Autism spectrum disorder in childhood 001

  Aetiology

  aetiology

  and professional awareness, and improved and altered diagnos-

   This change is thought to be largely driven by increased public

  0.3% autism, 0.2% Asperger’s syndrome, 0.5% PDD-other).

  Autism shows the highest heritability estimates of any psychi- atric disorder (approximately 90%). The genetic inluences are complex, and so far no common genetic variants of major effect have been identiied. Non-genetic factors must also play a role as behavioural differences can be seen within affected monozygotic twins pairs. Despite many suggestions and much speculation, however, no clear environmental risk factors for ASD have so far been identiied.

   In approximately 10–15% of ASD cases, a primary medical

  are associated with autism

  What’s new?

• there is postnatal brain overgrowth in the irst three years
• submicroscopic, structural chromosomal copy number variants

  (M:F − autism 4:1, Asperger’s 10:1). There is no clear evidence that the prevalence of ASD differs as a function of socioeconomic status or ethnicity.

  Autism spectrum disorder (ASD) includes the diagnoses of autism, Asperger’s syndrome and atypical autism which fall within the pervasive developmental disorder (PDD) category of ICD-10.

  Clinical features

  developmental disorder

  Keywords autism spectrum disorder; child; development; pervasive

  the term autism spectrum disorder (asd) refers to a group of child- hood onset neurodevelopmental disorders characterised by problems with social communication and repetitive behaviours. these conditions are increasingly recognised and often associated with marked disability across the lifespan. Whilst the causes of asd remain uncertain, it is clear that genetic factors play a major role. diagnosis should take place following a multidisciplinary assessment which also identiies individual strengths and weaknesses. as yet, there is no cure for asd, and few evidence-based options for the treatment of core-features – educational, behavioural and occasionally pharmacological interventions can be used to good effect.

  Autism spectrum disorder in childhood armin raznahan patrick Bolton Abstract

• there is no good evidence that mmr vaccine plays a role in

   ASD is more prevalent in males, although the sex ratio varies

1 All

• impairments in verbal and non-verbal communication
• impairments in reciprocal social interaction • the presence of restricted interests and repetitive behaviours. ASD diagnoses differ from each other in early developmental proile and symptom severity. Diagnostic criteria, important dif- ferential diagnoses, comorbid disorders and associated features are shown A key feature of ASD is its marked variabil- ity in presentation. This greatly impacts on academic and clinical approaches to ASD.

  and the beneits of diagnostic assessment being carried out in a mul- tidisciplinary team setting by experienced clinicians. The best validated and most widely used research-diagnostic instruments are the Autism Diagnostic Interview-Revised

  three diagnoses are characterized by the presence of:

  Epidemiology

  Prevalence estimates of autism and ASD have shown a dramatic increase over the past 30 years: a recent UK study suggested that up to 1% of children may fulil criteria for an ASD (approximately

  Currently, the main purpose of physical investigations, such as genetic testing or brain scanning, in ASD is to aid

  , and they can be useful in the diagnosis of complex cases. Readers are strongly advised to refer to the National Autism Plan for detailed guidance (

  

  and the Autism Diagnostic Observation Schedule (ADOS)

  

  Patrick Bolton PhD FRCPsych is a Professor of Child Psychiatry at the Institute of Psychiatry, King’s College London, UK. Competing interests: none declared.

  Competing interests: none declared.

  They emphasize the need for effective surveillance in primary care, the use of appropriate screening

  

  National guidelines available for ASD assessment adopt staged

   Assessment

  Neuroimaging studies in people with ASD have found there to be early brain overgrowth, as well as structural and functional abnormalities within and between speciic brain regions (fronto-temporal cortices, limbic system, basal ganglia

  

  disorder can be identiied (e.g. tuberous sclerosis, Fragile X syndrome). The remainder of cases are considered ‘idiopathic’ and thought to relect the combined action of multiple risk alleles for ASD. New approaches in genetic research, however, are changing our models for how genes might relate to behav- iour in

  Armin Raznahan MRCPCH MRCPsych is a MRC Clinical Research Training Fellow at the Institute of Psychiatry, King’s College London, UK

  

  Table 1

  requires a total of 6 symptoms from rsi, Com and rrBi domains. diagnosis is excluded if the presentation is attributable to: another pdd, speciic developmental disorder of receptive language, attachment disorder or learning disability problems with ≥ 1 of: (i) language as used in social communication (ii) development of selective social attachments /reciprocal social interaction (iii) Functional or symbolic play

  deined by atypicality in: age of onset, symptomatology, or both

  Atypical autism − subtypes

  requirements for are the same as for autism except rrBi (iii) and (iv) are rarely seen. early motor development may be delayed and clumsiness is usual. diagnosis is excluded if the presentation is attributable to another pdd or mental disorder (e.g. oCd) no clinically signiicant general delay in spoken or receptive language or cognitive development same as for autism not required for diagnosis same as for autism

  Asperger’s syndrome (AS) – rsi and rrBi symptom

  ≥ 1 of: (i) an encompassing preoccupation with one or more stereotyped and restricted patterns of interest (ii) apparently compulsive adherence to speciic, non-functional routines or rituals (iii) stereotyped and repetitive motor mannerisms (iv) preoccupations with part-objects/non-functional elements of play materials

  ≥ 1 of: (i) a delay, or a total lack of, development of spoken language that is not accompanied by an attempt to compensate through the use of non- verbal communication (ii) relative failure to initiate or sustain conversational interchange in which there is reciprocal responsiveness to the other person (iii) stereotyped and repetitive use of language or idiosyncratic use of words or phrases (iv) lack of varied spontaneous make-believe or social imitative play

  ≥ 2 of: (i) Failure to use non- verbal communication to regulate social interaction (ii) Failure to develop peer relationships that involve a mutual sharing of interests and emotions (iii) lack of socio- emotional reciprocity (iv) lack of spontaneous seeking to share enjoyment, interests or achievements with other people

  Autism – a diagnosis

  identiication of an underlying medical disorder. Whilst there is some disagreement about exactly how and why to use such tests,

  Communication (Com) restricted repertoire of behavioural interests (rrBi)

  Before age 3 Symptom domains reciprocal social interaction (rsi)

  ICD-10 criteria for research diagnoses within the autism spectrum (abbreviated) Category Diagnostic criteria

• /− abnormalities or impairments in development a lack of suficient demonstrable abnormalities in one or two of these three domains as would be required for the diagnosis of autism asd, autism spectrum disorder; ld, learning disability; pdd, pervasive developmental disorder; oCd, obsessive compulsive disorder.

  Generic aspects of any management plan should include psycho-education, offering details of voluntary agencies and support groups, ensuring educational provision is appropriate and making sure carers and teachers are able to tailor their approach to the child in an ‘ASD-appropriate’ way pitching com- munications at the right level and using non-verbal means of

  Management General principles

  most would agree that all children should have a karyo- type analysis carried out, and be tested for Fragile X syndrome. Further genetic tests and structural magnetic resonance imag- ing (sMRI) should be requested if there is evidence from history or examination of a neurogenetic syndrome (e.g. severe learn- ing disability, epilepsy, facial dysmorphology, neurocutaneous stigmata).

   communicating if appropriate, fostering social skills, establishing structure in daily routines, being aware of sensory sensitivities. On a wider level there is a need to promote people’s understand- ing of ASD in order to reduce stigma in school, work and the community.

  Psychosocial

  2 General developmental assessment Content Output

  6 sebat J, lakshmi B, malhotra d, et al. strong association of de novo copy number mutations with autism. Science 2007; 316: 445–49.

  7 Geschwind dh, levitt p. autism spectrum disorders: developmental disconnection syndromes. Curr Opin Neurobiol 2007; 17: 103–11. 8 palmen sJ, van engeland h. review on structural neuroimaging indings in autism. J Neural Transm 2004; 111: 903–29.

  9 Johnson Cp, myers sm, the Council on Children With disabilities.

  identiication and evaluation of children with autism spectrum disorders. Pediatrics 2007; 120: 1183–215.

  Simplified summary of recommended stages of autism spectrum disorder assessment process as outlined in the National Autism Plan

  1 Identification of concerns

  refer on for general developmental assessment

  Clear identiication of concerns immediate feedback to family developmental history opportunity for family to discuss outcome examination notify educational authority if indicated investigations place on special needs register if appropriate

  5 ronald a, happe F, Bolton p, et al. Genetic heterogeneity between

  If possible ASD - refer on for multi-agency assessment

  3 Multi-agency assessment Content Output

  Gathering of all available information diagnostic formulation asd speciic developmental history assessment report observational assessment in >1 setting

  Feedback and discussion of these with family Cognitive assessment Genetic predisposition counselling Communication, speech and language assessment

  Facilitate access to local support groups/ agencies Behaviour and mental health assessment provision of information regarding local educational authority provision

  Family assessment Begin needs-based planning of treatment physical examination If diagnosis uncertain refer for

  tertiary assessment

  medical investigations

  the three components of the autism spectrum: a twin study. J Am Acad Child Adolesc Psychiatry 2006; 45: 691–99.

  Disabil Res 2005; 49: 231–38.

  There is insuficient data to draw any deinitive conclusions about the effectiveness and cost:beneit proile of psychosocial treat- ments aimed at targeting the core features of ASD, although it is generally felt that early behavioural interventions (EBI) have some beneits

   Prognosis

   However, there is a need to establish exactly which

  components of EBI lead to improvements in symptomatology and functioning, as well as the ideal intensity and setting within which EBI should be delivered. Work on psychosocial interven- tions based on basic neuropsychological research in ASD has only just begun.

   Learning theory based behavioural therapy can be effective in the treatment of maladaptive behaviours in ASD.

  Pharmacological

  There is some evidence that antipsychotic medications such as

  

  and selective serotonin reuptake inhibitor (SSRI) drugs (e.g. luoxetine) can be useful adjunctive treatments of maladaptive or restricted and repetitive behaviours in ASD. These treatments are not however without side effects (to which people with ASD may be especially prone) and should only be

  There is marked variability in long-term outcome in ASD, although impairments of one form or another tend to persist into adult- hood. As a result, a signiicant proportion of children with ASD remain dependent on others for support in adulthood. Those with normal intelligence and/or functional speech by the age of 5 years have the best outcomes

  3 Wazana a, Bresnahan m, Kline J. the autism epidemic: fact or artifact? J Am Acad Child Adolesc Psychiatry 2007; 46: 721–30. 4 rutter m. aetiology of autism: indings and questions. J Intellect

  

  but the severity of social impairments and repetitive behaviours are also relevant in prognosis.

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