CHAPTER 1
An Introduction to Autism

Munib Haroon

OVERVIEW

• Autism is a relatively common neurodevelopmental condition with a prevalence of over 1% in many populations.
• Autism is defined by the presence of social communication and social interaction difficulties and restricted, repetitive patterns of behaviour, interests and activities which can vary in severity.
• Autism has a heterogeneous clinical presentation because of variations in the core features and the presence or absence of associated conditions.
• The diagnosis of autism is a clinical diagnosis.
• There is no cure for autism but early intervention can have a significant impact upon overall well-being.

Definition

Autism spectrum disorder (or autism) is a relatively common neurodevelopmental condition with a heterogeneous underlying basis which is incompletely understood. The definition of autism is based on the presence of impairments in social communication and social interaction and restricted, repetitive patterns of behaviour, interests or activities (Figure 1.1). These impairments vary greatly in severity, and whilst often noticeable during childhood can go undetected until later in life.

Figure 1.1 Autism is defined by the presence of features in two broad categories.

The neurodiversity movement has had a large impact on the terms of discourse when referring to autism and, for many people, use of the term 'autism spectrum condition' is preferred to the use of the term '. disorder', whilst plural terminology (e.g. 'disorders') is also often used to highlight the heterogeneous nature of the condition. The terms 'autism,' 'autism spectrum disorder(s)' and, occasionally, 'autism spectrum condition', are therefore used interchangeably in this book. (However, for diagnostic purposes, in a clinical setting, it remains sensible to use conventional terminology in a consistent way to avoid confusion.)

History

The term 'autism' is derived from the Greek word 'autos,' meaning 'self,' and was first used in 1910 by Eugen Bleuler (Figure 1.2) in relation to schizophrenia, to describe the withdrawal of schizophrenic patients into their own fantasies. However, the earliest clinically based descriptions of what we would now recognise to be autistic patients were not written until many years later (although there is considerable interest amongst researchers in older historical descriptions of individuals who seem to possess autistic traits). The first well-described clinical account was written by Sukhareva in 1926 although credit for the first detailed descriptions of autism are usually attributed to Leo Kanner in 1943 and then to Hans Asperger in 1944. Opinion is divided over who 'got there first', and who knew what about the other's work - a controversial area which lies outside the scope of this book. Asperger's seminal contribution to the field fell into neglect in the years around the Second World War before being rehabilitated in 1981 by Lorna Wing who coined the eponymous term 'Asperger's syndrome'.

Figure 1.2 A timeline involving some of the early pioneers in autism.

Epidemiology

The reported prevalence of autism has increased in recent decades, with estimates of over 1% being made in some large-scale surveys. It is not yet clear how much of this increase could be caused by an actual increased incidence or whether it is just that the change is the result of better public awareness, improved recognition by professionals and a widening of the diagnostic criteria.

Large-scale studies have shown that autism affects 2-3 times more males than females. This could be because of under-recognition in females or because of a genuine sex difference.

Aetiology

Controversy over aetiology has dogged the condition from early on. It was seen - erroneously - by some as an acquired condition resulting from parent-child interactions, with 'blame' in some quarters attached to 'refrigerator mums' - a theory that was popularised in the 1950s by Bruno Bettelheim. The 1960s saw a shift from 'nurture-based' explanatory models towards 'nature-based' models and towards undertaking research to address the biological basis for the disease. This biological basis remains incompletely understood. What is clear is that there is a strong genetic basis for autism, along with a clear role for environmental risk factors. It has been known for some time that a sibling of an affected individual is more likely to have autism than a general member of the population: 10% in comparison to 1%. Furthermore, the risk of a monozygotic twin having autism is greater than the risk in a dizygotic twin. More recent research has identified that there are multiple candidate genetic mutations, many of which are uncommon or rare, whose interactions may have a role in how the autistic phenotype is expressed. It is thought that the non-genetic risk factors that have been identified may interact with genetic factors and thus affect how a phenotype is expressed in an individual. Some of this work has not been without controversy, most notably the well-publicised scare over a study (published and subsequently retracted by The Lancet) that erroneously showed an association between the mumps, measles and rubella (MMR) vaccine and autism and which led to a significant decline in immunisation rates in the UK in the early 21st century.

Clinical features

Whilst the origin of the term 'autism' suggests a person's withdrawal into themselves, the idea that everyone with autism is highly withdrawn and isolated is incorrect and only describes a proportion of individuals with the condition. The term 'spectrum' is used to denote the heterogeneity that is seen in the clinical features of different individuals with the condition. In addition, the autistic phenotype is often expressed differently within the same individual as they move from childhood to adolescence and adulthood.

As well as the core features, those with autism can present with co-morbid or associated conditions: mood disorders, anxiety disorders, attention deficit hyperactivity disorder (ADHD), learning disability, dyspraxia and epilepsy.

Diagnosis

The diagnosis of autism can theoretically be made at any age, although it would take confidence to make a diagnosis in a child below the age of 2-3 years. The mean age of diagnosis in the UK is currently about 5 years although a diagnosis can occur several decades after this. Such a late diagnosis occurs in many contexts: where the presentation is subtle and associated with normal IQ and speech, in looked-after children, or where there is a significant learning disability or other co-morbidity making recognition of the underlying autistic features difficult.

A diagnosis is made based on clinical assessment including history (including developmental and psychiatric information), examination, observations from other parties and, sometimes, the use of diagnostic clinical examination tools. At present there is no role for blood tests or imaging to make a diagnosis although they may help to diagnose associated or underlying conditions.

Management

The core features of autism cannot be cured or removed with treatment. However, support, particularly early intervention, can have positive effects, whilst co-morbidities are amenable to treatment if recognised. Medication can, in the right circumstances, be used to manage many associated medical problems and co-morbidities: sleep difficulties, ADHD, aggression, mood disorders and anxiety.

Prognosis and outcome

A normal trajectory for the development of childhood communication skills and normal IQ seem to be good predictors for later outcome. The presence of associated co-morbidities is likely to have a significant effect on how a person with autism manages in life and so the early identification and management of these, if and when they arise, is important. Non-biological factors such as the nearby presence of friends and family and the ability to take part in some sort of social activities can also be very important - and, importantly, more malleable than biological factors.

It is increasingly recognised that individuals with autism are at an increased risk of early mortality due to epilepsy, and suicide (because of psychiatric illness), whilst those with significant levels of social communication difficulty and cognitive impairment can struggle with many aspects of day-to-day life including school, employment, long-term relationships and independent living (Box 1.1). But, at the same time, many people with autism lead rich, fulfilling, independent or semi-independent lives whilst making valuable contributions to society. Every person with autism - like every person without autism - is a unique individual and should be treated as such.

Box 1.1 Outcomes for autism

• Less than 20% of adults with autism have a full-time job
• Less than 20% of...