title: The brief negative symptom scale: validation of the German translation and convergent validity with self-rated anhedonia and observer-rated apathy.
abstract: BACKGROUND
  Negative symptoms are considered core symptoms of schizophrenia. The Brief Negative Symptom Scale (BNSS) was developed to measure this symptomatic dimension according to a current consensus definition. The present study examined the psychometric properties of the German version of the BNSS. To expand former findings on convergent validity, we employed the Temporal Experience Pleasure Scale (TEPS), a hedonic self-report that distinguishes between consummatory and anticipatory pleasure. Additionally, we addressed convergent validity with observer-rated assessment of apathy with the Apathy Evaluation Scale (AES), which was completed by the patient's primary nurse.
  
  
  METHODS
  Data were collected from 75 in- and outpatients from the Psychiatric Hospital, University Zurich diagnosed with either schizophrenia or schizoaffective disorder. We assessed convergent and discriminant validity, internal consistency and inter-rater reliability.
  
  
  RESULTS
  We largely replicated the findings of the original version showing good psychometric properties of the BNSS. In addition, the primary nurses evaluation correlated moderately with interview-based clinician rating. BNSS anhedonia items showed good convergent validity with the TEPS.
  
  
  CONCLUSIONS
  Overall, the German BNSS shows good psychometric properties comparable to the original English version. Convergent validity extends beyond interview-based assessments of negative symptoms to self-rated anhedonia and observer-rated apathy.
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Lenggstrasse 31, 8032, Zurich, Switzerland. martinbischof@gmail.com.
authors.forename: Martin
authors.initials: M
authors.lastname: Bischof
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Lenggstrasse 31, 8032, Zurich, Switzerland.
authors.forename: Caitriona
authors.initials: C
authors.lastname: Obermann
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Lenggstrasse 31, 8032, Zurich, Switzerland.|Laboratory for Social and Neural Systems Research, Department of Economics, University of Zurich, Bluemlisalpstrasse 10, 8006, Zurich, Switzerland.
authors.forename: Matthias N
authors.initials: MN
authors.lastname: Hartmann
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Lenggstrasse 31, 8032, Zurich, Switzerland.|Laboratory for Social and Neural Systems Research, Department of Economics, University of Zurich, Bluemlisalpstrasse 10, 8006, Zurich, Switzerland.
authors.forename: Oliver M
authors.initials: OM
authors.lastname: Hager
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Lenggstrasse 31, 8032, Zurich, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Kirschner
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Lenggstrasse 31, 8032, Zurich, Switzerland.
authors.forename: Agne
authors.initials: A
authors.lastname: Kluge
authors.affiliation: Department of Psychology, State University of New York at Binghamton, Binghamton, NY, 13902-6000, USA.
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Strauss
authors.affiliation: Laboratory for Social and Neural Systems Research, Department of Economics, University of Zurich, Bluemlisalpstrasse 10, 8006, Zurich, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Kaiser
mesh_terms: D000328:Adult; D059445:Anhedonia; D057565:Apathy; D005260:Female; D006801:Humans; D008297:Male; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data*; D011594:Psychometrics; D011618:Psychotic Disorders / Q000175:diagnosis*; D015203:Reproducibility of Results; D012565:Schizophrenic Psychology; D057566:Self Report; D014177:Translations
keywords: Assessment; Negative symptoms; Rating scale; Schizophrenia