Psychological Medicine

Editorial Review

Interventionist causal models in psychiatry: repositioning the mind–body problem

K. S. Kendlera1a2 c1 and J. Campbella3

a1 Virginia Institute of Psychiatric and Behavioral Genetics, Medical College of Virginia/Virginia Commonwealth University, Richmond, VA, USA

a2 Department of Psychiatry, and Human and Molecular Genetics, Medical College of Virginia/Virginia Commonwealth University, Richmond, VA, USA

a3 Department of Philosophy, University of California, Berkeley, CA, USA


Background The diversity of research methods applied to psychiatric disorders results in a confusing plethora of causal claims. To help make sense of these claims, the interventionist model (IM) of causality has several attractive features. First, it connects causation with the practical interests of psychiatry, defining causation in terms of ‘what would happen under interventions’, a question of key interest to those of us whose interest is ultimately in intervening to prevent and treat illness. Second, it distinguishes between predictive-correlative and true causal relationships, an essential issue cutting across many areas in psychiatric research. Third, the IM is non-reductive and agnostic to issues of mind–body problem. Fourth, the IM model cleanly separates issues of causation from questions about the underlying mechanism. Clarifying causal influences can usefully structure the search for underlying mechanisms. Fifth, it provides a sorely needed conceptual rigor to multi-level modeling, thereby avoiding a return to uncritical holistic approaches that ‘everything is relevant’ to psychiatric illness. Sixth, the IM provides a clear way to judge both the generality and depth of explanations. In conclusion, the IM can provide a single, clear empirical framework for the evaluation of all causal claims of relevance to psychiatry and presents psychiatry with a method of avoiding the sterile metaphysical arguments about mind and brain which have preoccupied our field but yielded little of practical benefit.

(Received February 19 2008)

(Revised August 05 2008)

(Accepted September 05 2008)

(Online publication October 10 2008)


c1 Address for correspondence: K. Kendler, M.D., Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University Medical School, Box 980126, 800 E. Leigh Street, Room 1-123, Richmond, VA 23298-0126, USA. (Email: