title: Measuring adherence to medication in schizophrenia: the relationship between attitudes toward drug therapy and plasma levels of new-generation antipsychotics.
abstract: BACKGROUND
  Nonadherence to medication is still a major problem in the treatment of schizophrenia. The current longitudinal study investigated whether the patients' attitudes toward treatment correlated with the ratio of observed vs expected plasma levels of antipsychotic drugs as an objective measurement of adherence.
  
  
  METHODS
  Data of patients starting monotherapy with a new-generation antipsychotic were collected 2, 4, and 12 weeks after the initiation of treatment. Next to the assessment of patients' attitudes toward medication by means of the Drug Attitude Inventory, the ratio of the observed vs expected plasma level was calculated. Antipsychotic-induced side effects were evaluated by means of the Udvalg for Kliniske Undersogelser Side Effect Rating Scale.
  
  
  RESULTS
  A total of 93 patients were eligible for statistical analysis. About one-half of the ratios of observed vs expected plasma levels ranged from 0.5 to 2 and were considered normal, whereas the other ratios were considered either too low (<0.5) or too high (>2). No consistent correlation between patients' attitude toward drug therapy and the individual ratios of observed vs expected plasma levels of medication was detected. This finding was not affected by side effects.
  
  
  CONCLUSIONS
  Our results highlight the importance of recognizing the complex nature of adherence to medication in schizophrenia patients. Importantly, we found no consistent correlation between subjective and objective measures of medication adherence. Therefore, monitoring adherence to medication remains a challenge in clinical practice.
authors.affiliation: Biological Psychiatry Division (Drs Yalcin-Siedentopf, Wartelsteiner, Kaufmann, Biedermann, Edlinger, Rettenbacher, Widschwendter, Fleischhacker, and Hofer), and General and Social Psychiatry Division (Drs Kemmler and Zernig), Medical University Innsbruck, Department of Psychiatry and Psychotherapy, Innsbruck, Austria.
authors.forename: Nursen
authors.initials: N
authors.lastname: Yalcin-Siedentopf
authors.affiliation: Biological Psychiatry Division (Drs Yalcin-Siedentopf, Wartelsteiner, Kaufmann, Biedermann, Edlinger, Rettenbacher, Widschwendter, Fleischhacker, and Hofer), and General and Social Psychiatry Division (Drs Kemmler and Zernig), Medical University Innsbruck, Department of Psychiatry and Psychotherapy, Innsbruck, Austria.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Wartelsteiner
authors.affiliation: Biological Psychiatry Division (Drs Yalcin-Siedentopf, Wartelsteiner, Kaufmann, Biedermann, Edlinger, Rettenbacher, Widschwendter, Fleischhacker, and Hofer), and General and Social Psychiatry Division (Drs Kemmler and Zernig), Medical University Innsbruck, Department of Psychiatry and Psychotherapy, Innsbruck, Austria.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kaufmann
authors.affiliation: Biological Psychiatry Division (Drs Yalcin-Siedentopf, Wartelsteiner, Kaufmann, Biedermann, Edlinger, Rettenbacher, Widschwendter, Fleischhacker, and Hofer), and General and Social Psychiatry Division (Drs Kemmler and Zernig), Medical University Innsbruck, Department of Psychiatry and Psychotherapy, Innsbruck, Austria.
authors.forename: Falko
authors.initials: F
authors.lastname: Biedermann
authors.affiliation: Biological Psychiatry Division (Drs Yalcin-Siedentopf, Wartelsteiner, Kaufmann, Biedermann, Edlinger, Rettenbacher, Widschwendter, Fleischhacker, and Hofer), and General and Social Psychiatry Division (Drs Kemmler and Zernig), Medical University Innsbruck, Department of Psychiatry and Psychotherapy, Innsbruck, Austria.
authors.forename: Monika
authors.initials: M
authors.lastname: Edlinger
authors.affiliation: Biological Psychiatry Division (Drs Yalcin-Siedentopf, Wartelsteiner, Kaufmann, Biedermann, Edlinger, Rettenbacher, Widschwendter, Fleischhacker, and Hofer), and General and Social Psychiatry Division (Drs Kemmler and Zernig), Medical University Innsbruck, Department of Psychiatry and Psychotherapy, Innsbruck, Austria.
authors.forename: Georg
authors.initials: G
authors.lastname: Kemmler
authors.affiliation: Biological Psychiatry Division (Drs Yalcin-Siedentopf, Wartelsteiner, Kaufmann, Biedermann, Edlinger, Rettenbacher, Widschwendter, Fleischhacker, and Hofer), and General and Social Psychiatry Division (Drs Kemmler and Zernig), Medical University Innsbruck, Department of Psychiatry and Psychotherapy, Innsbruck, Austria.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Rettenbacher
authors.affiliation: Biological Psychiatry Division (Drs Yalcin-Siedentopf, Wartelsteiner, Kaufmann, Biedermann, Edlinger, Rettenbacher, Widschwendter, Fleischhacker, and Hofer), and General and Social Psychiatry Division (Drs Kemmler and Zernig), Medical University Innsbruck, Department of Psychiatry and Psychotherapy, Innsbruck, Austria.
authors.forename: Christian G
authors.initials: CG
authors.lastname: Widschwendter
authors.affiliation: Biological Psychiatry Division (Drs Yalcin-Siedentopf, Wartelsteiner, Kaufmann, Biedermann, Edlinger, Rettenbacher, Widschwendter, Fleischhacker, and Hofer), and General and Social Psychiatry Division (Drs Kemmler and Zernig), Medical University Innsbruck, Department of Psychiatry and Psychotherapy, Innsbruck, Austria.
authors.forename: Gerald
authors.initials: G
authors.lastname: Zernig
authors.affiliation: Biological Psychiatry Division (Drs Yalcin-Siedentopf, Wartelsteiner, Kaufmann, Biedermann, Edlinger, Rettenbacher, Widschwendter, Fleischhacker, and Hofer), and General and Social Psychiatry Division (Drs Kemmler and Zernig), Medical University Innsbruck, Department of Psychiatry and Psychotherapy, Innsbruck, Austria.
authors.forename: W Wolfgang
authors.initials: WW
authors.lastname: Fleischhacker
authors.affiliation: Biological Psychiatry Division (Drs Yalcin-Siedentopf, Wartelsteiner, Kaufmann, Biedermann, Edlinger, Rettenbacher, Widschwendter, Fleischhacker, and Hofer), and General and Social Psychiatry Division (Drs Kemmler and Zernig), Medical University Innsbruck, Department of Psychiatry and Psychotherapy, Innsbruck, Austria a.hofer@i-med.ac.at.
authors.forename: Alex
authors.initials: A
authors.lastname: Hofer
mesh_terms: D000284:Administration, Oral; D000328:Adult; D014150:Antipsychotic Agents / Q000008:administration & dosage* / Q000009:adverse effects / Q000097:blood / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D055118:Medication Adherence / Q000523:psychology*; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000188:drug therapy*; D012565:Schizophrenic Psychology; D013997:Time Factors
chemical_list: D014150:Antipsychotic Agents
keywords: adherence; drug attitude; ratio; schizophrenia; therapeutic drug monitoring