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Autism spectrum
1943; one spectrum 2013· Condition or disorder
Well replicatedStrong, repeated evidence.
A lifelong neurodevelopmental condition in social communication and sensory experience, with focused interests and repetitive behaviors.
See it on the Psychology map →What it says
Leo Kanner described 11 children in Baltimore in 1943; Hans Asperger described similar boys in Vienna in 1944. DSM-5 (2013) merged autism, Asperger's and related labels into one spectrum, with support levels from minimal to very substantial. The CDC now counts about 1 in 31 US eight-year-olds as autistic, a rise driven largely by broader criteria and better screening. Heritability is about 80 percent. The 1950s 'refrigerator mother' theory blaming cold parents was wrong.
Why it matters
Early support helps, many autistic adults went undiagnosed, and the neurodiversity movement has reframed autism as a difference with strengths as well as challenges.
The evidence
Twin and genome studies; the CDC monitoring network; large studies, including a 2019 Danish one of 650,000 children, finding no link to vaccines. Wakefield's 1998 vaccine paper was retracted as fraudulent.
Open questions
Why diagnoses keep rising is debated. A 2025 US government claim tying prenatal acetaminophen to autism rests on disputed data; a Swedish sibling study of 2.5 million children found no link.
Connections (3)
▸Applied behavior analysis (ABA) is widely used for Autism spectrumMixed evidence
The connection
ABA breaks skills such as speech, play or toileting into small steps and rewards each success, tracking progress with data. Ivar Lovaas's 1987 report of dramatic gains made intensive early ABA the dominant autism therapy in the US, and all 50 states now require many health plans to cover it.
Who showed it and when
UCLA, 1960s–1987 (Lovaas); state insurance mandates spread from 2001 and reached all 50 states by 2019.
How solid is it?
Reviews find early intensive behavioral programs improve some skills, but most studies are small and few are randomized; a 2018 Cochrane review rated the evidence low quality.
Open questions
Many autistic adults criticize ABA, especially older forms, for aiming at compliance and masking; supporters say modern play-based ABA differs. The debate is active.
▸Theory of mind (the false-belief test) is often delayed in Autism spectrumMixed evidence
The connection
In 1985 Simon Baron-Cohen, Alan Leslie and Uta Frith found most autistic children failed a false-belief test (where will Sally look for her marble?) that most younger typical children passed. They proposed that difficulty imagining others' minds is a core feature of autism.
Who showed it and when
London, 1985 ('Does the autistic child have a theory of mind?'); 80 percent of the autistic children failed, versus about 15 percent of the comparison children.
How solid is it?
Many studies replicate delays on such tests, but many autistic people pass them, especially with age, strong language skills or extra time.
Open questions
The 'double empathy' idea (Damian Milton, 2012) argues understanding breaks down in both directions between autistic and non-autistic people, not just one.
▸Autism spectrum is listed as a neurodevelopmental condition among Mental disorders: what they are and how commonWell replicated
The connection
DSM-5 lists autism among neurodevelopmental conditions, alongside ADHD, which often co-occurs with it. Autistic people have higher rates of anxiety, depression and epilepsy. Many autistic adults reject the 'disorder' framing, seeing autism as a different way of being that needs support and acceptance rather than cure.
Who showed it and when
DSM-III listed 'infantile autism' separately from childhood schizophrenia in 1980; DSM-5 created the single autism spectrum in 2013.
The evidence
Clinical studies document high co-occurrence of ADHD and anxiety; surveys show many autistic adults prefer identity-first language such as 'autistic person'.
Open questions
How to balance the neurodiversity view with the needs of autistic people with high support needs, including intellectual disability, is contested.