Autism spectrum disorder (ASD) is a group of genetic neurodevelopmental pathologies with varying degrees of impairments in three social domains: social interaction, communication skills, and repetitive and stereotyped patterns of behaviour, interests, and activities. The autism phenotype exhibits a broad spectrum of symptoms at presentation, differences in course and outcome, adaptive and cognitive levels and response to treatment. ASD are lifetime disorders that also need to be recognized in adult psychiatric patients.
To evaluate ASD in adults, firstly, a clinical history of neurodevelopment in childhood should be collected referring to three ASD social domains. Intellectual functioning should be appropriately evaluated and screening testing may be helpful. Next, as the second step, ASD diagnosis should be confirmed by specific testing, such as the Autism Diagnostic Observation Schedule (ADOS), Autism Diagnostic Interview-Revised (ADI-R), Gilliam Autism Rating Scale (GARS) and Gilliam Asperger’s Disorder Scale (GADS) or RAADS-R (Ritvo Autism Asperger Diagnostic Scale-Revised). Biomedical and genetic investigation can be added to complete the evaluation.
ASD should also be considered as a possible diagnosis in adulthood. High functioning ASD patients, such as those with Asperger’s syndrome, can first be evaluated by a psychiatrist in adulthood, and may require consultation for depressive or anxiety symptoms activated by impairment in social cognition.
First-line ASD detection should be considered by all psychiatrists, and diagnosis by specialized second-line centres can be improved.