Pharmacogenetics, race, and psychiatry: prospects and challenges

Racial and Ethnic Considerations for the Clinical Practice of Psychopharmacology and Research Methodology: A Narrative Review of the Growing Body of Literature

BACKGROUND

Race and ethnicity are important but often underexamined factors in psychopharmacology research and clinical practice. This review summarizes key findings on ethnic and racial considerations for researchers, medical practitioners, and clinical psychopharmacologists. We hope it serves an important function in highlighting a critically important, yet still emerging issue to inform research and therapeutic use of psychotropics to improve their effectiveness.

METHODS

We queried major databases (PubMed, PsycInfo, Embase) using a search strategy that included MeSH (Medical Subject Headings) terms and conducted a snowball search to identify studies addressing ethnic or racial aspects of psychopharmacological practice. Findings were synthesized and presented in clinically applicable areas.

RESULTS

The clinically relevant ethnic and racial considerations identified in this review can be broadly categorized into the following areas: (1) variations in therapeutic and adverse dose-responses (eg, non-Whites attaining therapeutic and adverse effects at lower doses with certain medications); (2) interracial differences in prescription patterns of psychotropics, with lower prescription rates among under-represented minority groups and greater use of first-generation antipsychotics in African American populations; and (3) variations in attitudes toward psychopharmacotherapy. While differences in medication response can be partially explained by genetic variations in metabolism or receptor sensitivity, systemic racism and social determinants of health continue to have an influence.

CONCLUSIONS

The evidence base for ethnic and racial considerations in psychopharmacology research and clinical practice continues to evolve with growing consideration for diversity and inclusivity in training, research, and clinical practice. This is critical to promoting equitable and effective care to a diverse population. Key questions are highlighted to draw attention to these critical needs.

A scoping review of guidelines for the use of race, ethnicity, and ancestry reveals widespread consensus but also points of ongoing disagreement

The use of population descriptors such as race, ethnicity, and ancestry in science, medicine, and public health has a long, complicated, and at times dark history, particularly for genetics, given the field's perceived importance for understanding between-group differences. The historical and potential harms that come with irresponsible use of these categories suggests a clear need for definitive guidance about when and how they can be used appropriately. However, while many prior authors have provided such guidance, no established consensus exists, and the extant literature has not been examined for implied consensus and sources of disagreement. Here, we present the results of a scoping review of published normative recommendations regarding the use of population categories, particularly in genetics research. Following PRISMA guidelines, we extracted recommendations from n = 121 articles matching inclusion criteria. Articles were published consistently throughout the time period examined and in a broad range of journals, demonstrating an ongoing and interdisciplinary perceived need for guidance. Examined recommendations fall under one of eight themes identified during analysis. Seven are characterized by broad agreement across articles; one, "appropriate definitions of population categories and contexts for use," revealed substantial fundamental disagreement among articles. Additionally, while many articles focus on the inappropriate use of race, none fundamentally problematize ancestry. This work can be a resource to researchers looking for normative guidance on the use of population descriptors and can orient authors of future guidelines to this complex field, thereby contributing to the development of more effective future guidelines for genetics research.

The usefulness of genotyping cytochrome P450 enzymes in the treatment of depression

INTRODUCTION

Pharmacogenomics, which is derived from genome-wide association studies (GWAS), and pharmacogenetics, which involves candidate gene association studies (CGASs), are proving increasingly useful in personalized cancer care. Research in psychiatric applications has primarily involved genetic polymorphisms of P450 CYP enzymes, which mediate oxidative metabolism, particularly CYP2D6, which is involved in the metabolism of at least 30 psychotropic medications. This work has been supplemented by genotyping of proteins for the drug efflux pump P-glycoprotein (P-gp), serotonin receptors, and the serotonin reuptake pump.

AREAS COVERED

This review covers principles of pharmacogenetics and pharmacogenomics, previous analyses of pharmacokinetic and pharmacodynamics studies, newer studies of the predictive value of genetic testing in the treatment of depression, obstacles to implementation of genetic testing in predicting treatment response and side effects, and suggestions for future research.

EXPERT OPINION

Studies of multiple genes have produced some positive results in groups of patients, but genetic testing does not yet seem to be applicable to choosing medications for a specific patient.

Troubling "environments": postgenomics, Bajan wheezing, and Lévi-Strauss

Postgenomics is intended to move beyond the search for genes to explore disease as a result of genes interacting with their environment, revealing how they have relevance for health. This addition of environment confers genomic research with new cultural life, making it relevant to public health discourse, government interventions, and health disparities. Drawing on ethnographic research following an American genetics of asthma study conducted in Barbados, I explore the ways environment gets construed by the multiple communities involved-U.S. researchers, Bajan officials, medical practitioners, and patient participants. I draw on Lévi-Strauss to argue that plural competing environments give mana to the American postgenomic project as intervention on racial injustice, household practices, pollution, and other aspects of asthma.

Practice parameter for cultural competence in child and adolescent psychiatric practice

The United States faces a rapidly changing demographic and cultural landscape, with its population becoming increasingly multiracial and multicultural. In consequence, cultural and racial factors relating to mental illness and emotional disturbances deserve closer attention and consideration. This Practice Parameter outlines clinical applications of the principle of cultural competence that will enable child and adolescent mental health clinicians to better serve diverse children, adolescents, and their families.

Impact of a novel mutation in the 5'-flanking region of natriuretic peptide precursor B gene on the antihypertensive effects of sodium nitroprusside in patients with hypertension

Our aim was to identify the possible mutations of the natriuretic peptide precursor B (NPPB) gene in a family with hereditary hypertension, and determine whether the mutations are associated with the antihypertensive effect of sodium nitroprusside. The subjects included one family with hereditary hypertension, 36 cases of sporadic hypertension and 120 healthy controls. The 5'-flanking sequence of NPPB was amplified with PCR, and the presence of mutations was analyzed by direct sequencing. Patients with hypertension were treated with sodium nitroprusside and blood pressure data and serum B-type natriuretic peptide (BNP) levels were measured. A novel complex mutation in 5'-flanking sequence of the NPPB gene was detected in three patients (II 2, III 2, and III 5) of the hypertension family, which included c.-1195_ -1176 insert 5'-CCTTCTTTCTTTCTTTCTTT-3', c.-1208 T>A, c.-1214 T>C, and c.-1216 T>A. Patients with this mutation were less sensitive to sodium nitroprusside treatment. Sporadic hypertension patients (without NPPB gene mutation) and patients with the c.-1181 T>A point mutation were sensitive to sodium nitroprusside treatment. BNP levels of patients with the complex mutation were significantly lower than that of sporadic hypertension patients and c.-1181 T>A mutation patients before and during the early stage of sodium nitroprusside treatment. The complex mutation of the NPPB gene might be an etiological factor of hereditary malignant hypertension, and it is associated with low sensitivity to the antihypertensive effect of sodium nitroprusside.

Variability in the efficacy of psychopharmaceuticals: contributions from pharmacogenomics, ethnopsychopharmacology, and psychological and psychiatric anthropologies

Psychological and psychiatric anthropology have long questioned the universality of psychiatric diagnoses, bringing to light the fluidity of mental disorder, and recognizing that the experience and expression of psychopathology is influenced by complex and interacting genetic, environmental, and cultural factors. The majority of our discussions, however, have remained centered around the role of culture in shaping mental illness: drawing attention to subjective experiences of mental illness and culturally patterned modes of symptom presentation, and interrogating the cogency of universal diagnostic rubrics. Psychological and psychiatric anthropology have yet to robustly engage the broadly assumed universal validity of psychiatric medications and the ways in which they are prescribed and experienced. This article provides an introduction into the fields of pharmacogenomics and ethnopsychopharmacology, areas of inquiry seeking to understand the ways in which genetic variability occurring between, and within, large population groups influences individual ability to metabolize psychotropic medications. This piece further addresses the complex issue of psychopharmaceutical efficacy, stressing the ways in which, just as with psychopathology, medications and their outcomes are likewise influenced by the complex interactions of genes, environment, and culture. Lastly, ways in which anthropology can and should engage with the growing fields of pharmacogenomics and ethnopsychopharmacology are suggested.

Hyperdiagnostics: postcolonial utopics of race-based biomedicine

The expansion of biomedical research into countries outside the United States and Western Europe is positing new biological links between populations based on race. This expansion includes six international projects occurring in Barbados, premised on the idea that the population is genetically representative of other black people. Based on ethnographic research tracking one such study, a genetics of asthma project, this article explores the ways Caribbean meanings of ethnicity and illness are reworked as Barbadian state medical practitioners become involved in facilitating the international genetics research on race and disease. As the state attempts to participate in an imagined future of genetic medicine, the hyperspecificity of genetic technologies create new medical meanings of race and disease. These changes rely on a paradoxical response by medical practitioners toward the high technology American genetic research as both authoritative and inapplicable, creating unexpected etiologies of illness and ethnicity.

Once More Into the Breach

This article summarizes the main themes in the book What is Emotion? by Jerome Kagan (Yale University Press, 2007). The issues considered include: (1) the advantage of studying each phase of the cascade that begins with a brain reaction to an incentive and ends with an appraisal of a feeling state and/or a behavioral reaction; (2) distinguishing among appraisals with different origins; (3) replacing the current concern with consequences with more attention to the features of the brain and feeling states; (4) a recognition of the weak relation between the language used to describe a feeling and both the underlying brain profile and a response; and (5) the reasons for variation in the feelings evoked by an incentive and for the appraisals of the feelings.

Fish ingestion and congener specific polychlorinated biphenyl and p,p'-dichlorodiphenyldichloroethylene serum concentrations in a great lakes cohort of pregnant African American women

A cohort of low income, city dwelling, pregnant African American Women (delivered from 1994-1999) was assembled to identify factors related to organochlorine exposure through consumption of Great Lakes resources. The cohort is known as the Great Lakes Cohort of Pregnant African American Women (GLCPAAW). Pregnant women from metropolitan Chicago, IL area clinics were administered a questionnaire on diet, demographics, and health history. Weight, height, and serum lipids were measured at delivery along with serum organochlorines such as PCBs and DDE. Congener specific concentrations of PCBs and p,p'-DDE found in the maternal serum are reported. Dominant PCB congeners found in the serum of the pregnant women at delivery included PCB 101, 118, 138, 153, and 180. The high prevalence and magnitude of PCB 101 (greater than the limit of detection in >80% of the women in the cohort) are unique characteristics of this cohort. Great Lakes fish has been identified as a source of exposure to organochlorines in several studies. Spearman correlations and robust regression models were utilized to identify the impact of Great Lakes fish ingestion on cohort serum organochlorine concentrations. Several potential confounders of the relationship between serum organochlorines and Great Lakes fish consumption were identified. Covariates related to organochlorines in correlations as well as regression models included age, body surface area, fish ingestion, lipids, parity, race and smoking. Lower chlorinated PCB congeners do not follow the same trends as the higher chlorinated congeners and DDE. The higher chlorinated PCB congeners (PCB 138, 153, and 180) and DDE were correlated with age while the lower chlorinated congeners were not. PCB 153 and 180 regression models included age as a significant covariate. None of the higher chlorinated congeners correlated to race, while both lower chlorinated congeners were correlated to race. Race was also significant in both lower chlorinated congeners' regression models. PCB 101, a lower chlorinated congener seldom found in human serum, is readily found in the cohort. Airborne PCB exposure as well as diminished metabolism of PCB 101 in African Americans may explain the increased presence of PCB 101 and it's correlation with race. High end sport fish consumers (> or =1 meal per week) carried elevated levels of DDE and higher chlorinated PCB congeners (138, 153, and 180) compared to non-sport fish eaters. Unexpectedly, DDE was correlated more consistently with fish ingestion and age (a marker of bioaccumulation) in comparison to PCBs. Small correlations were found between serum PCBs and fish ingestion (Spearman correlation=0.19 for total PCBs and fish meals per year). Additionally, Serum PCBs in low end Great Lakes sport fish consumers were not higher than non-consumers. These findings suggest the women of the cohort are being exposed to PCBs through other routes in addition to Great lakes sport fish. One major route of exposure may be Chicago air. The observed trends amongst individual PCB congeners has important ramifications because lower chlorinated congeners or their metabolites may be mediators of toxicity. Organochlorine exposure through Great Lakes fish ingestion was clearly identified in high end fish consumers while associations with race, metabolism, and possible airborne exposures pose new questions.

Attitudes toward psychopharmacology among hospitalized patients from diverse ethno-cultural backgrounds

BACKGROUND

Biological factors influencing individual response to drugs are being extensively studied in psychiatry. Strikingly, there are few studies addressing social and cultural differences in attitudes toward psychotropic medications. The objective of this study was to investigate ethno-culturally determined beliefs, expectations and attitudes toward medication among a sample of hospitalized psychiatric patients.

METHODS

An ad hoc questionnaire was designed to assess patients' expectations, attitudes and prejudice toward medication. The study included 100 adult patients hospitalized in Geneva, Switzerland.

RESULTS

Patients were in majority male (63%), originated from Switzerland (54%) and spoke the local language fluently (93%). They took on the average 3 different psychotropic drugs. Sixty-eight percent of patients expected side effects and 60% were ready to stop medication because of them. Thirty percent of patients expected negative personal changes with treatment and 34% thought that their mental disorder could have been treated without drugs. Thirty six percent of the sample used alternative or complementary medicines. 35% of immigrant patients believed that medication had different effects on them than on local patients. When compared with Swiss patients, they more often reported that significant others had an opinion about medication (p = 0.041) and more frequently valued information provided by other patients about treatment (p = 0.010).

CONCLUSION

Patients' attitudes toward medication should be investigated in clinical practice, as specific expectations and prejudice exist. Targeted interventions, especially for immigrant patients, might improve adherence.

Pharmacogenetics of major depression: insights from level 1 of the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) trial

Major depression is a serious mental illness frequently associated with devastating consequences for those affected. Suicide rates are significantly elevated, creating a sense of urgency to identify effective yet safe treatment options. A plethora of antidepressants are available on the market today, designed to act on different neurotransmitter systems in the brain, providing the clinician with several treatment strategies. There is, however, very little guidance as to which antidepressant may be most successful in a certain individual. Biomarkers that can predict treatment outcome would thus be of great value, shortening the time until remission and reducing costs for the healthcare system by reducing unsuccessful treatment attempts. The proven contribution of heredity to major depression risk suggests that genetic markers may be good biomarkers for treatment outcome.The Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study and a large ancillary pharmacogenetic study in 1953 STAR*D participants constitute the largest effort to date to identify genetic predictors of antidepressant treatment outcome. In this review, the results of candidate gene studies carried out so far are summarized and discussed, and some future directions are proposed.

Pharmacogenetic studies of antidepressant response: how far from the clinic?

Because the US FDA has begun to focus on disclosure of pharmacogenetic testing results in applications for new drug approval and review of existing drugs (see, eg, http://www.fda.gov/OHRMS/DOCKETS/AC/05/slides/2005-4194S1_Slide-Index.htm), the application of such testing in a clinical setting is likely to increase substantially. Instead of small cohorts of patients, potentially nearly every participant in the large pivotal trials required for drug approval could help inform the future application of that drug. Psychiatry as a whole, and antidepressant prescribing ni particular, stands to benefit in the near term from the identification of newer treatment targets that may overcome some of the limitations of current therapeutics. On the other hand, despite the excitement about the rapid pace of development in psychiatric pharmacogenetics, a number of key issues remain to be addressed before these discoveries are applied in a clinical setting. Close coordination will be required between those who study treatment efficacy and effectiveness and those who study genetic variation in populations to ensure that studies yield results that have scientific importance and clinical importance as well.