Causes & Treatment of ASD

Causes of Autism Spectrum Disorder

ASD has no single cause. It results from complex interactions between genetic and environmental factors affecting early brain development.

Genetic Factors (Primary Cause)

Heritability:

Highly genetic: 80-90% heritability (higher than ADHD)
Strongest evidence for genetic basis among neurodevelopmental disorders
If one identical twin has ASD: 60-90% chance for other twin
If one sibling has ASD: 10-20% chance for another sibling
Recurrence risk increases with multiple affected siblings

Genetic Mechanisms:

Multiple Genes Involved (Polygenic):

No single “autism gene”
100s of genes contribute to risk
Each contributes small effect
Different combinations in different individuals

Types of Genetic Variants:

Common Genetic Variants: Small effects, present in general population
Rare Gene Mutations: Larger effects, specific to individual/family
Copy Number Variants (CNVs): Deletions or duplications of DNA segments
De novo mutations: New mutations not present in parents (10-30% of cases)

Known Genetic Syndromes Associated with ASD:

Fragile X Syndrome (most common single-gene cause, 2-5% of ASD)
Rett Syndrome
Tuberous Sclerosis
Down Syndrome
Angelman Syndrome
Timothy Syndrome

What Genes Affect:

Synaptic function (connections between neurons)
Brain development and connectivity
Neurotransmitter systems
Neuronal migration

Brain Differences

Structural Abnormalities:

Brain Size:

Increased head circumference in ~20% (macrocephaly)
Accelerated brain growth in early childhood (first 2 years)
Then growth slows or stops
Enlarged brain volume in some regions

Specific Regions Affected:

Frontal lobes: Social cognition, executive function
Temporal lobes: Language, social perception
Amygdala: Emotion processing, face recognition
Cerebellum: Motor coordination, also cognitive functions
Corpus callosum: Connection between hemispheres (often smaller)

Functional Differences:

Connectivity Problems:

Underconnectivity: Reduced long-range connections between brain regions
Overconnectivity: Increased local connections within regions
Affects integration of information across brain
Theory: “Weak central coherence” - focus on details, miss big picture

Neural Activity:

Different activation patterns during social tasks
Reduced activity in “social brain” (medial prefrontal cortex, superior temporal sulcus)
Different face processing (don’t use face-specific brain areas as much)
Atypical processing of language and communication

Mirror Neuron System:

Possible dysfunction in mirror neurons (neurons that activate when observing others’ actions)
May relate to difficulty understanding others’ intentions and emotions
Controversial theory

Prenatal/Perinatal Risk Factors

Environmental Risk Factors (Increase risk but don’t directly cause):

Maternal Factors During Pregnancy:

Advanced parental age (especially fathers over 40; mothers over 35)
Maternal infections during pregnancy (rubella, influenza with fever)
Medications: Valproic acid (anti-seizure), thalidomide
Maternal autoimmune conditions
Gestational diabetes
Severe stress

Birth Complications:

Prematurity (especially very premature, <28 weeks)
Very low birth weight
Oxygen deprivation during birth
Birth trauma

Important Note: These are risk factors, not causes; vast majority of children with these factors do NOT develop ASD; interact with genetic vulnerability

Neurobiological Theories

Neurotransmitter Imbalances:

Serotonin: Elevated in 30% (but role unclear)
GABA/Glutamate: Imbalance in excitatory/inhibitory signaling
Oxytocin: Social bonding hormone; possibly reduced
Dopamine: Possible dysregulation

Synaptic Dysfunction:

Problems with synapse formation and pruning
Too many or too few connections
Immature or unstable synapses

Immunological Factors

Immune System Involvement:

Maternal immune activation during pregnancy (possible factor)
Autoantibodies to fetal brain proteins in some mothers
Neuroinflammation in some individuals with ASD
Gastrointestinal issues linked to immune dysfunction

Note: Active research area; role still being clarified

Debunked Myth

VACCINES DO NOT CAUSE AUTISM:

Original study (Wakefield 1998) was fraud, retracted, author lost medical license
Dozens of large studies found NO link between vaccines (MMR or any vaccine) and autism
Timing coincidence: Symptoms emerge around age vaccinations given
Vaccine rejection puts children at risk for dangerous diseases
Scientific consensus: No link whatsoever

Other Debunked/Unsupported Theories

Refrigerator mothers (cold, emotionless parenting): Completely disproven, harmful myth
Heavy metals (mercury, thimerosal): No evidence
Gluten/casein: No general causative role (though some may have food sensitivities)

Treatment of Autism Spectrum Disorder

Important Note: No cure for ASD; treatment focuses on maximizing potential and quality of life

Early Intensive Behavioral Intervention (EIBI)

Gold Standard Treatment:

Start as early as possible (before age 4 ideal; diagnosis often by age 2-3)
Intensive: 20-40 hours per week
Based on Applied Behavior Analysis (ABA) principles
Highly structured, individualized
Evidence: Most effective intervention, especially if started early

Applied Behavior Analysis (ABA):

Principles:

Break skills into small steps
Positive reinforcement for desired behaviors
Repetition and practice
Data-driven (measure progress objectively)
Generalization across settings

Types of ABA:

Discrete Trial Training (DTT):

Highly structured, one-on-one
Clear beginning, middle, end to each trial
Immediate feedback
Teaches specific skills systematically

Natural Environment Teaching (NET):

Uses child’s interests and natural opportunities
Less structured than DTT
Teaching in natural contexts
Play-based

Pivotal Response Training (PRT):

Targets “pivotal” areas (motivation, self-management, social initiations)
Child-directed
Natural reinforcers

Early Start Denver Model (ESDM):

Combines ABA with developmental relationship-based approach
Play-based, naturalistic
For very young children (12-48 months)
Evidence-based

Effectiveness:

Significant improvements in IQ, language, adaptive behavior
Best outcomes with early, intensive intervention
Some children make dramatic progress
Not all respond equally

Controversy:

Some autistic self-advocates critique ABA as trying to make autistic people “normal”
Concerns about focus on compliance, suppressing autistic behaviors
Modern ABA increasingly incorporates child preferences, natural reinforcement
Debate continues

Speech and Language Therapy

Essential for Most with ASD:

Goals:

Developing verbal communication (if nonverbal/minimally verbal)
Improving conversation skills
Understanding and using nonverbal communication
Pragmatic language (social use of language)
Receptive language (understanding)
Expressive language (expressing needs, thoughts)

Augmentative and Alternative Communication (AAC):

For Minimally Verbal or Nonverbal (25-30% of ASD):

Picture Exchange Communication System (PECS): Using pictures to communicate
Speech-generating devices: Tablets with communication apps
Sign language: Some use sign
Important: AAC doesn’t prevent speech development; often helps

Occupational Therapy (OT)

Addresses:

Sensory processing issues (very common in ASD)
Fine motor skills (writing, buttoning, cutting)
Daily living skills (dressing, eating, hygiene)
Play skills
Motor planning and coordination

Sensory Integration Therapy:

For sensory processing difficulties
Graded sensory experiences
Helps with regulation
Mixed evidence but widely used

Teaching Social Interaction:

Structured Programs:

Social skills groups (peers with similar challenges)
Teaching specific skills (conversation, reading social cues, friendship)
Role-playing and practice
Video modeling (watching and imitating social behaviors)

Peer-Mediated Interventions:

Typically developing peers taught to engage with autistic child
Natural social opportunities
Effective in schools

Social Stories:

Short stories describing social situations and appropriate responses
Help understand social expectations
Visual supports

Cognitive Behavioral Therapy (CBT)

For Higher-Functioning Individuals:

Address anxiety (very common comorbidity)
Depression
Anger management
Modified for ASD (more concrete, visual, structured)

Medications

No Medication for Core Symptoms of ASD:

Medications treat associated/comorbid symptoms only

Commonly Prescribed:

For Irritability, Aggression, Self-Injury:

Risperidone (Risperdal): FDA-approved for irritability in ASD, ages 5+
Aripiprazole (Abilify): FDA-approved for irritability in ASD, ages 6+
Both are atypical antipsychotics
Side effects: Weight gain, sedation, metabolic issues

For ADHD Symptoms:

Stimulants (methylphenidate, amphetamines)
Atomoxetine
Guanfacine
Many with ASD have co-occurring ADHD

For Anxiety/Depression:

SSRIs (Prozac, Zoloft, etc.)
Use cautiously; some with ASD react differently

For Sleep Problems:

Melatonin (commonly used, fairly safe)
Sleep hygiene first

Other:

Anti-seizure medications (if epilepsy present)

Important:

Medications are adjunct, not primary treatment
Carefully monitor side effects
Start low, go slow
Individualized

Educational Interventions

Individualized Education Plan (IEP):

Required in U.S. for special education services
Individualized goals and accommodations
Regular progress monitoring

Classroom Accommodations:

Visual schedules and supports
Structured, predictable environment
Preferential seating
Breaks from sensory stimulation
Modified assignments
Social stories for transitions
Extra time for tasks

Inclusion vs. Specialized Settings:

Inclusion: General education classroom with supports
- Benefits: Social exposure, high expectations, typical peer models
Specialized classroom: Smaller, specialized instruction
- Benefits: More intensive support, adapted curriculum
Depends on individual needs; movement toward inclusion with supports

Transition Planning:

Essential for adolescents
Planning for post-high school (employment, college, independent living)
Vocational training

Parent Training and Support

Parent Education:

Understanding ASD
Managing behaviors
Implementing strategies at home
Advocacy skills

Parent Support Groups:

Autism Society
Autism Speaks (controversial in autistic community)
Local support groups
Connection, shared experiences, resources

Developmental and Relationship-Based Approaches

DIR/Floortime:

Focus on emotional and relationship development
Follow child’s lead in play
Build on interests
Less evidence than ABA but some support

Relationship Development Intervention (RDI):

Focus on building motivation for social connection
Parent-implemented
Limited research evidence

Complementary and Alternative Treatments

Many Families Try Alternative Treatments:

Some Support:

Omega-3 fatty acids: Modest improvements in some studies
Melatonin: For sleep (evidence-based)
Exercise: Benefits behavior and health
Music therapy: May help communication, reduce anxiety

No Evidence/Potentially Harmful:

Chelation therapy (removing “toxins”): No evidence, can be dangerous
Hyperbaric oxygen therapy: No evidence
Bleach enemas (MMS): Dangerous, abusive
Secretin: No evidence
Gluten-free/casein-free diet: No evidence benefits most (unless specific allergy/intolerance)
High-dose vitamins: No evidence, possible side effects

Important: Many unproven treatments exploit desperate families; stick with evidence-based approaches

Assistive Technology

Communication Apps:

Proloquo2Go
TouchChat
LAMP Words for Life

Visual Supports:

Visual schedules
First-Then boards
Choice boards

Organizational Tools:

Timers
Checklists
Reminder apps

Lifespan Considerations

Preschool:

Early intensive behavioral intervention (EIBI)
Speech therapy
OT for sensory issues
Family support

School-Age:

Continue therapies
Social skills training
Academic support
Inclusion with supports when possible

Adolescence:

Transition planning
Vocational training
Social skills (dating, peer relationships)
Independence skills
Address mental health (anxiety, depression common)

Adults:

Employment support (many adults unemployed/underemployed)
Independent living skills or supported living
Social opportunities
Mental health support
Some need lifelong care; others live independently

Prognosis

Highly Variable:

Factors Affecting Outcome:

IQ: Higher IQ, better prognosis
Language development: Meaningful speech by age 5-6 predicts better outcome
Early intervention: Dramatic impact on outcomes
Symptom severity: Less severe symptoms, better outcomes
Comorbidities: Fewer co-occurring conditions, better prognosis

Possible Outcomes:

Some: Achieve independence, employment, relationships, may marry
Some: Need ongoing support in some areas, semi-independent
Some: Require lifelong comprehensive support
Optimal outcome: Small percentage lose diagnosis (catch up developmentally with intensive early intervention)

Adulthood:

Many capable of employment with support
Some attend college
Some live independently or semi-independently
Quality of life can be good with appropriate support
Challenges with employment, relationships common

Neurodiversity Perspective

Important Movement:

Key Ideas:

Autism is a different way of being, not a disease
Focus on acceptance, not “curing”
Value autistic strengths (attention to detail, pattern recognition, honesty, deep focus)
Society should accommodate differences
“Nothing about us without us” (include autistic voices)