Neural hypersensitivity to pleasant touch in women remitted from anorexia nervosa

Abstract

Interoception, or the sensing and integration of bodily state signals, has been implicated in anorexia nervosa (AN), given that the hallmark symptoms involve food restriction and body image disturbance. Here we focus on brain response to the anticipation and experience of affective interoceptive stimuli. Women remitted from AN (RAN; N = 18) and healthy comparison women (CW; N = 26) underwent a pleasant affective touch paradigm consisting of gentle strokes with a soft brush administered to the forearm or palm during functional neuroimaging. RAN had a lower brain response relative to CW during anticipation of touch, but a greater response when experiencing touch in the right ventral mid-insula. In RAN, this reduced anticipatory response was associated with higher levels of harm avoidance. Exploratory analyses in RAN also suggested that lower response during touch anticipation was associated with greater body dissatisfaction and higher perceived touch intensity ratings. This reduced responsivity to the anticipation of pleasant affective interoceptive stimuli in association with higher harm avoidance, along with an elevated response to the experience of touch, suggests an impaired ability in AN to predict and interpret incoming physiological stimuli. Impaired interoception may thus impact one’s sense of self, thereby supporting observations of disturbed body image and avoidance of affective and social stimuli. Therapeutic approaches that help AN to better anticipate and interpret salient affective stimuli or improve tolerance of interoceptive experiences may be an important addition to current interventions.

Genome-wide Association Study of Multisite Chronic Pain in UK Biobank

“…Opposing direction of effect of genetic variants on MCP versus low RA may mean that insomnia and other sleep difficulties (for which low RA represents a proxy phenotype) associated with MCP are due to environmental and lifestyle factors related to chronic pain, rather than shared genetic factors predisposing to increased risk for both traits. There was also significant negative genetic correlation between MCP and both AN and ASD, which may be linked to changes in interoception and atypical pain experience seen in individuals with these conditions (Strigo et al, 2013;Bär et al, 2015;Clarke, 2015;Bischoff-Grethe et al, 2018;Gu et al, 2018), and may suggest a genetic basis for increased pain thresholds.…”

“…This has been observed for Major Depressive Disorder (MDD) (Nicholl et al, 2014;McIntosh et al, 2016), post-traumatic stress-disorder (PTSD) (Shipherd et al, 2007;Dunn et al, 2011;Phifer et al, 2011;Outcalt et al, 2015;Akhtar et al, 2018), schizophrenia (Watson, Chandarana and Merskey, 1981;de Almeida et al, 2013;Engels et al, 2014) and bipolar disorder (BD) (Nicholl et al, 2014;Stubbs et al, 2015). There are also reported differences in the perception of pain and interoception (sensing and integration of bodily signals) for people with schizophrenia (Lévesque et al, 2012;Urban-Kowalczyk, Pigońska and Śmigielski, 2015), anorexia nervosa (AN) (Strigo et al, 2013;Bär et al, 2015;Bischoff-Grethe et al, 2018) and autism spectrum disorders (ASD) (Clarke, 2015;Gu et al, 2018), with some evidence of an increase in pain thresholds for AN and ASD.…”

Increased anticipatory brain response to pleasant touch in women remitted from bulimia nervosa

“…After excluding three women remitted from BN (RBN) and one control woman (CW) with incomplete or unusable imaging data, our final sample included 23 RBN based on DSM-IV criteria (11 with a prior history of anorexia nervosa) and 25 demographically-matched healthy CW. Data from CW were previously reported in a similar study of anorexia nervosa 51 . Remittance was defined as the absence of binge eating, purging, restrictive eating behaviors, and cognitive symptoms, occurrence of regular menstrual cycles, and a weight above 85% of ideal body weight with no fluctuations >3 kg for at least 1 year prior to the study 62 .…”

“…As in prior research 51 , during each of two task runs, participants completed a continuous performance task, whereby they were presented with a left-or rightward pointing arrow on a gray rectangular background (3 s). Subjects were asked to press the left or right button of a button box to indicate the direction of the arrow, using the index and middle fingers of the right hand.…”

“…To determine whether BN is associated with a generalized (non-food-related) deficit in interoception, we examined whether RBN and control women (CW) differ in brain response to anticipation or experience of pleasant affective touch. Women remitted from BN were studied to avoid confounding physiological effects of active symptoms (e.g., malnutrition, electrolyte imbalances) with brain alterations and maintain consistency with other studies in remitted samples 43,48,50,51 . Affective touch is a pleasant interoceptive stimulus 10,11,52,53 .…”