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clinically unfathomed decisions should be avoided. Precision in the classification and subtypes carries implications for outcome and response to treatment. References Cantwell, D. P., & Baker, L. (1991). Psychiatric and developmental disorders in children with communication disorder . Washington, DC: American Psychiatric Press. Giddan, J. J., & Milling, L. (1999). Comorbidity of psychiatric and communication disorders in children. Language Disorders , 8 (1), 19–36. Goin-Kochel, R. P., Mackintosh, V. H., & Meyers, B. J. (2006). How many doctors does it take to make an Autism spectrum diagnosis? Autism , 10 , 439–451. Gualtieri, C. T., Koriath, U., & Van Bourgondien, M., et al. (1983). Language disorders in children referred for psychiatric services. Journal of American Academy of Child Psychiatry , 22 , 165. Im-Bolter, N., & Cohen, N. J. (2007). Language impairment and psychiatric comorbidities. Pediatric Clinics of North America , 54 , 525–542. Lord, C., Rutter, M., DiLavore, P. M., & Risi, S. (2003). Autism Diagnostic Observation Scale . Los Angeles, CA: Western Psychological Services. Lord, C., Risi, S., Lambrecht, L., Cook, E. H., Leventhal, B. L., DiLavore, P. C., Pickles, A., & Rutter, M. (2000). The Autism Diagnostic Observation Schedule – Generic: A standard measure of social and communication deficits associated with the spectrum of autism. Journal of Autism and Developmental Disorders , 30 (3), 205–223. Mahoney, W. J., Szatmari, P., MacLean, J. E., Bryson, S. E., Bartolucci, M. D., Walter, S. D., Jones, M. B., & Zwaigenbaum, L. (1998). Reliability and accuracy of differentiating pervasive developmental disorder subtypes. Journal of American Academy of Child and Adolescent Psychiatry , 37 (3), 278–285. Shattuck, P. T. (2006). The contribution of diagnostic substitution to the growing administrative prevalence of autism in US special education. Pediatrics , 117 , 1028–1037. Sikora, D. M., Hartley, S. L., McCoy, R., Gerrard-Morris, A. E., & Dill, K. (2008). The performance of children with mental health disorders on the ADOS-G: A question of diagnostic utility. Research in Autism Spectrum Disorders , 2 (1), 188–197. Wetherby, A. M., Prizant, B., & Hutchinson, T. A. (1998). Communicative, social/affective, and symbolic profiles of children with autism and pervasive developmental disorders. American Journal of Speech-Language Pathology , 7 (2), 79–91. World Health Organization (1992). The ICD-10 Classification of Mental and Behavioural Disorders: Clinical Descriptions and Diagnostic Guidelines . Geneva: Author. Nickolina Aloizos completed her undergraduate degree in speech pathology at University of Queensland followed by her Master of Health Science (Speech-Language Pathology), University of Sydney. She also has a teacher’s diploma in Speech and Drama from Trinity College of Music. Nickolina currently works at the North West CYMHS in Brisbane. She has an interest in the differential diagnosis and treatment for communication, developmental and mental health disorders in young people.

relation to social activities), on returning to school, and on alleviating the familial stress in relation to his anxiety. Sam was referred for an ADOS assessment for clarification of whether his social difficulties and anxiety were exacerbated by an underlying co-morbid PDD condition. Sam’s ADOS-G score suggested a diagnosis of autism. Despite this, a diagnosis of autism did not appear to be appropriate to explain his presenting concerns. First, for a diagnosis of autism to be warranted, the young person must show developmental difficulties by the age of 3 years old. As his development was reported to be normal until the age of approximately 10 years, he did not meet this criterion. Second, impairments in the quality of social relationships must always have been present. Again, he was reported not to have shown difficulties in his social development until 10 years of age. Additionally, during the assessment of the ADOS-G, his social interactions improved in quality over time suggesting that his social skills deficits may be attributed to his marked anxiety. Third, autism is also characterised by restricted, stereotyped and/or repetitive interests. He showed no evidence of exhibiting such behaviours or interests, showed no evidence of rigidity of behaviour, and did not perseverate on any object or topic during the assessment. Finally, his significant language impairment was likely to have impacted on the ADOS-G score by artificially inflating the result. Therefore, it was concluded that his difficulties could be better explained by his high levels of anxiety, his diagnosed language impairment and non-verbal learning disorder, and his poor social skills that were likely to have been exacerbated due to his long period of school refusal. Sam’s profile gives clear evidence of the complexity of the difficulties inherent in assessing young people who present to a mental health service with mental health and developmental disorders. The ADOS-G was an essential diagnostic tool for clear diagnostic clarification and had a direct impact on treatment provided. For Sam, ADOS-G gave a false positive diagnosis and he therefore did not get a PDD diagnosis. However, the mental health diagnosis for his anxiety and school refusal were addressed by the family and education staff, and appropriate supports and interventions were implemented at home and at his high school. Both his language and learning difficulties were targeted in the intervention program. This case example supports the view that ADOS-G can be regarded as a useful clinical tool to assist with the differential diagnosis. As Sikora et al. (2008) pointed out, several clinical issues should alert clinicians to avoid making hasty and clinically unsupported diagnoses. These include 1) the risk of a false positive diagnosis of PDD, 2) a relative risk of incorrectly classifying mood disorders, and 3) a relatively lower risk of misclassifying disruptive behaviour disorders. The need for multiple sources of information during the diagnostic process, accurate differentiation of mental health disorders from PDD, as well as the identification of co-morbid mental health disorders and PDD warrant careful consideration. The referral pathway recommended provides a guideline for clinicians to follow so that the complex and subtle clinical issues can be identified and addressed. Conclusion The referral pathway currently used in CYMHS has been established to ensure that information from multiple sources and the ADOS-G may be used to help inform clinical judgment for making a differential diagnosis for this client group. Importantly, ADOS-G should not be used as the sole piece of evidence for an ASD diagnosis and hasty and

Correspondence to: Nickolina Aloizos Speech Pathologist North West CYMHS phone: 07 3335 8737 email: nicki_aloizos@health.qld.gov.au

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ACQ uiring knowledge in speech, language and hearing