Het Autisme(mijn handicap) / Austistic my handicap

Autisme (Under the Dutch page is an English page)

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Historisch overzicht

Hoewel de eerste beschrijving van autisme stamt van halverwege de negentiende eeuw in Engeland, wordt doorgaans de Amerikaanse kinderpsychiater Leo Kanner als eerste beschrijver van het infantiel of vroegkinderlijk autisme beschouwd. Hij nam het woord over van de Zwitserse psychiater Eugen Bleuler (1857-1939). Deze gebruikte de term echter voor schizofrene patiënten die moeite hadden om met andere mensen in contact te treden.

In 1944 beschreef Hans Asperger, een Oostenrijks psychiater, een hoger functionerende vorm van autisme, die nu bekend staat als het syndroom van Asperger. Het artikel was onafhankelijk van dat van Kanner geschreven en in dezelfde periode, maar Asperger schreef in het Duits en kreeg weinig aandacht.

In de DSM III en verdere (1980-) wordt autisme ingedeeld in de categorie pervasieve ontwikkelingsstoornissen. Deze groep wordt vaak als synoniem van autistische stoornissen gebruikt.

Sinds de eerste opname in het handboek zijn enige andere ziektebeelden beschreven. Wel vaak samen genoemd met PDD; McDD is niet opgenomen in de DSM.

 Definitie van autisme

Benadering

Autisme wordt bestudeerd door verscheidene takken van de wetenschap. Naargelang het vakgebied kan de omschrijving van autisme behoorlijk verschillen. In de psychologische vakliteratuur dient (observeerbaar) gedrag als basis voor (de diagnose van) autisme. In deze gedragsstudies bestaan verschillende scholen waarvan de Britse de dominante is in Europa.

De neurowetenschap houdt zich bezig met hersenfuncties. Eén van de theorieën die worden onderzocht, is dat stoornissen in spiegelneuronsystemen met autistische verschijnselen samenhangen.[1]

Triade

Autisme is een pervasieve ontwikkelingsstoornis, d.w.z. een ontwikkelingsstoornis die het hele functioneren van de persoon beïnvloedt.

Drie kenmerkende eigenschappen, die in voortdurende wisselwerking met elkaar staan, zijn:

  • afwijkingen in communicatie (zowel verbaal als nonverbaal)
  • afwijkingen in de verbeelding (blindheid voor de context) en
  • afwijkingen in sociale interacties (met name met betrekking tot wederkerigheid).

De stoornis, gecombineerd met een andere denkstijl, kan in onaangepaste omgevingen leiden tot een handicap. Per individu kan de mate en het aantal (zeer weinig personen vertonen álle symptomen) waarin de kenmerken van autisme zich voordoen sterk verschillen. De handicap kan dus in min of meerdere mate aanwezig zijn. Dit hangt onder andere samen met het karakter van de persoon, van zijn ontwikkelingsleeftijd en van omgevingsfactoren.

Communicatie

Communicatie is gebaseerd op betekenisverlening. Waar taal meestal geen probleem vormt voor mensen met autisme en een normale begaafdheid, is het toekennen van betekenis aan woorden dat vaak wel.

In de communicatie onderscheidt men: de expressieve communicatie (het uiten) en de receptieve communicatie (het begrijpen). Voor beide soorten geldt dat voor mensen met autisme de techniek van de taal (onder andere zinsopbouw en woordenschat) begrijpelijk is, maar dat de sociale aspecten van communicatie de moeilijkheid vormen. Hieraan ligt de problematiek van onder meer samenhang aanbrengen binnen de taal en het beperkte inlevings- en verplaatsingsvermogen ten grondslag.

In de praktijk betekent dit dat mensen met autisme goed kunnen omgaan met alles wat 'letterlijk' en concreet is. Problemen doen zich voor, als de andere partij bijvoorbeeld woordgrapjes of sarcastische, spreekwoordelijke of emotioneel gekleurde begrippen gaat gebruiken. Hoe abstracter de begrippen worden, hoe moeilijker het wordt voor mensen met autisme.

Verbeelding

Verbeelding is hetgeen mensen gebruiken om een betekenis toe te kennen aan een bepaald symbool. De meeste mensen kunnen betekenissen en symbolen op velerlei wijzen toepassen en vanuit deze basis die toepassingen ook weer in nieuwe situaties te gebruiken, zonder alles opnieuw te moeten leren.

Voor mensen met autisme geldt dit niet. Het gebruik van de betekenis van een symbool in situatie A, helpt hen niet voor het gebruik van hetzelfde symbool in situatie B. Bij kinderen kan dit bijvoorbeeld betekenen, dat zij in de badkamer hun tanden poetsen, omdat het gebruik van de tandenborstel gekoppeld is aan de badkamer. Wil men dan dat het kind in de keuken zijn tanden poetst, zal het kind opnieuw betekenis aan de tandenborstel moeten leren toekennen. De tandenborstel had namelijk enkel een betekenis in combinatie met de badkamer ('tanden poetsen') en niet met de keuken.

Doordat mensen met autisme in stukjes denken (fragmentarisch) is het voor hen ook moeilijk om het grote geheel te zien. Als het beeld dat ze kennen verandert, zullen ze opnieuw beginnen met het waarnemen van alle individuele kenmerken van het beeld, en met het inpuzzelen van deze kenmerken wederom komen tot het grote geheel.

Sociale interacties

De stoornis binnen de sociale interactie is vaak het opvallendste kenmerk van autisme. Mensen verwachten van elkaar een bepaalde vorm van socialiteit, zeker als het gaat om de opbouw van een relatie, waarin ook wederkerigheid wordt verwacht.

Voor mensen met autisme kunnen dit soort zaken erg moeilijk zijn, omdat er voor sociale interacties geen duidelijke en vaste regels zijn en zij dus weinig houvast hebben. Door hun probleem met empathie en "theory of mind" is het ook erg moeilijk voor hen om zich respectievelijk in de gevoelens en gedachtegang van de ander te verplaatsen. Ook zijn sommige mensen met autisme zelf niet goed in het verwoorden van hun gevoelens, omdat deze veel te abstract zijn om daar een concrete betekenis aan toe te kennen

Cognitieve tekorten

Daarnaast is het aanleren van deze zaken moeilijk, omdat mensen met autisme ook problemen hebben op het kennisniveau. Deze problemen zijn te onderscheiden in:

  1. Centrale coherentiestoornis (problemen met het aanbrengen van een samenhang)
  2. Beperking van de theory of mind (problemen met het inleven of verplaatsen in een ander individu)
  3. Problemen met executieve functies (problemen met de uitvoerende functie)

 Autisme versus autistiform gedrag

Het is voor de praktijk van belang onderscheid te maken tussen personen met autisme en personen met autistiform gedrag.

Waar bij personen met autisme de volledige triade aan kenmerken aanwezig is, doet zich bij mensen met autistiform gedrag slechts een enkel kenmerk van autisme voor. Autistiform gedrag kan hinderlijk zijn, maar behoeft niet direct te leiden tot ongewenste gedragingen. Bij mensen met een verstandelijke beperking kan autistiform gedrag eveneens voorkomen.

 De diagnose

Omschrijving en belang

De diagnose is de erkenning door een autismedeskundige of een diagnosecentrum van het autisme op basis van gedrags- of biologische criteria. De diagnose kan de basis vormen voor verwerking, ondersteuning en leren. Voor de verwerking is vooral de erkenning van de diagnose door de omgeving erg belangrijk. Voor ondersteuning vragen overheidsinstanties een diagnose ter staving. Eén van de meest voorkomende aandoening die dezelfde symptomen oplevert (differentiële diagnose) is verwaarlozing. Kinderen die erg verwaarloosd zijn (bv kastkinderen) kunnen gedrag vertonen dat lijkt op autisme maar dit is zeker geen autisme.

 Diagnosecentra

In Vlaanderen zijn mogelijke diagnosecentra onder andere: een revalidatiecentrum, Centrum voor Ontwikkelingsstoornissen, Psychiatrisch Centrum, Centrum voor Geestelijke Gezondheidszorg, Psychiatrische Afdeling van een Algemeen Ziekenhuis (PAAZ) of een Centrum voor Gespecialiseerde Voorlichting bij Beroepskeuze. Diensten als een consultatiebureau Kind en Gezin en een Centrum voor leerlingenbegeleiding zijn goed geplaatst om (vermoeden van) autisme te signaleren en door te verwijzen naar meer een meer gespecialiseerd diagnosecentrum.

In Nederland kan men terecht bij de GGD, het RIAGG of bij een autismecentrum in de regio (zoals bijvoorbeeld het Dr. Leo Kannerhuis of C.A.J. de Steiger).

 Diagnose op basis van gedrag

Bij het onderzoek naar een diagnose van autisme kijkt de deskundige vooral naar de (sociale) ontwikkelingsgeschiedenis, de medische voorgeschiedenis, taalontwikkeling, stereotiep gedrag/interesses/handelingen, cognitief functioneren, neuropsychologische eigenschappen (zie ook Sally en Anne), motorische vaardigheden, zelfredzaamheid, en psychisch en sociaal-emotioneel functioneren.

Hoewel diagnostische instrumenten zoals gedragsvragenlijsten en observatieschalen de betrouwbaarheid verhogen, blijft de juiste diagnose dus sterk afhankelijk van de klinische ervaring en de intuïtie van de diagnosticus in het herkennen van een bepaald gedragspatroon. Met andere woorden, er is nog steeds een aanzienlijk subjectief element in de diagnostiek.

Toch maakt men voor de medische beeldvorming wel gebruik van een SPECT-scan of MRI-scan.

Diagnose op basis van biologische kenmerken

  • Genetisch onderzoek. Wat autisme betreft zijn er nog veel vermoedens, maar er is wetenschappelijk nooit iets gevonden. De theorie is dat autisme wordt veroorzaakt door een complexe interactie van verschillende genen . Een genetische screening om autisme op te sporen is er nog lang niet. Autisme kan nog steeds een andere oorzaak hebben dan een genetische afwijking bijvoorbeeld vergifiging tijdens de zwangerschap. Gedragsobservaties blijven voorlopig de algemeen aanvaarde basis voor het stellen van een diagnose van autisme als psychische aandoening. Dit kan al op jonge leeftijd.
  • Stofwisselingsonderzoek: Aan sommige universiteiten meent men autisme te kunnen vaststellen op basis van urinetesten naar de stof IAG. Toch is dit net als het genetisch onderzoek nog in een embryonale onderzoeksfase.

Autisme lijkt wel genetisch bepaald. De kans op autisme neemt immers flink toe als de stoornis in de familie voorkomt. Autisme komt vaker voor bij mannen. Autisme is een sociale stoornis en vrouwen zijn biologisch gezien ook meer socialer dan mannen. Vrouwen hebben meer DNA en zijn ook genetisch minder kwetsbaar. Hoewel de kans klein is dat een echte autist zich voorplant zijn er wel studies geweest die vonden dat vaders van autisten vaak technische beroepen erop na hielden en vaak een beetje een "loner" waren.

Bij wie komt autisme voor?

Tot voor enkele jaren, toen men enkel het klassiek autisme als ‘echt’ beschouwde, werd aangenomen dat autisme bij 1 op 2200 mensen voorkwam. (Sommige cijfers zeggen 1 op de 10.000).

Het Steunpunt Expertisenetwerken Vlaanderen spreekt van 1 op 165. In Vlaanderen zou dat neerkomen op 36.000 mensen met een stoornis binnen het autismespectrum, dus om meer mensen dan met een louter verstandelijke beperking. De uitbreiding van de definitie en de verbetering van de diagnose zijn de twee belangrijkste redenen waarom dit cijfer zo is veranderd.

Het Vlaamse Autisme Centraal geeft aan dat 1 op 200 mensen zich binnen het autismespectrum bevinden en 1 op 1000 klassiek autisme hebben.

Een op vier mensen met autisme zou vrouw zijn, maar een lagere intelligentie hebben. Vooral in de groep van normaal begaafden lijken mannen oververtegenwoordigd te zijn. Dit is echter niet heel zeker, het zou kunnen dat vrouwen, en zeker normaal begaafde vrouwen, minder kans hebben een diagnose te krijgen. [2]

 Ondersteuning & verwerking

Eens de diagnose gesteld, rijst de vraag hoe erop te reageren. Aan het ene uiterste bevinden zich mensen die te vinden zijn voor de volledige behandeling van autisme. Zij vinden dat mensen met autisme alleen door ondersteuning op maat (onder andere therapie) gelukkig en zelfstandig kunnen leven en hun omgeving moeten ontlasten. Het andere uiterste vindt dat mensen met autisme gerespecteerd moeten worden in hun eigenheid. De maatschappij moet veranderen en autismevriendelijker worden.

Doorgaans begint ondersteuning met herkenning van de mogelijkheden en een vroegtijdige diagnose. Voor de meeste mensen met autisme helpt een autismevriendelijke (concrete & rustige) omgeving en ondersteuning op vlak van onderwijs (bijvoorbeeld GON-begeleiding of inclusief onderwijs) en werk (arbeidstrajectbegeleiding) heel wat om zonder conflicten samen te leven.

Ondersteuning voor de omgeving is vaak de meest laagdrempelige hulp. Duidelijkheid over de diagnose, informatie- en ervaringsuitwisseling en inclusief handelen van hulpverleners helpen de omgeving in de omgang met mensen met autisme. Dit gebeurt onder meer via thuisbegeleiding.

In sommige gevallen is er ook behandeling nodig. Reguliere behandelingsvormen vertrekken op basis van het diagnoserapport en werken meestal op de triade interactie-communicatie-interesses.

De bekendste voorbeelden van algemene benaderingen zijn gedragstherapie en het stimulus-responsmodel.

Meer specifieke benaderingen bestaan uit

  • therapieën met de sociale interactie centraal (bedoeling is de sociale ontwikkeling te begeleiden en te stimuleren),
  • therapieën met de communicatie centraal (bedoeling is het opstandig gedrag functioneel te maken en mensen aan te zetten tot communicatie (bijvoorbeeld Pivotal Response Training),
  • therapieën met het stereotyp gedrag & interessepatroon centraal (bedoeling is in te spelen op de typerende beperkte belangstellingswereld, de rigiditeit in routines en rituelen, en stereotype gedragingen).

De meer alternatieve vormen van behandelingen kunnen gericht zijn op beïnvloeding van het gedrag, de hersenactiviteit stimuleren, of de spiritualiteit en/of mystieke kant, of kunnen specifiek gericht zijn op het kind of de autistische stoornis zelf.

In alle gevallen is het nuttig om meer informatie over autisme te verzamelen om tot een betere zelfkennis te komen. Ook is lotgenotencontact zeer goed voor de ontwikkeling. Hiervoor zijn diverse instanties zoals Vereniging PAS (Personen uit het Autisme Spectrum) (welke zich richt op volwassenen met autisme) en de NVA (Nederlandse Vereniging voor Autisme (welke zich vooral richt op ouders met autistische kinderen).

Comorbiditeit

Er zijn eerst en vooral bijkomende problemen die niet typisch autistisch zijn maar vaak voorkomen, zoals ongewone reacties op zintuiglijke prikkels (hypersensiviteit of hyposensitiviteit), afwijkende motoriek, extreme en schijnbaar onlogische angsten, non-specifieke gedragsproblemen, een disharmonisch ontwikkelingsprofiel en een opvallende vaardigheid op een bepaald vlak (tekenen, musiceren, een geheugen voor data, hoofdrekenen of vroegtijdig kunnen lezen), de idiot savant.

Daarnaast zijn er ook verscheidene comorbide stoornissen (die samen met autisme optreden).
Comorbide stoornissen [3] zijn onder meer:

 Voetnoten

  1. ^ Mirella Dapretto, Understanding emotions in others: mirror neuron dysfunction in children with autism spectrum disorders, Nature Neuroscience, Vol. 9, No. 1, pp. 28-30, 2006-01
  2. ^ Deze cijfers worden soms betwijfeld vanuit het vermoeden dat er nog een aantal mensen met hoogfunctionerend autisme zou zijn die (nog) geen diagnose hebben gehad. Het zou gaan om een groep mensen van middelbare en hogere leeftijd.
    Sinds de jaren tachtig van vorige eeuw, met de opkomst van de autismespectrumtheorie, is de psychologische diagnosticering rond autisme immers veel grover en breder geworden. Voor die tijd hadden uitsluitend mensen met autistische stoornis recht op het label 'autisme'. Met de groeiende bekendheid van het werk van Hans Asperger is ook de definitie van autisme verruimd. Mensen die voorheen andere diagnoses kregen, of die geen erkenning kregen voor hun last, kunnen nu aanspraak maken op een diagnose, erkenning en ondersteuning.
  3. ^ . De percentages hieronder hebben betrekking op de personen die in het begin van de 21e eeuw een diagnose autisme(spectrumstoornis) hebben (gekregen). Naarmate meer mensen met een normale of hogere begaafdheid deze diagnose krijgen, zullen deze veranderen.

Autism

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Autism

Classification and external resources

Young red-haired boy facing away from camera, stacking a seventh can atop a column of six food cans on the kitchen floor. An open pantry contains many more cans.
Repetitively stacking or lining up objects may indicate autism.

ICD-10

F84.0

ICD-9

299.00

OMIM

209850

DiseasesDB

1142

MedlinePlus

001526

eMedicine

med/3202  ped/180

MeSH

[1]

Autism is a brain development disorder characterized by impaired social interaction and communication, and by restricted and repetitive behavior. These signs all begin before a child is three years old.[1] Autism involves many parts of the brain; how this occurs is not well understood.[2] The two other autism spectrum disorders (ASD) are Asperger syndrome, which lacks delays in cognitive development and language, and PDD-NOS, diagnosed when full criteria for the other two disorders are not met.[3]

Autism has a strong genetic basis, although the genetics of autism are complex and it is unclear whether ASD is explained more by rare mutations, or by rare combinations of common genetic variants.[4] In rare cases, autism is strongly associated with agents that cause birth defects.[5] Controversies surround other proposed environmental causes, such as heavy metals, pesticides or childhood vaccines;[6] the vaccine hypotheses are biologically implausible and lack convincing scientific evidence.[7] The prevalence of ASD is about 6 per 1,000 people, with about four times as many males as females. The number of people known to have autism has increased dramatically since the 1980s, partly due to changes in diagnostic practice; the question of whether actual prevalence has increased is unresolved.[8]

Parents usually notice signs in the first two years of their child's life. Although early behavioral or cognitive intervention can help children gain self-care, social, and communication skills, there is no known cure.[9] Not many children with autism live independently after reaching adulthood, though some become successful.[10] An autistic culture has developed, with some individuals seeking a cure and others believing autism should be tolerated as a difference and not treated as a disorder.[11]

[edit] Characteristics

Autism is a highly variable brain development disorder[12] that first appears during infancy or childhood, and generally follows a steady course without remission.[13] Overt symptoms gradually begin after the age of six months, become established by age two or three years,[14] and tend to continue through adulthood, although often in more muted form.[15] It is distinguished not by a single symptom, but by a characteristic triad of symptoms: impairments in social interaction; impairments in communication; and restricted interests and repetitive behavior. Other aspects, such as atypical eating, are also common but are not essential for diagnosis.[16] Autism's individual symptoms occur in the general population and appear not to associate highly, without a sharp line separating pathologically severe from common traits.[17]

[edit] Social development

Social deficits distinguish autism and the related autism spectrum disorders (ASD; see Classification) from other developmental disorders.[15] People with autism have social impairments and often lack the intuition about others that many people take for granted. Noted autistic Temple Grandin described her inability to understand the social communication of neurotypicals, or people with normal neural development, as leaving her feeling "like an anthropologist on Mars".[18]

Unusual social development becomes apparent early in childhood. Autistic infants show less attention to social stimuli, smile and look at others less often, and respond less to their own name. Autistic toddlers differ more strikingly from social norms; for example, they have less eye contact and turn taking, and are more likely to communicate by manipulating another person's hand.[19] Three- to five-year-old autistic children are less likely to exhibit social understanding, approach others spontaneously, imitate and respond to emotions, communicate nonverbally, and take turns with others. However, they do form attachments to their primary caregivers.[20] They display moderately less attachment security than usual, although this feature disappears in children with higher mental development or less severe ASD.[21] Older children and adults with ASD perform worse on tests of face and emotion recognition.[22]

Contrary to common beliefs, autistic children do not prefer being alone. Making and maintaining friendships often proves to be difficult for those with autism. For them, the quality of friendships, not the number of friends, predicts how lonely they feel. Functional friendships, such as those resulting in invitations to parties, may affect their quality of life more deeply.[23]

There are many anecdotal reports, but few systematic studies, of aggression and violence in individuals with ASD. The limited data suggest that, in children with mental retardation, autism is associated with aggression, destruction of property, and tantrums. A 2007 study interviewed parents of 67 children with ASD and reported that about two-thirds of the children had periods of severe tantrums and about one-third had a history of aggression, with tantrums significantly more common than in children with a history of language impairment.[24] A 2008 Swedish study found that, of individuals aged 15 or older discharged from hospital with a diagnosis of ASD, those who committed violent crimes were significantly more likely to have other psychopathological conditions such as psychosis.[25]

[edit] Communication

About a third to a half of individuals with autism do not develop enough natural speech to meet their daily communication needs.[26] Differences in communication may be present from the first year of life, and may include delayed onset of babbling, unusual gestures, diminished responsiveness, and vocal patterns that are not synchronized with the caregiver. In the second and third years, Children with Autism have less frequent and less diverse babbling, consonants, words, and word combinations; their gestures are less often integrated with words. Children with ASD are less likely to make requests or share experiences, and are more likely to simply repeat others' words (echolalia)[27][28] or reverse pronouns.[29] Joint attention seems to be necessary for functional speech, and deficits in joint attention seem to distinguish infants with ASD:[3] for example, they may look at a pointing hand instead of the pointed-at object,[19][28] and they consistently fail to point at objects in order to comment on or share an experience.[3] Autistic children may have difficulty with imaginative play and with developing symbols into language.[27][28]

In a pair of studies, high-functioning children with Autism aged 8–15 performed equally well, and adults better than individually matched controls at basic language tasks involving vocabulary and spelling. Both Autism groups performed worse than controls at complex language tasks such as figurative language, comprehension and inference. As people are often sized up initially from their basic language skills, these studies suggest that people speaking to autistic individuals are more likely to overestimate what their audience comprehends.[30]

[edit] Repetitive behavior

Young boy asleep on a bed, facing the camera, with only the head visible and the body off-camera. On the bed behind the boy's head is a dozen or so toys carefully arranged in a line, ordered by size.

A young boy with autism, and the precise line of toys he made

Individuals with Autism display many forms of repetitive or restricted behavior, which the Repetitive Behavior Scale-Revised (RBS-R)[31] categorizes as follows.

  • Stereotypy is repetitive movement, such as hand flapping, making sounds, head rolling, or body rocking.
  • Compulsive behavior is intended and appears to follow rules, such as arranging objects in a stacks or lines.
  • Sameness is resistance to change; for example, insisting that the furniture not be moved or refusing to be interrupted.
  • Ritualistic behavior involves an unvarying pattern of daily activities, such as an unchanging menu or a dressing ritual. This is closely associated with sameness and an independent validation has suggested combining the two factors.[31]
  • Restricted behavior is limited in focus, interest, or activity, such as preoccupation with a single television program, toy, or game.
  • Self-injury includes movements that injure or can injure the person, such as eye poking, skin picking, hand biting, and head banging.[3] A 2007 study reported that self-injury at some point affected about 30% of children with ASD.[24]

No single repetitive behavior seems to be specific to autism, but only autism appears to have an elevated pattern of occurrence and severity of these behaviors.[32]

[edit] Other symptoms

Individuals with Autism may have symptoms that are independent of the diagnosis, but that can affect the individual or the family.[16] An estimated 0.5% to 10% of individuals with ASD show unusual abilities, ranging from splinter skills such as the memorization of trivia to the extraordinarily rare talents of prodigious autistic savants.[33] Many individuals with ASD show superior skills in perception and attention, relative to the general population.[34] Sensory abnormalities are found in over 90% of those with autism, and are considered core features by some,[35] although there is no good evidence that sensory symptoms differentiate autism from other developmental disorders.[36] Differences are greater for under-responsivity (for example, walking into things) than for over-responsivity (for example, distress from loud noises) or for sensation seeking (for example, rhythmic movements).[37] Several studies have reported associated motor problems that include poor muscle tone, poor motor planning, and toe walking; ASD is not associated with severe motor disturbances.[38]

Unusual eating behavior occurs in about three-quarters of children with ASD, to the extent that it was formerly a diagnostic indicator. Selectivity is the most common problem, although eating rituals and food refusal also occur;[24] this does not appear to result in malnutrition. Although some children with autism also have gastrointestinal (GI) symptoms, there is a lack of published rigorous data to support the theory that autistic children have more or different GI symptoms than usual;[39] studies report conflicting results, and the relationship between GI problems and ASD is unclear.[9]

At some point in childhood, about two-thirds of individuals with ASD are affected by sleep problems; these most commonly include symptoms of insomnia such as difficulty in falling asleep, frequent nocturnal awakenings, and early morning awakenings. Sleep problems are associated with difficult behaviors and family stress, and are often a focus of clinical attention over and above the primary ASD diagnosis.[40]

Parents of children with ASD have higher levels of stress.[41] Siblings of children with ASD report greater admiration of and less conflict with the affected sibling than siblings of unaffected children or those with Down syndrome; siblings of individuals with ASD have greater risk of negative well-being and poorer sibling relationships as adults.[42]

[edit] Classification

Head and shoulders of a man in his early 60s in coat and tie, facing slightly to his right. He is balding and has a serious but slightly smiling expression.

Leo Kanner introduced the label early infantile autism in 1943.

Autism is one of the five pervasive developmental disorders (PDD), which are characterized by widespread abnormalities of social interactions and communication, and severely restricted interests and highly repetitive behavior.[13] These symptoms do not imply sickness, fragility, or emotional disturbance.[15]

Of the five PDD forms, Asperger syndrome is closest to autism in signs and likely causes; Rett syndrome and childhood disintegrative disorder share several signs with autism, but may have unrelated causes; PDD not otherwise specified (PDD-NOS; also called atypical autism) is diagnosed when the criteria are not met for a more specific disorder.[43] Unlike with autism, people with Asperger syndrome have no substantial delay in language development.[1] The terminology of autism can be bewildering, with autism, Asperger syndrome and PDD-NOS often called the autism spectrum disorders (ASD)[9] or sometimes the autistic disorders,[44] whereas autism itself is often called autistic disorder, childhood autism, or infantile autism. In this article, autism refers to the classic autistic disorder; in clinical practice, though, autism, ASD, and PDD are often used interchangeably.[45] ASD, in turn, is a subset of the broader autism phenotype (BAP), which describes individuals who may not have ASD but do have autistic-like traits, such as avoiding eye contact.[46]

The manifestations of autism cover a wide spectrum, ranging from individuals with severe impairments—who may be silent, mentally disabled, and locked into hand flapping and rocking—to high functioning individuals who may have active but distinctly odd social approaches, narrowly focused interests, and verbose, pedantic communication.[47] Sometimes the syndrome is divided into low-, medium- or high-functioning autism (LFA, MFA, and HFA), based on IQ thresholds,[48] or on how much support the individual requires in daily life; these subdivisions are not standardized and are controversial. Autism can also be divided into syndromal and non-syndromal autism; the syndromal autism is associated with severe or profound mental retardation or a congenital syndrome with physical symptoms, such as tuberous sclerosis.[49] Although individuals with Asperger syndrome tend to perform better cognitively than those with autism, the extent of the overlap between Asperger syndrome, HFA, and non-syndromal autism is unclear.[50]

Some studies have reported diagnoses of autism in children due to a loss of language or social skills, as opposed to a failure to make progress, typically from 15 to 30 months of age. The validity of this distinction remains controversial; it is possible that regressive autism is a specific subtype,[19][27][51][52] or that there is a continuum of behaviors between autism with and without regression.[53]

Research into causes has been hampered by the inability to identify biologically meaningful subpopulations[54] and by the traditional boundaries between the disciplines of psychiatry, psychology, neurology and pediatrics.[55] Newer technologies such as fMRI can help identify biologically-relevant phenotypes (observable traits) that can be viewed on brain scans, to help further neurogenetic studies of autism.[56] It has been proposed to classify autism using genetics as well as behavior, with the name Type 1 autism denoting rare autism cases that test positive for a mutation in the CNTNAP2 gene.[57]

[edit] Causes

Main article: Causes of autism

It has long been presumed that there is a common cause at the genetic, cognitive, and neural levels for autism's characteristic triad of symptoms.[58] However, there is increasing suspicion that autism is instead a complex disorder whose core aspects have distinct causes that often co-occur.[58][59]

Deletion (1), duplication (2) and inversion (3) are all chromosome abnormalities that have been implicated in autism.[60]

Autism has a strong genetic basis, although the genetics of autism are complex and it is unclear whether ASD is explained more by rare mutations with major effects, or by rare multigene interactions of common genetic variants.[4] Complexity arises due to interactions among multiple genes, the environment, and epigenetic factors which do not change DNA but are heritable and influence gene expression.[15] Early studies of twins estimated heritability explains more than 90% of the risk of autism, assuming a shared environment and no other genetic or medical syndromes.[44] However, most of the mutations that increase autism risk have not been identified. Typically, autism cannot be traced to a Mendelian (single-gene) mutation or to a single chromosome abnormality like Angelman syndrome or fragile X syndrome, and none of the genetic syndromes associated with ASDs has been shown to selectively cause ASD.[4] Numerous candidate genes have been located, with only small effects attributable to any particular gene.[4] The large number of autistic individuals with unaffected family members may result from copy number variations—spontaneous deletions or duplications in genetic material during meiosis.[61] Hence, a substantial fraction of autism cases may be traceable to genetic causes that are highly heritable but not inherited: that is, the mutation that causes the autism is not present in the parental genome.[60]

Autism caused by some rare mutations may disrupt some synaptic pathways, such as those involved with cell adhesion.[62] Gene replacement studies in mice suggest that autistic symptoms are closely related to later developmental steps that depend on activity in synapses and on activity-dependent changes.[63] All known teratogens (agents that cause birth defects) related to the risk of autism appear to act during the first eight weeks from conception, and though this does not exclude the possibility that autism can be initiated or affected later, it is strong evidence that autism arises very early in development.[5] Although evidence for other environmental causes is anecdotal and has not been confirmed by reliable studies,[6] extensive searches are underway.[64] Environmental factors that have been claimed to contribute to or exacerbate autism, or may be important in future research, include certain foods, infectious disease, heavy metals, solvents, diesel exhaust, PCBs, phthalates and phenols used in plastic products, pesticides, brominated flame retardants, alcohol, smoking, illicit drugs, vaccines,[8] and prenatal stress.[65] Parents may first become aware of autistic symptoms in their child around the time of a routine vaccination, and this has given rise to theories that vaccines or their preservatives cause autism. Although these theories lack convincing scientific evidence and are biologically implausible, parental concern about autism has led to lower rates of childhood immunizations and higher likelihood of measles outbreaks.[7]

[edit] Mechanism

Autism's symptoms result from maturation-related changes in various systems of the brain.[66] Despite extensive investigation, how autism occurs is not well understood. Its mechanism can be divided into two areas: the pathophysiology of brain structures and processes associated with autism, and the neuropsychological linkages between brain structures and behaviors.[66] The behaviors appear to have multiple pathophysiologies.[17]

[edit] Pathophysiology

Two diagrams of major brain structures implicated in autism. The upper diagram shows the cerebral cortex near the top and the basal ganglia in the center, just above the amygdala and hippocampus. The lower diagram shows the corpus callosum near the center, the cerebellum in the lower rear, and the brain stem in the lower center.

Autism affects the amygdala, cerebellum, and many other parts of the brain.[2]

Unlike many other brain disorders such as Parkinson's, autism does not have a clear unifying mechanism at either the molecular, cellular, or systems level; it is not known whether autism is a few disorders caused by mutations converging on a few common molecular pathways, or is (like intellectual disability) a large set of disorders with diverse mechanisms.[12] Autism appears to result from developmental factors that affect many or all functional brain systems,[67] and to disturb the timing of brain development more than the final product.[2] Neuroanatomical studies and the associations with teratogens strongly suggest that autism's mechanism includes alteration of brain development soon after conception.[5] This anomaly appears to start a cascade of pathological events in the brain that are significantly influenced by environmental factors.[68] Although many major structures of the human brain have been implicated, almost all postmortem studies have been of individuals who also had mental retardation, making it difficult to draw conclusions.[2] Brain weight and volume and head circumference tend to be greater in autistic children.[69] The cellular and molecular bases of pathological early overgrowth are not known, nor is it known whether the overgrown neural systems cause autism's characteristic signs. Current hypotheses include:

Interactions between the immune system and the nervous system begin early during the embryonic stage of life, and successful neurodevelopment depends on a balanced immune response. Several symptoms consistent with a poorly regulated immune response have been reported in autistic children. It is possible that aberrant immune activity during critical periods of neurodevelopment is part of the mechanism of some forms of ASD.[76] As autoantibodies have not been associated with pathology, are found in conditions other than ASD, and are not always present in ASD,[77] the relationship between immune disturbances and autism remains unclear and controversial.[71]

Several neurotransmitter abnormalities have been detected in autism, notably increased blood levels of serotonin. Whether these cause structural or behavioral abnormalities is unclear.[66] Some data suggest an increase in several growth hormones; other data argue for diminished growth factors.[78] Also, some inborn errors of metabolism are associated with autism but probably account for less than 5% of cases.[79]

The mirror neuron system (MNS) theory of autism hypothesizes that distortion in the development of the MNS interferes with imitation and leads to autism's core features of social impairment and communication difficulties. The MNS operates when an animal performs an action or observes another animal perform the same action. The MNS may contribute to an individual's understanding of other people by enabling the modeling of their behavior via embodied simulation of their actions, intentions, and emotions.[80] Several studies have tested this hypothesis by demonstrating structural abnormalities in MNS regions of individuals with ASD, delay in the activation in the core circuit for imitation in individuals with Asperger syndrome, and a correlation between reduced MNS activity and severity of the syndrome in children with ASD.[81] However, individuals with autism also have abnormal brain activation in many circuits outside the MNS[82] and the MNS theory does not explain the normal performance of autistic children on imitation tasks that involve a goal or object.[83]

Autistic individuals tend to use different areas of the brain (yellow) for a movement task compared to a control group (blue). This image was generated by fMRI,[84] which is used in autism research to measure neural activity.[85]

ASD-related patterns of low function and aberrant activation in the brain differ depending on whether the brain is doing social or nonsocial tasks.[86] In autism there is evidence for reduced functional connectivity of the default network, a large-scale brain network involved in social and emotional processing, with intact connectivity of the task-positive network, used in sustained attention and goal-directed thinking. In people with autism the two networks are not negatively correlated in time, suggesting an imbalance in toggling between the two networks, possibly reflecting a disturbance of self-referential thought.[87] A 2008 brain-imaging study found a specific pattern of signals in the cingulate cortex which differs in individuals with ASD.[88]

The underconnectivity theory of autism hypothesizes that autism is marked by underfunctioning high-level neural connections and synchronization, along with an excess of low-level processes.[89] Evidence for this theory has been found in functional neuroimaging studies on autistic individuals[30] and by a brain wave study that suggested that adults with ASD have local overconnectivity in the cortex and weak functional connections between the frontal lobe and the rest of the cortex.[90] Other evidence suggests the underconnectivity is mainly within each hemisphere of the cortex and that autism is a disorder of the association cortex.[91]

From studies based on event-related potentials, transient changes to the brain's electrical activity in response to stimuli, there is considerable evidence for differences in autistic individuals with respect to attention, orientiation to auditory and visual stimuli, novelty detection, language and face processing, and information storage; several studies have found a preference for non-social stimuli.[92] For example, magnetoencephalography studies have found evidence in autistic children of delayed responses in the brain's processing of auditory signals.[93]

[edit] Neuropsychology

Two major categories of cognitive theories have been proposed about the links between autistic brains and behavior.

The first category focuses on deficits in social cognition. The empathizing–systemizing theory postulates that autistic individuals can systemize—that is, they can develop internal rules of operation to handle events inside the brain—but are less effective at empathizing by handling events generated by other agents. An extension, the extreme male brain theory, hypothesizes that autism is an extreme case of the male brain, defined psychometrically as individuals in whom systemizing is better than empathizing;[94] this extension is controversial, as many studies contradict the idea that baby boys and girls respond differently to people and objects[95].

These theories are somewhat related to the earlier theory of mind approach, which hypothesizes that autistic behavior arises from an inability to ascribe mental states to oneself and others. The theory of mind hypothesis is supported by autistic children's atypical responses to the Sally–Anne test for reasoning about others' motivations,[94] and the mirror neuron system theory of autism described in Pathophysiology maps well to the hypothesis.[81] However, most studies have found no evidence of impairment in autistic individuals' ability to understand other people's basic emotions or goals; instead, data suggests that impairments are found in understanding more complex social emotions or in considering others' viewpoints.[96]

The second category focuses on nonsocial or general processing. Executive dysfunction hypothesizes that autistic behavior results in part from deficits in working memory, planning, inhibition, and other forms of executive function.[97] Tests of core executive processes such as eye movement tasks indicate improvement from late childhood to adolescence, but performance never reaches typical adult levels.[98] A strength of the theory is predicting stereotyped behavior and narrow interests;[99] two weaknesses are that executive function is hard to measure[97] and that executive function deficits have not been found in young autistic children.[22]

Weak central coherence theory hypothesizes that a limited ability to see the big picture underlies the central disturbance in autism. One strength of this theory is predicting special talents and peaks in performance in autistic people.[100] A related theory—enhanced perceptual functioning—focuses more on the superiority of locally oriented and perceptual operations in autistic individuals.[101] These theories map well from the underconnectivity theory of autism.

Neither category is satisfactory on its own; social cognition theories poorly address autism's rigid and repetitive behaviors, while the nonsocial theories have difficulty explaining social impairment and communication difficulties.[59] A combined theory based on multiple deficits may prove to be more useful.[102]

[edit] Screening

About half of parents of children with ASD notice their child's unusual behaviors by age 18 months, and about four-fifths notice by age 24 months.[52] As postponing treatment may affect long-term outcome, any of the following signs is reason to have a child evaluated by a specialist without delay:

  • No babbling by 12 months.
  • No gesturing (pointing, waving goodbye, etc.) by 12 months.
  • No single words by 16 months.
  • No two-word spontaneous phrases (other than instances of echolalia) by 24 months.
  • Any loss of any language or social skills, at any age.[16]

The American Academy of Pediatrics recommends that all children be screened for ASD at the 18- and 24-month well-child doctor visits, using autism-specific formal screening tests.[3] In contrast, the UK National Screening Committee recommends against screening for ASD in the general population, because screening tools have not been fully validated and interventions lack sufficient evidence for effectiveness.[103] Screening tools include the Modified Checklist for Autism in Toddlers (M-CHAT), the Early Screening of Autistic Traits Questionnaire, and the First Year Inventory; initial data on M-CHAT and its predecessor CHAT on children aged 18–30 months suggests that it is best used in a clinical setting and that it has low sensitivity (many false-negatives) but good specificity (few false-positives).[52] It may be more accurate to precede these tests with a broadband screener that does not distinguish ASD from other developmental disorders.[104] Screening tools designed for one culture's norms for behaviors like eye contact may be inappropriate for a different culture.[105] Genetic screening for autism is generally still impractical.[106]

[edit] Diagnosis

Diagnosis is based on behavior, not cause or mechanism.[17][107] Autism is defined in the DSM-IV-TR as exhibiting at least six symptoms total, including at least two symptoms of qualitative impairment in social interaction, at least one symptom of qualitative impairment in communication, and at least one symptom of restricted and repetitive behavior. Sample symptoms include lack of social or emotional reciprocity, stereotyped and repetitive use of language or idiosyncratic language, and persistent preoccupation with parts of objects. Onset must be prior to age three years, with delays or abnormal functioning in either social interaction, language as used in social communication, or symbolic or imaginative play. The disturbance must not be better accounted for by Rett syndrome or childhood disintegrative disorder.[1] ICD-10 uses essentially the same definition.[13]

Several diagnostic instruments are available. Two are commonly used in autism research: the Autism Diagnostic Interview-Revised (ADI-R) is a semistructured parent interview, and the Autism Diagnostic Observation Schedule (ADOS) uses observation and interaction with the child. The Childhood Autism Rating Scale (CARS) is used widely in clinical environments to assess severity of autism based on observation of children.[19]

A pediatrician commonly performs a preliminary investigation by taking developmental history and physically examining the child. If warranted, diagnosis and evaluations are conducted with help from ASD specialists, observing and assessing cognitive, communication, family, and other factors using standardized tools, and taking into account any associated medical conditions.[108] A pediatric neuropsychologist is often asked to assess behavior and cognitive skills, both to aid diagnosis and to help recommend educational interventions.[109] A differential diagnosis for ASD at this stage might also consider mental retardation, hearing impairment, and a specific language impairment[108] such as Landau–Kleffner syndrome.[110] The presence of autism can make it harder to diagnose coexisting psychiatric disorders such as depression.[111]

Clinical genetics evaluations are often done once ASD is diagnosed, particularly when other symptoms already suggest a genetic cause.[45] Although genetic technology allows clinical geneticists to link an estimated 40% of cases to genetic causes,[112] consensus guidelines in the U.S. and UK are limited to high-resolution chromosome and fragile X testing.[45] A genotype-first model of diagnosis has been proposed, which would routinely assess the genome's copy number variations.[113] As new genetic tests are developed several ethical, legal, and social issues will emerge. Commercial availability of tests may precede adequate understanding of how to use test results, given the complexity of autism's genetics.[106] Metabolic and neuroimaging tests are sometimes helpful, but are not routine.[45]

ASD can sometimes be diagnosed by age 14 months, although diagnosis becomes increasingly stable over the first three years of life: for example, a one-year-old who meets diagnostic criteria for ASD is less likely than a three-year-old to continue to do so a few years later.[52] In the UK the National Autism Plan for Children recommends at most 30 weeks from first concern to completed diagnosis and assessment, though few cases are handled that quickly in practice.[108] A 2009 U.S. study found the average age of formal ASD diagnosis was 5.7 years, far above recommendations, and that 27% of children remained undiagnosed at age 8 years.[114] Although the symptoms of autism and ASD begin early in childhood, they are sometimes missed; years later, adults may seek diagnoses to help them or their friends and family understand themselves, to help their employers make adjustments, or in some locations to claim disability living allowances or other benefits.[115]

Underdiagnosis and overdiagnosis are problems in marginal cases, and much of the recent increase in the number of reported ASD cases is likely due to changes in diagnostic practices. The increasing popularity of drug treatment options and the expansion of benefits has given providers incentives to diagnose ASD, resulting in some overdiagnosis of children with uncertain symptoms. Conversely, the cost of screening and diagnosis and the challenge of obtaining payment can inhibit or delay diagnosis.[116] It is particularly hard to diagnose autism among the visually impaired, partly because some of its diagnostic criteria depend on vision, and partly because autistic symptoms overlap with those of common blindness syndromes.[117]

[edit] Management

Main article: Autism therapies

A three-year-old with autism points to fish in an aquarium, as part of an experiment on the effect of intensive shared-attention training on language development.[84]

The main goals of treatment are to lessen associated deficits and family distress, and to increase quality of life and functional independence. No single treatment is best and treatment is typically tailored to the child's needs.[9] Studies of interventions have methodological problems that prevent definitive conclusions about efficacy.[118] Although many psychosocial interventions have some positive evidence, suggesting that some form of treatment is preferable to no treatment, the methodological quality of systematic reviews of these studies has generally been poor, their clinical results are mostly tentative, and there is little evidence for the relative effectiveness of treatment options.[119] Intensive, sustained special education programs and behavior therapy early in life can help children acquire self-care, social, and job skills,[9] and often improve functioning and decrease symptom severity and maladaptive behaviors;[120] claims that intervention by around age three years is crucial are not substantiated.[121] Available approaches include applied behavior analysis (ABA), developmental models, structured teaching, speech and language therapy, social skills therapy, and occupational therapy.[9] Educational interventions have some effectiveness in children: intensive ABA treatment has demonstrated effectiveness in enhancing global functioning in preschool children[122] and is well-established for improving intellectual performance of young children.[120] Neuropsychological reports are often poorly communicated to educators, resulting in a gap between what a report recommends and what education is provided.[109] It is not known whether treatment programs for children lead to significant improvements after the children grow up,[120] and the limited research on the effectiveness of adult residential programs shows mixed results.[123]

Many medications are used to treat ASD symptoms that interfere with integrating a child into home or school when behavioral treatment fails.[15][124] More than half of U.S. children diagnosed with ASD are prescribed psychoactive drugs or anticonvulsants, with the most common drug classes being antidepressants, stimulants, and antipsychotics.[125] Aside from antipsychotics,[126] there is scant reliable research about the effectiveness or safety of drug treatments for adolescents and adults with ASD.[127] A person with ASD may respond atypically to medications, the medications can have adverse effects,[9] and no known medication relieves autism's core symptoms of social and communication impairments.[128] Experiments in mice have reversed or reduced some symptoms related to autism by replacing or modulating gene function after birth,[63] suggesting the possibility of targeting therapies to specific rare mutations known to cause autism.[62]

Although many alternative therapies and interventions are available, few are supported by scientific studies.[22][129][130] Treatment approaches have little empirical support in quality-of-life contexts, and many programs focus on success measures that lack predictive validity and real-world relevance.[23] Scientific evidence appears to matter less to service providers than program marketing, training availability, and parent requests.[131] Though most alternative treatments, such as melatonin, have only mild adverse effects[132] some may place the child at risk. A 2008 study found that compared to their peers, autistic boys have significantly thinner bones if on casein-free diets;[133] in 2005, botched chelation therapy killed a five-year-old child with autism.[134]

Treatment is expensive; indirect costs are more so. For someone born in 2000, a U.S. study estimated an average lifetime cost of $3.66 million (net present value in 2009 dollars, inflation-adjusted from 2003 estimate[135]), with about 10% medical care, 30% extra education and other care, and 60% lost economic productivity.[136] Publicly supported programs are often inadequate or inappropriate for a given child, and unreimbursed out-of-pocket medical or therapy expenses are associated with likelihood of family financial problems;[137] one 2008 U.S. study found a 14% average loss of annual income in families of children with ASD,[138] and a related study found that ASD is associated with higher probability that child care problems will greatly affect parental employment.[139] After childhood, key treatment issues include residential care, job training and placement, sexuality, social skills, and estate planning.[130]

[edit] Prognosis

There is no known cure.[9] Children recover occasionally, so that they lose their diagnosis of ASD;[140] this occurs sometimes after intensive treatment and sometimes not. It is not known how often recovery happens;[120] reported rates in unselected samples of children with ASD have ranged from 3% to 25%.[140] A few autistic children have acquired speech at age 5 or older.[141] Most children with autism lack social support, meaningful relationships, future employment opportunities or self-determination.[23] Although core difficulties tend to persist, symptoms often become less severe with age.[15] Few high-quality studies address long-term prognosis. Some adults show modest improvement in communication skills, but a few decline; no study has focused on autism after midlife.[142] Acquiring language before age six, having an IQ above 50, and having a marketable skill all predict better outcomes; independent living is unlikely with severe autism.[143] A 2004 British study of 68 adults who were diagnosed before 1980 as autistic children with IQ above 50 found that 12% achieved a high level of independence as adults, 10% had some friends and were generally in work but required some support, 19% had some independence but were generally living at home and needed considerable support and supervision in daily living, 46% needed specialist residential provision from facilities specializing in ASD with a high level of support and very limited autonomy, and 12% needed high-level hospital care.[10] A 2005 Swedish study of 78 adults that did not exclude low IQ found worse prognosis; for example, only 4% achieved independence.[144] A 2008 Canadian study of 48 young adults diagnosed with ASD as preschoolers found outcomes ranging through poor (46%), fair (32%), good (17%), and very good (4%); 56% of these young adults had been employed at some point during their lives, mostly in volunteer, sheltered or part-time work.[145] Changes in diagnostic practice and increased availability of effective early intervention make it unclear whether these findings can be generalized to recently diagnosed children.[8]

[edit] Epidemiology

Main article: Epidemiology of autism

Reports of autism cases per 1,000 children grew dramatically in the U.S. from 1996 to 2007. It is unknown how much, if any, growth came from changes in autism's prevalence.

Most recent reviews tend to estimate a prevalence of 1–2 per 1,000 for autism and close to 6 per 1,000 for ASD;[8] because of inadequate data, these numbers may underestimate ASD's true prevalence.[45] PDD-NOS's prevalence has been estimated at 3.7 per 1,000, Asperger syndrome at roughly 0.6 per 1,000, and childhood disintegrative disorder at 0.02 per 1,000.[146] The number of reported cases of autism increased dramatically in the 1990s and early 2000s. This increase is largely attributable to changes in diagnostic practices, referral patterns, availability of services, age at diagnosis, and public awareness,[146][147] though unidentified environmental risk factors cannot be ruled out.[6] The available evidence does not rule out the possibility that autism's true prevalence has increased;[146] a real increase would suggest directing more attention and funding toward changing environmental factors instead of continuing to focus on genetics.[64]

Boys are at higher risk for ASD than girls. The sex ratio averages 4.3:1 and is greatly modified by cognitive impairment: it may be close to 2:1 with mental retardation and more than 5.5:1 without.[8] Although the evidence does not implicate any single pregnancy-related risk factor as a cause of autism, the risk of autism is associated with advanced age in either parent, and with diabetes, bleeding, and use of psychiatric drugs in the mother during pregnancy.[148] Most professionals believe that race, ethnicity, and socioeconomic background do not affect the occurrence of autism.[149]

Autism is associated with several other conditions:

  • Genetic disorders. About 10–15% of autism cases have an identifiable Mendelian (single-gene) condition, chromosome abnormality, or other genetic syndrome,[150] and ASD is associated with several genetic disorders.[151]
  • Mental retardation. The fraction of autistic individuals who also meet criteria for mental retardation has been reported as anywhere from 25% to 70%, a wide variation illustrating the difficulty of assessing autistic intelligence.[152] For ASD other than autism, the association with mental retardation is much weaker.[153]
  • Anxiety disorders are common among children with ASD; there are no firm data, but studies have reported prevalences ranging from 11% to 84%. Many anxiety disorders have symptoms that are better explained by ASD itself, or are hard to distinguish from ASD's symptoms.[154]
  • Epilepsy, with variations in risk of epilepsy due to age, cognitive level, and type of language disorder.[155]
  • Several metabolic defects, such as phenylketonuria, are associated with autistic symptoms.[79]
  • Minor physical anomalies are significantly increased in the autistic population.[156]
  • Preempted diagnoses. Although the DSM-IV rules out concurrent diagnosis of many other conditions along with autism, the full criteria for ADHD, Tourette syndrome, and other of these conditions are often present and these comorbid diagnoses are increasingly accepted.[157]

[edit] History

Further information: History of Asperger syndrome and Sociological and cultural aspects of autism

A few examples of autistic symptoms and treatments were described long before autism was named. The Table Talk of Martin Luther contains the story of a 12-year-old boy who may have been severely autistic.[158] According to Luther's notetaker Mathesius, Luther thought the boy was a soulless mass of flesh possessed by the devil, and suggested that he be suffocated.[159] The earliest well-documented case of autism is that of Hugh Blair, as detailed in a 1747 court case in which his brother successfully petitioned to annul Blair's marriage to gain Blair's inheritance.[160] The Wild Boy of Aveyron, a feral child caught in 1798, showed several signs of autism; the medical student Jean Itard treated him with a behavioral program designed to help him form social attachments and to induce speech via imitation.[161]

The New Latin word autismus (English translation autism) was coined by the Swiss psychiatrist Eugen Bleuler in 1910 as he was defining symptoms of schizophrenia. He derived it from the Greek word autós (αὐτός, meaning self), and used it to mean morbid self-admiration, referring to "autistic withdrawal of the patient to his fantasies, against which any influence from outside becomes an intolerable disturbance".[162]

The word autism first took its modern sense in 1938 when Hans Asperger of the Vienna University Hospital adopted Bleuler's terminology autistic psychopaths in a lecture in German about child psychology.[163] Asperger was investigating an ASD now known as Asperger syndrome, though for various reasons it was not widely recognized as a separate diagnosis until 1981.[161] Leo Kanner of the Johns Hopkins Hospital first used autism in its modern sense in English when he introduced the label early infantile autism in a 1943 report of 11 children with striking behavioral similarities.[29] Almost all the characteristics described in Kanner's first paper on the subject, notably "autistic aloneness" and "insistence on sameness", are still regarded as typical of the autistic spectrum of disorders.[59] It is not known whether Kanner derived the term independently of Asperger.[164]

Kanner's reuse of autism led to decades of confused terminology like infantile schizophrenia, and child psychiatry's focus on maternal deprivation led to misconceptions of autism as an infant's response to "refrigerator mothers". Starting in the late 1960s autism was established as a separate syndrome by demonstrating that it is lifelong, distinguishing it from mental retardation and schizophrenia and from other developmental disorders, and demonstrating the benefits of involving parents in active programs of therapy.[165] As late as the mid-1970s there was little evidence of a genetic role in autism; now it is thought to be one of the most heritable of all psychiatric conditions.[166] Although the rise of parent organizations and the destigmatization of childhood ASD have deeply affected how we view ASD,[161] parents continue to feel social stigma in situations where their autistic children's behaviors are perceived negatively by others,[167] and many primary care physicians and medical specialists still express some beliefs consistent with outdated autism research.[168] The Internet has helped autistic individuals bypass nonverbal cues and emotional sharing that they find so hard to deal with, and has given them a way to form online communities and work remotely.[169] Sociological and cultural aspects of autism have developed: some in the community seek a cure, while others believe that autism is simply another way of being.[11][170