Autism spectrum disorder is a neurodevelopmental disorder defined by persistent deficits in social communication and social interaction AND restricted, repetitive patterns of behavior, interests, or activities. DSM-5 collapsed previous categorical diagnoses (autism, Asperger's syndrome, PDD-NOS) into a single spectrum with severity levels reflecting support needs.
Two required domains:
(A) Social communication and interaction deficits: difficulties with social-emotional reciprocity (back-and-forth conversation, sharing of interests, emotional response), nonverbal communication (eye contact, gestures, facial expressions), developing and maintaining relationships appropriate to developmental level.
(B) Restricted, repetitive patterns of behavior, interests, or activities (at least two of): stereotyped or repetitive motor movements or speech (echolalia, scripting, hand-flapping), insistence on sameness (distress at small changes, rigid routines), highly restricted fixated interests (intense focus on specific topics), hyper- or hypo-reactivity to sensory input (sound, texture, light, touch, smell).
The spectrum nature is essential. Severity ranges from patients requiring substantial support (often with comorbid intellectual disability, limited functional language) to patients with average or above-average intellectual function who hide their differences through learned strategies but experience substantial internal cost. The diagnosis spans this range — the same label applies to patients whose lives look very different.
Prevalence has risen dramatically over recent decades to current estimates around 2-3% of children. Increase reflects multiple factors: broader diagnostic criteria, better recognition (particularly in girls and adults who were missed), increased awareness, and possibly true prevalence change. Substantial female under-recognition — girls often present with internalizing patterns and learned masking that obscures classic features.
Adult autism evaluation has become increasingly common, particularly women self-identifying in adulthood. Approach: structured assessment (ADOS-2, AQ, RAADS-14 for screening), probe developmental history (autism by definition is lifelong, so signs from childhood should be discoverable even if missed), consider learned compensation strategies (camouflaging) that mask presentation. Many adults describe diagnosis as validating — finally an explanation for lifelong differences.
Early intensive behavioral intervention for young children with substantial support needs has the strongest evidence base. ABA-based approaches predominate (controversial in some autistic adult communities; ongoing dialogue about appropriate adaptation). Naturalistic developmental behavioral interventions (Early Start Denver Model, JASPER) are evidence-based alternatives. Speech-language therapy, OT for sensory and motor issues, social skills training.
Pharmacotherapy addresses comorbid conditions rather than core autism features. Anxiety, depression, ADHD, OCD, irritability — each treated with standard evidence-based approaches adapted for the autism context. Atypical antipsychotics (risperidone, aripiprazole) FDA-approved for irritability in autism. Avoid the urge to medicate the autism itself.
When you encounter a patient with possible autism — child or adult — comprehensive assessment matters. Treatment of comorbid conditions, support services, identity-affirming framing, family education. The patient is not broken; the patient is differently wired and may benefit from specific support.