Role of ethnicity in antipsychotic-induced weight gain and tardive dyskinesia: genes or environment?

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.

CYP2D6 Genetic Variation and Antipsychotic-Induced Weight Gain: A Systematic Review and Meta-Analysis

BACKGROUND

Antipsychotic-induced weight gain is a contributing factor in the reduced life expectancy reported amongst people with psychotic disorders. CYP2D6 is a liver enzyme involved in the metabolism of many commonly used antipsychotic medications. We investigated if CYP2D6 genetic variation influenced weight or BMI among people taking antipsychotic treatment.

METHODS

We conducted a systematic review and a random effects meta-analysis of publications in Pubmed, Embase, PsychInfo, and CENTRAAL that had BMI and/or weight measurements of patients on long-term antipsychotics by their CYP2D6-defined metabolic groups (poor, intermediate, normal/extensive, and ultra-rapid metabolizers, UMs).

RESULTS

Twelve studies were included in the systematic review. All cohort studies suggested that the presence of reduced-function or non-functional alleles for CYP2D6 was associated with greater antipsychotic-induced weight gain, whereas most cross-sectional studies did not find any significant associations. Seventeen studies were included in the meta-analysis with clinical data of 2,041 patients, including 93 poor metabolizers (PMs), 633 intermediate metabolizers (IMs), 1,272 normal metabolizers (NMs), and 30 UMs. Overall, we did not find associations in any of the comparisons made. The estimated pooled standardized differences for the following comparisons were (i) PM versus NM; weight = -0.07 (95%CI: -0.49 to 0.35, p = 0.74), BMI = 0.40 (95%CI: -0.19 to 0.99, p = 0.19). (ii) IM versus NM; weight = 0.09 (95% CI: -0.04 to 0.22, p = 0.16) and BMI = 0.09 (95% CI: -0.24 to 0.41, p = 0.60). (iii) UM versus EM; weight = 0.01 (95% CI: -0.37 to 0.40, p = 0.94) and BMI = -0.08 (95%CI: -0.57 to 0.42, p = 0.77).

CONCLUSION

Our systematic review of cohort studies suggested that CYP2D6 poor metabolizers have higher BMI than normal metabolizers, but the data of cross-sectional studies and the meta-analysis did not show this association. Although our review and meta-analysis constitutes one of the largest studies with comprehensively genotyped samples, the literature is still limited by small numbers of participants with genetic variants resulting in poor or UMs status. We need further studies with larger numbers of extreme metabolizers to establish its clinical utility in antipsychotic treatment. CYP2D6 is a key gene for personalized prescribing in mental health.

Factors Associated With Off-Label Utilization of Second-Generation Antipsychotics Among Publicly Insured Adults

OBJECTIVE

Off-label utilization of second-generation antipsychotic medications may expose patients to significant risks. The authors examined the prevalence, temporal trends, and factors associated with off-label utilization of second-generation antipsychotics among publicly insured adults.

METHODS

A retrospective repeated panel was used to examine monthly off-label utilization of second-generation antipsychotics among fee-for-service Medicare, Medicaid, and dually eligible White, Black, and Latino adult beneficiaries filling prescriptions for second-generation antipsychotics in California, Georgia, Mississippi, and Oklahoma from July 2008 through June 2013.

RESULTS

Among 301,367 users of second-generation antipsychotics, between 36.5% and 41.9% had utilization that was always off-label. Payer did not modify effects of race-ethnicity on off-label utilization. Compared with Whites, Blacks had lower monthly odds of off-label utilization in all four states, and Latinos had lower odds of utilization in California and Georgia. Payer was associated with off-label utilization in California, Mississippi, and Oklahoma. California Medicaid beneficiaries were 1.12 (95% confidence interval=1.10-1.13) times as likely as dually eligible beneficiaries to have off-label utilization. Off-label utilization increased relative to the baseline year in all states, but a downward trend followed in three states.

CONCLUSIONS

Off-label utilization of second-generation antipsychotics was prevalent despite the drugs' cardiometabolic risks and little evidence of their effectiveness. The lower likelihood of off-label utilization among patients from racial-ethnic minority groups might stem from prescribers' efforts to minimize risks, given a higher baseline risk for these groups, or from disparities-associated factors. Variation among payers suggests that payer policies can affect off-label utilization.

The increasing challenge of the possible impact of ethnicity on psychopharmacology

Ethnic differences may significantly influence the outcome of psychopharmacological treatment, in terms of prescription, adherence, clinical response, emergence of side effects, as well as pharmacokinetics and pharmacodynamics. The purpose of this review was to explore the available literature in order to provide general suggestions to help clinicians in choosing the best therapeutic option for patients, taking into account ethnicity. Although findings are sometimes controversial, the overall published studies suggest that ethnicities other than Caucasians tend to show a lower response to antidepressants and a reduced compliance. Africans tend to be more prescribed with antipsychotics, probably due to cultural stereotypes, except with clozapine, probably for their chronic benign neutropenia. Asians usually require less antipsychotic dosages than Caucasians. The differential response and side effect profile of antidepressants and antipsychotics have been related to individual intrinsic factors, to genetic make-up, but also to cultural and contextual variables. Interestingly, albeit limited data suggest ethnic-related genetic heterogeneity at the level of the serotonin transporters, the cytochromes and some neuroreceptors. Taken together, no conclusive findings are available about the role and impact of ethnicity in psychopharmacology. One of the main problems is that the majority of the studies in psychopharmacology have been conducted on Caucasians, so that there is an urgent need to have data in other populations. Furthermore, in the era of precision medicine, the role of ethnicity may be also supported by genetic analysis.

Significance and Factors Associated with Antipsychotic Polypharmacy Utilization Among Publicly Insured US Adults

Antipsychotic polypharmacy (APP) lacks evidence of effectiveness in the care of schizophrenia or other disorders for which antipsychotic drugs are indicated, also exposing patients to more risks. Authors assessed APP prevalence and APP association with beneficiary race/ethnicity and payer among publicly-insured adults regardless of diagnosis. Retrospective repeated panel study of fee-for-service (FFS) Medicare, Medicaid, and dually-eligible white, black, and Latino adults residing in California, Georgia, Iowa, Mississippi, Oklahoma, South Dakota, or West Virginia, filling antipsychotic prescriptions between July 2008 and June 2013. Primary outcome was any monthly APP utilization. Across states and payers, 11% to 21% of 397,533 antipsychotic users and 12% to 19% of 9,396,741 person-months had some APP utilization. Less than 50% of person-months had a schizophrenia diagnosis and up to 19% had no diagnosed mental illness. Payer modified race/ethnicity effects on APP utilization only in CA; however, the odds of APP utilization remained lower for minorities than for whites. Elsewhere, the odds varied by race/ethnicity only in OK, with Latinos having lower odds than whites (odds ratio 0.76; 95% confidence interval 0.60-0.96). The odds of APP utilization varied by payer in several study states, with odds generally higher for Dual eligibles, although the differences were generally small; the odds also varied by year (lower at study end). APP was frequently utilized but mostly declined over time. APP utilization patterns varied across states, with no consistent association with race/ethnicity and small payer effects. Greater use of APP-reducing strategies are needed, particularly among non-schizophrenia populations.

Pharmacogenomics of Cognitive Dysfunction and Neuropsychiatric Disorders in Dementia

Symptomatic interventions for patients with dementia involve anti-dementia drugs to improve cognition, psychotropic drugs for the treatment of behavioral disorders (BDs), and different categories of drugs for concomitant disorders. Demented patients may take >6-10 drugs/day with the consequent risk for drug-drug interactions and adverse drug reactions (ADRs >80%) which accelerate cognitive decline. The pharmacoepigenetic machinery is integrated by pathogenic, mechanistic, metabolic, transporter, and pleiotropic genes redundantly and promiscuously regulated by epigenetic mechanisms. CYP2D6, CYP2C9, CYP2C19, and CYP3A4/5 geno-phenotypes are involved in the metabolism of over 90% of drugs currently used in patients with dementia, and only 20% of the population is an extensive metabolizer for this tetragenic cluster. ADRs associated with anti-dementia drugs, antipsychotics, antidepressants, anxiolytics, hypnotics, sedatives, and antiepileptic drugs can be minimized by means of pharmacogenetic screening prior to treatment. These drugs are substrates, inhibitors, or inducers of 58, 37, and 42 enzyme/protein gene products, respectively, and are transported by 40 different protein transporters. APOE is the reference gene in most pharmacogenetic studies. APOE-3 carriers are the best responders and APOE-4 carriers are the worst responders; likewise, CYP2D6-normal metabolizers are the best responders and CYP2D6-poor metabolizers are the worst responders. The incorporation of pharmacogenomic strategies for a personalized treatment in dementia is an effective option to optimize limited therapeutic resources and to reduce unwanted side-effects.

Exploring Biologic Predictors Response Disparities to Atypical Antipsychotics among Blacks: A Quasi-Systematic Review

Purpose

Management of schizophrenia among Blacks in the United States is affected by persistent disparities. This review explored response to atypical antipsychotics among Blacks compared with other groups to assess systematic variation that may contribute to disparities.

Methods

We conducted a quasi-systematic review of studies reporting response to atypical antipsychotics among Blacks compared with other groups, including effects of genetic variation.

Results

Of 48 identified research articles, 29 assessed differences in outcomes without inclusion of genetic variation and 20 explored effects of genetic variation; of note: one article included both types of data. Analysis of the 29 papers with clinical outcomes only suggests that while data on efficacy and risk of movement disorders were heterogeneous, findings indicate increased risk of metabolic effects and neutropenia among Blacks. Of the 20 articles exploring effects of genetic variation, allelic or genotypic variations involving several genes were associated with altered efficacy or safety among Blacks but not Whites, including risk of decreased response involving variation in DRD4 and DRD1, and improved efficacy associated with variants in DRD2, COMT, and RGS4. Others showed significant improvement in treatment response only among Whites, including variation in DTNBP1, DRD4, and GNB3.

Conclusions

The current analysis can help tailor management among Blacks using an atypical antipsychotic. Heterogeneity in genetic variation effects and response allele frequency suggests that pharmacogenetics approaches for atypical antipsychotics will need to explicitly incorporate race and ethnicity.

No differences in olanzapine- and risperidone-related weight gain between women and men: a meta-analysis of short- and middle-term treatment

OBJECTIVE

A plethora of data deriving from single studies as well as meta-analyses demonstrates that weight gain is associated with the exposure to the majority of antipsychotics (AP). However, potential sex differences have widely evaded the attention of AP treatment trials. It is hypothesised that female patients gain more weight compared with male patients due to their enhanced susceptibility to adverse drug reactions.

METHOD

A meta-analysis was conducted using clinical trials of AP that reported weight change separately for female and male patients. Duration of AP use was stratified in four categories: <6 weeks, 6-16 weeks, 16-38 weeks and >38 weeks. Forest plots were generated for men and women separately, stratified by AP as well as by duration of use. Sex differences were tested by performing meta-regression.

RESULTS

Data of 26 studies were used in the present analysis because sufficient data were available only for olanzapine, risperidone and the no-medication group. Both female and male patients showed considerable weight gain after switch or initiate of olanzapine or risperidone, but meta-regression analyses did not show significant sex differences.

CONCLUSION

The present meta-analysis revealed that sex differences in AP-related weight gain have been under investigated hampering the detection of sex-specific patterns. In chronic patients switching to olanzapine or risperidone receiving short-or middle-term treatment, AP were associated with weight gain in both sex subgroups and no significant differences were reported.

Development of multivariable models to predict change in Body Mass Index within a clinical trial population of psychotic individuals

Many antipsychotics promote weight gain, which can lead to non-compliance and relapse of psychosis. By developing models that accurately identify individuals at greater risk of weight gain, clinicians can make informed treatment decisions and target intervention measures. We examined clinical, genetic and expression data for 284 individuals with psychosis derived from a previously published randomised controlled trial (IMPACT). These data were used to develop regression and classification models predicting change in Body Mass Index (BMI) over one year. Clinical predictors included demographics, anthropometrics, cardiac and blood measures, diet and exercise, physical and mental health, medication and BMI outcome measures. We included genetic polygenic risk scores (PRS) for schizophrenia, bipolar disorder, BMI, waist-hip-ratio, insulin resistance and height, as well as gene co-expression modules generated by Weighted Gene Co-expression Network Analysis (WGCNA). The best performing predictive models for BMI and BMI gain after one year used clinical data only, which suggests expression and genetic data do not improve prediction in this cohort.

An Inter-Ethnic Comparison Study of Ziprasidone Plasma Levels, Dosage and Clinical Response in Patients with Schizophrenia

OBJECTIVE

The aim of this study was to investigate ziprasidone plasma concentration, daily dose and clinical efficacy and safety in Han Chinese and Mongolian patients with first-episode schizophrenia.

METHODS

A total of 123 inpatients affected by schizophrenia were recruited from the Mental Health Center of Inner Mongolia in China. Ziprasidone plasma concentration, clinical efficacy and side effects were systematically evaluated at baseline, and at 1, 2, 4, and 6 weeks. Metabolic measures such as changes in weight, body mass index (BMI), fasting blood glucose (FBG), triglycerides, and cholesterol, were also recorded.

RESULTS

90 patients completed the study. Compared with Han patients, on average, Mongolian patients received a significantly higher ziprasidone dosage for adequate symptom control during the 6-week period and had a lower plasma concentration-to-dose ratio. The Mongolian patients also experienced greater increases in weight and BMI. No significant differences between the two ethnic groups were found in the rate of reduction in the Positive and Negative Syndrome Scale (PANSS) score, Treatment Emergent Symptom Scale (TESS) total score, FBG, triglycerides, cholesterol or Q-Tc interval.

CONCLUSION

Compared to Han Chinese patients, Mongolian patients appeared to have increased ziprasidone clearance and require higher doses to achieve effective treatment for schizophrenia.

Gender and race disparities in weight gain among offenders prescribed antidepressant and antipsychotic medications

BACKGROUND

Studies have found that antipsychotics and antidepressants are associated with weight gain and obesity, particularly among women and some minority groups. Incarcerated populations (also referred to as offenders, prisoners or inmates) have a high prevalence of mental health problems and 15 % of offenders have been prescribed medications. Despite rates of antidepressant and antipsychotic use, investigations of weight gain and obesity in regard to these agents seldom have included offenders.

METHODS

This retrospective descriptive study (2005-2011) was conducted with a Department of Corrections in the east south central United States to investigate the relationship between antidepressant and antipsychotic agents, weight gain, obesity and race or gender differences. We sampled adult offenders who had an active record, at least two weight observations and height data. Offenders were classified into one of four mutually exclusive groups depending upon the type of medication they were prescribed: antidepressants, antipsychotics, other medications or no pharmacotherapy.

RESULTS

The sample population for this study was 2728, which was 25.2 % of the total population. The population not on pharmacotherapy had the lowest baseline obesity rate (31.7 %) compared to offenders prescribed antipsychotics (43.6 %), antidepressants (43.6 %) or other medications (45.1 %). Offenders who were prescribed antidepressants or antipsychotics gained weight that was significantly different from zero, p < .001 and p = .019, respectively. Women in the antidepressant group gained 6.4 kg compared to 2.0 kg for men, which was significant (p = .007). Although women in the antipsychotic group gained 8.8 kg compared to 1.6 kg for men, the finding was not significant (p = .122). Surprisingly, there were no significant differences in weight gain between African Americans and Whites in regard to antidepressants (p = .336) or antipsychotic agents (p = .335).

CONCLUSION

This study found that women and men offenders prescribed antidepressant or antipsychotic agents gained weight during their incarceration. Women prescribed antidepressants gained significantly more weight than men. However, there was no significant difference in weight gain between African Americans and Whites. Results suggest further investigation is needed to understand the effect of medication history, metabolic syndrome and to explain gender disparities.

Comparing self-reported ethnicity and structure-determined ethnicity: analysis of antipsychotic-induced weight gain

Response to: Kaufman JS, Hamra G. In Chan et al. the difference between p < 0.05 and p < 0.05 is p > 0.05. Pharmacogenomics14(16), 1941–1942 (2013).

In Chan et al. the difference between p < 0.05 and p < 0.05 is p > 0.05

Response to: Chan LF, Zai C, Monda M et al. Role of ethnicity in antipsychotic-induced weight gain and tardive dyskinesia: genes or environment? Pharmacogenomics 14(11), 1273–1281 (2013).