What are the signs of autism?

Signs of Autism Spectrum Disorder

Autism spectrum disorder presents with two core domains: impairments in social communication/interaction and restricted, repetitive patterns of behavior, with onset in early childhood. 1

Core Social Communication Deficits

The social impairments in autism are striking and represent the most defining feature:

• Poor or absent eye contact is a hallmark feature, particularly noticeable in preschool children 2
• Marked lack of interest in other people, in stark contrast to the profound social interest of normal infants 1
• Failure to respond to name when called, often leading parents to worry the child might be deaf 1, 3
• Refusal to be held or cuddled, indicating impaired social-emotional reciprocity 2
• Impaired peer relationships, with lack of interest in playing with other children 1, 4
• Absent or limited use of gestures in communication, such as not pointing to show interest or using conventional gestures 1, 3
• Lack of imaginative or make-believe play that would be developmentally appropriate 1, 3

Communication and Language Abnormalities

Language deficits vary widely but are universally present:

• Delayed or total lack of spoken language, with no attempt to compensate through alternative means 1
• Language regression, where a child speaks and then stops, though this is less common than delayed onset 2
• Echolalia (immediate or delayed repetition of words or phrases) 1
• Pronoun reversal (e.g., saying "you" instead of "I") 1
• Stereotyped, repetitive, or idiosyncratic language patterns 1
• Concrete, literal interpretation of language 1
• One-sided, pedantic speech in higher-functioning individuals, often focused on circumscribed interests 1

Restricted, Repetitive Behaviors and Interests

These behaviors become more prominent over time:

• Stereotyped motor mannerisms, such as hand flapping, finger mannerisms, or body rocking 1, 2
• Extreme distress with changes in routine or environment, with marked resistance to transitions 1, 2
• Adherence to apparently nonfunctional routines or rituals 1
• Encompassing preoccupations with restricted topics or objects 1
• Persistent preoccupation with parts of objects rather than their intended use 1
• Self-stimulatory behaviors, which may include self-injury 1

Age-Specific Presentations

Infants and Toddlers (First 2 Years)

• May seem "too good" and undemanding as infants 1
• No response to name by 12 months 3
• Lack of joint attention behaviors (not showing or sharing interest) 1
• Inconsistent responsiveness to sounds or voices 1

Preschool Age (2-5 Years)

• Marked lack of interest in peers during typical ages for parallel and interactive play 4
• Absent or severely delayed speech and communication 1
• Restricted interests become more apparent 1
• Stereotyped movements are prominent 1

School Age and Adolescence

• Social and communication skills may increase somewhat, but deficits persist 1
• Problems with change and transitions may become more prominent 1
• A small subset shows marked developmental gains, while another subgroup may behaviorally deteriorate with tantrums, self-injury, or aggression 1

Critical Diagnostic Considerations

The male-to-female ratio is approximately 4:1, though females with autism tend to have more severe intellectual disability. 1

Two behaviors consistently differentiate autistic children from language-impaired peers: pointing for interest and use of conventional gestures. 1

The presence of communicative speech by age 5 years is a positive prognostic indicator, while its absence is a negative predictor of ultimate outcome. 1, 2

Common Pitfalls to Avoid

• Do not dismiss autism concerns because other developmental domains appear intact - children with autism may have normal or even advanced skills in some areas while showing profound social impairments 4
• Do not attribute all symptoms to intellectual disability alone - the social deficits in autism are qualitatively different and more severe than expected for cognitive level 1
• Do not confuse language delay alone with autism - children with pure language disorders maintain social interest, use gestures, and show attention to voice, which autistic children do not 1
• Recognize that some children may have a period of apparently normal development before regression, though most show abnormalities from infancy 1

Co-occurring Features

Children with autism have substantially elevated rates of:

• Epilepsy (approximately 20-25% have EEG abnormalities or seizure disorders, with higher rates in those with intellectual disability) 1, 3
• Intellectual disability (present in a significant subset) 3
• Anxiety disorders (11% vs 5% in general population) 3
• Depression (20% vs 7% in general population) 3
• Sleep difficulties (13% vs 5% in general population) 3
• Increased risk for accidental death, particularly drowning 1