Psychological Mechanisms of Medically Unexplained Symptoms: An Integrative Conceptual Model.

Abstract

Theories of medically unexplained illness based on the concepts of dissociation, conversion, and somatization are summarized. Evidence cited in support of these theories is described and the conceptual strengths and shortcomings of each approach are considered. It is argued that each of these approaches adds to the understanding of unexplained illness but that none is able to provide a comprehensive explanation of the phenomenon. An integrative conceptual model of unexplained illness based on cognitive psychological principles is then presented. This model attempts to combine existing theoretical approaches within a single explanatory framework, extending previous theory by explaining how compelling symptoms can exist in the absence of organic pathology. The clinical and empirical implications of the model are then considered.

Basal cortisol is positively correlated to threat vigilance in patients with psychogenic nonepileptic seizures

“…The relationship between baseline cortisol and threat vigilance in patients with PNES in our study is relevant in the light of recent observations of increased basal cortisol levels in patients with PNES [8,9] and may contribute to our insight into possible stress factors implicated in the increased threat vigilance in PNES. According to cognitive theories of medically unexplained symptoms (MUS) [16] and more recent integrated psychoneurobiological theories of MUS [2], increased activity in neurobiological stress systems and increased attention to threat make part of a state of hypervigilance that, in turn, may play a crucial role in the presence of MUS as well as dissociative symptoms [7,9]. In addition, increased threat vigilance on a masked emotional Stroop task [17], as well as hypercortisolism [18], has been reported for patients with a primary diagnosis of dissociative disorder as well.…”

Symptoms and the body: Taking the inferential leap

“…The notable lack of evidence that peripheral physiological abnormalities play a specific and causal role in functional somatic syndromes has contributed to growing interest among researchers in the concept of central sensitization as a potential common ground for functional somatic syndromes (see further; Kim and Chang, 2012;Nijs et al, 2012;Bourke et al, 2015). More generally, theorizing seems to have evolved towards identifying MUS as perceptual (or interoceptive) conditions (e.g., Brown, 2004;Edwards et al, 2012). …”

“…At higher levels of representation, this includes abstract information about both normative (e.g., temporary dehydration; physical exercise) and non-normative causes (e.g., disease). The latter are broadly equivalent to the symptom schemata, symptom representations and illness representations described in other models (e.g., Leventhal et al, 1992;Pennebaker, 1982;Cioffi, 1991;Brown, 2004). Whether the input is experienced as a symptom or a sensation depends on the nature of the bestfitting model.…”

“….the perception of physical symptoms is generally preceded by peripheral, physiological changes" (Kolk et al, 2003(Kolk et al, , p. 2344) ; see Table 1). It builds on previous accounts of MUS (the Integrative Cognitive Model, ICM; Brown, 2004Brown, , 2006Brown, , 2013Brown and Reuber, 2016) and functional neurological and motor symptoms ("conversion symptoms"; Edwards et al, 2012), which assume that peripheral physiological input is neither necessary nor sufficient for symptoms to be experienced. By this view, top-down processes not only influence how, but also whether we experience symptoms.…”

“…External context, selective attention and negative affectivity may influence hightened attention and detection Meanings and attributions guided by illness beliefs and schemata determine the interpretation of the sensations as specific symptoms Brown (2004) Aims to explain MUS and somatoform disorders Peripheral input is not necessary, chronically activated symptom schemata in an unconscious primary attentional system (PAS) may under some circumstances exceed the awareness threshold and lead to conscious symptom experiences…”