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  • Print publication year: 2008
  • Online publication date: August 2009

4 - Ethnic differences in psychotropic drug response and pharmacokinetics



There is increasing awareness that ethnic and cultural influences can alter individual responses to medications (Lambert & Minas, 1998). Ethno-psychopharmacology investigates cultural variations and differences that influence the effectiveness of prescription medicines used in the treatment of mental illnesses. Differences in response can be explained by both genetic and psychosocial variations. They range from genetic variants in drug metabolism to cultural practices, which may affect diet, adherence to prescribed patterns of medication use, placebo response, and the simultaneous use of traditional and alternative healing methods (Lin et al., 1991).

However, predictions regarding genetic expression based on ethnicity alone need to be exercised with caution. Although connections between ethnicity and drug metabolism were recognized early, for example primaquine induced hemolysis based on G6PD deficiency in some Afro-Americans (Alving et al., 1956), such differences are based more on genetic endowment per se rather than racial or ethnic divisions. The validity of therapy based solely on racial differences has been questioned, for example, in relation to differential drug responses in cardiology for Black and White patients (Schwartz, 2001).

All populations irrespective of racial group exhibit substantial intra-population variability (Jorde & Wooding, 2004). Within a single racial population between 93 and 95% of all human genetic variability is captured (Jones & Perlis, 2006). A small amount of genetic variation (∼0.02% of all nucleotides) distinguishes populations from each other and no single marker can identify race or ancestry.

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