Hysteria: a new look

Hysteria has a long and controversial history. In one contemporary manifestation, conversion disorder, it has come to refer to the exhibition of neurological signs incompatible with organic disease. Such signs (e.g. limb weakness) appear anatomically incoherent and temporally inconsistent. Indeed, the methods deployed by neurologists to detect such inconsistencies often resemble ‘catching the patient out’. Yet, the problem is said to be ‘unconscious’, an unknowing response to distress. In psychoanalytic theoretical terms such manifestations reflect the primary gain of an emotional conflict avoided, and the secondary gain of a sick role adopted. Pivotal to the diagnosis is the belief, on the part of those treating the patient, that the latter does not know what they are doing, i.e. that they are not consciously feigning disorder. This is a difficult diagnosis to defend, seemingly reliant upon the doctor knowing what the patient is intending (or rather, not intending). However, if one considers conversion behaviour from the perspective of a contemporary cognitive neurobiological account of action, then its phenomenology becomes easier to understand in computational, neuroanatomical terms. Conversion symptoms ‘behave like’ purposeful actions: the patient must attend to the symptom in order for it to be reliably reproduced; if distracted or sedated his performance normalizes. When conversion dyskinesias are investigated neurophysiologically their correlates implicate the contribution of ‘higher’ brain systems to their execution, a conclusion borne out by available functional neuroimaging studies. Conversion symptoms are the product of executive control, disturbed or otherwise; though they may be heterogeneous in aetiology they implicate prefrontal systems.