Association of Ethnicity with Antipsychotic Dosage Using STRUCTURE Analysis

Abstract

Introduction:

Several studies have examined whether ethnicity as an independent factor can influence the individual’s dosage of antipsychotics. However, there has been inconsistency in the results of these studies, particularly between white and non-white populations. This retrospective study tests the hypothesis of different dosing of antipsychotics in white Europeans vs. non-white Europeans considering both the self-reported ethnicity and the geographical ancestry calculated using 196 DNA markers.

Methods:

We collected self-reported ethnicity and DNA samples from 209 schizophrenia patients. We tested the association between self-reported and genetically-determined ethnicity with the chlorpromazine equivalent dose of each antipsychotic prescribed at the time of the assessment.

Results:

We did not find any significant difference between self-reported white European ­ethnicity and chlorpromazine equivalent doses (p=0.972). Furthermore, when we considered the geographical ancestry determined by the 196 SNPs, we could not find any correlation between the European ancestry and chlorpromazine equivalent dose.

Discussion:

Our preliminary analysis shows that there is no evidence that different ethnic groups receive different dose of antipsychotics.

Key words

schizophrenia - antipsychotics - ethnicity - chlorpromazine equivalent - structure analysis

• References

• 1 Poolsup N, Li Wan Po A, Knight TL. Pharmacogenetics and psychopharmacotherapy. J Clin Pharm Ther 2000; 25: 197-220
• 2 Plesnicar BK. Personalized antipsychotic treatment: the adverse effects perspectives. Psychiatr Danub 2010; 22: 329-334
• 3 Lehman AF, Lieberman JA, Dixon LB et al. Practice guideline for the treatment of patients with schizophrenia, second edition. Am J Psychiatry 2004; 161 (2 Suppl) 1-56
• 4 Collins FS. What we do and don’t know about “race”, “ethnicity”, genetics and health at the dawn of the genome era. Nat Genet 2004; 36 (11 Suppl) S13-S15
• 5 Seeman MV. Gender differences in the prescribing of antipsychotic drugs. Am J Psychiatry 2004; 161: 1324-1333
• 6 Remington GJ, Prendergast P, Bezchlibnyk-Butler KZ. Neuroleptic dosing in chronic schizophrenia: a 10-year follow-up. Can J Psychiatry 1997; 42: 53-57
• 7 Citrome L, Volavka J. Optimal dosing of atypical antipsychotics in adults: a review of the current evidence. Harv Rev Psychiatry 2002; 10: 280-291
• 8 Prior TI, Baker GB. Interactions between the cytochrome P450 system and the second-generation antipsychotics. J Psychiatry Neurosci 2003; 28: 99-112
• 9 Diaz FJ, De Leon J. Excessive antipsychotic dosing in 2 US state hospitals. J Clin Psychiatry 2002; 63: 998-1003
• 10 Walkup JT, McAlpine DD, Olfson M et al. Patients with schizophrenia at risk for excessive antipsychotic dosing. J Clin Psychiatry 2000; 61: 344-348
• 11 Strakowski SM, Shelton RC, Kolbrener ML. The effects of race and comorbidity on clinical diagnosis of inpatients with psychosis. J Clin Psychiatry 1993; 54: 96-102
• 12 Segal S, Bola J, Watson M. Race, quality of care, and antipsychotic prescribing practices in psychiatric emergency services. Psychiatr Serv 1996; 47: 282-286
• 13 Schwartz T, Stahl S. Treatment strategies for dosing the second generation antipsychotics. CNS Neurosci Ther 2011; 17: 110-117
• 14 Dickey B, Normand SL, Elsen S et al. Association between adherence to guidelines for antipsychotic dose and health status, side effects, and patient care experiences. Med Care 2006; 44: 827-834
• 15 Naber D. A self-rating to measure subjective effects of neuroleptic drugs, relationships to objective psychopathology, quality of life, compliance and other clinical variables. Int Clin Psychopharmacol 1995; 10 (Suppl. 03) 133-138
• 16 Yamin S, Vaddadi K. Are we using excessive neuroleptics? An argument for systematic neuroleptic dose reduction in stable patients with schizophrenia with specific reference to clozapine. Int Rev Psychiatry 2010; 22: 138-147
• 17 Kinon BJ, Hill AL, Liu H et al. Olanzapine orally disintegrating tablets in the treatment of acutely ill non-compliant patients with schizophrenia. Int J Neuropsychopharmacol 2003; 6: 97-102
• 18 Edday M, Grogg A, Locklear J. Assessment of compliance with anti­psychotic treatment and resource utilization in a Medicaid population. Clin Ther 2005; 27: 263-272
• 19 Lindstrom E, Bingefors K. Patient compliance with drug therapy in schizophrenia. Economic and clinical issues. Pharmacoeconomics 2000; 18: 106-124
• 20 Lehman AF, Steinwachs DM. Pattern of usual care for schizophrenia: Initial results from the schizophrenia patient outcomes research team (PORT) client survey. Schizophr Bull. 1998; 24: 11-20 discussion 20–32
• 21 Lin KM, Poland RE, Nuccio I et al. A longitudinal assessment of haloperidol doses and serum concentrations in Asian and Caucasian schizophrenic patients. Am J Psychiatry 1989; 146: 1307-1311
• 22 Matsuda KT, Cho MC, Lin KM et al. Clozapine dosage, serum levels, efficacy, and side-effect profiles: a comparison of Korean-American and Caucasian patients. Psychopharmacol Bull 1996; 32: 253-257
• 23 Potkin SG, Shen Y, Pardes H et al. Haloperidol concentrations elevated in Chinese patients. Psychiatry Res 1984; 12: 167-172
• 24 Connolly A, Taylor D, Sparshatt A et al. Antipsychotic prescribing in black and white hospitalized patients. J Psychopharmacol 2011; 25: 704-709
• 25 Connolly A, Rogers P, Taylor D. Antipsychotic prescribing quality and ethnicity: a study of hospitalized patients in southeast London. J Psychopharmacol 2007; 21: 191-197
• 26 Connolly A, Taylor D. Ethnicity and quality of antipsychotic prescribing among in-patients in south London. Br J Psychiatry 2008; 193: 161-162
• 27 Yang BZ, Zhao H, Kranzler HR et al. Practical population group assignment with selected informative markers: characteristics and properties of Bayesian Clustering via STRUCTURE. Genet Epidemiol 2005; 28: 302-312
• 28 Gardner DM, Murphy AL, O’Donnell H et al. International consensus study of antipsychotic dosing. Am J Psychiatry 2010; 167: 686-693
• 29 Pritchard JK, Stephens M, Donnelly P. Inference of population structure using multilocus genotype data. Genetics 2000; 155: 945-959
• 30 Nose M, Tansella M, Thornicroft G et al. Is the defined daily dose system a reliable tool for standardizing antipsychotic dosages?. Int Clin Psychopharmacol 2008; 23: 287-290
• 31 Brotman AW, McCormick S. Converting doses of fluphenazine decanoate to oral equivalent. Am J Psychiatry 1989; 146: 815-816