Excitatory and inhibitory conversive experiences: neurobiological features involving positive and negative conversion symptoms

Abstract

<jats:title>Abstract</jats:title><jats:p>Previous reviews have focused on neurobiological and physiological mechanisms underlying conversion disorder, but they do not usually distinguish between negative and positive conversion symptoms. Some authors have proposed that different phenomena should underlie both situations and that diverse emotion regulation strategies (under- vs. overregulation of affect) should be related to different internal experiences (excitatory experiences with hyperarousal manifestations vs. inhibitory experiences coexisting with hypoarousal states, respectively). After a careful review of the literature, we conclude that there is not a unique theory comprising all findings. Nevertheless, we have also collected some replicated findings that should be salient. Patients manifesting positive conversion symptoms tended to present with limbic hyperfunction, not sufficiently counteracted by prefrontal control. This leads to underregulation of affect mechanisms, increased emotional reactivity and autonomic hyperarousal. The opposite pattern (with a prefrontal overfunction working as a cognitive brake over the limbic system) has been described during negative conversion manifestations. We also highlight the influence of fronto-limbic circuits over cortico-striato-thalamo-cortical circuits’ regulation, whose horizontal and vertical synchronization has been at the spotlight of the genesis of conversion and dissociative disorders.</jats:p>

Emotional Dysregulation and Temperament-Character Traits in Adolescents With Functional Neurological Symptom Disorder (Conversion Disorder)

“…In another study using the DERS and Affective Style Questionnaire, it has been shown that patients diagnosed with PNES had higher levels of emotional dysregulation compared with healthy controls (Krámská et al, 2020). Negative conversion symptoms such as deafness, hysterical paralysis, aphonia, blindness, and sensory loss and positive conversion symptoms such as pseudoseizures, gait disturbances, excessive activity manifested by aberrant movements, and psychogenic tremors have been associated with different neurobiological and physiological features and different emotion regulation strategies (Del Río-Casanova et al, 2016; Kozlowska et al, 2011; van Dijke et al, 2010). Studies conducted on patients with FNSD have found two main opposite patterns of emotion dysregulation.…”

“…The first is that positive conversion symptomatic patients—known as hyperreactive patients—have poor affect regulation (underregulation of affect), are unable to manage their overwhelming emotions, and frequently feel hyperreactive. Second, patients with negative conversion symptoms are known as emotionally flattened patients and experience the overregulation of affect as a result of inhibitory experiences, and they are emotionally flattened and disconnected (Del Río-Casanova et al, 2016; Del Río-Casanova et al, 2018; Kozlowska et al, 2011; van Dijke et al, 2010). Another diagnosis in the category of somatic symptom and related disorders in DSM-5-TR is somatic symptom disorder (SSD).…”

Improvement of functional neurological disorder after administration of esketamine nasal spray: a case report

“…However, emotional circuits, (mainly limbic networks), and their influence on the regulation ofcortico–striato–thalamo–cortical circuits, are thought to be relevant. 17 Classic psychedelics, which act through serotoninergic agonism, but have similar downstream effects to esketamine via glutamatergic neurotransmission, have recently been proposed as plausible candidates to treat FND. 18 , 19 One of the main theoretical frameworks in this regard lies in their capacity to influence neural networks, especially the default mode network.…”