It is widely acknowledged that the diagnostic categories of mental disorders, classified by the Diagnostic and Statistical Manual of Mental Disorders (DSM), are not biologically validated. That is, there is no well-established biological factor reliably associated with any of these conditions. Nonetheless, researchers persistently attempt to find reliable associations between DSM conditions and biological factors. This situation in psychiatric research poses interesting questions both for psychiatry and for the philosophy of psychiatry. One of them concerns the exact role biological factors play with regard to psychiatric conditions. Most researchers in psychiatry are inclined to define psychiatric conditions in terms of the biological factors that could be reliably associated with them, and attempt to provide definitions of the form “psychiatric condition C is biological dysfunction X”. From a philosophical point of view, this has significant consequences. In particular, thus defining psychiatric conditions would imply that biological factors are necessary and sufficient for them. My research focuses on evaluating this consequence. Contrary to it, I claim that biological factors are neither necessary nor sufficient for psychiatric conditions. This means that the latter are not biological entities, and I explore alternative ways to philosophically account for them. In particular, I propose that psychiatric conditions are just patterns of thought and behaviour that have certain characteristics.
Very recently I became interested in the philosophy of medicine, and I am currently working on a piece about the concept of “disease”, broadly conceived. One of the views regarding disease available in the philosophy of medicine is naturalism, i.e., the view that biological dysfunction is necessary and sufficient for a disease. The most influential naturalist account is the biostatistical theory, and it has been seriously criticised in the literature. I make a novel, defeating objection to it -namely, that a contradiction can be derived from the theory. Consequently, I argue that said theory should be definitively rejected, and that new naturalist alternatives should be pursued by those favouring naturalism.