Mechanisms and Reduction in Psychiatry

The view that psychiatry should be elucidating the mechanisms behind mental phenomena is gaining momentum. This view, coupled with an intuition that such mechanisms must, by nature, be biological, has inspired the field to look to cognitive neuroscience for classification of mental illnesses. One example of this kind of reorientation can be seen in the recent introduction of the Research Domain Criteria project (RDoC) by the U.S National Institute of Mental Health. The RDoC project is an attempt to introduce a new classification system based on brain circuits. The central idea behind the project is that mental disorders can be understood in terms of brain disorders and I argue that the project embodies a reductionist approach. The problem with this kind of reductionism is that multilevel explanations citing mental and social factors as part of the causal structures underlying mental disorders are rejected as non-scientific, or accepted only as provisional “stand-ins” for explanations to be found at the biological level. However, it is precisely such multilevel explanations that are necessary for progress in this fundamentally interdisciplinary science. This paper analyses the reductive nature of the RDoC project and investigates the potential for an interventionist account of causation and mechanism to bridge the gap between mechanistic explanations and multilevel explanations of mental disorders.