Lecture 1: Introduction to Atypical Development

neurodevelopmental condition

-lifelong condition that affects how the brain develops and leads to atypical development

-ranges from mild differences to severe difficulties

-caused by genetic or environmental factors or both

misguided historical language

• idiocy and imbecile to describe people with mental ages lower than 2

• idiots savants - Langdon Down (1887)

-describes patients with exceptional abilities in an extremely narrow field (autism)

• attentio volubilis (1775)

-describes patients who are easily distracted (ADHD)

Mental Deficiency Act (1913)

-institutionalisation for children labelled ‘mentally defective’

-children received same care as adults with the same conditions 

-Cyril Burt was first government appointed psychologist

-he identified children who should be institutionalised 

Commonwealth Fund (late 1920s)

-funded child guidance clinics

-funded by American philanthropic body to improve child guidance services in Britain

-used to direct child-rearing principles and to guide the behaviour of problem children

The Mental Health Act (1959)

-emphasised the importance of human rights and dignity for individuals with mental health conditions

-children no longer mandatorily institutionalised

-local authorities now responsible for their care and many institutions closed

-mainly led by parent advocacy

universalising concepts (1960s-1980s)

-a largescale movement to universalise neurodevelopmental concepts across psychiatry, psychology and neuroscience

-different places used different terms and there was no consensus or easy way to share information

-driven by need for standardised diagnosis and treatments

autism official recognition

-Leo Kanner 

-1943

ADD official recognition

-APA 

-late 1960s

down syndrome official recognition

-John Langdon Down

-1866

Williams’s syndrome official recognition

-JCP Williams

-1961

fetal alcohol syndrome official recognition

-David Smith & Kenneth Jones

-1973

intellectual disability official recognition

-had previously been viewed as part of other diagnosis and not a diagnosis within its own right 

-DSM III 

-1980

historical perspective 

-reference to different conditions mentioned in historical accounts but not by name but rather recognisable descriptions

-each condition was treated as a discrete, standalone diagnosis 

-concept of developmental disorders created in 1820

-neurodevelopmental conditions as a label didn’t appear until DSM-V

DSM-III

-increased scientific research and growing understanding of neurodevelopmental conditions led to greater recognition of their distinct characteristics and impact

-provided the foundation for developing specific diagnostic criteria

-need for consistency and reliability → emphasis on observable and measurable behaviours

-wasn’t understood that neurology underlined these conditions

categorical approach (DSM-III)

-developmental conditions were placed into distinct categories with specific criteria:

• learning disorders

• mental retardation

• motor skills disorders

• communication disorders

• pervasive developmental disorders

DSM-V

-recognises many developmental disorders have underlying neurological and biological origins

-acknowledges that many conditions share behaviours

-groups conditions into one broad category of neurodevelopmental conditions, including:

• intellectual disability

• ASD

• ADHD

• specific learning disorder

• motor disorders

• communication disorders

reasons for atypical development

• pre-natal effects

• environmental effects

• genetic effects

• unknown effects (likely multifaceted)

developmental conditions with known genetic cause

• William’s syndrome 

• Down’s syndrome 

• 16p.11.2 

basic genetics

-DNA contains instructions for building proteins

-basis for all development

-DNA is packaged into genes

-genes are contained in chromosomes

chromosome arm

-on each chromosome:

• short arm → labelled as p

• longer arm → labelled as q

chromosome region 

-labelled with numbers

-lower numbers representing a region of the chromosome that is closest to the centre 

16p11.2 (known genetic cause)

-duplication or deletion of chromosome 16, section 11.2

-associated with ADHD, autism, intellectual disability, anxiety and OCD

-may remain undetected due to no physical or developmental symptoms

16p11.2 deletion

-ASD

-ID 

-epilepsy/seizures

-DF/CA

-macrocephaly 

-speech/language delay

-motor/developmental delay

-obesity

-depression/anxiety

-ADHD

16p11.2 duplication 

-ASD

-ID

-epilepsy/seizures

-DF/CA

-microcephaly 

-speech/language delay 

-low BMI 

-depression/anxiety

-ADHD

-schizophrenia 

-BPD

chromosomal abnormalities

-genetic abnormalities are too many or too few of particular genes due to:

-addition of a chromosome

-duplication or deletion of a certain part of the chromosome → extra copies of some genes or missing copies of some genes

• these are called COPY NUMBER VARIANTS (CNVs)

William’s Syndrome (known genetic cause)

-caused by spontaneous deletion at chromosome 7q11.2.

-characterised by a distinct facial appearance, cardiac anomalies, highly sociable personality, atypical cognitive profile and connective tissues abnormalities

facial appearance (William’s Syndrome)

-sunken nasal bridge

-puffiness around the eyes

-can see eyelid

-blue eyes with starry pattern

-long upper lip length

-small and widely spaced teeth

-wide mouth

-prominent lower lip

-small chin

cognitive profile (William’s Syndrome)

-strong language and speech production abilities 

-very low spatial abilities 

-low IQ

Down Syndrome (known genetic cause)

-caused by a duplication of chromosome 21 

-can be due to a full duplication (one extra chromosome)

-can be due to partial duplication (half an extra chromosome)

physical characteristics (Down Syndrome)

-decreased or poor muscle tone

-shorter neck 

-flattened facial profile and nose 

-upward slanting eyes 

-wide, short hands with short fingers 

-single, deep crease across the palm of the hand 

cognitive characteristics (Down Syndrome)

-short attention span

-impulsive behaviour

-slow learning

-delayed language and speech development

-variable IQ → average between 30-70

developmental conditions with known environmental cause

• fetal alcohol spectrum disorder (FASD)

mechanisms of FASD

-alcohol is a teratogen

-unclear on the amount of alcohol needed to lead to FASD →

• depends on gestation period

• binge drinking leads to more severe symptoms

-ethanol thought to alter DNA and protein synthesis and inhibit cell migration, leading to an array of physical and cognitive changes

teratogen (FASD)

-an agent which causes change in an embryo

FASD

-diagnostic term describing the constellation of effects that result from prenatal alcohol exposure 

FASD diagnostic criteria

-abnormal facial features

-small head size

-shorter height

-low body weight

-poor coordination

-hyperactive behaviour

-learning disabilities

-speech and language delays

-vision or hearing problems

developmental conditions with unknown causes

-intellectual disability

-ASD

-ADHD

intellectual disability (unknown causes)

-diagnosis based on IQ evaluation as well as investigation of adaptive behaviour, classified as mild, moderate, severe or profound

-is a diagnosis on its own but often co-occurs with other neurodevelopmental conditions

mild intellectual disability

• 52-69 IQ

moderate intellectual disability

• 36-51 IQ

severe intellectual disability

• 20-35 IQ

profound intellectual disability

• IQ lower than 19

diagnosing intellectual disability 

-measured on 3 domains: 

• conceptual domain → academic, writing, language, maths, etc.,

• social domain → how do they interact with peers, family, romantic relationships, issues with understanding relationships 

• practical domain → how do they function in the real world 

ADHD and autism (unknown causes)

-no clear cause for either 

• likely numerous contributing factors 

-no definitive genetic test 

-diagnosis is made by behavioural observations