The DSM-V diagnostic criteria for autism spectrum disorders includes all of the following:

1. Persistent deficits in social communication and interactions in multiple settings with each of the following:
   1. Social-emotional reciprocity
   2. Nonverbal communicative behaviors used for social interaction
   3. Developing, maintaining, and understanding relationships
2. Restricted, repetitive patterns of behavior, interests, or activities as demonstrated by at least 2 of the following:
   1. Stereotyped or repetitive movements, use of objects, or speech
   2. Insistence on sameness, unwavering adherence to routines, or ritualized patterns of behavior
   3. Highly restricted, fixated interests that are abnormal in strength or focus
   4. Increased or decreased response to sensory input or unusual interest in sensory aspects of the environment
3. The symptoms must impair function.
4. The symptoms must be present in the early developmental period. However, they may become apparent only after social demands exceed limited capacity; in later life, symptoms may be masked by learned strategies.
5. The symptoms are not better explained by intellectual disability or global developmental delay.

The severity of social communication/interaction and restricted/repetitive behavior can be graded using the following

1. Level 1 – Requiring Support
2. Level 2 – Requiring Substantial Support
3. Level 3 – Requiring Very Substantial Support

Testing Tools Available

• Autism Behavior Checklist (ABC)
  • 57 questions
  • 5 categories
    • Sensory, elating, body and object use, language, and social and self-help
• Gilliam Autism Rating Score (GARS-3)
  • 56 questions
  • 6 categories
    • Restrictive/repetitive behaviors, social interaction, social communication, emotional responses, cognitive style, and maladaptive speech
• Autism Diagnostic Interview-Revised (ADI-R)
  • 2-3 hour clinical interview
• Childhood Autism Rating Scale – Second Edition (CARS-2)
  • 15 item focused interview
• Autism Diagnostic Observation Schedule – Second Edition (ADOS-2)
  • Reference standard in research

References

1. American Psychiatric Association. Autism spectrum disorder. In: Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, American Psychiatric Association, Arlington, VA 2013. p.50.
2. Krug DA, Arick J, Almond P. Behavior checklist for identifying severely handicapped individuals with high levels of autistic behavior. Journal of Child Psychology and Psychiatry, and Allied Disciplines. 1980;21(3):221-9. [pubmed]
3. Gilliam JE. Gilliam Autism Rating Scale (GARS). Pro-Ed, Austin, TX 1995.
4. Lord C, Rutter M, Le Couteur A. Autism Diagnostic Interview-Revised: a revised version of a diagnostic interview for caregivers of individuals with possible pervasive developmental disorders. Journal of Autism and Developmental Disorders. 1994;24(5):659-85. [pubmed]
5. Filipek PA, Accardo PJ, Baranek GT. The screening and diagnosis of autistic spectrum disorders. Journal of Autism and Developmental Disorders. 1999;29(6):439-84.[pubmed]