The severity of symptoms varies greatly, but all people with autism have some core symptoms in the areas of:
Social interactions and relationships. Symptoms may include:
- Significant problems developing nonverbal communication skills, such as eye-to-eye gazing, facial expressions, and body posture.
- Failure to establish friendships with children the same age.
- Lack of interest in sharing enjoyment, interests, or achievements with other people.
- Lack of empathy. People with autism may have difficulty understanding another person's feelings, such as pain or sorrow.
Verbal and nonverbal communication. Symptoms may include:
- Delay in, or lack of, learning to talk. As many as 40% of people with autism never speak.1
- Problems taking steps to start a conversation. Also, people with autism have difficulties continuing a conversation after it has begun.
- Stereotyped and repetitive use of language. People with autism often repeat over and over a phrase they have heard previously (echolalia).
- Difficulty understanding their listener's perspective. For example, a person with autism may not understand that someone is using humor. They may interpret the communication word for word and fail to catch the implied meaning.
Limited interests in activities or play. Symptoms may include:
- An unusual focus on pieces. Younger children with autism often focus on parts of toys, such as the wheels on a car, rather than playing with the entire toy.
- Preoccupation with certain topics. For example, older children and adults may be fascinated by video games, trading cards, or license plates.
- A need for sameness and routines. For example, a child with autism may always need to eat bread before salad and insist on driving the same route every day to school.
- Stereotyped behaviors. These may include body rocking and hand flapping.
Symptoms during childhood
Symptoms of autism are usually noticed first by parents and other caregivers sometime during the child's first 3 years. Although autism is present at birth (congenital), signs of the disorder can be difficult to identify or diagnose during infancy. Parents often become concerned when their toddler does not like to be held; does not seem interested in playing certain games, such as peekaboo; and does not begin to talk. Sometimes, a child with autism will start to talk at the same time as other children the same age, then lose his or her language skills. Parents also may be confused about their child's hearing abilities. It often seems that a child with autism does not hear, yet at other times, he or she may appear to hear a distant background noise, such as the whistle of a train.
With early and intensive treatment, most children improve their ability to relate to others, communicate, and help themselves as they grow older. Contrary to popular myths about children with autism, very few are completely socially isolated or "live in a world of their own."
Symptoms during teen years
During the teen years, the patterns of behavior often change. Many teens gain skills but still lag behind in their ability to relate to and understand others. Puberty and emerging sexuality may be more difficult for teens who have autism than for others this age. Teens are at an increased risk for developing problems related to depression, anxiety, and epilepsy.
Symptoms in adulthood
Some adults with autism are able to work and live on their own. The degree to which an adult with autism can lead an independent life is related to intelligence and ability to communicate. At least 33% are able to achieve at least partial independence.2
Some adults with autism need a lot of assistance, especially those with low intelligence who are unable to speak. Part- or full-time supervision can be provided by residential treatment programs. At the other end of the spectrum, adults with high-functioning autism are often successful in their professions and able to live independently, although they typically continue to have some difficulties relating to other people. These individuals usually have average to above-average intelligence.
Many people with autism have symptoms similar to attention deficit hyperactivity disorder (ADHD). But these symptoms, especially problems with social relationships, are more severe for people with autism.
About 10% of people with autism have some form of savant skills—special limited gifts such as memorizing lists, calculating calendar dates, drawing, or musical ability.1
Many people with autism have unusual sensory perceptions. For example, they may describe a light touch as painful and deep pressure as providing a calming feeling. Others may not feel pain at all. Some people with autism have strong food likes and dislikes and unusual preoccupations.
Sleep problems occur in about 40% to 70% of people with autism.3
Almost half of the children who have autism spectrum disorders tend to "wander off" from a caregiver, or "elope." For many caregivers of these children, elopement is one of the most stressful behaviors they must learn to cope with. Studies show that behavioral assessment interventions, such as applied behavioral analysis, may reduce the number of times a child wanders off.4
Autism is one of several types of autism spectrum disorders (ASDs), once known as pervasive developmental disorders. It is not unusual for autism to be confused with other ASDs, such as Asperger's syndrome, or to have overlapping symptoms. A similar condition is called unspecified neurodevelopmental disorder. This condition occurs when children display similar behaviors but do not meet the criteria for autism. Also, other conditions with similar symptoms may also have similarities to or occur with autism.