Body representations and basic symptoms in schizophrenia Marcello Costantini a,b , Anatolia Salone c , Giovanni Martinotti b,c , Federica Fiori d , Francesca Fotia e , Massimo Di Giannantonio b,c , Francesca Ferri b,c, ⁎ a Department of Psychological, Health and Territorial Sciences, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy b Institute for Advanced Biomedical Technologies, ITAB, “G. d'Annunzio” University of Chieti-Pescara, Chieti, Italy c Department of Neuroscience, Imaging and Clinical Sciences, University of Chieti-Pescara, Chieti, Italy d Local Health Authority 2, Lanciano-Vasto-Chieti, Italy e Department of Psychology, University of Essex, Colchester CO4 3SQ, UK abstract article info Article history: Received 23 October 2019 Received in revised form 24 December 2019 Accepted 16 May 2020 Available online xxxx Keywords: Schizophrenia Basic symptoms Body structural representation (BSR) Body ownership Rubber hand illusion Patients with schizophrenia report a wide range of anomalous body experiences. According to the basic symptom model of schizophrenia, disturbances of body perception and awareness are among the most powerful predictors of the changes in the subjective experience of the self in schizophrenia. In this study we first investigated the body structural representation (BSR), a specific aspect of body awareness, and its association to basic symptoms in patients with schizophrenia. Using a finger localization task, we found that patients are significantly less accu- rate than healthy controls when asked to identify pairs of fingers touched by the experimenter, when the hand is hidden from view. Most importantly, patients' performance at the finger localization task was negatively associ- ated to basic symptoms: the worse the individual accuracy, the higher the SPI-A total score. Moreover, the accu- racy at the finger localization task was also negatively correlated with the malleability of the sense of body ownership: the less the individual ability to localize fingers, the stronger the rubber hand illusion. These results are in agreement with the idea that self-disorders in schizophrenia reveal a disconnectedness that can be regarded as a problem of disembodiment and traced back to abnormal body experiences. © 2020 Elsevier B.V. All rights reserved. 1. Introduction Disturbed sense of self was paramount to the notion of schizophre- nia from the beginning (Minkowski, 1927; Schneider, 1950; Schultze- Lutter, 2009). A core component of selfhood is the bodily self, namely a coherent representation of one's own body and a stable sense of owning it. Patients with schizophrenia report a wide range of anoma- lous bodily self-experiences (Brent et al., 2014; Chapman et al., 1978; Lysaker and Lysaker, 2010; Nelson et al., 2012), such as transient changes in the shape, size, or location of their own body parts (Chapman et al., 1978), as well as a disrupted sense of body ownership and self-other boundary (Di Cosmo et al., 2018; Thakkar et al., 2011; van der Weiden et al., 2015). Importantly, disturbances in body perception are regarded among the basic symptoms of schizophrenia, that is, the earliest subjectively experienced symptoms and the most immediate expression of the neurobiological correlates of the illness (Schultze- Lutter, 2009). Basic symptoms can be evaluated using either the Bonn Scale for the Assessment of Basic Symptoms (BSABS) or the Schizophrenia Proneness Instrument for adults (SPI-A, Schultze-Lutter, 2009). Despite the former allows a more in-depth and comprehensive investigation of the basic symptoms (see Table 1), it is also less manage- able, and patients often experience a progressive affliction, with conse- quent decrease in the ability to describe their own mental state. For these reasons, to assess basic symptoms SPI-A is more commonly used. Coherently with the clinical reports, empirical studies on primary so- matosensory functions (e.g., touch perception, proprioception) in schizophrenia show reduced tactile sensitivity (Chang and Lenzenweger, 2001, 2004, 2005; Lenzenweger, 2000) and impaired proprioception (Michael and Park, 2016; Thakkar et al., 2011). Studies on higher order somatosensory functions, on the other hand, mainly focus on abnormalities of the subjective sense of body ownership (for a review, see (Klaver and Dijkerman, 2016), but see also (Shaqiri et al., 2018)) and of the bodily-self boundary (e.g., (Di Cosmo et al., 2018; Holt et al., 2015; Park et al., 2009)), while mostly neglecting another crucial aspect of the bodily self, which is the body structural representa- tion (BSR; (Longo, 2016)). BSR mediates the spatial configuration of bodies, damage to which results in conditions such as finger agnosia (Kinsbourne and Warrington, 1962). In finger agnosia, individuals are impaired at tasks, such as the finger localization task (Benton et al., 1983) that require identifying which of their fingers are touched and lo- cating them within a structural model of the hand. Whether and to what Schizophrenia Research xxx (xxxx) xxx ⁎ Corresponding author at: Department of Neuroscience, Imaging, and Clinical science, G. d'Annunzio University, ITAB, Institute for Advanced Biomedical Technologies, Via Luigi Polacchi 11, Chieti, 66013, Italy. E-mail address: francesca.ferri@unich.it (F. Ferri). SCHRES-08838; No of Pages 7 https://doi.org/10.1016/j.schres.2020.05.038 0920-9964/© 2020 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Schizophrenia Research journal homepage: www.elsevier.com/locate/schres Please cite this article as: M. Costantini, A. Salone, G. Martinotti, et al., Body representations and basic symptoms in schizophrenia, Schizophrenia Research, https://doi.org/10.1016/j.schres.2020.05.038