Autism is primarily characterized by differences and difficulties in social interaction and communication, alongside restricted or repetitive patterns of interests, activities, or behaviors (
stimming), and, in many cases, distinctive reactions to sensory input. The specific presentation varies widely. Clinicians often consider assessment for autism when these characteristics are present, especially if they are associated with difficulty obtaining or sustaining employment or education, difficulty initiating or maintaining social relationships, involvement with mental health or learning disability services, or a history of neurodevelopmental conditions (including learning disabilities and
ADHD) or mental health conditions. In most cases, signs of autism are first observable in infancy or early childhood and remain throughout life. Autistic people may be significantly disabled in some respects, but average—or, in some cases,
superior—in others.
Social and communication skills Autistic people may have differences in social communication and interaction, which can lead to challenges in environments structured around non-autistic norms. Diagnostic criteria for autism require difficulties across three social domains: social-emotional reciprocity, nonverbal communication, and developing and maintaining relationships.
Social–emotional reciprocity Common early signs of autism include little or no
babbling in infancy. Difficulties may also be apparent in traditional forms of reciprocal social interaction, such as games like
peek-a-boo as well as in
shared attention to objects of interest; Historically, autistic children were said to be delayed in developing a
theory of mind, and the
empathizing–systemizing theory proposed that while autistic people may have compassion (
affective empathy) for others with similar autistic traits, they often have limited, though not necessarily absent,
cognitive empathy. This may present as social naïvety, lower-than-average intuitive perception of the meaning or utility of
body language, social reciprocity, or social expectations, including the
habitus,
social cues, and certain aspects of sarcasm, which to some degree may be influenced by co-occurring
alexithymia. A 2019 meta-analysis found that alexithymia commonly co-occurs in autism (49.93%) and infrequently in neurotypicals (4.89%); the random effects risk ratio (6.50) was statistically significant (p Differences in verbal communication often become noticeable in early childhood, as many autistic children develop language skills at an uneven pace. Speech may emerge later than is typical or not at all (
non-speaking autism), while reading ability may be present before school age (
hyperlexia). About 25–35% of autistic school-age children are non-speaking or minimally speaking. The age at which speech develops and the complexity of early language development are significant predictors of verbal communication abilities in later life. Conversely, some autistic people make eye contact that others perceive as intense or unrelenting. They may recognize fewer
emotions or interpret
facial expressions differently, and may not respond with expressions expected by their non-autistic peers. They can also have difficulty inferring social context or subtext in conversation or text, resulting in different interpretations of meaning. Speech characteristics such as volume, rhythm, and intonation (
prosody) can vary,
Developing and sustaining relationships Signs of autism in childhood include less apparent interest in other children or caregivers, possibly with more interest in objects. Children on the autism spectrum are more likely than their non-autistic peers to be involved in
bullying, most often as victims. Among autistic people who seek friendships, reduced friendship quality and quantity are often associated with increased loneliness. Autistic people also face greater challenges in developing romantic relationships than non-autistic people. Over time, many autistic people learn to observe and form models of social patterns, and develop
coping strategies, such as "
masking". Masking is associated with poorer mental health outcomes as well as delayed diagnosis, which can limit access to appropriate supports. It is increasingly argued that these characteristics should be accepted, which is supported by their recognized functions, such as self-regulation. Focused interests can also provide personal fulfillment and contribute to the development of specialized knowledge. on a cork coaster
Repetitive behaviors Repetitive behaviors found in autism include rocking, hand flapping, finger flicking, head banging, and repeating phrases or sounds (including
echolalia These behaviors may occur consistently or primarily when the person is stressed, anxious, or upset. They are also known as
stimming. Other examples include playing with toys in ways others might consider limited or unusual Many adults learn to suppress (or "mask") these behaviors, which can increase their stress and anxiety.
Resistance to change Autistic people may have a strong preference for routine, such as performing daily tasks in a specific order or showing distress in response to changes others may consider minor. They may become distressed if their routine changes or is disrupted.
Sensory reactivity Atypical responses may arise in autistic people in response to certain sensory input, such as aversion to specific sounds or textures, fascination with lights or movement, or apparent indifference to pain or temperature. This is experienced by 90% of autistic people. They can be hyperactive or hypoactive in response to sensory input. Some underreact to pain and temperature while others have a stronger reaction to it.
Self-injury Self-harm occurs about three times more often in autistic people than in non-autistic people. Behaviors can include head-banging, hand-biting, and skin-picking, and can lead to serious injury or, in rare cases, death. Several explanations have been proposed for the development and persistence of self-harm among people with developmental conditions such as autism. Communication difficulties may lead some autistic people to use self-injury to express needs, distress, or other feelings. or modulate pain perception, particularly for those with chronic discomfort or medical conditions. The propensity for elopement increases with the severity of the autism. and
traffic injuries are among the dangers associated with elopement. It is described as distinct from but similar to
occupational burnout and is often linked to the pressure to hide autistic traits in social interactions. It may manifest as a feeling of being "stuck": people find it challenging to begin a task, shift focus to a different activity, or disengage from an action, even when they want to. A meltdown may occur if, upon processing large amounts of information, an autistic person experiences anxiety or feels overwhelmed. Triggers may be sensory or social, and often include unpredictability, unmet basic needs, and emotional situations, which tend to accumulate. The otherwise rare
savant syndrome, characterized by an isolated skill in a narrow area, is more common among autistic people, but studies of its prevalence have found different results. These special skills are related to prodigious memory. Most common are splinter skills, such as memorization of sports trivia or historical facts. Research has also reported enhanced performance by autistic participants on certain perceptual and attentional tasks.
Other features Autistic people may exhibit traits or characteristics that are not part of the formal diagnostic criteria but can nonetheless affect their personal well-being or family dynamics. • An estimated 60–80% of autistic people have motor signs that include
poor muscle tone,
poor motor planning, and
toe walking; difficulties in motor coordination appear common across the autism spectrum. • Unusual or atypical eating behavior occurs in about 70% of children on the autism spectrum, to the extent that it was once considered a diagnostic indicator. == Causes ==