####What are autism spectrum disorders? Autism spectrum disorders (ASD) are complex neurodevelopmental conditions which impair the development of social communication, reciprocal social interaction, behaviour and imaginary thought. The diagnostic term includes autism in which impaired development occurs before the age of three years; atypical autism, where these impairments become apparent after the age of three years; pervasive developmental disorder not otherwise specified (PDD-NOS), where the child may not meet the full criteria for autistic disorder; and Asperger’s syndrome, where speech and language milestones are relatively unaffected and intellect is in the normal range. Common to all the conditions is a difficulty in social and emotional reciprocity that affects the establishment of peer relationships which involve sharing of interests, activities and emotions. The symptoms and signs are captured in clinical classifications such as ICD10 and DSM IV.[1,2] All children with ASD have impairments in the way in which they use their language. However, this can range from a failure to compensate for a total lack of speech by using non-verbal means and gestures to extensive speech development but a difficulty in knowing how to hold a conversation. Affected children have difficulties with restricted and repetitive behaviour. This may be very striking in autism, such that the interests are very intense and the child is distressed if the behaviours are prevented, or may be a more subtle disturbance as in Asperger’s disorder, where a child may favour systematising and collecting activities. This latter disorder is often accompanied by particular difficulty with co-ordination and motor planning. Often children also have unusual sensory interests or intolerances and they may have stereotyped and repetitive motor mannerisms that particularly involve hand and finger movements. While children and young people affected with Asperger’s syndrome have by definition an intellect in the normal range, a learning disability is a common accompaniment of an ASD and affects more than 70% of children with childhood autism. Some form of cognitive impairment is universal in ASD and, even for children with Asperger’s syndrome, there may be difficulties in executive dysfunction (such as problems in planning, responding appropriately to feedback, self organisation and working memory capacity), ‘central coherence’ (where there are difficulties in identifying salient sensory stimuli), imaginary thought, play and mentalising (theory of mind: imputing the thoughts of others). ####How are autism spectrum disorders diagnosed? There is no satisfactory screening tool for ASD for the typically developing childhood population, but there are very useful screening instruments for children who may be at high risk of the disorder. These groups include children presenting speech and language delay, emotional and behavioural problems as well as those with learning disabilities and genetic syndromes. Autism spectrum disorder is common and affects around 1% of the childhood population. A speech and language delay is a very common presentation to child development clinics and ASD should always be considered as a possible differential diagnosis for preschool children who are presenting with perturbations in their speech and language milestones. Some of the restricted and repetitive behaviours can be either less evident in this age group, or difficult to tease out from the rigid behaviours that can characterise the toddler years. Therefore all professionals charged with evaluating developmental delays in children should be comfortable in recognising the warning signs of possible ASD.[1,2,3] These signs might include features such as being unable to share pleasure and a lack of, respectively, turn-taking, pointing to share interest, eye contact and monitoring of other people’s gaze (Table 1). School-aged children may have abnormalities in their communication which can be accompanied by an unusual tone of voice or prosody (rhythm, stress and intonation in speech that affect aspects such as conveying emotion), difficulties in joining in play with other children and picking up on social conventions. In adolescence this difficulty in maintaining and making peer friendships may seem at odds with more facility in building relationships with adults. The rigidity of thinking with highly specific narrow interests or hobbies and longstanding difficulties in understanding appropriate social behaviour are all features that might occur in children presenting with an ASD (Table 2 and Table 3). Once the condition is considered, timely referral for specialist assessment is indicated. In order to capture the breadth of information required for the diagnosis, different professional groups should participate in the assessment process and this should always involve capture of the child or young person’s presenting symptoms and signs in different settings outwith the clinic. There are a range of specialised history-taking interviews and observational tools such as the Autism Diagnostic Interview-Revised (ADI-R) and Autism Diagnostic Observation Schedule (ADOS) that assist diagnosis, particularly when used in conjunction with classification systems. ####What is the cause of ASD? Although there are a very large number of recognised causes for ASD, autistic symptoms can accompany other features arising, for example, from structural brain lesions. The aetiology is established in around 10% of cases. The majority of the recognised causes are genetic, many of which are regarded as syndrome ASD conditions. They include fragile X disorder, tuberous sclerosis, Angelman’s syndrome and 22q deletion. Many other rare genetic syndromes have a high proportion of affected individuals with an autism presentation, including neurofibromatosis, Cornelia de Lange syndrome, Down’s, Joubert’s, Soto’s, Potocki-Lupski and Smith-Lemli-Opitz syndromes. Advances in genetics continue to add to the recognised aetiologies of ASD and high-resolution chromosome analysis and whole gene microarray studies have revealed cryptic chromosomal deletions and duplications such as those recently reported from chromosome 16. Numerous susceptibility genes have also been described and include 2q, 7q, 15q, 15p14.1 and X. Thus there are many mutations and structural variations in any of several genes that can dramatically alter the risk of ASD. How these operate and translate into the subtle anomalies of functioning seen on functional magnetic resonance imaging brain imaging is a very active area of research. It builds on the understanding that there is a strong genetic influence on ASD disorder; 25 times the background population prevalence for siblings, siblings and parents showing borderline ASD phenotypes, and twin studies showing higher rates of ASD in concordant twins. It is very rare for children with ASD to have a non-genetic cause for their disorder, but this has been described in those surviving congenital intrauterine infection with rubella and cytomegalovirus, as well as in some children who have been exposed to teratogens as in fetal alcohol syndrome or prenatal exposure to valproate and thalidomide. Rarely, an onset disorder such as herpes encephalitis can result in ASD. An ASD-like picture might also accompany the regression that occurs in paroxysmal disorders such as infantile spasms in tuberous sclerosis or convulsive dysphasia in Landau Kleffner syndrome. However, regression in communication is very common in preschool children presenting with autism and affects up to one third of these individuals, with an onset around the age of 12–18 months. Electroencephalography study is not particularly helpful in this situation and should be confined to part of the clinical work-up for suspected epilepsy. Epilepsy is a common comorbid disorder with autism. ####Can you treat autism? There is presently no cure for most children affected with an ASD. Not surprisingly, there is a great deal of interest in biomedical interventions such as those that employ exclusionary diets and nutritional supplements and this area is identified as a key priority by members of the National Autistic Society. However, although the potential biomedical investigations and interventions that have been explored are extensive (see the appendix in the recent SIGN guidelines[2]), unfortunately all of these at the present time either have insufficiently rigorous research and trials or have been refuted, such as the excess opioid peptide theory of dietary casein. There is a large range of psychoeducational interventions. These have been recently reviewed and most of them are based on behavioural theory, underpinned with neuropsychological understanding of ASD, are communication focused and support the difficulties in this area. Behavioural interventions can be very effective if they are aimed at specific behaviours, often in an attempt to reduce the frequency of maladaptive behaviour. Parent intervention programmes are also helpful in the way that they promote parental satisfaction and empowerment and facilitate children's communication and interaction with their families. Visual supports to communication and intervention to support social communication can all be considered. Taking these into account in order to adapt the communicative, social and physical environment in which children or young people with ASD find themselves can all improve and facilitate their development and behaviour. Pharmacological interventions can be useful in treating targeted symptoms such as hyperactivity and attention difficulties (which might respond to methylphenidate), aggression and self-injury (which might respond to risperidone) and intractable sleep problems (which might respond to melatonin). Intervention in autism remains an important and active area of research. This may be assisted by the recent development of an animal model for autism which employs a mutation in the X chromosome gene for neuroligin-3. The charity [Research Autism](www.researchautism.net) brings together evidence that is peer-reviewed into a user-friendly website. At the present time it has evaluated more than 100 different interventions with evidence graded as basic, intermediate and advanced, in order to meet the needs of both the general public and professionals. ####What is the long-term outlook for a child or young person with ASD? In terms of prognosis, the quality of social engagement with peers appears to predict better functioning and quality of life for individuals with ASD. Cognitive functioning and academic achievements are also very important and the outlook for living independently is much reduced if a child has an IQ below 70 and accompanying poor language development. Focus groups with able young people with ASD confirmed that they appreciate being told the truth about their condition as they find that supportive. They also have an expressed preference that their peers know about the kind of difficulties they are experiencing and what might help. Children, young people and their families can be encouraged to continue to learn about ASD through interventions and support, particularly from the voluntary sector, including the [National Autistic Society](www.autism.org.uk) and the [Scottish Society for Autism](www.autism-in-scotland.org.uk). There is help from material developed particularly for parents and carers and for young people affected by autism published by SIGN.[2] #####Acknowledgements The Friends Endowment Autism Research Fund, Royal Hospital for Sick Children, Edinburgh; Marion Rutherford, Royal Hospital for Sick Children, Edinburgh; Hanen More Than Words Early Intervention Group parents; GPs and paediatricians within the Scottish Association for Community Child Health all assisted with a University of Edinburgh SSC2 project on ‘Autism: Causes and Controversies’ to highlight their areas of interest and concern, which in turn orientated this article. #####Further reading New York State Department of Health Early Intervention Program. [*Clinical practice guideline on autism/pervasive developmental disorders: assessment and intervention for young children (age 0–3 years)*](http://www.health.state.ny.us/community/infants_children/early_intervention/autism)Albany: NYS Department of Health; 1999. 2009-07-09T12:04:13Z None declared. 110 2009-07-09T00:00:00Z 2009-07-29T14:37:23Z autism-spectrum-disorders-asd 2009-07-29T14:37:23Z

Autism spectrum disorders (ASD) affect around 1% of the childhood population and, from debates over causes to research into treatments, often make the headlines. Professor Anne O’Hare and her team from the Department of Child Life and Health at the University of Edinburgh provide a straightforward review of a topic that can cause a great deal of anxiety to parents.

2009-07-29T14:37:23Z