title: The role of ethnicity in treatment refractory schizophrenia.
abstract: OBJECTIVE
  The goal of this research was to describe the relationship between treatment resistant schizophrenia, defined using the APA criteria and ethnic background in patients with schizophrenia spectrum disorders in a Canadian sample. A secondary goal was to analyze the number of antipsychotics failed due to side effects and number of antipsychotics failed due to non-response.
  
  
  METHODS
  We included 497 patients diagnosed with schizophrenia spectrum disorders using the SCID. The medication history was extracted from the electronic health records. Data collection included demographics (sex, age, ethnicity), principal diagnosis according to SCID (Diagnostic and Statistical Manual of Mental Disorders, 4th edition), duration of mental illness, number of psychiatric admissions and treatment information. If patients were on clozapine or polypharmacy treatment, this was recorded at the time of the SCID interview. Additional data, including prior antipsychotic history, were collected from the health records.
  
  
  RESULTS
  Thirty per cent of the patients were classified as resistant according to the APA criteria. There were significantly more white European subjects in the treatment resistant group (p=0.031). The duration of illness was significantly higher in the resistant group then in the non-resistant group (21.0 vs 15.1 years; p<0.001). Patients who were treatment resistant were more likely to be on polypharmacy compared with non-resistant patients (p=0.001; OR=2.424; 95%CI=1.446-4.065). When we considered the number of drug trials failed due to non response and drug trial failed because of side effects, we found a strong negative correlation in both white Europeans and non-white Europeans.
  
  
  CONCLUSIONS
  White European ethnicity is associated with treatment resistant schizophrenia. In addition, patients with treatment-resistant schizophrenia were on polypharmacy at higher rate than non resistant patients.
authors.affiliation: CAMH, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada M5T 1R8.
authors.forename: Celine
authors.initials: C
authors.lastname: Teo
authors.forename: Carol
authors.initials: C
authors.lastname: Borlido
authors.forename: James L
authors.initials: JL
authors.lastname: Kennedy
authors.forename: Vincenzo
authors.initials: V
authors.lastname: De Luca
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D002170:Canada; D003024:Clozapine / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019338:Polypharmacy; D018967:Risperidone / Q000627:therapeutic use; D012559:Schizophrenia / Q000188:drug therapy / Q000208:ethnology*; D012737:Sex Factors; D017211:Treatment Failure
chemical_list: D014150:Antipsychotic Agents; D003024:Clozapine; D018967:Risperidone