From the Guidelines
Autism Spectrum Disorder (ASD) is diagnosed using criteria from the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), which focuses on two main areas: persistent deficits in social communication/interaction and restricted, repetitive patterns of behavior, interests, or activities. The diagnostic criteria for ASD, as outlined in the DSM-5, require a person to show difficulties in social-emotional reciprocity, nonverbal communication, and developing relationships, as well as display at least two types of repetitive behaviors such as repetitive movements, inflexible routines, fixated interests, or sensory sensitivities 1. These symptoms must be present in early childhood, cause significant impairment in functioning, and cannot be better explained by intellectual disability or global developmental delay. Diagnosis typically involves comprehensive evaluation by specialists including developmental pediatricians, child psychologists, or child psychiatrists who use standardized assessment tools, direct observation, and parent/caregiver interviews 1. Some key points to consider in the diagnosis of ASD include:
- Persistent deficits in social communication and social interaction across multiple contexts
- Restricted, repetitive patterns of behavior, interests, or activities
- The presence of symptoms in the early developmental period, although they may not become apparent until social demands exceed the individual’s capacities
- A wide range of abilities from extremely gifted to severely challenged
- Significant impacts on families and individuals, as well as widespread social and economic effects Early diagnosis is crucial, often possible by age 2-3, as it enables timely intervention with evidence-based approaches like applied behavior analysis (ABA), speech therapy, occupational therapy, and social skills training 1. Severity levels (1-3) are assigned based on the amount of support needed, helping to tailor treatment plans to individual needs 1.
From the Research
Diagnostic Criteria for Autism Spectrum Disorder (ASD)
The diagnostic criteria for ASD are based on deficits in social communication and the presence of restricted, repetitive behaviors or interests 2. The criterion standard for the diagnosis of ASD is a comprehensive evaluation with a multidisciplinary team of clinicians, which includes:
- Semistructured direct observation of the child's behavior
- Semistructured caregiver interview focused on the individual's development and behaviors using standardized measures, such as the Autism Diagnostic Observation Schedule-Second Edition and the Autism Diagnostic Interview 2 The diagnostic criteria for ASD focus on two core domains:
- Social communication impairment
- Restricted interests/repetitive behaviors 3
Diagnostic Assessment
Diagnostic assessment should start within three months of referral, and the decision to refer should be made on the basis of signs or symptoms 4. Information from all sources, including medical history, parental concerns, and clinical judgement, should be used to diagnose ASD based on ICD-10 or DSM-IV criteria 4. The diagnosis is established by application of the diagnostic criteria for ASD of the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM V) 5.
Screening Tools
Several screening tools are available to aid in the diagnosis of ASD, including:
- Childhood Autism Rating Scale (CARS)
- The Autism Spectrum Disorder-Observation for Children (ASD-OC)
- The Developmental, Dimensional, and Diagnostic Interview (3di) 3
- CHAT or the modified version (M-CHAT) 4 These tools can identify clinical features indicative of increased risk but should not be used to rule out ASD 4.
Comprehensive Assessment
Comprehensive assessment comprises a step-wise approach that includes:
- Taking a detailed history
- Performing a holistic examination
- Observing the child closely in relation to play, social interaction, and behavior 5 Functional assessment identifies an individual's strengths and weaknesses, which is important to formulate a customized intervention plan along with the family 5.