Autism spectrum disorders (ASD) are characterized by social-interaction difficulties, communication challenges and a tendency to engage in repetitive behaviors. However, symptoms and their severity vary widely across these three core areas. Taken together, they may result in relatively mild challenges for someone on the high functioning end of the autism spectrum. For others, symptoms may be more severe, as when repetitive behaviors and lack of spoken language interfere with everyday life.
As illustrated by the graph on the left, the basic symptoms of autism are often accompanied other medical conditions and challenges. These, too, can vary widely in severity.
While autism is usually a life-long condition, all children and adults benefit from interventions, or therapies, that can reduce symptoms and increase skills and abilities. Although it is best to begin intervention as soon as possible, the benefits of therapy can continue throughout life.
Typically developing infants are social by nature. They gaze at faces, turn toward voices, grasp a finger and even smile by 2 to 3 months of age. By contrast, most children who develop autism have difficulty engaging in the give-and-take of everyday human interactions. By 8 to 10 months of age, many infants who go on to develop autism are showing some symptoms such as failure to respond to their names, reduced interest in people and delayed babbling. By toddlerhood, many children with autism have difficulty playing social games, don't imitate the actions of others and prefer to play alone. They may fail to seek comfort or respond to parents' displays of anger or affection in typical ways.
Research suggests that children with autism are attached to their parents. However the way they express this attachment can be unusual. To parents, it may seem as if their child is disconnected. Both children and adults with autism also tend to have difficulty interpreting what others are thinking and feeling. Subtle social cures such as a smile, wave or grimace may convey little meaning. To a person who misses these social cues, a statement like "Come here!" may mean the same thing, regardless of whether the speaker is smiling and extending her arms for a hug or frowning and planting her fists on her hips. Without the ability to interpret gestures and facial expressions, the social world can seem bewildering.
Many persons with autism have similar difficulty seeing things from another person's perspective. Most five year olds understand that other people have different thoughts, feelings and goals than they have. A person with autism may lack such understanding. This, in turn, can interfere with the ability to predict or understand another person's actions.
It is common - but not universal - for those with autism to have difficulty regulating emotions. This can take the form of seemingly "immature" behavior such as crying or having outbursts in inappropriate situations. It can also lead to disruptive and physically aggressive behavior. The tendency to "lose control" may be particularly pronounced in unfamiliar, overwhelming or frustrating situations. Frustration can also result in self-injurious behaviors such as head banging, hair pulling or self-biting.
By age three, most children have passed predictable milestones on the path to learning language. One of the earliest is babbling. By the first birthday, most typically developing toddlers say a word or two, turn and look when they hear their names, point to objects they want or want to show to someone (not all cultures use pointing in this way). When offered something distasteful, they can make clear - by sound or expression - that the answer is "no."
By contrast, young children with autism tend to be delayed in babbling and speaking and learning to use gestures. Some infants who later develop autism coo and babble during the first few months of life before losing these communicative behaviors. Others experience significant language delays and don't begin to speak until much later. With therapy, however, most people with autism do learn to use spoken language and all can learn to communicate.
Many nonverbal or nearly nonverbal children and adults learn to use communication systems such as pictures, sign language, electronic word processors or even speech-generating devices.
When language begins to develop, the person with autism may use speech in unusual ways. Some have difficulty combining words into meaningful sentences. They may speak only single words or repeat the same phrase over and over. Some go through a stage where they repeat what they hear verbatim (echolalia).
Some mildly affected children exhibit only slight delays in language or even develop precocious language and unusually large vocabularies - yet have difficulty sustaining a conversation. Some children and adults with autism tend to carry on monologues on a favorite subject, giving others little chance to comment. In other words, the ordinary "give and take" of conversation proves difficult. Some children with ASD with superior language skills tend to speak like little professors, failing to pick up on the "kid-speak" that's common among their peers.
Another common difficulty is the inability to understand body language, tone of voice and expressions that aren't meant to be taken literally. For example, even an adult with autism might interpret a sarcastic "Oh, that's just great!" as meaning it really is great.
Conversely, someone affected by autism may not exhibit typical body language. Facial expressions, movements and gestures may not match what they are saying. Their tone of voice may fail to reflect their feelings. Some use a high-pitched sing-song or a flat, robot-like voice. This can make it difficult for others know what they want and need. This failed communication, in turn, can lead to frustration and inappropriate behavior (such as screaming or grabbing) on the part of the person with autism. Fortunately, there are proven methods for helping children and adults with autism learn better ways to express their needs. As the person with autism learns to communicate what he or she wants, challenging behaviors often subside.
Unusual repetitive behaviors and/or a tendency to engage in a restricted range of activities are another core symptom of autism. Common repetitive behaviors include hand-flapping, rocking, jumping and twirling, arranging and rearranging objects, and repeating sounds, words, or phrases. Sometimes the repetitive behavior is self-stimulating, such as wiggling fingers in front of the eyes.
The tendency to engage in a restricted range of activities can be seen in the way that many children with autism play with toys. Some spend hours lining up toys in a specific way instead of using them for pretend play. Similarly, some adults are preoccupied with having household or other objects in a fixed order or place. It can prove extremely upsetting if someone or something disrupts the order. Along these lines many children and adults with autism need and demand extreme consistency in their environment and daily routine. Slight changes can be extremely stressful and lead to outbursts.
Repetitive behaviors can take the form of intense preoccupations, or obsessions. These extreme interests can prove all the more unusual for their content (e.g. fans, vacuum cleaners or toilets) or depth of knowledge (e.g. knowing and repeating astonishingly detailed information about Thomas the Tank Engine or astronomy). Older children and adults with autism may develop tremendous interest in numbers, symbols, dates or science topics.
Some children with autism have an identifiable genetic condition that affects brain development. These genetic disorders include Fragile X syndrome, Angelman syndrome, tuberous sclerosis and chromosome 15 duplication syndrome and other single-gene and chromosomal disorders. While further study is needed, single gene disorders appear to affect 15 to 20 percent of those with ASD. Some of these syndromes have characteristic features or family histories, the presence of which may prompt your doctor to refer to a geneticist or neurologist for further testing. The results can help guide treatment, awareness of associated medical issues and life planning.
GI distress is common among persons with autism, and affects up to 85 percent of children with ASD. These conditions range in severity from a tendency for chronic constipation or diarrhea to inflammatory bowel disease. Pain caused by GI issues can prompt behavioral changes such as increased self soothing (rocking, head banging, etc) or outbursts of aggression or self-injury. Conversely, appropriate treatment can improve behavior and quality of life. Please see our treatment section on "Gastrointestinal Disorders." It includes discussion of popular dietary interventions. Thanks to donor support, Autism Speaks continues to fund research into causes and treatments.
Seizure disorders, including epilepsy, occur in as many as 39 percent of those with autism. It is more common in people with autism who also have intellectual disability than those without. Someone with autism may experience more than one type of seizure. The easiest to recognize is the grand mal, or tonic-clonic, seizure. Others include "petit mal" seizures (when a person temporarily appears "absent") and subclinical seizures, which may be apparent only with electroencephalogram (EEG) testing.
Seizures associated with autism tend to start in either early childhood or adolescence. But they may occur at any time. If you are concerned that you or your child may be having seizures, it is important to raise the issue with your doctor for possible referral to a neurologist for further evaluation.
Sleep problems are common among children and adolescents with autism and may likewise affect many adults.
Many persons with autism have unusual responses to sensory input. They have difficulty processing and integrating sensory information, or stimuli, such as sights, sounds smells, tastes and/or movement. They may experience seemingly ordinary stimuli as painful, unpleasant or confusing.
Some of those with autism are hypersensitive to sounds or touch, a condition also known as sensory defensiveness. Others are under-responsive, or hyposensitive. An example of hypersensitivity would be the inability to tolerate wearing clothing, being touched or being in a room with normal lighting. Hyposensitivity can include failure to respond when one's name is called. Many sensory processing problems can be addressed with occupational therapy and/or sensory integration therapy.
Pica is a tendency to eat things that are not food. Eating non-food items is a normal part of development between the ages of 18 and 24 months. However, some children and adults with autism and other developmental disabilities continue to eat items such as dirt, clay, chalk or paint chips. For this reason, it is important to test for elevated blood levels of lead in those who persistently mouth fingers or objects that might be contaminated with this common environmental toxin.