title: Neurological soft signs discriminate schizophrenia from bipolar disorder.
abstract: BACKGROUND
  Although neurological soft signs have been consistently described in patients with schizophrenia, their diagnostic specificity is not well clarified.
  
  
  METHODS
  To test the hypothesis that neurological soft signs are specifically related to schizophrenia, we examined 305 subjects (patients with schizophrenia-spectrum disorder, n=167; patients with bipolar I disorder, n=88; controls, n=50). Neurological soft signs were assessed using the Neurological Evaluation Scale (NES). Multiple logistic regression analysis was used to compute the diagnostic predictive power of neurological soft signs.
  
  
  RESULTS
  Patients in the schizophrenia-spectrum disorder group were found to have significantly greater neurological impairment (NES total score=23.9, standard deviation [SD] 11.2) than those in the bipolar disorder group (NES total score=18.2, SD 7.6; p<0.001). Neurological functioning was closely associated with psychopathology (all p<0.001). The NES total score reliably distinguished patients with schizophrenia spectrum disorders from those with bipolar disorder in 68.7% of the cases (p<0.001). Moreover, a particular set of neurological soft signs showed specificity for the schizophrenia-spectrum disorder diagnostic group.
  
  
  CONCLUSIONS
  Our findings suggest that schizophrenia and bipolar disorder can be distinguished in terms of neurological impairment. Furthermore, we recommend the utility of neurological soft signs as a useful, quantifiable, sensitive, and inexpensive tool for the diagnostic work-up of schizophrenia.
authors.affiliation: RIGUCCI, DIMITRI-VALENTE, MANDARELLI, MANFREDI, COMPARELLI, DE FILIPPIS, GIRARDI, and FERRACUTI: Sant'Andrea Hospital, Faculty of Medicine and Psychology, Sapienza University of Rome, Italy; GHERARDELLI and BERSANI: Faculty of Pharmacy and Medicine, Sapienza University of Rome, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Rigucci
authors.forename: Giorgia
authors.initials: G
authors.lastname: Dimitri-Valente
authors.forename: Gabriele
authors.initials: G
authors.lastname: Mandarelli
authors.forename: Giovanni
authors.initials: G
authors.lastname: Manfredi
authors.forename: Anna
authors.initials: A
authors.lastname: Comparelli
authors.forename: Sergio
authors.initials: S
authors.lastname: De Filippis
authors.forename: Simona
authors.initials: S
authors.lastname: Gherardelli
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Bersani
authors.forename: Paolo
authors.initials: P
authors.lastname: Girardi
authors.forename: Stefano
authors.initials: S
authors.lastname: Ferracuti
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000503:physiopathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D011237:Predictive Value of Tests; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000503:physiopathology; D012559:Schizophrenia / Q000175:diagnosis* / Q000503:physiopathology