Autism

Characteristics

• Those who have autism are described as neuroatypical, as opposed to neurotypical (may have other neuropsychiatric conditions)  

• Long way away from treatment, some people may not want treatment  

• Defined as a pervasive developmental disorder à emerges during neurodevelopment and remains with an individual across their lifetime  

• Huge spectrum of traits associated with autism à makes it a challenge for diagnosis  

• A whole range of expression of normal human behaviour, but the constellation of their expression which results in its expression  

• Brain disorder à the symptoms originate from a difference in brain function 

• Highly genetically penetrant but largely polygenic (most genetically penetrant of psychiatric conditions) 

• Synaptopathy – dysfunction, disruption and change in synaptic function underlying the autism traits  

• Therapeutic treatments often treat the symptomologies rather than the underlying disorder 

Historical aspects

• Leo Kanner describes a cohort of children (early developmental effect) with stunted communication and social interaction 

• Motor behaviour disrupted and locked into repetitive behaviours  

• Aspergers – diluted version of Autism where the traits are less disrupted but less emphasis on  language dysfunction 

• 3 things that seem to define autism:

1. Impaired social interactions relevant for a young child  

2. Repetitive restricted behaviours  

3. Associated reduction in language skills 

Autism as a developmental disorder

• Development can mature over time à can initially receive a diagnosis of autism but can be better defined by other syndromes 

• Early diagnosis features don’t show the same trajectory in adulthood  

• Ability to describe the cognitive dysfunction a confound for achieving a diagnosis  

• Some defined syndromes where autism traits are present: Rett’s and Fragile X 

  • A syndrome is when there's a single gene which repeatedly gives rise to a genetic disruption and an associated disease profile 

  • Previously Rett’s and fragile X provided a good experimental platform for studying autism but as the genetics have been better understood in the previous years, shift away from using them as definable models of autism 

  • Similar to how syndromes can help us identify single penetrant genes, the number of single gene genetic disruptions associated with autism has increased, the most common being Syntaxin binding protein 1 

• 10 in 10,000 – quite prevalent  

• Some disorders like Heller’s childhood disintegrative disorder, can appear like autism in childhood but throughout development can progress in a much more cognitively disrupted individual. Symptoms can present in facial features as individual gets older.   

Diagnostic manuals

• Based off three main criteria: 

 

1. Persistent deficits in social interactions across different contexts  

• Deficits in social, emotional reciprocity à when children come together at a young age one will give, the other will take and vice versa 

• Deficits in non-verbal communicative behaviours à E.g: eye contact  

• Difficulties developing and maintaining relationships à E.g: difficulties adjusting behaviours to suit different social contexts 

2. Restricted repetitive patterns of behaviours, interests or activities  

• Stereotypes or repetitive speech  

• Excessive adherence to routine à may present as excessive resistance to change or extreme distress to small changes 

• Highly restricted, fixated interests  

• Hyper or hypo reactivity to sensory input or adverse response to specific sounds or textures is a recently emerging component of the diagnostic manual  

3. Symptoms must be present in early childhood but may not fully manifest until adulthood 

 

DSM-5 perspective on the spectrum of disorders

ased on where you lie in the spectrum the requirements to help you through life will increase:  Based

When does neurotypical become neuroatypical

• supposedly more prevalent and more often diagnosed in the male population. Suggestion is that females are better at empathising, whereas human males are supposedly better at understanding non-agentive things (systemisation). 

• Based off a population plot of E/S distribution  

• Increased systemisation, reduced empathy in autistic individuals à somewhat reflection of personality 

• These are measuring neurotrypical traits, that when added together make you more likely to get an autism diagnosis  

• If you express these traits in an extreme way can cause lifesytlc challenges and make day to day living more challenging  

Attempts to understand why women are less likely to express autism

• Increased white matter and local neuron connections suggesting that processing was more localised and less able to empathise 

• Females on the other hand have a more even distribution of connections 

• Theories around prenatal androgen expression which may be ore likely to give rise to different phenotype in males as androgen production can impact on early brain development 

Addressing autism in females

• Diagnosis is more biased towards male traits à to be neuroatypical, you would be expressing traits you would be more likely to be expressed in males  

• More likely to mask the social issues and behavioural traits 

• Most of the experiments based on male cohorts à For example: depending on where you are in the oestrogen cycle may affect anxiety state and so doing experiments with these contributing factors can be misleading  

• Not comparing the sex differences may be misleading, favouring the diagnosis in the male population