title: Factor structure of the Bern Psychopathology Scale in a sample of patients with schizophrenia spectrum disorders.
abstract: BACKGROUND
  The Bern Psychopathology Scale (BPS) is based on a system-specific approach to classifying the psychopathological symptom pattern of schizophrenia. It consists of subscales for three domains (language, affect and motor behaviour) that are hypothesized to be related to specific brain circuits. The aim of the study was to examine the factor structure of the BPS in patients with schizophrenia spectrum disorders.
  
  
  METHODS
  One hundred and forty-nine inpatients with schizophrenia spectrum disorders were recruited at the Department of Psychiatry II, Ulm University, Germany (n=100) and at the University Hospital of Psychiatry, Bern, Switzerland (n=49). Psychopathology was assessed with the BPS. The VARCLUS procedure of SAS(®) (a type of oblique component analysis) was used for statistical analysis.
  
  
  RESULTS
  Six clusters were identified (inhibited language, inhibited motor behaviour, inhibited affect, disinhibited affect, disinhibited language/motor behaviour, inhibited language/motor behaviour) which explained 40.13% of the total variance of the data. A binary division of attributes into an inhibited and disinhibited cluster was appropriate, although an overlap was found between the language and motor behaviour domains. There was a clear distinction between qualitative and quantitative symptoms.
  
  
  CONCLUSIONS
  The results argue for the validity of the BPS in identifying subsyndromes of schizophrenia spectrum disorders according to a dimensional approach. Future research should address the longitudinal assessment of dimensional psychopathological symptoms and elucidate the underlying neurobiological processes.
authors.affiliation: Department of Psychiatry and Psychotherapy II, Ulm University, Ludwig-Heilmeyer-Street 2, 89312 Günzburg, Germany. Electronic address: fabian.lang@uni-ulm.de.
authors.forename: Fabian U
authors.initials: FU
authors.lastname: Lang
authors.affiliation: Department of Psychiatry and Psychotherapy II, Ulm University, Ludwig-Heilmeyer-Street 2, 89312 Günzburg, Germany; Institute of Epidemiology and Medical Biometry, Ulm University, Schwabstraße 13, 89075 Ulm, Germany.
authors.forename: Annabel S
authors.initials: AS
authors.lastname: Stierlin
authors.affiliation: University Hospital of Psychiatry, Bollingenstraße 111, 3000 Bern 60, Switzerland.
authors.forename: Katharina
authors.initials: K
authors.lastname: Stegmayer
authors.affiliation: University Hospital of Psychiatry, Bollingenstraße 111, 3000 Bern 60, Switzerland.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Walther
authors.affiliation: Department of Psychiatry and Psychotherapy II, Ulm University, Ludwig-Heilmeyer-Street 2, 89312 Günzburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Becker
authors.affiliation: Department of Psychiatry and Psychotherapy II, Ulm University, Ludwig-Heilmeyer-Street 2, 89312 Günzburg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Jäger
mesh_terms: D000328:Adult; D000339:Affect / Q000502:physiology; D005260:Female; D005858:Germany; D006801:Humans; D007297:Inpatients / Q000523:psychology* / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011599:Psychopathology / Q000379:methods*; D015203:Reproducibility of Results; D012559:Schizophrenia / Q000175:diagnosis* / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D013557:Switzerland
keywords: Bern Psychopathology Scale; Factor analysis; Schizophrenia spectrum disorders; System-specific approach