.g., walking exclusively on tiptoe).

Children with autism spectrum disorder have trouble picking up on subtle nonverbal cues and using body language. This makes the “give-and-take” of social interaction very difficult.

Signs of inflexibility

  • Follows a rigid routine (e.g., insists on taking a specific route to school).
  • Has difficulty adapting to any changes in schedule or environment (e.g., throws a tantrum if the furniture is rearranged or bedtime is at a different time than usual).
  • Unusual attachments to toys or strange objects such as keys, light switches, or rubber bands. Obsessively lines things up or arranges them in a certain order.
  • Preoccupation with a narrow topic of interest, often involving numbers or symbols (e.g., memorizing and reciting facts about maps, train schedules, or sports statistics).
  • Spends long periods watching moving objects such as a ceiling fan, or focusing on one specific part of an object such as the wheels of a toy car.
  • Repeats the same actions or movements over and over again, such as flapping hands, rocking, or twirling (known as self-stimulatory behavior, or “stimming”). Some researchers and clinicians believe that these behaviors may soothe children with autism more than stimulate them.

Children with autism spectrum disorder are often restricted, inflexible, and even obsessive in their behaviors, activities, and interests.

Causes of autism

Until recently, most scientists believed that autism is caused mostly by genetic factors. But groundbreaking new research indicates that environmental factors may also be important in the development of autism.

Babies may be born with a genetic vulnerability to autism that is then triggered by something in the external environment, either while he or she is still in the womb or sometime after birth.

It’s important to note that the environment, in this context, means anything outside the body. It’s not limited to things like pollution or toxins in the atmosphere. In fact, one of the most important environments appears to be the prenatal environment.

Prenatal factors that may contribute to autism

Taking antidepressants during pregnancy, especially in the first 3 months.

Nutritional deficiencies early in pregnancy, particularly not getting enough folic acid.

The age of the mother and father.

Complications at or shortly after birth, including very low birth weight and neonatal anemia

Maternal infections during pregnancy.

Exposure to chemical pollutants, such as metals and pesticides, while pregnant.

More research on these prenatal risk factors is needed, but if you’re pregnant or trying to conceive, it can’t hurt to take steps now to reduce your baby’s risk of autism.

Autism and vaccines

While you can’t control the genes your child inherits, or shield him or her from every environmental danger, there is one very important thing you can do to protect the health of your child: make sure he or she is vaccinated on schedule.

Despite a lot of controversy on the topic, scientific research does not support the theory that vaccines or their ingredients cause autism. Five major epidemiologic studies conducted in the U.S., UK, Sweden, and Denmark, found that children who received vaccines did not have higher rates of autism. Additionally, a major safety review by the Institute of Medicine failed to find any evidence supporting the connection. Other organizations that have concluded that vaccines are not associated with autism include the Centers for Disease Control and Prevention (CDC), the U.S. Food and Drug Administration (FDA), the American Academy of Pediatrics, and the World Health Organization (WHO).

Myths and facts about childhood vaccinations
Myth: Vaccines aren’t necessary.

Fact: Vaccines protect your child from many serious and potentially deadly diseases, including measles, meningitis, polio, tetanus, diphtheria, and whooping cough. These diseases are uncommon today because vaccines are doing their job. But the bacteria and viruses that cause these diseases still exist and can be passed on to children who aren’t immunized.

Myth: Vaccines cause autism.

Fact: Despite extensive research and safety studies, scientists and doctors have not found a link between childhood vaccinations and autism or other developmental problems. Children who are not vaccinated do not have lower rates of autism spectrum disorders.

Myth: Vaccines are given too early.

Fact: Early vaccination protects your child from serious diseases that are most likely to occur—and most dangerous—in babies. Waiting to immunize your baby puts him or her at risk. The recommended vaccination schedule is designed to work best with children’s immune systems at specific ages. A different schedule may not offer the same protection.

Myth: Too many vaccines are given at once.

Fact: You may have heard theories that the recommended vaccine schedule overloads young children’s immune systems and may even cause autism. But research shows that spacing out vaccinations doesn’t improve children’s health or lower their risk of autism, and as noted above, actually puts them at risk for potentially fatal diseases.

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What to do if you’re worried

If your child is developmentally delayed, or if you’ve observed other red flags for autism, schedule an appointment with your pediatrician right away. In fact, it’s a good idea to have your child screened by a doctor even if he or she is hitting the developmental milestones on schedule. The American Academy of Pediatrics recommends that all children receive routine developmental screenings, as well as specific screenings for autism at 9, 18, and 30 months of age.

Schedule an autism screening. A number of specialized screening tools have been developed to identify children at risk for autism. Most of these screening tools are quick and straightforward, consisting of yes-or-no questions or a checklist of symptoms. Your pediatrician should also get your feedback regarding your child’s behavior.

[Read: Helping Your Child with Autism Thrive]

See a developmental specialist. If your pediatrician detects possible signs of autism during the screening, your child should be referred to a specialist for a comprehensive diagnostic evaluation. Screening tools can’t be used to make a diagnosis, which is why further assessment is needed. A specialist can conduct a number of tests to determine whether or not your child has autism. Although many clinicians will not diagnose a child with autism before 30 months of age, they will be able to use screening techniques to determine when a cluster of symptoms associated with autism is present.

Seek early intervention services. The diagnostic process for autism is tricky and can sometimes take a while. But you can take advantage of treatment as soon as you suspect your child has developmental delays. Ask your doctor to refer you to early intervention services. Early intervention is a federally funded program for infants and toddlers with disabilities. Children who demonstrate several early warning signs may have developmental delays. They will benefit from early intervention whether or not they meet the full criteria for an autism spectrum disorder. In other words, there is more risk involved in the wait-and-see approach than in receiving early intervention.

Ted Hutman, Ph.D. is Assistant Clinical Professor in Psychiatry at the David Geffen School of Medicine at UCLA and a licensed clinical psychologist practicing in Santa Monica, CA.

Last updated: November 2020