Why Mental Disorders Can Diminish Responsibility: Proposing a Theoretical Framework

Abstract

The view that mental disorders can excuse a person for a particular action is widespread. It is supported by psychiatrists, ethicists and lawyers and is reflected in criminal law, via the insanity defence. It remains a matter of debate, however, exactly how mental disorders affect a person’s moral responsibility. The purpose of this paper is to develop a conceptual framework that can help explicate and straightforwardly communicate our intuitions on mental disorder and diminished responsibility. Four factors are identified which contribute to the explanation of why mental disorders excuse. The first concerns the cluster of ‘free will’ or agency-related phenomena (like having alternative possibilities, or being the genuine source of the action); the second factor concerns extreme urges; the third factor concerns false beliefs; the fourth factor is moral sensitivity. Referring to one or more of these factors should enable us to explain the various instances in which we either partially or completely excuse a person because of a mental disorder.