title: A prospective study of risk factors for nonadherence with antipsychotic medication in the treatment of schizophrenia.
abstract: OBJECTIVE
  This study aimed to prospectively identify the best single predictor and the best set of predictors of risk for nonadherence with anti-psychotic medication in the treatment of patients with schizophrenia.
  
  
  METHODS
  We used data from 1579 patients in a 3-year, prospective, naturalistic, nonrandomized, multisite study of schizophrenia patients conducted from July 1997 to September 2003 (U.S. Schizophrenia Care and Assessment Program). Adherence with any oral antipsychotic medication was assessed using patient-reported medication adherence and an indirect adherence measure based on medical record prescription information. Patients who reported poor medication adherence or had a medication possession ratio < or = 80% (percentage of days with prescriptions for any oral antipsychotic) during the first year after enrollment were defined as nonadherent (N = 296, 18.8%). Thirty-nine previously reported potential risk factors of nonadherence with antipsychotic medication were assessed at enrollment with valid and reliable measures. Risk factors represented patient-, environment-, and treatment-related domains, including sociodemographics, symptom severity, substance use, threat to safety of self and others, other illness-related factors, need for supervision, medication-related adverse events, and prior medication-utilization patterns.
  
  
  RESULTS
  The best single predictor of future nonadherence was nonadherence during the 6 months prior to enrollment (odds ratio = 4.1, 95% confidence interval = 3.1 to 5.6, p < .001). The best set of predictors of nonadherence, ordered by strength of association, included prior non-adherence, recent illicit drug use, recent alcohol use, prior treatment with antidepressants, and greater patient-reported, medication-related cognitive impairment.
  
  
  CONCLUSIONS
  Nonadherence with antipsychotic medication is associated with a well-defined set of risk factors that can be used to identify patients who are predisposed to poor adherence.
authors.affiliation: Eli Lilly and Co., Lilly Corporate Center, Indianapolis, IN 46285, USA. haya@lilly.com
authors.forename: Haya
authors.initials: H
authors.lastname: Ascher-Svanum
authors.forename: Baojin
authors.initials: B
authors.lastname: Zhu
authors.forename: Douglas
authors.initials: D
authors.lastname: Faries
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Lacro
authors.forename: Christian R
authors.initials: CR
authors.lastname: Dolder
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000928:Antidepressive Agents / Q000627:therapeutic use; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D003072:Cognition Disorders / Q000139:chemically induced / Q000175:diagnosis / Q000453:epidemiology; D004363:Drug Utilization; D005260:Female; D005500:Follow-Up Studies; D006304:Health Status; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008499:Medical Records / Q000706:statistics & numerical data; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D012307:Risk Factors; D012559:Schizophrenia / Q000188:drug therapy* / Q000453:epidemiology; D012565:Schizophrenic Psychology; D016312:Treatment Refusal / Q000706:statistics & numerical data*; D014481:United States
chemical_list: D000928:Antidepressive Agents; D014150:Antipsychotic Agents