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Developmental Disabilities > Autism Information Center > Symptoms



As the name "autism spectrum disorders" suggests, ASDs cover a wide range of behaviors and abilities. People who have an ASD, like all people, are very different in how they act and what they can do. No two people with ASDs will have the same symptoms.

People with ASDs have serious impairments with social, emotional, and communication skills. They might repeat certain behaviors again and again and might have trouble changing their daily routine. Many people with ASDs also have different ways of learning, paying attention, or reacting to things. ASDs begin before the age of 3 and last throughout a person's life. It is important to note that some people without ASDs might also have some of these symptoms. But for people with ASDs, the impairment is bad enough to make life very challenging.

Social Skills
Social impairments are one of the main problems in all of the autism spectrum disorders (ASDs). People with ASDs do not have merely social “difficulties” like shyness. The social impairments they have are bad enough to cause serious problems in everyday life. These social problems are often combined with the other areas of deficit, such as communication skills and unusual behaviors and interests. For instance, the inability to have a back-and-forth conversation is both a social and a communication problem.

Typical infants are very interested in the world and people around them. By the first birthday, a typical toddler tries to imitate words, uses simple gestures such as waving “bye bye,” grasps fingers, and smiles at people. But the young child with autism may have a very hard time learning to interact with other people. One way very young children interact with others is by imitating actions—for instance, clapping when mom claps.  Children with ASDs may not do this, and they may not show interest in social games like peek-a-boo or pat-a-cake. Although the ability to play pat-a-cake is not an important life skill, the ability to imitate is. We learn all the time by watching others and by doing what they do—especially in new situations and in the use of language.

People with ASDs might not interact with others the way most people do. They might not be interested in other people at all. Some might want friends but have social problems that make those relationships difficult. They might not make eye contact and might just want to be alone. Many children with ASDs have a very hard time learning to take turns and share—much more so than other children. This can make other children unwilling to play with them.

People with ASDs may have problems with expression, so they might have trouble understanding other people's feelings or talking about their own feelings. Many people with ASDs are very sensitive to being touched and might not want to be held or cuddled. Self-stimulatory behaviors, common among people with ASDs, may seem odd to others or make them uncomfortable, causing them to shy away from a person with an ASD. 

Social issues such as trouble interacting with peers, saying whatever comes to mind even if it’s inappropriate, difficulty adapting to change, and even poor grooming habits can sometimes make it hard for adults with ASDs  to get and/or  keep a job at their intellectual level. Anxiety and depression, which affect some people with ASDs, can make existing social impairments even harder to manage.

Social skills that many people learn by watching others may need to be taught directly to people with ASDs. When deciding what to teach, remember the social value of learning independent living skills such as toilet training and other basic grooming skills (bathing, tooth brushing, dressing appropriately, etc.). Click here to learn more about autism treatment.

Because children and adolescents with ASDs are “different,” and because they are often very literal and sometimes naïve and overly trusting, they are often the target of bullies and might be easily taken advantage of. It is very important to teach all children from a very young age to be tolerant and accepting of differences. It is also important to teach children and adolescents with ASDs about personal safety and tell them to go to a parent, teacher, or other trusted adult if they need help. 

There are many strategies and curriculum supplements for teaching children and adolescents with and without ASDs about bullying and other personal safety issues.  These can be found by visiting a local bookstore, searching an online book seller, or by contacting a publishing company that specializes in disability-specific and/or education publications. Teachers and health care professionals are often good resources for this type of information as well.

For more examples of the social issues related to ASDs, click here.

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Each person with an ASD has different communication skills. Some people may have relatively good verbal skills, with only a slight language delay with impaired social skills. Others may be not speak at all or have limited ability or interest in communicating and interacting with others. About 40% of children with ASDs do not talk at all. Another 25%–30% of children with autism have some words at 12 to 18 months of age and then lose them.[1] Others may speak, but not until later in childhood.

People with ASDs who do speak may use language in unusual ways. They may not be able to combine words into meaningful sentences. Some people with ASDs speak only single words, while others repeat the same phrases over and over. Some children repeat what others say, a condition called echolalia. The repeated words might be said right away or at a later time. For example, if you ask someone with an ASD, "Do you want some juice?" he or she might repeat "Do you want some juice?" instead of answering your question. Although many children without ASDs go through a stage where they repeat what they hear, it normally passes by age 3. Some people with ASDs can speak well but may have a hard time listening to what other people say.

People with ASDs may have a hard time using and understanding gestures, body language, or tone of voice. For example, people with ASDs might not understand what it means to wave goodbye. Facial expressions, movements, and gestures may not match what they are saying. For instance, people with ASDs might smile while saying something sad. They might say "I" when they mean "you," or vice versa. Their voices might sound flat, robot-like, or high-pitched. People with ASDs might stand too close to the people they are talking to, or might stick with one topic of conversation for too long. They might talk a lot about something they really like, rather than have a back-and-forth conversation with someone. Some children with relatively good language skills speak like little adults, failing to pick up on the “kid-speak” that is common in their peers.

For more examples of the communication issues related to ASDs, click here.

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Repeated Behaviors and Routines
Unusual behaviors such as repetitive motions may make social interactions difficult.

Repetitive motions are actions repeated over and over again. They can involve part of the body or the entire body or even an object or toy. For instance, people with ASDs may spend a lot of time repeatedly flapping their arms or rocking from side to side. They might repeatedly turn a light on and off or spin the wheels of a toy car in front of their eyes. These types of activities are known as self-stimulation or “stimming.”

People with ASDs often thrive on routine. A change in the normal pattern of the day—like a stop on the way home from school—can be very upsetting or frustrating to people with ASDs. They may “lose control” and have a “melt down” or tantrum, especially if they’re in a strange place.

Also, some people with ASDs develop routines that might seem unusual or unnecessary. For example, a person might try to look in every window he or she walks by in a building or may always want to watch a video in its entirety—from the previews at the beginning through the credits at the end. Not being allowed to do these types of routines may cause severe frustration and tantrums. 

For more examples of repetitive behaviors and routines related to ASDs, click here.

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Additional Disabilities and Conditions

Children with an ASD may also have one of several other developmental disabilities such as mental retardation/intellectual impairment, epilepsy, fragile X syndrome, or tuberous sclerosis.  A study published by CDC in 2003 found that 62% of the children who had an ASD had at least one additional disability or epilepsy (glossary). Of those children, 68% had mental retardation/intellectual impairment, 8% had epilepsy, 5% had cerebral palsy, 1% had vision impairment, and 1% had hearing loss. Other studies show that 5% to 38% of adults with ASDs have epilepsy.[2] And some people with ASDs may have mental disorders such as depression and anxiety. Although these additional conditions may not be key to the ASD diagnosis, they do add challenges for the person with ASD and his or her family.  

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Associated Features
People with ASDs might have a range of other behaviors associated with the disorder. These include hyperactivity, short attention span, impulsivity, aggressiveness, self-injury, and temper tantrums. They may have unusual responses to touch, smell, sound, and other sensory input. For example, they may over- or under-react to pain or to a loud noise. They may have abnormal eating habits. For instance, some people with ASDs limit their diet to only a few foods, and others may eat nonfood items like dirt or rocks (this is called pica). They may also have odd sleeping habits. People with ASDs may seem to have abnormal moods or emotional reactions. They may laugh or cry at unusual times or show no emotional response at times you would expect one. They may not be afraid of dangerous things, and they could be fearful of harmless objects. People with ASDs may also have gastrointestinal issues such as chronic constipation or diarrhea. 

It is important to remember that children with ASDs can get sick or injured just like children without ASDs. Regular medical and dental exams should be part of a child’s intervention plan. Often it is hard to tell if a child’s behavior is related to the ASD or is caused by a separate health problem. For instance, head banging could be a symptom of an ASD, or it could be a sign that the child is having headaches. In those cases, a careful physical exam is important.

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Pattern of Development

Some children with ASDs show hints of future problems within the first few months of life. In others, symptoms may not show up until 24 months or later. Studies have shown that one third to half of parents of children with ASDs noticed a problem before their child’s first birthday, and nearly 80%–90% saw problems by 24 months. Some children with ASDs seem to develop normally until 18–24 months of age and then they stop gaining new language and social skills, or they lose the skills they had.

Children with ASDs develop at different rates in different areas of growth. They may have delays in language, social, and learning skills, while their motor skills are about the same as other children their age. They might be very good at putting puzzles together or solving computer problems, but they might have trouble with social activities like talking or making friends. Children with ASDs might also learn a hard skill before they learn an easy one. For example, a child might be able to read long words but not be able to tell you what sound a "b" makes.

Children develop at their own pace, so it can be difficult to tell exactly when a child will learn a particular skill. But there are age-specific developmental milestones used to measure a child’s social and emotional progress in the first few years of life. To learn more about developmental milestones, visit “Learn the Signs. Act Early,” a campaign designed by CDC and a coalition of partners to teach parents, health care professionals, and child care providers about early childhood development, including possible ”red flags” for autism spectrum disorders.

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Possible Red Flags for Autism Spectrum Disorders

Children and adults with an autism spectrum disorder might:

  • Not play "pretend" games (pretend to "feed" a doll)

  • Not point at objects to show interest (point at an airplane flying over)

  • Not look at objects when another person points at them

  • Have trouble relating to others or not have an interest in other people at all

  • Avoid eye contact and want to be alone

  • Have trouble understanding other people's feelings or talking about their own feelings

  • Prefer not to be held or cuddled or might cuddle only when they want to

  • Appear to be unaware when other people talk to them but respond to other sounds

  • Be very interested in people, but not know how to talk to, play with, or relate to them

  • Repeat or echo words or phrases said to them, or repeat words or phrases in place of normal language (echolalia)

  • Have trouble expressing their needs using typical words or motions

  • Repeat actions over and over again

  • Have trouble adapting to changes in routine

  • Have unusual reactions to the way things smell, taste, look, feel, or sound

  • Lose skills they once had (for instance, stop saying words they were once using)

Talk to your child’s doctor or nurse if your child loses skills at any age.

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What can I do if I think my child has an ASD?
If you or your doctor thinks there could be a problem, ask for a referral to see a developmental pediatrician or other specialist. You can also call your local early intervention agency (for children under 3) or public school (for children 3 and older). To find out who to speak to in your area, check with the National Dissemination Center for Children with Disabilities.

Today, the main research-based  treatment for ASDs is intensive structured teaching of skills, often called behavioral intervention. It is very important to start this intervention as early as possible to help your child reach his or her full potential. Acting early can make a real difference! To find out more about treatment and therapy, click here.

Even if your child has not been diagnosed with an ASD, he or she may be eligible for early intervention services. The Individuals with Disabilities Education Act (IDEA) says that children under the age of 3 who are at risk of having serious developmental delays may be eligible for services. These services are provided through an early intervention system in your state. Through this system, you can ask for an evaluation. To learn more about early intervention, click here.

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Disclaimer: We have provided a link to these sites because they have information that may be of interest to you. CDC does not necessarily endorse the views or information presented on these sites. Furthermore, CDC does not endorse any commercial products or information that may be presented or advertised on these sites.

[1] Johnson, C.P. Early Clinical Characteristics of Children with Autism.  In: Gupta, V.B. ed: Autistic Spectrum Disorders in Children.  New York: Marcel Dekker, Inc., 2004:85-123.

[2] Tuchman,R., and Rapin, I. Epilepsy in autism. Lancet Neurology 2002; 1(6):352-358.


Date: November 01, 2007
Content source: National Center on Birth Defects and Developmental Disabilities


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