Autism is a brain disorder that is associated with a wide range of developmental problems, especially in communication and social interaction.
According to the American Psychiatric Association, autism is classified as a type of autism spectrum disorder (ASD). These disorders are characterized by problems with communication, social interaction, as well as unusual, repetitive behaviors.
Some professionals use a broader term, called pervasive development disorder (PDD), to describe autism. In addition to autism, there are four other disorders that qualify as PDDs: Asperger's syndrome, childhood disintegrative disorder, pervasive developmental disorder-not otherwise specified (PDD-NOS), and Rett syndrome.
The cause of autism remains unknown.
Although most children are not diagnosed with autism until they are around preschool age, the first signs of autism generally appear between 12 and 18 months of age. The severity of symptoms varies among patients. Some patients are able to live independently once they become adults, while others may need lifelong support.
A minority of autistic patients may also be considered savants. These patients are autistic but express extraordinary mental abilities in a very specific area. Autistic savants often have exceptional skills with numbers, art, or music. Not all savants are autistic. However, the number of autistic savants far exceeds the number of non-autistic savants.
As many as 1.5 million Americans may have autism. Researchers estimate that one to six out of every 1,000 children have autism. The number of children diagnosed with autism has increased over the years. However, it is unclear whether more children are developing the disorder or better diagnostic techniques have helped doctors identify the disorder in more patients.
For unknown reasons, boys are three to four times more likely to develop autism than girls.
In the 1940s, when autism was first described, most autistic patients were institutionalized. Today, however, most autistic patients are able to live with their families. Although there is currently no cure for autism, treatments and therapies have been shown to help autistic patients live healthy, relatively normal lives. Regardless of how severe the patient's symptoms are, appropriate treatment and education can help autistic patients become integrated into their communities.

Related Terms

ASDS, Asperger's syndrome, autistic, autism screening questionnaire, autism spectrum disorders, brain disorder, CHAT, checklist for autism in toddlers, childhood disintegrative disorder, developmental disorder, epilepsy, fragile X syndrome, genetic disease, genetic disorder, Heller's syndrome, language pathologist, neurologic, neurological, neurological disease, neurological disorder, PDD, pervasive development disorders, physical therapist, psychiatrist, psychologist, Rett syndrome, savant, speech pathologist, social worker, Tourette's syndrome, tuberous sclerosis.

other types of pervasive developmental disorders (pdds)

Asperger's syndrome: Patient's with Asperger's syndrome have many of the same symptoms as autistic patients, in terms of problems with social interaction and communication. However, patients with Asperger's syndrome have normal intelligence and verbal skills. Although these patients typically have strong verbal and grammar skills, they usually have other language problems, such as being too literal and/or having difficulty understanding non-verbal communications, such as body language. Other symptoms may include motor skill problems (e.g. clumsy movements), obsessive or repetitive routines and schedules, and sensitivity to sensory information (e.g. sound, light, or taste).
Childhood disintegrative disorder: Childhood disintegrative disorder, also called Heller's syndrome, is a rare condition in which children develop normally until they are about three or four years old. However, as they get older, children begin to experience a dramatic loss of social and communication skills, as well as motor skills. Patients may also develop stereotypical movements, such as hand wringing or flapping. These patients may develop specific routines or rituals and they may not respond well to changes or transitions. Some patients may become catatonic, which means they maintain a fixed posture or body position.
Childhood disintegrative disorder is sometimes confused with late-onset autism because both of these disorders involve normal development followed by a loss of learned skills. However, autism generally occurs at an earlier age. Also, patients with childhood disintegrative disorder typically suffer from a much more dramatic loss of skills and greater likelihood of mental retardation than autistic patients.
Pervasive developmental disorder-not otherwise specified (PDD-NOS): Pervasive developmental disorder-not otherwise specified (PDD-NOS) is a term used to describe patients who meet most, but not all, of the criteria for a PDD. Although these patients have many of the same symptoms associated with a PDD, they cannot be definitively diagnosed with a specific type of PDD.
Rett syndrome: Rett syndrome is a progressive brain disorder that mostly affects females. Infants with Rett syndrome appear to develop normally at first, but over time, they stop developing and lose most of their previously developed skills. Eventually, these patients become intellectually disabled.
Symptoms of Rett syndrome become noticeable when the patient is between the ages of three months and three years old. Patients typically lose purposeful hand movements (e.g. reaching or grasping for things) and they are no longer able to speak. Patients have difficulty balancing and poor coordination. This often prevents the patient from walking on his/her own. Patients may develop stereotypical hand movements, such as hand wringing or clapping. Breathing problems, including hyperventilation, breath holding, or apnea, may develop. Patients may also develop anxiety and social behavioral problems.

when to visit a doctor

Early diagnosis and prompt treatment has been shown to help improve autistic patients' long-term prognoses.
According to the National Institute of Child Health and Human Development (NICHHD), children who experience certain developmental problems should visit their doctors.
Children who have not made gestures, such as waving or pointing by the age of 12 months, should visit their doctors.
Children who have not said a single word by the age of 16 months should visit their doctors.
Children who have not said two-word phrases by 24 months of age should visit their doctors.
Children who experience any loss of language or social skills at any age should visit their doctors.