title: Neurological soft signs might be endophenotype candidates for patients with deficit syndrome schizophrenia.
abstract: BACKGROUND
  Schizophrenia is a chronic, disabling, disorder that affects approximately 1% of the population. The nature of schizophrenia is heterogeneous, and unsuccessful efforts to subtype this disorder have been made. Deficit syndrome schizophrenia (DS) is a clinical diagnosis that has not been placed in main diagnostic manuals. In this study, we aimed to investigate and compare neurological soft signs (NSS) in DS patients, non-deficit schizophrenia (NDS) patients, and healthy controls (HCs). We suggest that NSS might be an endophenotype candidate for DS patients.
  
  
  METHODS
  Sixty-six patients with schizophrenia and 30 HCs were enrolled in accordance with our inclusion and exclusion criteria. The patients were sub-typed as DS (n=24) and NDS (n=42) according to the Schedule for the Deficit Syndrome. The three groups were compared in terms of sociodemographic and clinical variables and total scores and subscores on the Physical and Neurological Examination for Soft Signs (PANESS). Following the comparison, a regression analysis was performed for predictability of total PANESS score and its subscales in the diagnosis of DS and NDS.
  
  
  RESULTS
  The groups were similar in terms of age, sex, and smoking status. The results of our study indicated that the total PANESS score was significantly higher in the DS group compared to the NDS and HC groups, and all PANESS subscales were significantly higher in the DS group than in the HC group. The diagnosis of DS was predicted significantly by total PANESS score (P<0.001, odds ratio =9.48, 95% confidence interval: 0.00-4.56); the synergy, graphesthesia, stereognosis, motor tasks, and ability to maintain posture subscales were found to be significant predictors.
  
  
  CONCLUSIONS
  This study confirms that NSS were higher in patients with DS. In addition, we suggest that our results might support the notion of DS as a different and distinct type of schizophrenia. NSS might also be a promising candidate as an endophenotype for DS. However, large sampled, multicentric studies are needed to clarify the place of NSS as an endophenotype in DS.
authors.affiliation: Department of Psychiatry, Faculty of Medicine, Namık Kemal University, Tekirdag, Turkey.
authors.forename: Yakup
authors.initials: Y
authors.lastname: Albayrak
authors.affiliation: Department of Psychiatry, Yenimahalle Education and Research Hospital, Ankara, Turkey.
authors.forename: Esra Soydaş
authors.initials: ES
authors.lastname: Akyol
authors.affiliation: Department of Psychiatry, Faculty of Medicine, Namık Kemal University, Tekirdag, Turkey.
authors.forename: Murat
authors.initials: M
authors.lastname: Beyazyüz
authors.affiliation: Department of Psychiatry, Faculty of Medicine, Namık Kemal University, Tekirdag, Turkey.
authors.forename: Saliha
authors.initials: S
authors.lastname: Baykal
authors.affiliation: Department of Psychiatry, Faculty of Medicine, Akdeniz University, Antalya, Turkey.
authors.forename: Murat
authors.initials: M
authors.lastname: Kuloglu
keywords: biomarker; clinical subtypes of schizophrenia; psychosis; sign