Association of Ethnicity with Antipsychotic Dosage Using STRUCTURE Analysis

Abstract

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

Ethnic Differences in Antipsychotic treatment responses in Early Intervention in Psychosis

“…[6] A prolonged DUP may indicate the need for higher doses of antipsychotics, but ethnicity has been seen not to be a factor in determining DUP. [7] With respect to variations in prescribing practices which are based on ethnic variations, some studies did find that such differences did exist. [8,9] Whilst other studies showed that antipsychotic prescribing practice did not differ between patients from the Black and White ethnic groups.…”

“…[4] However a similarly sized study comparing antipsychotic dosing of all antipsychotics using chlorpromazine-equivalent calculations in white Europeans compared to non-white Europeans found no significant differences using both self -reported ethnicity and geographical ancestry determined by DNA sample. [7] The contradictions between these studies could perhaps be explained by the different approaches: homing in on individual medications sharpens the focus on ethnic differences in response to that treatment which is lost when comparing with many other drugs all at once. Alternatively given that the interplay between genes and environment is notoriously complex, there may also be differences in European responses compared with those from other continents.…”