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. (Journal of Psychiatric Practice 2014;20:147–153)
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.
All authors of this paper have no relevant affiliations or financial involvement to disclose. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. No writing assistance was utilized in the production of this manuscript. The study was not funded.
Please send correspondence to: Silvia Rigucci, MD, Unit of Psychiatry, Sant’Andrea Hospital, Via di Grottarossa 1035, 00189 Rome, Italy. firstname.lastname@example.org