What is Autism?

Autism, a brain disorder that affects 1 to 2 in 1,000 Americans, ¹ too often results in a lifetime of impaired thinking, feeling and social functioning-our most uniquely human attributes. Autism typically affects a person's ability to communicate, form relationships with others, and respond appropriately to the external world. The disorder becomes apparent in children generally by the age of 3. ²

Some people with autism can function at a relatively high level, with speech and intelligence intact. Others have serious cognitive impairments and language delays, and some never speak. In addition, individuals with autism may seem closed off and shut down, or locked into repetitive behaviors and rigid patterns of thinking. An infant with autism may avoid eye contact, seem deaf, and abruptly stop developing language. The child may act as if unaware of the coming and going of others, or physically attack and injure others without provocation. Infants with autism often remain fixated on a single item or activity, rock or flap their hands, seem insensitive to burns and bruises, and may even mutilate themselves. Although autism is about 3 to 4 times more common in boys, girls with the disorder tend to have more severe symptoms and greater cognitive impairment. ²

Individuals with autism often have symptoms of various co-occurring mental disorders, including ADHD, psychoses, depressive disorders, obsessive-compulsive disorder, and other anxiety disorders. ³ About one-third of children and adolescents with autism develop seizures.

Research Findings and Directions

The National Institute of Mental Health-in collaboration with the National Institute of Child Health and Human Development, the National Institute of Neurological Disorders and Stroke, and the National Institute of Deafness and other Communication Disorders-is searching for answers about the causes, diagnosis, prevention, and treatment of this devastating disorder. Research findings have made it possible to identify earlier those children who show signs of developing autism and thus to initiate early intervention, which can lead to improved cognitive and behavioral outcomes. ^4,5

Improved early diagnosis and differentiation of various forms of autism is a goal of brain imaging studies that are building a database on normal brain development in children. Scans of the normal structural and functional maturation of the brain will be compared with those from individuals with autism, speeding development of targeted treatments and evaluations of their effects. Yet even the most advanced scanners cannot substitute for post-mortem brain tissue. Brain banks, such as the Harvard Brain Tissue Resource Center, are working with families to arrange for tissue donation following the deaths of individuals with autism.

While it is known that heredity plays a major role in complex disorders like autism, the identification of specific genes that confer vulnerability to such disorders has proven extremely difficult. ⁶ Once autism-linked genes are identified, however, scientists will bring to bear sophisticated research tools to find out what activates them, what brain components they code for, and how they affect behavior. The prospect of acquiring such molecular knowledge holds great hope for the engineering of new therapies.

Evidence suggests that unaffected family members may share with their ill relatives genes that predispose for milder behavioral characteristics that are qualitatively similar to those of autism. ⁷ For example, some relatives of people with autism may have mild social, language, or reading problems. Family members also may share telltale neurochemical signatures that may be implicated in the disorder. ⁸ Researchers are studying such families to characterize these behavioral and biological traits, in hopes of tracing the variations in the genetic blueprint that contribute to autism.

Treatments

The behavioral and cognitive functioning of individuals with autism can improve with the help of psychosocial and pharmacological interventions. ⁴ Among psychosocial treatments, intensive, sustained special education programs and behavior therapy early in life can increase the ability of children with autism to acquire language and the ability to learn. ^4,5 NIMH-funded research teams are evaluating the effectiveness of parent-training interventions that are tailored to the particular characteristics of the child and family.

In adults with autism, some studies have found beneficial effects of the antidepressant medications clomipramine and fluoxetine. ^9,10 There is also evidence that the antipsychotic medication haloperidol can be helpful; however, the risk of serious side effects is significant in children. ¹¹

The increasing use of psychotropic medications to treat autism in children has spotlighted an urgent need for more studies of such drugs in youths. A network of five NIMH-supported research centers that combine expertise in psychopharmacology and psychiatry are evaluating the atypical antipsychotic risperidone for reducing aggressive self-injurious behavior in children with autism. Other NIMH research is investigating valproate for diminishing this behavior in adolescents with autism. Studies are examining dose range and regimen of medications, and their mechanisms of action, safety, efficacy, and effects on cognition, behavior, and development.

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All material in this fact sheet is in the public domain and may be copied or reproduced without permission from the Institute. Citation of the source is appreciated.

NIH Publication No. 01-4590

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References

¹ Bryson SE, Smith IM. Epidemiology of autism: prevalence, associated characteristics, and service delivery. Mental Retardation and Developmental Disabilities Research Reviews, 1998; 4: 97-103.

² Fombonne E. Epidemiology of autism and related conditions. In: Volkmar FR, ed. Autism and Pervasive Development Disorders. Cambridge, England: Cambridge University Press, 1998; 32-63.

³ Volkmar F, Cook EH Jr, Pomeroy J, et al. Practice parameters for the assessment and treatment of children, adolescents, and adults with autism and other pervasive developmental disorders. American Academy of Child and Adolescent Psychiatry Working Group on Quality Issues. Journal of the American Academy of Child and Adolescent Psychiatry, 1999; 38(12 Suppl): 32S-54S.

⁴ Bristol MM, Cohen DJ, Costello EJ, et al. State of the science in autism: report to the National Institutes Health. Journal of Autism and Developmental Disorders, 1996; 26(2): 121-54.

⁵ McEachin JJ, Smith T, Lovaas OI. Long-term outcome for children with autism who received early intensive behavioral treatment. American Journal of Mental Retardation, 1993; 97(4): 359-72; discussion 373-91.

⁶ NIMH Genetics Workgroup. Genetics and mental disorders. NIH Publication No. 98-4268. Rockville, MD: National Institute of Mental Health, 1998.

⁷ Piven J, Palmer P, Jacobi D, et al. Broader autism phenotype: evidence from a family history study of multiple-incidence autism families. American Journal of Psychiatry, 1997; 154(2): 185-90.

⁸ Cook EH. Autism: review of neurochemical investigation. Synapse, 1990; 6(3): 292-308.

⁹ McDougle CJ, Naylor ST, Cohen DJ, et al. A double-blind, placebo-controlled study of fluvoxamine in adults with autistic disorder. Archives of General Psychiatry, 1996; 53(11): 1001-8.

¹⁰ Gordon CT, State RC, Nelson JE, et al. A double-blind comparison of clomipramine, desipramine, and placebo in the treatment of autistic disorder. Archives of General Psychiatry, 1993; 50(6): 441-7.

¹¹ Campbell M, Armenteros JL, Malone RP, et al. Neuroleptic-related dyskinesias in autistic children: a prospective, longitudinal study. Journal of the American Academy of Child and Adolescent Psychiatry, 1997; 36(6): 835-43.