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Autism – Definition and Signs

Autism Spectrum Disorder (ASD) is a complex developmental disability that can cause significant social, communication, and behavioral challenges.

WHAT IS AUTISM?

Autism Spectrum Disorder (ASD) is a complex developmental disability that can cause significant social, communication, and behavioral challenges. People with ASD have difficulty understanding verbal and nonverbal communication and learning appropriate ways of relating to others and events. No two people with ASD are the same. Some of the behaviors associated with autism include:

  • Delayed learning of language
  • Difficulty making eye contact or holding a conversation
  • Difficulty with Executive Functioning, which relates to reasoning and planning
  • Narrow, intense interests
  • Poor motor skills and sensory sensitivities

A person with autism might have many of these behaviors or just a few. A diagnosis of autism spectrum disorder is applied based on an analysis of all behaviors and their severity.

While typically diagnosed in childhood, it is a lifelong condition that spans every age. ASD’s most obvious signs can typically be detected between two and three years of age, but sometimes appear as early as eighteen months. Some children don’t receive a final diagnosis until much older.

In 2013, the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-d) was published. In it, the diagnostic criteria for autism spectrum disorder (ASD) was revised.

Autism Spectrum Disorder 299.00 (F84.0)

  1. Persistent deficits in social communication and social interaction across multiple contexts, as manifested by the following, currently or by history (examples are illustrative, not exhaustive, see text):
    1. Deficits in social-emotional reciprocity, ranging, for example, from abnormal social approach and failure of normal back-and-forth conversation; to reduced sharing of interests, emotions, or affect; to failure to initiate or respond to social interactions.
    2. Deficits in nonverbal communicative behaviors used for social interaction, ranging, for example, from poorly integrated verbal and nonverbal communication; to abnormalities in eye contact and body language or deficits in understanding and use of gestures; to a total lack of facial expressions and nonverbal communication.
    3. Deficits in developing, maintaining, and understanding relationships, ranging, for example, from difficulties adjusting behavior to suit various social contexts; to difficulties in sharing imaginative play or in making friends; to absence of interest in peers.

    Specify current severity: Severity is based on social communication impairments and restricted repetitive patterns of behavior (see Table 2).

  2. Restricted, repetitive patterns of behavior, interests, or activities, as manifested by at least two of the following, currently or by history (examples are illustrative, not exhaustive; see text):
    1. Stereotyped or repetitive motor movements, use of objects, or speech (e.g., simple motor stereotypies, lining up toys or flipping objects, echolalia, idiosyncratic phrases).
    2. Insistence on sameness, inflexible adherence to routines, or ritualized patterns or verbal nonverbal behavior (e.g., extreme distress at small changes, difficulties with transitions, rigid thinking patterns, greeting rituals, need to take same route or eat food every day).
    3. Highly restricted, fixated interests that are abnormal in intensity or focus (e.g, strong attachment to or preoccupation with unusual objects, excessively circumscribed or perseverative interest).
    4. Hyper- or hyporeactivity to sensory input or unusual interests in sensory aspects of the environment (e.g., apparent indifference to pain/temperature, adverse response to specific sounds or textures, excessive smelling or touching of objects, visual fascination with lights or movement).

    Specify current severity: Severity is based on social communication impairments and restricted, repetitive patterns of behavior (see Table 2).

  3. Symptoms must be present in the early developmental period (but may not become fully manifest until social demands exceed limited capacities, or may be masked by learned strategies in later life).
  4. Symptoms cause clinically significant impairment in social, occupational, or other important areas of current functioning.
  5. These disturbances are not better explained by intellectual disability (intellectual developmental disorder) or global developmental delay. Intellectual disability and autism spectrum disorder frequently co-occur; to make comorbid diagnoses of autism spectrum disorder and intellectual disability, social communication should be below that expected for general developmental level.

SIGNS OF AUTISM – ACT EARLY

If you have concerns about your child’s development, it’s important to act early. Contact your pediatrician or a developmental pediatrician about getting an assessment of your child’s skills and challenges. This is key in helping them reach their full potential.

The CDC encourages parents and caregivers to monitor children’s development to ensure their attain developmental milestones (Developmental Milestones):



How your child plays, learns, speaks, acts, and moves offers important clues about your child’s development. Developmental milestones are things most children can do by a certain age.Check the milestones your child has reached by the end of 2 months. Take this with you and talk with your child’s doctor at every visit about the milestones your child has reached and what to expect next.

What most babies do by this age:

Social and Emotional

  • Begins to smile at people
  • Can briefly calm herself (may bring hands to mouth and suck on hand)
  • Tries to look at parent

Language/Communication

  • Coos, makes gurgling sounds
  • Turns head toward sounds

Cognitive (learning, thinking, problem-solving)

  • Pays attention to faces
  • Begins to follow things with eyes and recognize people at a distance
  • Begins to act bored (cries, fussy) if activity doesn’t change

Movement/Physical Development

  • Can hold head up and begins to push up when lying on tummy
  • Makes smoother movements with arms and legs

Act early by talking to your child’s doctor if your child:

  • Doesn’t respond to loud sounds
  • Doesn’t watch things as they move
  • Doesn’t smile at people
  • Doesn’t bring hands to mouth
  • Can’t hold head up when pushing up when on tummy


How your child plays, learns, speaks, acts, and moves offers important clues about your child’s development. Developmental milestones are things most children can do by a certain age.

Check the milestones your child has reached by the end of 4 months. Take this with you and talk with your child’s doctor at every visit about the milestones your child has reached and what to expect next.

What most babies do by this age:

Social and Emotional

  • Smiles spontaneously, especially at people
  • Likes to play with people and might cry when playing stops
  • Copies some movements and facial expressions, like smiling or frowning

Language/Communication

  • Begins to babble
  • Babbles with expression and copies sounds he hears
  • Cries in different ways to show hunger, pain, or being tired

Cognitive (learning, thinking, problem-solving)

  • Lets you know if he is happy or sad
  • Responds to affection
  • Reaches for toy with one hand
  • Uses hands and eyes together, such as seeing a toy and reaching for it
  • Follows moving things with eyes from side to side
  • Watches faces closely
  • Recognizes familiar people and things at a distance

Movement/Physical Development

  • Holds head steady, unsupported
  • Pushes down on legs when feet are on a hard surface
  • May be able to roll over from tummy to back
  • Can hold a toy and shake it and swing at dangling toys
  • Brings hands to mouth
  • When lying on stomach, pushes up to elbows

Act early by talking to your child’s doctor if your child:

  • Doesn’t watch things as they move
  • Doesn’t smile at people
  • Can’t hold head steady
  • Doesn’t coo or make sounds
  • Doesn’t bring things to mouth
  • Doesn’t push down with legs when feet are placed on a hard surface
  • Has trouble moving one or both eyes in all directions


Check the milestones your child has reached by the end of 6 months. Take this with you and talk with your child’s doctor at every visit about the milestones your child has reached and what to expect next.

What most babies do by this age:

Social and Emotional

  • Knows familiar faces and begins to know if someone is a stranger
  • Likes to play with others, especially parents
  • Responds to other people’s emotions and often seems happy
  • Likes to look at self in a mirror

Language/Communication

  • Responds to sounds by making sounds
  • Strings vowels together when babbling (“ah,” “eh,” “oh”) and likes taking turns with parent while making sounds
  • Responds to own name
  • Makes sounds to show joy and displeasure
  • Begins to say consonant sounds (jabbering with “m,” “b”)

Cognitive (learning, thinking, problem-solving)

  • Looks around at things nearby
  • Brings things to mouth
  • Shows curiosity about things and tries to get things that are out of reach
  • Begins to pass things from one hand to the other

Movement/Physical Development

  • Rolls over in both directions (front to back, back to front)
  • Begins to sit without support
  • When standing, supports weight on legs and might bounce
  • Rocks back and forth, sometimes crawling backward before moving forward

Act early by talking to your child’s doctor if your child:

  • Doesn’t try to get things that are in reach
  • Shows no affection for caregivers
  • Doesn’t respond to sounds around him
  • Has difficulty getting things to mouth
  • Doesn’t make vowel sounds (“ah”, “eh”, “oh”)
  • Doesn’t roll over in either direction
  • Doesn’t laugh or make squealing sounds
  • Seems very stiff, with tight muscles
  • Seems very floppy, like a rag doll



Check the milestones your child has reached by the end of 9 months. Take this with you and talk with your child’s doctor at every visit about the milestones your child has reached and what to expect next.

What most babies do by this age:

Social and Emotional

  • May be afraid of strangers
  • May be clingy with familiar adults
  • Has favorite toys

Language/Communication

  • Understands “no”
  • Makes a lot of different sounds like “mamamama” and “bababababa”
  • Copies sounds and gestures of others
  • Uses fingers to point at things

Cognitive (learning, thinking, problem-solving)

  • Watches the path of something as it falls
  • Looks for things she sees you hide
  • Plays peek-a-boo
  • Puts things in his mouth
  • Moves things smoothly from one hand to the other
  • Picks up things like cereal o’s between thumb and index finger

Movement/Physical Development

  • Stands, holding on
  • Can get into sitting position
  • Sits without support
  • Pulls to stand
  • Crawls

Act early by talking to your child’s doctor if your child:

  • Doesn’t bear weight on legs with support
  • Doesn’t sit with help
  • Doesn’t babble (“mama”, “baba”, “dada”)
  • Doesn’t play any games involving back-and-forth play
  • Doesn’t respond to own name
  • Doesn’t seem to recognize familiar people
  • Doesn’t look where you point
  • Doesn’t transfer toys from one hand to the other


Check the milestones your child has reached by his or her 1st birthday. Take this with you and talk with your child’s doctor at every visit about the milestones your child has reached and what to expect next.

What most children do by this age:

Social and Emotional

  • Is shy or nervous with strangers
  • Cries when mom or dad leaves
  • Has favorite things and people
  • Shows fear in some situations
  • Hands you a book when he wants to hear a story
  • Repeats sounds or actions to get attention
  • Puts out arm or leg to help with dressing
  • Plays games such as “peek-a-boo” and “pat-a-cake”

Language/Communication

  • Responds to simple spoken requests
  • Uses simple gestures, like shaking head “no” or waving “bye-bye”
  • Makes sounds with changes in tone (sounds more like speech)
  • Says “mama” and “dada” and exclamations like “uh-oh!”
  • Tries to say words you say

Cognitive (learning, thinking, problem-solving)

  • Explores things in different ways, like shaking, banging, throwing
  • Finds hidden things easily
  • Looks at the right picture or thing when it’s named
  • Copies gestures
  • Starts to use things correctly; for example, drinks from a cup, brushes hair
  • Bangs two things together
  • Puts things in a container, takes things out of a container
  • Lets things go without help
  • Pokes with index (pointer) finger
  • Follows simple directions like “pick up the toy”

Movement/Physical Development

  • Gets to a sitting position without help
  • Pulls up to stand, walks holding on to furniture (“cruising”)
  • May take a few steps without holding on
  • May stand alone

Act early by talking to your child’s doctor if your child:

  • Doesn’t crawl
  • Can’t stand when supported
  • Doesn’t search for things that she sees you hide
  • Doesn’t say single words like “mama” or “dada”
  • Doesn’t learn gestures like waving or shaking head
  • Doesn’t point to things
  • Loses skills he once had


Check the milestones your child has reached by his or her 2nd birthday. Take this with you and talk with your child’s doctor at every visit about the milestones your child has reached and what to expect next.

What most children do by this age:

Social and Emotional

  • Copies others, especially adults and older children
  • Gets excited when with other children
  • Shows more and more independence
  • Shows defiant behavior (doing what he has been told not to)
  • Plays mainly beside other children, but is beginning to include other children, such as in chase games

Language/Communication

  • Points to things or pictures when they are named
  • Knows names of familiar people and body parts
  • Says sentences with 2 to 4 words
  • Follows simple instructions
  • Repeats words overheard in conversation
  • Points to things in a book

Cognitive (learning, thinking, problem-solving)

  • Finds things even when hidden under two or three covers
  • Begins to sort shapes and colors
  • Completes sentences and rhymes in familiar books
  • Plays simple make-believe games
  • Builds towers of 4 or more blocks
  • Might use one hand more than the other
  • Follows two-step instructions such as “Pick up your shoes and put them in the closet.”
  • Names items in a picture book such as a cat, bird, or dog

Movement/Physical Development

  • Stands on tiptoe
  • Kicks a ball
  • Begins to run
  • Climbs onto and down from furniture without help
  • Walks up and down stairs holding on
  • Throws ball overhand
  • Makes or copies straight lines and circles

Act early by talking to your child’s doctor if your child:

  • Doesn’t use 2-word phrases (for example, “drink milk”)
  • Doesn’t know what to do with common things, like a brush, phone, fork, spoon
  • Doesn’t copy actions and words
  • Doesn’t follow simple instructions
  • Doesn’t walk steadily
  • Loses skills she once had


Check the milestones your child has reached by his or her 3rd birthday. Take this with you and talk with your child’s doctor at every visit about the milestones your child has reached and what to expect next.

What most children do by this age:

Social and Emotional

  • Copies adults and friends
  • Shows affection for friends without prompting
  • Takes turns in games
  • Shows concern for crying friend
  • Understands the idea of “mine” and “his” or “hers”
  • Shows a wide range of emotions
  • Separates easily from mom and dad
  • May get upset with major changes in routine
  • Dresses and undresses self

Language/Communication

  • Follows instructions with 2 or 3 steps
  • Can name most familiar things
  • Understands words like “in,” “on,” and “under”
  • Says first name, age, and sex
  • Names a friend
  • Says words like “I,” “me,” “we,” and “you” and some plurals (cars, dogs, cats)
  • Talks well enough for strangers to understand most of the time
  • Carries on a conversation using 2 to 3 sentences

Cognitive (learning, thinking, problem-solving)

  • Can work toys with buttons, levers, and moving parts
  • Plays make-believe with dolls, animals, and people
  • Does puzzles with 3 or 4 pieces
  • Understands what “two” means
  • Copies a circle with pencil or crayon
  • Turns book pages one at a time
  • Builds towers of more than 6 blocks
  • Screws and unscrews jar lids or turns door handle

Movement/Physical Development

  • Climbs well
  • Runs easily
  • Pedals a tricycle (3-wheel bike)
  • Walks up and down stairs, one foot on each step

Act early by talking to your child’s doctor if your child:

  • Falls down a lot or has trouble with stairs
  • Drools or has very unclear speech
  • Can’t work simple toys (such as peg boards, simple puzzles, turning handle)
  • Doesn’t speak in sentences
  • Doesn’t understand simple instructions
  • Doesn’t play pretend or make-believe
  • Doesn’t want to play with other children or with toys
  • Doesn’t make eye contact
  • Loses skills he once had


Check the milestones your child has reached by his or her 4th birthday. Take this with you and talk with your child’s doctor at every visit about the milestones your child has reached and what to expect next.

What most children do by this age:

Social and Emotional

  • Enjoys doing new things
  • Plays “Mom” and “Dad”
  • Is more and more creative with make-believe play
  • Would rather play with other children than by himself
  • Cooperates with other children
  • Often can’t tell what’s real and what’s make-believe
  • Talks about what she likes and what she is interested in

Language/Communication

  • Knows some basic rules of grammar, such as correctly using “he” and “she”
  • Sings a song or says a poem from memory such as the “Itsy Bitsy Spider” or the “Wheels on the Bus”
  • Tells stories
  • Can say first and last name

Cognitive (learning, thinking, problem-solving)

  • Names some colors and some numbers
  • Understands the idea of counting
  • Starts to understand time
  • Remembers parts of a story
  • Understands the idea of “same” and “different”
  • Draws a person with 2 to 4 body parts
  • Uses scissors
  • Starts to copy some capital letters
  • Plays board or card games
  • Tells you what he thinks is going to happen next in a book

Movement/Physical Development

  • Hops and stands on one foot up to 2 seconds
  • Catches a bounced ball most of the time
  • Pours, cuts with supervision, and mashes own food

Act early by talking to your child’s doctor if your child:

  • Can’t jump in place
  • Has trouble scribbling
  • Shows no interest in interactive games or make-believe
  • Ignores other children or doesn’t respond to people outside the family
  • Resists dressing, sleeping, and using the toilet
  • Can’t retell a favorite story
  • Doesn’t follow 3-part commands
  • Doesn’t understand “same” and “different”
  • Doesn’t use “me” and “you” correctly
  • Speaks unclearly
  • Loses skills he once had


Check the milestones your child has reached by his or her 5th birthday. Take this with you and talk with your child’s doctor at every visit about the milestones your child has reached and what to expect next.

What most children do by this age:

Social and Emotional

  • Wants to please friends
  • Wants to be like friends
  • More likely to agree with rules
  • Likes to sing, dance, and act
  • Is aware of gender
  • Can tell what’s real and what’s make-believe
  • Shows more independence (for example, may visit a next-door neighbor by himself [adult supervision is still needed])
  • Is sometimes demanding and sometimes very cooperative

Language/Communication

  • Speaks very clearly
  • Tells a simple story using full sentences
  • Uses future tense; for example, “Grandma will be here.”
  • Says name and address

Cognitive (learning, thinking, problem-solving)

  • Counts 10 or more things
  • Can draw a person with at least 6 body parts
  • Can print some letters or numbers
  • Copies a triangle and other geometric shapes
  • Knows about things used every day, like money and food

Movement/Physical Development

  • Stands on one foot for 10 seconds or longer
  • Hops; may be able to skip
  • Can do a somersault
  • Uses a fork and spoon and sometimes a table knife
  • Can use the toilet on her own
  • Swings and climbs

Act early by talking to your child’s doctor if your child:

  • Doesn’t show a wide range of emotions
  • Shows extreme behavior (unusually fearful, aggressive, shy or sad)
  • Unusually withdrawn and not active
  • Is easily distracted, has trouble focusing on one activity for more than 5 minutes
  • Doesn’t respond to people, or responds only superficially
  • Can’t tell what’s real and what’s make-believe
  • Doesn’t play a variety of games and activities
  • Can’t give first and last name
  • Doesn’t use plurals or past tense properly
  • Doesn’t talk about daily activities or experiences
  • Doesn’t draw pictures
  • Can’t brush teeth, wash and dry hands, or get undressed without help
  • Loses skills he once had