DSM-5 Criteria for Autism Spectrum Disorder
The DSM-5 consolidated previous pervasive developmental disorders into a single diagnosis of Autism Spectrum Disorder (ASD) with two core diagnostic domains: (1) persistent deficits in social communication and social interaction, and (2) restricted, repetitive patterns of behavior, interests, or activities. 1
Core Diagnostic Domains
Domain 1: Social Communication and Interaction Deficits
All of the following must be present (currently or by history):
- Deficits in social-emotional reciprocity
- Deficits in nonverbal communicative behaviors used for social interaction (such as eye contact, body language, gestures)
- Deficits in developing, maintaining, and understanding relationships
Domain 2: Restricted, Repetitive Patterns of Behavior, Interests, or Activities
At least two of the following must be present (currently or by history):
- Stereotyped or repetitive motor movements, use of objects, or speech
- Insistence on sameness, inflexible adherence to routines, or ritualized patterns of verbal or nonverbal behavior
- Highly restricted, fixated interests that are abnormal in intensity or focus
- Hyper- or hypo-reactivity to sensory input or unusual interest in sensory aspects of the environment
Key Diagnostic Changes from DSM-IV-TR
The DSM-5 reduced diagnostic domains from three to two, eliminating the separate communication domain and incorporating it into social communication deficits. 1 This change reflects evidence showing little support for reliable diagnostic differences among the previous categories (autistic disorder, Asperger's disorder, PDD-NOS). 1
Critical Modifications:
- Onset timing: Changed from "before 3 years of age" to "onset in the early developmental period" 1
- Sensory features: Now explicitly incorporated as part of restricted/repetitive behaviors 1
- Historical symptoms: Criteria allow for symptoms that may not be currently present but were documented historically, recognizing that intervention or development may reduce some symptoms over time 1
- Severity specifiers: Added three levels (1-3) for each core domain indicating level of support needed 1
Additional Diagnostic Specifiers
The DSM-5 requires documentation of:
- Presence or absence of intellectual impairment
- Presence or absence of language impairment
- Association with known medical, genetic, or environmental factors
- Association with catatonia
- Severity level for each core domain (Level 1: requiring support; Level 2: requiring substantial support; Level 3: requiring very substantial support)
Important Clinical Caveats
The severity levels show significant variability in clinical application, with less than half (40.4%) of children with documented ASD diagnoses having any severity level specified in their records. 3 Agreement between clinicians on severity ratings is only fair for social communication (κ = 0.318) and slight for restricted/repetitive behaviors (κ = 0.195), even when overall diagnostic agreement is high. 4 This suggests that assigning severity levels represents a distinct clinical decision beyond making the diagnosis itself.
The elimination of separate diagnoses (Asperger's, PDD-NOS) under the ASD umbrella was controversial but based on lack of evidence for reliable differentiation. 1 Clinicians should be aware that some individuals previously diagnosed under DSM-IV-TR criteria may not meet DSM-5 criteria, though the practical impact on prevalence remains under study.