[Functional cognitive disorders and dissociative amnesia: the contribution of double listening].

Abstract

Cognitive neurofunctional disorders (NFDs) and dissociative amnesia (DA) are distinct clinical entities, although they may share common pathophysiological mechanisms, vulnerabilities, and risk factors. When carefully assessed, cognitive neurofunctional disorders appear to be relatively common in memory clinics, accounting for up to 20% of consultations. The widespread adoption of the term "functional" over the past decade reflects the non-organic nature of these disorders and is generally well understood by patients. This terminology has progressively replaced earlier terms such as "psychogenic" and the older concept of hysteria. Functional cognitive complaints are often unusual or incongruent and display distinctive clinical features that may appear symbolic, disproportionate, or inconsistent with anatomical, physiological, or theoretical models. Cognitive symptoms are frequently excessive in relation to the clinical context, neurological examination, biological findings, or psychometric results. Symptom onset may occur after a delay following a precipitating somatic or psychological event. Marked subjective complaints or exaggerated impairment during testing may contrast with preserved autonomy in everyday life. Loss of automatic procedures, such as writing or signing one's name, is frequently observed. The pathophysiology of these disorders remains poorly understood. However, amplification of emotional processes, elevated stress hormones, and heightened attentional focus may, under certain conditions, inhibit specific neural networks. Such dysfunction may be demonstrated by hypometabolism on functional neuroimaging studies. Dissociative amnesia, previously referred to as "functional amnesia" in the 1990s, also appears to involve emotional and stress-related mechanisms. Clinically, it is characterized by altered consciousness, particularly disturbances of identity, together with disproportionate retrograde amnesia of variable extent, which explains the current preference for the term "dissociative." Careful listening and clinical attention are essential for improving the identification of these disorders. Large-scale neuroscientific studies are urgently needed to better understand their pathophysiology and to develop therapeutic trials, including non-pharmacological approaches. Achieving this goal will require improved clinical characterization of these conditions.