Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a complex developmental disorder involving difficulties with social communication and relationships, restricted interests and repetitive behaviours. The degree of functional impairment caused by these challenges varies from person to person, as does the severity of the difficulties (hence "spectrum").

Although autism can be diagnosed at any age, it is described as a "developmental disorder" because symptoms are usually noticeable within the first three years of life. Autistic individuals with high levels of functioning (Asperger's syndrome – a subtype of ASD) may not be diagnosed until later in life. Autism Spectrum Disorder therefore occurs across all age, racial, ethnic and socio-economic groups.

Autism symptoms occur across three main areas (the so-called autism triad):

• Social interaction
• Verbal and non-verbal communication
• Repetitive or ritualistic behaviours

The causes of Autism Spectrum Disorder are not fully understood. A number of possible causes have been identified, including:

Genetic causes of autism spectrum disorders

Several genetic factors may, in complex ways, increase the risk of autism. Individuals with Fragile X syndrome and tuberous sclerosis are at increased risk of an autism diagnosis. Genetic influences are clearly evident: having a sibling with autism also increases the likelihood of a child being diagnosed with autism. Genetic factors account for close to 30% of autism cases.

Environmental causes of autism

The environment may also play a role in the development of autism. Certain medications, such as valproic acid and thalidomide, taken during pregnancy have also been linked to a higher risk of autism.

Other factors that increase the risk of autism

Older parental age at the time of pregnancy is also associated with a greater risk of autism, as is early damage to the central nervous system. On the other hand, vaccines have not been shown to increase the likelihood of an autism diagnosis, and race, ethnicity or socio-economic status do not appear to be linked either.

Autism is diagnosed more often in male children than in female children. The exact reasons for this disparity are not fully understood. It may be due to biological differences between the sexes. Some experts suggest it may also reflect how autism is currently defined and diagnosed, as well as the more frequent camouflaging (masking) of autism in females.

Autistic individuals have a nervous system that functions differently from what is considered typical. These differences are particularly evident in three main areas: language and communication, social relationships and emotional responses, and differences in sensory processing.

Cognitive abilities Findings suggest that signs of autism are also present as deficits in certain executive functions and tasks requiring a complex approach, while fluid intelligence and problem-solving tend to be areas of strength.

Language and communication Individuals with ASD also display a range of atypical language features, such as echolalia, pedantic speech, difficulty understanding figurative language, and other features arising from pragmatic language impairments. Some may be entirely non-verbal, some may have limited speech, and others may speak fluently and clearly. Nonetheless, challenges with language and communication are a defining feature of autism.

Sensory features Over 90% of autistic people experience atypical sensory perception, which can affect any of the senses. Sensory hypersensitivity is also a common feature of autism. Sounds that are too loud or clothing that feels uncomfortable are examples of factors that can lead to significant stress and discomfort.

Stimming Characteristic behavioural patterns are observed in ASD. Many autistic people engage in routine self-stimulation. There are various theories as to why people engage in self-stimulatory behaviours. Such behaviour may provide sensory stimulation, or it may be used to regulate sensory input — either increasing stimulation or reducing sensory overload. Stimming appears to help some autistic children and teenagers cope with emotions and overwhelming situations. If stimming causes harm to the child or to others, replacing it with a safer behaviour may be considered.

Examples of stimming include:

• hand and finger movements — for example, finger-flicking and hand-flapping
• body movements — for example, rocking back and forth while sitting or standing
• posture — for example, holding the hands or fingers at an angle, or arching the back while sitting

ADHD and autism

Autism is often diagnosed alongside other conditions. Attention Deficit Hyperactivity Disorder (ADHD) is the most common mental health condition among children and adolescents. Research has shown that some ADHD symptoms overlap with those of ASD; ASD should therefore be considered during an ADHD assessment where significant interpersonal difficulties are also present. High distractibility in ADHD and reduced mental flexibility in ASD can both present as reduced attention. In addition, both conditions can lead to interpersonal difficulties, and both can involve an unusual capacity for deep, focused engagement with personal interests.

Symptoms of autism spectrum disorder in children

Signs of autism in children can appear as early as infancy. Autism is most often identified in children between the ages of 2 and 3. The earliest signs of autism can sometimes be observed even in infancy. Careful observation of the child is important. A more objective indicator during infancy is provided by hearing tests. Studies show that infants with a slower brain response to sound during ABR (auditory brainstem response) testing go on to receive an ASD diagnosis. Early diagnosis of autism is important, as it can help create better conditions for the child's development.

"Childhood autism" is an outdated term. It has now been absorbed into the broader category of autism spectrum disorder, along with Asperger's syndrome, atypical autism and other pervasive developmental disorders.

Social interaction Symptoms of autism spectrum disorder in children mainly relate to communication and social interaction.

Behaviours seen in autistic children:

• Avoids or does not sustain eye contact
• Does not respond to their name by 9 months of age
• Does not respond to instructions; does not play with peers
• Does not use facial expressions to show happiness, sadness, anger or surprise by 9 months of age
• Does not play simple interactive games by 12 months of age
• Uses few or no gestures by 12 months of age (e.g. does not wave goodbye)
• Does not share interests with others by 15 months of age
• Does not point to show interest in something by 18 months of age
• Does not notice when others are hurt or upset by 24 months of age
• Does not notice other children or join them in play by 36 months of age
• Does not engage in pretend play, e.g. pretending to be a teacher or superhero, by 48 months of age
• Does not sing or dance for others by 60 months of age

Restricted or repetitive patterns of behaviour or interests

Autistic children display behaviours or interests that may seem unusual, for example:

• Lining up toys or other objects and becoming upset when the order is changed
• Repeating words or phrases over and over (so-called echolalia)
• Playing with toys the same way every time
• Focusing on parts of objects (e.g. wheels)
• Becoming upset by minor changes
• Having intense, focused interests
• Needing to follow specific routines
• Hand-flapping, body-rocking or spinning
• Having unusual reactions to how things sound, smell, taste, look or feel

Impaired communication and language

• High-pitched or flat intonation: Some autistic children speak in a high-pitched or sing-song voice, or may sound flat and robotic.
• Reciting: It is not uncommon for autistic children to recite lines from a film word for word, or to talk at length about a favourite topic that is unrelated to the wider conversation.
• Difficulty understanding slang/metaphors/sarcasm: Autistic children tend to interpret language literally and may not understand slang or the "child-speak" used by their peers.
• Repetition: Autistic children often repeat the same phrase over and over — for example, counting from one to five repeatedly, or asking questions they already know the answer to.
• Echolalia: Echolalia occurs when a child repeats what someone has just said or asked them.
• Uneven verbal and language development: A child with high-functioning autism may develop a rich vocabulary or become an early reader, but this often relates only to a specific area of interest.

It should be noted that children with ASD may not display all, or even most, of the behaviours listed here as examples. Asperger's syndrome is a subtype of autism in which no language delay or cognitive delay is observed.

Other possible symptoms

• Delayed language skills
• Delayed motor skills
• Delayed cognitive or learning skills
• Hyperactive, impulsive and/or inattentive behaviour
• Epilepsy
• Unusual eating and sleeping habits
• Anxiety, stress or excessive worry
• Absence of fear, or fear greater than expected

Symptoms of autism spectrum disorder in teenagers

For most young people, including those with ASD, adolescence and young adulthood bring a wealth of new challenges, opportunities and responsibilities. Research shows that fewer young people with ASD have the same opportunities as their peers without ASD. This is reflected in the following statistics:

Low participation in education after secondary school Most continue to live with family members or relatives Limited opportunities for social activity — almost 40% spend little or no time with friends In addition, autistic people may experience changes in ASD symptoms, behaviours and co-occurring conditions during adolescence and early adulthood. These changes can affect their ability to function and take part in social life.

Social isolation and bullying at school: Friendship is an essential social experience for children. It provides a context in which they can practise and develop the social skills needed for friendship, including social adaptability, emotional understanding, empathy and care for others. Children with ASD struggle with these social skills and therefore find it difficult to build relationships. They have difficulty interpreting the finer details of non-verbal language, gestures and facial expressions, do not fully understand humour and metaphor, have restricted and sometimes unusual interests, and may speak with an unusual intonation. All of these challenges, combined with a lack of social skills, leave them more vulnerable to interpersonal difficulties and more likely to become the target of teasing by peers. Over 40% of children with ASD have experienced bullying at school. It is not uncommon for autistic people to leave school as a result of significant anxiety and depressive symptoms arising from interpersonal difficulties.

Symptoms of autism spectrum disorder in adults – differences from childhood presentation

The classic symptoms of childhood autism are not always present in autistic adults, particularly those who were not diagnosed as children. This is most often referred to as the ASD-AS subtype (Asperger's syndrome).

Autistic adults often display symptoms related to:

• social and communication difficulties
• repetitive behaviours
• difficulties with sensory processing
• difficulties with executive function and theory of mind

The areas affected by autism are outlined below.

Social difficulties Social difficulties include problems with communication and understanding, which can sometimes make the normal back-and-forth of social conversation more difficult. Autistic adults often find it hard to see things from another person's perspective and to interpret non-verbal cues such as eye-rolling, shrugging or facial expressions.

Examples include:

• A somewhat flat affect, or a unique way of expressing emotion non-verbally
• Difficulty holding a conversation and staying on topic — long monologues or very brief responses
• Language used in social interaction that can sometimes seem rigid
• Difficulty expressing their own thoughts
• An unusually strong focus on detail — such as facts or names
• Difficulty understanding figurative language — interpreting things literally

Repetitive behaviours Repetitive behaviours include restricted schedules and activities, a preference for a consistent environment, and intense interests or preoccupations. Choosing the same activities or foods provides relief for an autistic person — a response to overstimulation and a sign of difficulties with sensory processing.

Examples include:

• Self-stimulatory behaviours (stimming), such as rubbing a hand on the thigh or a finger in a pocket, or tapping a foot
• A preference for sameness and routine — they may experience stress or frustration when this is unexpectedly disrupted
• Wearing comfortable clothing even where this runs counter to social expectations (to limit sensory input from tight-fitting or scratchy fabrics)
• Being easily distracted by sounds or visual stimuli

Executive function Executive function refers to the abilities and skills involved in planning, organisation, sustained attention and self-regulation. Autistic adults may find complex planning challenging, making it harder to see the "bigger picture". As a result, an autistic person:

• May need support setting long-term goals and schedules
• May unintentionally arrive late for, or forget, appointments
• May find it challenging to grasp general concepts while also mastering the finest details
• May need support in understanding other people's expectations and perspectives

A comprehensive approach is important when diagnosing ASD. Because autism spectrum disorders vary considerably in their symptoms and severity, reaching a diagnosis can be difficult. There is no specific medical test that can identify this condition.

The autism diagnostic process

Screening Screening tests are not used to make a diagnosis; instead, they help identify individuals who require further assessment. General developmental screening to identify language, cognitive and motor delays is recommended at 9, 18 and 30 months of age. Parental input is also important. However, these tests are not sensitive enough to pick up differences in social interaction, play and repetitive behaviours associated with autism spectrum disorders. It is therefore recommended that ASD screening combines:

A – Routine developmental surveillance at every visit: Developmental surveillance for ASD involves asking parents or carers about any concerns, observing carer–child interaction, and monitoring symptoms at every routine check-up.

B – Standardised, autism-specific screening tools at 18 and 24 months of age: These screening tools have been developed based on early ASD signs that can be identified by healthcare providers or carers.

Diagnostic assessment Where screening or developmental surveillance indicates a risk of ASD, a comprehensive diagnostic assessment is recommended to establish whether ASD is present and whether early intervention is needed.

Standard psychiatric assessment

A standard psychiatric assessment, including a full interview with the patient and carers, is needed to obtain an accurate history — including descriptions of behaviour during formal testing, reports of behaviour in other settings, past and current educational and behavioural interventions, family history, and relevant psychosocial factors. The interview and assessment should be carried out with careful reference to the DSM-5 diagnostic criteria. An assessment by a psychologist able to evaluate pervasive developmental disorder can also be helpful (for children, this would be a child psychologist).

Assessment tools

A range of tools has been developed for assessing ASD. While none of these questionnaires is sufficient on its own to establish a diagnosis, they can provide a structured approach and support an experienced clinician in applying the ASD diagnostic criteria.

Assessment of co-occurring developmental conditions

Attention to other potentially co-occurring diagnoses is also an important part of the assessment. Co-occurring conditions can affect ASD symptomatology in different ways and at different ages. A formal assessment of language, cognitive, motor, sensory and adaptive functioning is therefore an important part of the diagnostic process.

Medical investigations

Genetic testing: Potential benefits of establishing a genetic diagnosis include improved counselling for the patient and family. Neuroimaging: MRI is not recommended for routine assessment, although it may be indicated in the presence of certain conditions, such as atypical regression, seizures or an abnormal neurological examination. EEG: May be indicated in some cases involving seizures, atypical regression, or other neurological symptoms.

Autism spectrum test

This test does not constitute a formal diagnosis and does not replace a consultation with a specialist. It may, however, highlight the need to see a psychiatrist for an in-depth diagnostic assessment.

It may be worth seeking a specialist assessment for autism if:

• You were diagnosed with a mental health condition or intellectual disability in childhood or adolescence, but suspect you may have autism
• You struggle with feelings of social isolation and of being different
• Your child or another family member has been diagnosed with autism, or you feel that some of the autism traits described here apply to you

Once you have received an autism diagnosis, you can work with a clinician to identify therapy and support tailored to your needs. Getting involved with the community can help you understand autism better and provide access to support through local groups.

What are the benefits of a diagnosis (even later in life)?

Getting a professional diagnosis can help you access the support and help you may need or want. The ability to manage social interactions more effectively Your family, friends and colleagues may understand you and your needs better — allowing them to support you more effectively. You may gain a stronger sense of your own identity through a better understanding of yourself and the spectrum. You may gain a better understanding of your experiences as a child or teenager. You may feel more confident knowing you are part of a wider group of adults who may share similar experiences.

ASD therapy methods aim to reduce symptoms that interfere with day-to-day functioning and quality of life for people on the autism spectrum. ASD affects every person differently, meaning that autistic individuals have unique strengths, challenges and needs. For this reason, the therapy plan is tailored to each patient's individual needs.

Behavioural interventions Behavioural interventions begin early in life and are based on behaviour modification and learning theory. It should be emphasised that behavioural therapies are not aimed at "curing" ASD and are far removed from conversion therapy. Instead, the focus is on issues associated with the lived experience of being autistic: depression, stress, anger, aggression, anxiety, and difficulties with social interaction. Evidence-based intervention models include Applied Behaviour Analysis (ABA), an intensive behavioural intervention process aimed, for example, at increasing socially beneficial behaviours and reducing behaviours that may interfere with functioning. Even where therapy aims to change behaviour, it should focus on building skills rather than simply suppressing harmful or challenging behaviour. For example, if a child screams in order to communicate, therapy should aim to help them learn to communicate in a more constructive way, rather than simply teaching them to be quiet.

A widely supported ABA programme is Early Intensive Behavioural Intervention for young children — a highly individualised programme that uses a range of methods to teach simple skills before progressing to more complex ones. ABA techniques have been shown to be effective for social skills, academic tasks, communication, life skills and vocational skills.

Educational interventions Children with ASD need a structured educational plan. The aim is to improve verbal and non-verbal communication, as well as social, academic and motor skills.

Speech and language interventions Communication is a key focus of ASD therapy. Speech and language therapy is the most common intervention used with children with ASD, and includes strategies such as reinforcing speech sounds, exaggerated imitation, reinforcing communicative acts, and sound imitation.

Developmental interventions Developmental interventions are designed around developmental theory. Children learn social interaction, communication and emotional regulation through interaction with others. Developmental interventions focus on the relationship between the patient and an adult (parent or carer).

Pharmacological interventions Sleep disorders, anxiety disorders, and mood disorders such as depression, which often co-occur in people with ASD, may require pharmacological treatment.

Neurostimulation Neurostimulation methods such as TMS therapy (transcranial magnetic stimulation) and TPS (transcranial pulse stimulation) offer a non-invasive way of influencing activity in specific brain areas. TMS protocols used in autism spectrum disorder aim to regulate the activity of structures involved in sensory processing. TMS is being investigated as a targeted way of addressing the mechanisms thought to underlie ASD symptoms. Research suggests that TPS may lead to changes across large-scale neural networks and to improvements in social communication and behavioural flexibility.

EEG Biofeedback EEG Biofeedback is a non-invasive, non-pharmacological therapeutic method based on self-regulation. A number of studies have found that EEG biofeedback reduces symptoms of autism spectrum disorder (ASD).

Nutritional psychology Research suggests that a diet rich in essential omega-3 fatty acids and B vitamins may be beneficial for people on the autism spectrum. Low-glycaemic-index foods, such as certain vegetables and wholegrain products, help stabilise blood sugar levels, which has a positive effect on cognitive functioning and can make it easier to manage some of the difficulties autistic people may face, such as sensory overload. A nutritional psychologist also takes many other factors into account when developing a dietary plan. People with ASD often experience gastrointestinal symptoms, and their intensity can affect behavioural difficulties. Appropriate nutritional intervention, tailored to the patient's needs, can reduce gastrointestinal symptoms.

• https://www.ncbi.nlm.nih.gov/books/NBK557548/
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