title: D-serine serum levels in patients with schizophrenia: relation to psychopathology and comparison to healthy subjects.
abstract: OBJECTIVE
  The main objective was to test the hypothesis of the association between D-serine serum levels and negative symptoms in patients with schizophrenia. Secondary objective was to examine the assumption of D-serine serum levels difference between a population of mostly chronic patients with schizophrenia and healthy controls.
  
  
  METHODS
  We recruited outpatients with schizophrenia and age and gender matched healthy controls for the study. D-serine and total serine serum levels were measured by high-performance liquid chromatography (HPLC). The Positive and Negative Syndrome Scale (PANSS) and The Scale for the Assessment of Negative Symptoms (SANS) were used to assess schizophrenic symptoms. Non-parametric statistics was used to test the differences in D-serine and total serine serum levels and rank correlation was used to detect the associations with psychopathology.
  
  
  RESULTS
  We did not find any differences between patients (n=50) and controls (n=50) in D-serine serum levels. Patients had significantly lower total serine serum levels and higher D-serine/total serine ratio. D-serine serum levels were not associated with the PANSS or the SANS total and subscales scores. Total se-rine serum levels inversely correlated with the SANS total and the PANSS negative symptom subscale scores.
  
  
  CONCLUSIONS
  Decreased, not increased, serum levels of total serine negatively associated with intensity of negative symptoms were detected in patients with schizophrenia. We did not find any relationship between D-serine serum levels and negative symptoms among the patients. These findings do not agree with the previous reports of decreased D-serine and increased total serine serum levels in schizophrenia.
authors.affiliation: Department of Psychiatry, University Hospital Hradec Kralove, Czech Republic. honsj@lfhk.cuni.cz
authors.forename: Jaromir
authors.initials: J
authors.lastname: Hons
authors.forename: Rastislav
authors.initials: R
authors.lastname: Zirko
authors.forename: Martina
authors.initials: M
authors.lastname: Ulrychova
authors.forename: Eva
authors.initials: E
authors.lastname: Cermakova
authors.forename: Jan
authors.initials: J
authors.lastname: Libiger