Sunday, May 13, 2012

Autism in DSM-V: what to expect

Autism or ASD is diagnosed using criteria defined by the DSM-IV and ICD-10. Soon, both these manuals will be updated to DSM-V and ICD-11. Importantly, there are a number of changes to the definition of autism. ASD will consist of two behvaioural categories, not three. Social communication and social interaction will be combined into one category of behaviours, and the second involves repetitive and restricted behaviours (RRBs). The new criteria also subsumes all ASDs within the one title, thereby eliminating the confusion that surrounds the distinction between Asperger Syndrome, PDD-NOS and autism without intellectual disability or language delay. Hence, the prevalence rates of NOS and AS will not need to be considered. Social communication and impairment without RRBs constitute a new DSM category: Social Communication Disorder (SCD).

For researchers, this affects project design. For many years, suitable controls for ASD have been a matter of debate. Biomarkers unique to ASD (compared to typically developing (TD) individuals) may be shared by ADHD or other individuals with challenging behaviour. How autistic individuals differ from PDD-NOS, for example, will no longer be relevant. Suitable comparisons will be between ASD, SCD and TD. However, researchers are struggling to estimate or predict the prevalence of SCD. Hence, finding a suitable cohort of participants for research will be challenging.

A thorough review of the proposed changes is described here