Diagnosing autism spectrum disorders in elderly people

Background: As autism spectrum disorders (ASD) have largely been neglected in old-age psychiatry, the objective of the present paper is to describe the diagnostic process in elderly patients. Methods: A systematic review of the literature on ASD in older age was undertaken and illustrated by a case series of three elderly patients first diagnosed with ASD in later life by a tertiary mental health clinic. Results: The search of the literature only yielded three papers on late-life ASD, while the review of the available diagnostic procedures among adults suggests some relevance for screening instruments (Autism Questionnaire), diagnostic instruments (Module 4, Autism Diagnostic Observation Schedule), and neuropsychological examination to profile impairments. Nonetheless, the case reports clearly showed that taking a thorough history with the patient, corroborated and supplemented by a close relative or caregiver who has known the patient for at least ten years, still remains the most important diagnostic tool. Conclusion: The three case studies show that in clinical practice ASD can easily be missed in elderly individuals presenting with comorbid psychiatric disorders, potentially causing iatrogenic damage. Although further research on phenotyping and diagnosing ASD in older people is warranted, the most important step at this point is to create a greater awareness of the possibility of ASD in old age among health-care professionals working with people in this age group.