Agent-Responsibility and Psychiatric Diagnosis

In this post PhD student Benjamin Costello talks about his research. Ben is supervised by Lisa Bortolotti and Iain Law, and soon Hanna Pickard will join his supervisory team too.

Benjamin Costello

My research is concerned with the relationship between mental illness, involuntary hospitalisation, and the sequencing of actions and personal identity. My thesis can be broken-down into the following four areas:

Moral Sequencing: Accounting for the nature of and changes in agency, personality, and identity. I am in the process of examining the nature of agency, personality, and identity, ascertaining the link between them, and determining how these alter or change. I am devising new models of moral sequences that can be used to track the actions of agents, which account for changes in personality/identity, and can help ascertain if and when an intervention is justifiable. I argue that these models have ramifications for how personality disorders and dissociative disorders should be discussed and used both in psychiatry and in the DSM/ICD. By constructing these models, I hope to: (a) establish a relationship between agency and personality/identity; (b) assess the dangerousness of an individual and the need to intervene; (c) gauge the extent to which an identity-change undermines agent-responsibility; and (d) elucidate how detentions based solely on the presence of a mental disorder is morally unjustifiable.

The criteria for being labelled ‘dangerous’ and ascertaining when intervention is justifiable. With the aim of positively influencing the way mental disorders are perceived, I aim to debunk the idea that the mentally ill are ipso facto dangerous (either to themselves or to others). Within the models of moral sequencing, I aim to incorporate a method of ascertaining the justifiability of intervening to assess the dangerousness of agents and prevent dangerous people from harming by constructing a “quick but accurate” hybrid decision theory that amalgamates a calculated decision-making mechanism (based on Bayesian probability) with a fast-and-frugal mechanism (based on Damasio’s Somatic Marker Hypothesis).


The nature of agent-responsibility in light of an agent’s actions and psychiatric diagnosis. I will argue that agents who experience an identity-change during a sequence of events (demonstrable using the models of moral sequences I construct) have grounds on which to appeal for diminished responsibility. If agent responsibility can be said to rely on the retention of identity, and only an agent responsible for their actions can be held accountable for their actions, then, I argue, a change in identity in some way removes that agent’s full accountability for their actions.

The ethics of detaining and sectioning the mentally ill. My research will bring the above areas together, and further assess the nature and ethics of involuntary hospitalisations (sectioning), elucidating how sectioning amounts to an unethical detention. The mentally ill are (usually) detained due to their perceived dangerousness either to themselves or to others, but I argue that the mentally ill are no more dangerous as a class of individuals than those that are not mentally ill; and only those who harm or would, beyond reasonable doubt, harm should be considered dangerous and are thus liable to an involuntary detention. I will propose a new way of dealing with the ethical problems concerning detaining someone with a mental illness against their will, especially in relation to medicating them whilst detained.

My overarching aim is therefore to address how sectioning and diminished responsibility are understood and addressed in both the cognitive sciences and the legal system, especially in the Mental Health Act. I hope that my research might, in some small way, act as a stepping stone from which the practises of the cognitive sciences can be better understood and, in doing so, show how the rights of those with mental disorders can be protected.