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Can you just develop autism?

Autism spectrum disorder (ASD) refers to a range of neurodevelopmental disorders characterized by challenges with social skills, communication, and restricted/repetitive behaviors. Many people wonder if autism is something that can develop later in life or if it is present from birth. This article will examine the current research on whether autism is something that can develop in individuals after early childhood.

Is autism present from birth?

The current scientific consensus is that autism spectrum disorders originate very early in development, likely before birth. Here are some key points about the early origins of autism:

– Brain imaging and postmortem studies show that there are differences in brain structure and organization in autistic individuals that likely arise during prenatal development. Differences have been found in regions involved in social cognition, language, emotion regulation, and sensory processing.

– Studies of infants at high genetic risk for autism (siblings of diagnosed children) find early differences in aspects like attention, motor control, and social engagement beginning as early as 6 months of age. This suggests autism is not something that suddenly appears later.

– The behavioral symptoms of autism typically first become fully apparent between 12-24 months as social communication and language demands increase. However, subtle differences in things like gaze, attention, and sensory behaviors are often noticeable earlier.

– Autism has a strong genetic component, meaning it runs in families. The genes implicated are present from conception and affect early aspects of brain development. Environmental factors may play a role in modifying these genetic risks but do not by themselves cause autism later.

Overall, research strongly indicates autism originates very early, well before birth, even if the defining behavior symptoms do not show up until toddlerhood when a diagnosis is typically made. Autism likely involves fundamental differences in brain wiring that are present at birth.

Is it possible for autism to develop later in childhood?

While autism likely originates very early, could it ever develop later in a child that showed typical development as a toddler? There are a few extremely rare possibilities:

– Regression into an autistic-like state could potentially occur after epilepsy, brain injury, or infections that cause encephalitis. However, this regression is distinct from autism and does not have the same underlying causes.

– Landau-Kleffner syndrome involves language regression usually between 5-7 years old that can resemble aspects of autism. But it has a specific neurological cause involving epilepsy-like electrical abnormalities in the brain.

– Children severely deprived of social interaction in early childhood may develop some autistic-like behaviors. However, these will improve with intervention and are not true autism caused by underlying brain differences.

– Highly rare genetic diseases like Rett syndrome or Smith-Magenis syndrome initially appear typical but involve regression in mid-childhood that can have autistic-like features.

While these unique medical conditions can rarely involve autistic-like regression in childhood, they are distinct from the autism spectrum disorders that emerge in the first years of life and do not have the same causes. Most experts believe it is exceedingly unlikely for true autism to develop de novo later in childhood in individuals who previously had typical development.

Can adults develop new autistic characteristics?

What about adults – is it possible for someone to suddenly develop symptoms of autism or an autism spectrum disorder as an adult? This is also considered very rare, for a few reasons:

– Autism differences in social communication, language use, sensory issues, and restricted interests persist as an enduring part of an individual’s personality and abilities. These core features are not something that suddenly arises anew in adulthood.

– In some cases, adults may recognize autistic characteristics in themselves for the first time and seek a diagnosis. However, looking back, the signs were likely there from childhood but may have been missed or masked by coping strategies.

– Traumatic brain injury has very rarely been associated with the emergence of autistic-like symptoms in adults. However, this again is distinct from true autism that originates developmentally.

– Some neurodegenerative disorders like semantic dementia may involve autistic-like personality changes but are dementing illnesses not likely related to true autism.

While autism spectrum disorder is considered a lifelong neurodevelopmental condition, it is possible for some adults to recognize their autistic traits later in life. But it is unlikely for someone with no autism history to suddenly develop genuine autism de novo in adulthood. Any regression in an adult warrants medical investigation to uncover the cause.

Can newborns or infants ‘develop’ autism after birth?

Since autism likely originates before birth, could anything after birth trigger or cause autism to develop in a newborn or infant? Research does not support this:

– No links have been found between childhood vaccines and developing autism, even in kids with genetic susceptibility. Vaccines do not cause autism.

– Diet, gastrointestinal issues like reflux, and medications a child may take do not cause autism. Autism behaviors may sometimes improve with treatments for medical issues but these did not cause the autism.

– Traumatic experiences like abuse do not cause autism, though they may worsen some behaviors like social withdrawal. Autism differences are rooted in biology, not life experiences.

– Autism is not caused by certain parenting styles. While interventions targeting caregiver-child interactions can improve outcomes, parenting does not originate autism.

In extremely rare cases, infections or metabolic disorders in newborns that cause broader neurological damage may have autistic-like features. However, these medical conditions are distinct from idiopathic autism originating before birth with genetic influences. Overall, there is no evidence that postnatal experiences cause autism in a previously typical baby or infant.

Can head injury or dementia lead to new autistic symptoms?

In adults, new onset of autism-like symptoms is sometimes seen with two neurological conditions:

– Traumatic brain injury – Damage to certain areas involved in social cognition like the orbitofrontal cortex very rarely can mimic some symptoms of autism, like social-emotional disconnect. This is likely a distinct phenomenon from developmental autism.

– Frontotemporal dementia – This dementia more commonly presents with disinhibition, but some variants impair social cognition in an autism-like fashion. This reflects the progressive brain atrophy, unlike lifelong autism.

In these rare cases, new autistic-like signs reflect specific underlying neurological disease processes affecting relevant brain regions. This differs from the early neurodevelopmental origin of autism spectrum disorders arising in childhood that involves distributed differences in brain wiring.

Can mental illness lead to behaviors that resemble autism?

Certain mental health conditions involve social withdrawal or repetitive behaviors that may suggest autism to an outside observer:

– Social anxiety disorder often involves avoidance of social situations, which superficially resembles the social difficulties seen in autism. However, in anxiety the cause is excessive fear vs. inherent challenges processing social information.

– Obsessive compulsive disorder and related conditions like body dysmorphic disorder involve repetitive rituals and restricted interests. But these arise from intrusive thoughts rather than an innate need for sameness and routine.

– Schizoid personality displays detachment from social relationships and restricted emotional expression. But this reflects a voluntary choice rather than an inherent incapacity for social connection.

– Schizotypal personality exhibits social eccentricities and cognitive/perceptual distortions carrying a familial risk for schizophrenia. The social impairments differ from the more concrete social communication challenges in autism.

While certain mental health conditions may mimic autistic-like characteristics, careful assessment can distinguish these from bona fide autism spectrum disorder arising from biological and developmental differences in brain function.

Does autism ever ‘go away’ or lessen with age?

Autism spectrum disorder involves lifelong neurodevelopmental differences though the way it manifests can change over time:

– Core aspects like social communication challenges, sensitivity to sensory stimuli, preference for routine, and intense interests tend to persist over the lifetime as part of an individual’s innate neurology and personality.

– However, symptoms once defined as more “classically autistic” like lack of speech or repetitive motor behaviors often improve or lessen with age due to development and learning.

– Increased life experience and conscious coping strategies in adulthood can help compensate for and mask some difficulties interacting socially or managing new situations.

– Co-occurring conditions like anxiety, ADHD or depression may wax and wane across the lifespan and modulate how autism characteristics present.

– Rarely, a minority of individuals lose their autism diagnosis, but likely still have mild residual symptoms/differences from the norm.

So while autism is lifelong, the specific manifestations tend to evolve over time as development and adaptation occur. But the core neurodevelopmental differences underpinning autism remain rather than disappearing. Autism is not something that can resolve or go away completely later in life.


Based on a large body of scientific evidence, autism spectrum disorders originate very early in prenatal development due to a complex interplay of genetic and environmental factors that shape early brain growth. While autistic-like symptoms can rarely arise from distinct neurological conditions like brain injury or dementia, autism itself does not appear to develop de novo later in childhood or adulthood in individuals with no prior history. Core aspects of autism like social communication challenges, sensory issues, need for routine, and intense interests persist as an enduring intrinsic part of an individual’s abilities and personality, though adaptive strategies and developmental changes may lessen their impact over time. There is no evidence that autism is something individuals can suddenly “develop” after birth due to life experiences or other non-genetic factors. Rather, it reflects innate lifelong neurodevelopmental differences that are present from very early life.