Intro to Atypical Development - PSY2004

Historically individuals with developmental conditions were labeled with

terms now considered offensive

e.g. idiot, imbecile

The mental Deficiency Act (1913)

promoted institutionalisation

The Mental Health Act (1959)

shifted focus to human rights and community care, driven partly by parent advocacy.

When was the concept of developmental disorders introduced

in the early 1800's e.g. Georget, 1820

When did neurodevelopmental disorders appear in DSM

DSM-5 2013

Autism Spectrum Condition (ASC)

Deficits in social communication; restricted, repetitive behaviours and interests. Diagnosis based on DSM-5.

ADHD

Persistent patterns of inattention and/or hyperactivity-impulsivity that interfere with functioning or development.

Intellectual Disability

IQ below 70; limitations in adaptive behaviours. Can be mild, moderate, severe, or profound.

Down Syndrome

Caused by an extra copy of chromosome 21. Features include distinctive facial characteristics and variable IQ.

William's Syndrome

Caused by deletion at chromosome 7q11.2. Sociable personality, specific cognitive profile, facial features.

16p11.2 CNV

A deletion or duplication on chromosome 16. Can lead to autism, ADHD, ID, or be asymptomatic.

Fetal Alcohol Syndrome

Caused by prenatal alcohol exposure. Includes growth problems, facial anomalies, and cognitive/behavioural issues.

Genetic Causes

Inherited (e.g., some cases of intellectual disability).

Spontaneous mutations, such as Copy Number Variants (CNVs) — e.g. 16p11.2, William's Syndrome.

Chromosomal abnormalities, e.g. trisomy 21 in Down Syndrome.

Environmental Causes

Prenatal exposure

Perinatal Complications

Multifactorial Causes

Genes + Environment

Many conditions (e.g. Autism, ADHD) likely arise from multiple genetic and environmental factors, not a single cause.

Basic Genetics

DNA -> Genes -> Chromosomes -> Cells

DNA

Contains instructions to make proteins

Genes

are specific sections of NDA

Chromosomes

are structures that carry many genes

Humans have 23 pairs

Chromosomal abnormality

Refers to an atypical number or structure of chromosomes.

Disrupt protein production, brain development, leading to cognitive, behavioural, and physical traits associated with developmental conditions.

Extra chromosomes

Trisomy 21 in Down Syndrome

Deletions

Missing part of a chromosome e.g. Williams Syndrome 7q11.2

Duplications

Repeated sections e.g. 16p11.2 duplication

Societal attitudes have shifted

From viewing neurodevelopmental conditions as "deficits" to recognising them as differences.

Neurodiversity movement

promotes the idea that diversity in brain functioning is a natural and valuable part of human variation.

Importance of language

Avoid pathologising terms

Respect individual preference for identity-first or person-first

Use respectful, non-othering language

Current Debates

Discussions continue around inclusion, the medical model vs. social model of disability, and the value of behavioural diagnosis in light of genetic and environmental overlap.