Suicide explained!

Australian & New Zealand Journal of Psychiatry, 49(1) measurable features, may help refine categorical diagnoses, albeit with perhaps more than a degree of creative destruction as some categories may disappear, whilst others are born. Ultimately, an improved diagnostic system may emerge through re-invigoration by RDoC. However, a key feature of the RDoC is that it does not make any a priori assumptions about diagnosis, and therefore provides a non-circular starting point that could lead to identification of diagnostic borders. Inherent in this process is the assumption that current DSM/ ICD categories are invalid; this needs to be confirmed in the context of aetiopathogenesis. Conceptually, the RDoC may be a useful lens to focus on the neurocircuit basis of commonalities in various neuropsychiatric disorders as well as to better appreciate the interactions of structure, function and environment (including sociocultural factors). Neuropsychiatric disorders, dementia or neurocognitive disorders are in need of refinement of current broad descriptions of clusters of clinical features with numerous qualifiers, shoehorned prematurely into categories in the current DSM-5; which need to be developed into more nuanced categories integrating measurable neurobiologic, cognitive and emotional features. Functional neurologic disorders might also be better reconsidered through a similar process. How such refined categories relate to the prediction of treatment response is a separate matter, and this may be informed by the relative treatment responsiveness of subsets of dimensional clinical features as determined via RDoC. For example, a common endophenotype might be apathy manifest in dementia but also in other conditions, arising putatively from dysfunction of the anterior cingulate frontosubcortical circuit, the study of which neurobiologic circuitry may yield specific medication/interventions. While the Australasian psychiatrist aims at having a comprehensive understanding of the aetiopathogenesis of psychiatric illness, clinical decisions also boil down to why, when, and how to treat the patient. In this process, the apposite relation between the RDoC and DSM/ICD becomes evident. In clinical practice, aspects of the dimensional model of RDoC could provide an integrative explanatory model for the clinical symptoms and signs in neuropsychiatric disorders, enhancing understanding for patients and their families. It may also be possible to integrate the RDoC endophenotypic features into the explanation mapping to a diagnostic category. Is there a Scylla or Charybdis within the domains of DSM-5/ICD-11 or RDoC? Perhaps. It is clear there are different purposes and levels of classification inherent in categorical DSM-5/ICD-11 criteria versus dimensional RDoC criteria, and hopefully in the end one will inform the other. For clinical neuropsychiatry, the current struggle will be to map relevant diagnoses to a semblance of DSM-5/ ICD-11 for clinical classification and to guide broad treatment approaches. If the RDoC yields useful endophenotypes, categorical diagnoses and broad treatment approaches may be refined for specific clinical manifestations. Like Odysseus, we will sail on, edging closer or further as DSM-5/ICD-11/ RDoC permit, navigating towards the Ithaca of definitive diagnosis.