title: Pain-processing abnormalities in bipolar I disorder, bipolar II disorder, and schizophrenia: A novel trait marker for psychosis proneness and functional outcome?
abstract: Overlapping neural system dysfunctions, mainly involving the secondary somatosensory cortex (S2), the anterior cingulate cortex (ACC) and the anterior insular cortex (AIC), seem to be related to both pain-perception abnormalities and psychotic symptoms in schizophrenia (SCZ) and bipolar disorder (BD). Laser-evoked potentials (LEPs) were used to investigate pain-perception and central pain-processing abnormalities in SCZ, bipolar I disorder (BD-I), and bipolar II disorder (BD-II), and to evaluate their relationship with history of psychosis, and social-cognitive and functional impairments.
  
  
  
  Twenty patients with SCZ, 17 patients with BD-I, and 21 patients with BD-II who were all under similar pharmacological treatment underwent clinical, functional, and neuro-psychological assessment. LEPs were analyzed in patients and 19 healthy subjects (HS). LEPs elicit responses reflecting the activity of the S2 (N1 wave) and the ACC/AIC cortices (N2/P2 complex). A four-group ANOVA was conducted between patients and HS to compare pain-perceptive thresholds (PThs), N1, and N2/P2-LEP components.
  
  
  
  Compared to HS: (i) patients with SCZ showed pain-processing and pain-perception abnormalities, as revealed by significantly higher PTh (P<.01), and lower N1 (P<.01) and N2/P2 (P<.01) amplitudes, (ii) patients with BD-I showed only pain-processing abnormalities, as revealed by significantly lower N1 (P<.05) and N2 (P<.01) amplitudes; and patients with BD-II did not differ for any of the LEP variables investigated. N1 and N2 amplitudes negatively correlated to history of psychosis (P<.01), social-cognition (P<.05), and real-world functioning (P<.01) measures in the whole group of patients.
  
  
  
  To the best of our knowledge, this is the first study comparing central pain processing in patients with SCZ, BD-I, and BD-II. Our results suggest that pain-processing abnormalities may represent a novel locus of interest for research investigating trait markers of the psychosis spectrum.
authors: Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.|Department of Psychiatry, University of California San Diego, San Diego, CA, USA.
authors: Amedeo
authors: A
authors: Minichino
authors: Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors: Roberto
authors: R
authors: Delle Chiaie
authors: Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors: Giorgio
authors: G
authors: Cruccu
authors: Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors: Serena
authors: S
authors: Piroso
authors: Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors: Giulia
authors: G
authors: Di Stefano
authors: Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.|Department of Psychiatry, University of California San Diego, San Diego, CA, USA.
authors: Marta
authors: M
authors: Francesconi
authors: Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors: Francesco Saverio
authors: FS
authors: Bersani
authors: Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors: Massimo
authors: M
authors: Biondi
authors: Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors: Andrea
authors: A
authors: Truini
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000503:physiopathology / Q000523:psychology; D003071:Cognition / Q000502:physiology*; D005260:Female; D006801:Humans; D066331:Laser-Evoked Potentials / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009482:Neurophysiology / Q000379:methods; D010146:Pain / Q000503:physiopathology / Q000523:psychology; D058748:Pain Perception / Q000502:physiology*; D011618:Psychotic Disorders / Q000503:physiopathology / Q000523:psychology; D012559:Schizophrenia / Q000503:physiopathology*; D012919:Social Behavior; D013003:Somatosensory Cortex / Q000503:physiopathology
keywords: bipolar disorder; cingulate cortex; evoked potentials; insula; pain; psychosis; salience network; schizophrenia; somatosensory cortex