Acting on delusion and delusional inconsequentiality: A review

Two of Europe's most influential psychopathologists at the start of the twentieth century (Eugen Bleuler and Karl Jaspers) pointed out the fact that patients rarely act according to their delusions. This study proposes an investigation of how this issue is addressed in psychopathological literature.

This article offers a critical review of psychopathological literature which focuses on the influence of delusional ideation on behaviour.

Phenomenological psychiatry has relied on the paradox pointed out by Bleuler and Jaspers to emphasize disorders of self-experience in psychosis whereas analytical philosophy of delusion has focused on the psychological status of delusion, regarded as belief, certainty, or imagination. The empirical studies conducted during the past three decades - which were devoted to acting on delusion - focused on violent and safety-seeking behaviours. These studies have shown that these behavioural disorders are motivated by an emotional outburst (anger and/or fear) rather than by delusional content.

Delusional inconsequentiality can be clarified by conceptual research in phenomenological psychiatry and analytical philosophy, even though its role in the psychopathological processes has not yet been clearly identified or conceptualised. Empirical psychopathology on acting on delusion confirms the delusional inconsequentiality, but only implicitly, by highlighting the role of affectivity (rather than beliefs) in delusional actions. Given the major implications of better understanding this phenomenon, in terms of psychopathology and clinical practices, we suggest considering delusional inconsequentiality as a promising concept which could guide further research in contemporary psychopathology.