Next month, the American Psychiatric Association will release its new edition of the psychiatry diagnostic "bible" of mental disorders. The new Diagnostic and Statistical Manual of Mental Disorders (DSM-5) will have a strong impact on how clinicians diagnose many mental health conditions, including autism. In a new commentary, published 23 April in the open access journal PLOS Biology, scientists at the Autism Research Centre, University of Cambridge discuss the opportunities and challenges arising from the new manual, which defines autism using the umbrella term "Autism Spectrum Disorder" (ASD).

"Highlighting the dimensional nature of autism, and improving the organization of symptom descriptions, are excellent features of the new manual," said Dr. Meng-Chuan Lai, lead author of the commentary. He added that this unitary diagnostic label, together with an individualized assessment of needs for support--an important new feature--will be potentially beneficial in securing required levels of support for individuals with a diagnosis of ASD.

However, co-author Dr. Michael Lombardo expressed the team's reservations about the impact of such a revision on autism research. "Autism is extremely heterogeneous and is expressed differently in different individuals. While going back to one omnibus label of 'ASD' is beneficial in many ways, it may not be the best prescription for how research into causal factors should proceed. Understanding the driving factors behind the massive heterogeneity in autism requires a way of thinking for future research that goes beyond just one omnibus label."

Professor Simon Baron-Cohen, Director of the Autism Research Centre and another co-author of the paper, agreed: "To make progress in autism research, and ultimately to improve clinical practice, we need to move forward to the identification of subgroups within the autism spectrum."

The authors argue that potential subgroups may be identified by a more extensive use of "specifiers", such as different developmental patterns, different cognitive profiles, different genetic and environmental correlates, different co-occurring conditions, and even the differences arising from sex/gender. They suggest that all of these could aid subgrouping. They also argue that some clinical subgroups previously recognized, such as Asperger Syndrome, are still valuable categories that need further research.

Co-author Dr. Bhismadev Chakrabarti underlined the key message: "In a world that is moving toward individualized treatment, the identification of specific subgroups is a vital step forwards."