Using epidemiology to inform psychiatric classification (DSM-V and ICD-11)
NDARC Staff
Tim Slade, Maree Teesson and Katherine Mills
Other Investigators
Gavin Andrews (CRUfAD, UNSW), Andrew Baillie (Macquarie University), Mark Oakley Browne (Monash University) and Ayelet Meron Ruscio (University of Pennsylvania, USA)
Aims
The project aims to:
- develop, using epidemiological data, models of the typology of mental disorders that lead to improvements in the classification systems.
- contribute to the American Psychiatric Association's revision of DSM-IV to DSM-V and the World Health Organization's revision of ICD-10 to ICD-11.
Design and Method
This project relies on the appropriate application of statistical methodology to existing and future epidemiological data sets with the express aim of achieving valid, useful and empirically-supported classification systems. Data will be derived from three epidemiological surveys of mental disorders and the research plan will follow in three sequential and iterative stages:
- Identification and documentation of the key diagnostic parameters around 13 mental disorders.
- Identification of the latent structure of each of 13 major mental disorders with particular attention on the boundaries separating each disorder from normality. It is expected that the outcomes of this stage will address the following fundamental questions: (a) Is this disorder best conceived within a categorical or continuous framework? (b) Does the latent disorder correspond to one or more existing diagnostic categories, a variant or a subtype of an existing category, or an entirely new grouping? (c) What is the relation of the disorder to milder pathological states? (d) Is there evidence for meaningful subtypes or lower-order factors within the disorder, and if so, to what extent are they consistent with subtypes specified by current classification systems or contemporary theory? (e) Is there meaningful dimensional variation among affected cases that would support the addition of a severity score to the diagnostic criteria?
- Evaluation of the structural findings to determine their practical utility for DSM-V and ICD-11. It is expected that the outcomes of this stage will answer the following fundamental questions: (a) What are the best symptoms to identify each mental disorder at the latent level? (b) Should symptoms be differentially weighted in the diagnostic calculation? (c) Are these criteria applicable across all subtypes of the same disorder? (d) What are the best thresholds to identify categorical mental disorders? (e) Can defensible thresholds be identified for truly dimensional disorders? (f) What are the costs and benefits of making changes to the classification systems?
Funding
National Health and Medical Research Council