Autism Spectrum Disorder (ASD)

What autism is

Autism reflects differences in how the brain develops and processes information, starting before birth. It is not caused by parenting, and it is not an illness to be cured. Many autistic adults describe autism as part of their identity. At the same time, many autistic people face real difficulties, and some need substantial lifelong support.

The DSM-5 diagnosis requires both:

1. Persistent differences in social communication and interaction, such as in back-and-forth conversation, nonverbal communication (eye contact, gestures, facial expression), and developing and understanding relationships.
2. Restricted, repetitive patterns of behavior, interests or activities, such as repetitive movements or speech, insistence on sameness, intense focused interests, and over- or under-reaction to sensory input.

Severity is described in three support levels: requiring support, requiring substantial support, and requiring very substantial support. Asperger syndrome, an older term for autistic people without language or intellectual delay, is now included within ASD.

Signs of autism by age

Babies and toddlers

• little or no eye contact or social smiling
• not responding to their name by 12 months
• not pointing to show interest or to ask by 12 to 14 months
• limited babbling, delayed words or unusual speech
• not playing pretend games by 18 months
• lining up toys, spinning objects, flapping hands
• strong reactions to sounds, textures, lights or smells
• loss of words or skills they previously had (regression)

School-age children

• difficulty with two-way conversation or understanding jokes and sarcasm
• preferring to play alone or struggling to make friends
• very intense interests in specific topics
• distress at changes in routine
• literal understanding of language
• repetitive movements (stimming) when excited or stressed

Teenagers and adults

• social exhaustion and "masking" (copying others to fit in)
• difficulty reading unwritten social rules
• strong preference for routines and predictability
• sensory overload in busy environments
• deep expertise in particular interests
• anxiety, depression and burnout, which are common

Girls and women are more often missed or diagnosed late, because they may mask more and have socially typical interests.

Causes and risk factors

Autism is strongly genetic: it often runs in families, and siblings of autistic children have a higher chance of being autistic. Contributing factors include:

• many common gene variants and some rare ones
• genetic conditions such as fragile X syndrome, tuberous sclerosis and Rett syndrome
• older parental age
• premature birth and very low birth weight
• certain exposures in pregnancy, such as valproate

Vaccines do not cause autism. This has been studied extensively in millions of children.

Co-occurring conditions

Autistic people more often have:

• ADHD
• anxiety and depression
• intellectual disability (in about a third)
• epilepsy
• sleep problems
• constipation and other gut problems
• restricted eating (ARFID)
• speech and language disorders

Recognizing and treating these often improves quality of life more than anything else.

How autism is diagnosed

• Developmental surveillance at every well-child visit, with autism-specific screening (such as the M-CHAT-R/F questionnaire) at 18 and 24 months, as recommended by the AAP.
• Comprehensive assessment by a developmental pediatrician, child psychologist, psychiatrist or multidisciplinary team, including developmental history, observation (for example, ADOS-2), and speech, language and cognitive testing.
• Hearing test to rule out hearing loss.
• Genetic testing (chromosomal microarray, fragile X testing) is recommended for diagnosed children.
• Adult assessment by a psychologist or psychiatrist experienced in autism.

A reliable diagnosis can often be made by age 2, but the average age of diagnosis in the US is around 4 to 5 years.

Support and treatment

There is no medicine for autism itself. Support focuses on communication, independence, learning and wellbeing:

• Early intervention services from birth to age 3, and special education services through school
• Speech and language therapy, including augmentative and alternative communication (picture systems, devices)
• Occupational therapy for sensory and daily living skills
• Developmental and behavioral approaches, such as naturalistic developmental behavioral interventions and parent-mediated programs
• Social skills support and peer programs
• Accommodations at school and work: quiet spaces, clear instructions, predictable schedules
• Medicines for co-occurring conditions: ADHD medicines, sleep support, and risperidone or aripiprazole for severe irritability and aggression
• Mental health care adapted for autistic people

Be cautious of unproven treatments, such as chelation, special diets without a medical reason, or hyperbaric oxygen, which can be harmful.

Outlook

Autism is lifelong, but skills develop throughout life. Many autistic people finish education, work, have relationships and live independently, while others need ongoing support. Outcomes improve with early support, understanding environments, and attention to mental and physical health.

Frequently asked questions

What are the early signs of autism in toddlers?

Early signs include limited eye contact, not responding to their name by 12 months, not pointing or using gestures, delayed speech, little interest in pretend or shared play, repetitive movements, strong sensory reactions, and losing words or skills. Talk to your pediatrician if you notice these.

What causes autism?

Autism is mainly caused by genetic factors that shape brain development before birth. Premature birth, older parental age and some exposures in pregnancy add to the risk. Vaccines, parenting style and diet do not cause autism.

Can adults be diagnosed with autism?

Yes. Many adults, especially women, are diagnosed later in life after years of social difficulty, anxiety or burnout. A psychologist or psychiatrist experienced in adult autism can assess you. A diagnosis can help with understanding yourself and accessing support.

Is there a cure for autism?

No. Autism is a lifelong difference in brain development, not a disease. Support such as speech therapy, occupational therapy, educational help and treatment of co-occurring conditions helps autistic people communicate, learn and thrive.

What is the difference between autism and ADHD?

Autism mainly involves differences in social communication with repetitive behaviors and sensory sensitivities. ADHD mainly involves inattention, hyperactivity and impulsivity. They often occur together, and both can be diagnosed in the same person.