title: A brief version of the Subjects' Response to Antipsychotics questionnaire to evaluate treatment effects.
abstract: BACKGROUND
  Monitoring patients' experiences with antipsychotics may help to improve medication adherence and outcome. We aimed to develop a shorter version of a comprehensive 74-item self-report questionnaire suitable for routine monitoring of desired and undesired effects of antipsychotics.
  
  
  METHODS
  Included were patients with psychotic disorders from seven mental health care organizations in The Netherlands, using antipsychotic medication, who completed the Subjects' Response to Antipsychotics (SRA-74). Exploratory factor analysis (EFA) and similarity analysis based on mutual information were used to identify the latent factor structure of the SRA. Items were reduced according to their metric properties and clinical relevance upon consensus by an expert panel, using a Delphi procedure of three rounds. We determined the internal consistency of the shorter version using Cronbach's alpha.
  
  
  RESULTS
  SRA data of N=1478 patients (mean age of 40 years, 31% females) were eligible for analysis. EFA extracted thirteen factors from the SRA-74, including four factors for desired effects (e.g. recovery of psychosis, cognition and social functioning) and nine factors for undesired effects (e.g. weight gain, flattened affect and increased sleep). Based on this solution 12 items were eliminated for statistical reasons. The expert panel eliminated another 28 items with redundant content, resulting in a 34-item version. The SRA-34 includes 10 desired and 24 clinically relevant undesired effects. Both the subscales for desired and undesired effects have a Cronbach's alpha coefficient of 0.82.
  
  
  CONCLUSIONS
  The SRA-34 can be used to evaluate desired and undesired effects of antipsychotics in routine clinical practice and research.
authors.affiliation: Rob Giel Research Center (RGOc), University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Pharmacotherapy and Pharmaceutical Care, Department of Pharmacy, University of Groningen, The Netherlands. Electronic address: i.m.lako@rug.nl.
authors.forename: Irene M
authors.initials: IM
authors.lastname: Lako
authors.affiliation: Rob Giel Research Center (RGOc), University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; University Center of Psychiatry, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: r.bruggeman@umcg.nl.
authors.forename: Richard
authors.initials: R
authors.lastname: Bruggeman
authors.affiliation: Rob Giel Research Center (RGOc), University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Neuroimaging Center, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: e.j.liemburg@umcg.nl.
authors.forename: Edith J
authors.initials: EJ
authors.lastname: Liemburg
authors.affiliation: Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: e.r.van.den.heuvel@umcg.nl.
authors.forename: Edwin R
authors.initials: ER
authors.lastname: van den Heuvel
authors.affiliation: Rob Giel Research Center (RGOc), University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Neuroimaging Center, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Lentis Center for Mental Health Care, Groningen, The Netherlands. Electronic address: h.knegtering@lentis.nl.
authors.forename: Henderikus
authors.initials: H
authors.lastname: Knegtering
authors.affiliation: Rob Giel Research Center (RGOc), University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Department of Psychotic Disorders, Mental Health Centre Assen (GGZ Drenthe), Assen, The Netherlands. Electronic address: cees.slooff@ggzdrenthe.nl.
authors.forename: Cees J
authors.initials: CJ
authors.lastname: Slooff
authors.affiliation: Rob Giel Research Center (RGOc), University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: d.wiersma@umcg.nl.
authors.forename: Durk
authors.initials: D
authors.lastname: Wiersma
authors.affiliation: Pharmacotherapy and Pharmaceutical Care, Department of Pharmacy, University of Groningen, The Netherlands. Electronic address: k.taxis@rug.nl.
authors.forename: Katja
authors.initials: K
authors.lastname: Taxis
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D007389:Internal-External Control; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D017063:Outcome Assessment, Health Care; D011594:Psychometrics; D011618:Psychotic Disorders / Q000188:drug therapy* / Q000523:psychology*; D057566:Self Report; D011795:Surveys and Questionnaires
chemical_list: D014150:Antipsychotic Agents