Pharmacogenetics in psychiatry: translating research into clinical practice

Providers' Use of Pharmacogenetic Testing to Inform Antidepressant Prescribing: Results of Qualitative Interviews

OBJECTIVE

Pharmacogenetic testing (PGx) for patients experiencing depression has been associated with modest improvements in symptoms. However, little is known about providers' use of PGx, including how and for whom providers use the test results in clinical decision making. In this article, results from qualitative interviews on the experience of providers participating in a pragmatic trial of PGx are described; implications of the providers' experiences are highlighted to inform future implementation of PGx.

METHODS

Interviews were conducted with providers participating in the trial (N=61) who treated veterans who had depression. Questions were informed by the Consolidated Framework for Implementation Research. A rapid analytic approach was used.

RESULTS

Two main themes were identified: perceptions regarding which patients would likely benefit from PGx and approaches to using the test results in prescribing. Providers generally expressed positive experiences with using PGx results. However, the providers varied in application of the test results to clinical decision making regarding medications, were uncertain about how much to rely on the results, and differed in perceptions about which patients would benefit from PGx.

CONCLUSIONS

To support future implementation, policies and procedures are needed, as well as mechanisms to support ongoing provider education on PGx.

Individual Prediction of Optimal Treatment Allocation Between Electroconvulsive Therapy or Ketamine using the Personalized Advantage Index

Introduction

Electroconvulsive therapy (ECT) and ketamine are two effective treatments for depression with similar efficacy; however, individual patient outcomes may be improved by models that predict optimal treatment assignment. Here, we adapt the Personalized Advantage Index (PAI) algorithm using machine learning to predict optimal treatment assignment between ECT and ketamine using medical record data from a large, naturalistic patient cohort. We hypothesized that patients who received a treatment predicted to be optimal would have significantly better outcomes following treatment compared to those who received a non-optimal treatment.

Methods

Data on 2526 ECT and 235 mixed IV ketamine and esketamine patients from McLean Hospital was aggregated. Depressive symptoms were measured using the Quick Inventory of Depressive Symptomatology (QIDS) before and during acute treatment. Patients were matched between treatments on pretreatment QIDS, age, inpatient status, and psychotic symptoms using a 1:1 ratio yielding a sample of 470 patients (n=235 per treatment). Random forest models were trained and predicted differential patientwise minimum QIDS scores achieved during acute treatment (min-QIDS) scores for ECT and ketamine using pretreatment patient measures. Analysis of Shapley Additive exPlanations (SHAP) values identified predictors of differential outcomes between treatments.

Results

Twenty-seven percent of patients with the largest PAI scores who received a treatment predicted optimal had significantly lower min-QIDS scores compared to those who received a non-optimal treatment (mean difference=1.6, t=2.38, q<0.05, Cohen's D=0.36). Analysis of SHAP values identified prescriptive pretreatment measures.

Conclusions

Patients assigned to a treatment predicted to be optimal had significantly better treatment outcomes. Our model identified pretreatment patient factors captured in medical records that can provide interpretable and actionable guidelines treatment selection.

Frontal lobe fALFF measured from resting-state fMRI as a prognostic biomarker in first-episode psychosis

Clinical response to antipsychotic drug treatment is highly variable, yet prognostic biomarkers are lacking. The goal of the present study was to test whether the fractional amplitude of low-frequency fluctuations (fALFF), as measured from baseline resting-state fMRI data, can serve as a potential biomarker of treatment response to antipsychotics. Patients in the first episode of psychosis (n = 126) were enrolled in two prospective studies employing second-generation antipsychotics (risperidone or aripiprazole). Patients were scanned at the initiation of treatment on a 3T MRI scanner (Study 1, GE Signa HDx, n = 74; Study 2, Siemens Prisma, n = 52). Voxelwise fALFF derived from baseline resting-state fMRI scans served as the primary measure of interest, providing a hypothesis-free (as opposed to region-of-interest) search for regions of the brain that might be predictive of response. At baseline, patients who would later meet strict criteria for clinical response (defined as two consecutive ratings of much or very much improved on the CGI, as well as a rating of ≤3 on psychosis-related items of the BPRS-A) demonstrated significantly greater baseline fALFF in bilateral orbitofrontal cortex compared to non-responders. Thus, spontaneous activity in orbitofrontal cortex may serve as a prognostic biomarker of antipsychotic treatment.

Toward personalized medicine in schizophrenia: Genetics and epigenetics of antipsychotic treatment

Schizophrenia is a complex psychiatric disorder where genetic, epigenetic, and environmental factors play a role in disease onset, course of illness, and treatment outcome. Pharmaco(epi)genetic research presents an important opportunity to improve patient care through prediction of medication side effects and response. In this narrative review, we discuss the current state of research and important progress of both genetic and epigenetic factors involved in antipsychotic response, over the past five years. The review is largely focused on the following frequently prescribed antipsychotics: olanzapine, risperidone, aripiprazole, and clozapine. Several consistent pharmacogenetic findings have emerged, in particular pharmacokinetic genes (primarily cytochrome P450 enzymes) and pharmacodynamic genes involving dopamine, serotonin, and glutamate neurotransmission. In addition to studies analysing DNA sequence variants, there are also several pharmacoepigenetic studies of antipsychotic response that have focused on the measurement of DNA methylation. Although pharmacoepigenetics is still in its infancy, consideration of both genetic and epigenetic factors contributing to antipsychotic response and side effects no doubt will be increasingly important in personalized medicine. We provide recommendations for next steps in research and clinical evaluation.

How Can Drug Metabolism and Transporter Genetics Inform Psychotropic Prescribing?

Many genetic variants in drug metabolizing enzymes and transporters have been shown to be relevant for treating psychiatric disorders. Associations are strong enough to feature on drug labels and for prescribing guidelines based on such data. A range of commercial tests are available; however, there is variability in included genetic variants, methodology, and interpretation. We herein provide relevant background for understanding clinical associations with specific variants, other factors that are relevant to consider when interpreting such data (such as age, gender, drug-drug interactions), and summarize the data relevant to clinical utility of pharmacogenetic testing in psychiatry and the available prescribing guidelines. We also highlight areas for future research focus in this field.

Primary care and mental health providers' perceptions of implementation of pharmacogenetics testing for depression prescribing

BACKGROUND

Pharmacogenetic testing (PGx) has the potential to improve the quality of psychiatric prescribing by considering patients' genetic profile. However, there is limited scientific evidence supporting its efficacy or guiding its implementation. The Precision Medicine in Mental Health (PRIME) Care study is a pragmatic randomized controlled trial evaluating the effectiveness of a specific commercially-available pharmacogenetic (PGx) test to inform antidepressant prescribing at 22 sites across the U.S. Simultaneous implementation science methods using the Consolidated Framework for Implementation Research (CFIR) are integrated throughout the trial to identify contextual factors likely to be important in future implementation of PGx. The goal of this study was to understand providers' perceptions of PGx for antidepressant prescribing and implications for future implementation.

METHODS

Qualitative focus groups (n = 10) were conducted at the beginning of the trial with Primary Care and Mental Health providers (n = 31) from six PRIME Care sites. Focus groups were audio-recorded and transcribed and data were analyzed using rapid analytic procedures organized by CFIR domains.

RESULTS

Analysis revealed themes in the CFIR Intervention Characteristics domain constructs of Evidence, Relative Advantage, Adaptability, Trialability, Complexity, and Design that are important for understanding providers' perceptions of PGx testing. Results indicate: 1) providers had limited experience and knowledge of PGx testing and its evidence base, particularly for psychiatric medications; 2) providers were hopeful that PGx could increase their precision in depression prescribing and improve patient engagement, but were uncertain about how results would influence treatment; 3) providers were concerned about potential misinterpretation of PGx results and how to incorporate testing into their workflow; 4) primary care providers were less familiar and comfortable with application of PGx testing to antidepressant prescribing than psychiatric providers.

CONCLUSIONS

Provider perceptions may serve as facilitators or barriers to implementation of PGx for psychiatric prescribing. Incorporating implementation science into the conduct of the RCT adds value by uncovering factors to be addressed in preparing for future implementation, should the practice prove effective.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT03170362 ; Registered 31 May 2017.

Pharmacogenetics of Antipsychotic Drug Treatment: Update and Clinical Implications

Numerous genetic variants have been shown to be associated with antipsychotic response and adverse effects of schizophrenia treatment. However, the clinical application of these findings is limited. The aim of this narrative review is to summarize the most recent publications and recommendations related to the genetics of antipsychotic treatment and shed light on the clinical utility of pharmacogenetics/pharmacogenomics (PGx). We reviewed the literature on PGx studies with antipsychotic drugs (i.e., antipsychotic response and adverse effects) and commonly used commercial PGx tools for clinical practice. Publications and reviews were included with emphasis on articles published between January 2015 and April 2018. We found 44 studies focusing on antipsychotic response and 45 studies on adverse effects (e.g., antipsychotic-induced weight gain, movement disorders, hormonal abnormality, and clozapine-induced agranulocytosis/granulocytopenia), albeit with mixed results. Overall, several gene variants related to antipsychotic response and adverse effects in the treatment of patients with schizophrenia have been reported, and several commercial pharmacogenomic tests have become available. However, further well-designed investigations and replication studies in large and well-characterized samples are needed to facilitate the application of PGx findings to clinical practice.

Relationship of SNAP25 variants with schizophrenia and antipsychotic-induced weight change in large-scale schizophrenia patients

The SNAP25 gene is involved in the development of antipsychotic-induced weight gain (AIWG) or metabolic syndrome during antipsychotics use in Americans and Europeans, but its role in Asians remains unknown. To identify common variants in SNAP25 associated with schizophrenia and evaluate their effects on AIWG and antipsychotic responses in Han Chinese individuals with schizophrenia, we conducted a two-stage case-control study of 3,243 patients and 6,154 healthy controls. 2128 inpatients in the replication stage have received conventional treatment with an antipsychotic monotherapy (Haloperidol, Olanzapine or Risperidone) for 10 weeks at least. Weight change, antipsychotic responses and metabolic indices change were assessed during treatments. Three SNPs were significantly associated with schizophrenia in samples (rs6039769, P = 6.64 × 10^-7; rs3787283, P = 0.004283; rs3746544, P = 2.51 × 10^-6). Of these, rs6039769 is a novel schizophrenia-associated SNP and is uncorrelated with the other two variants, which have previously been associated with schizophrenia in European-ancestry samples. Rs6039769 was significantly associated with AIWG (P < 0.001), but not with antipsychotic responses or metabolic indices. Another two SNPs were not associated with AIWG or antipsychotic responses or metabolic indices. Overall, there were significant differences in antipsychotic responses and metabolic indices among the three treatment groups. Our findings suggest that SNAP25 gene may contribute to the susceptibility of AIWG and even metabolic disturbances. A prior identification of high-risk of patients with rs6039769 would contribute to a better precision of the pharmacological treatment.

Identification of Alzheimer's Disease-Related Genes Based on Data Integration Method

Alzheimer disease (AD) is the fourth major cause of death in the elderly following cancer, heart disease and cerebrovascular disease. Finding candidate causal genes can help in the design of Gene targeted drugs and effectively reduce the risk of the disease. Complex diseases such as AD are usually caused by multiple genes. The Genome-wide association study (GWAS), has identified the potential genetic variants for most diseases. However, because of linkage disequilibrium (LD), it is difficult to identify the causative mutations that directly cause diseases. In this study, we combined expression quantitative trait locus (eQTL) studies with the GWAS, to comprehensively define the genes that cause Alzheimer disease. The method used was the Summary Mendelian randomization (SMR), which is a novel method to integrate summarized data. Two GWAS studies and five eQTL studies were referenced in this paper. We found several candidate SNPs that have a strong relationship with AD. Most of these SNPs overlap in different data sets, providing relatively strong reliability. We also explain the function of the novel AD-related genes we have discovered.

Schizophrenia Polygenic Risk Score as a Predictor of Antipsychotic Efficacy in First-Episode Psychosis

OBJECTIVE

Pharmacogenomic studies of antipsychotics have typically examined effects of individual polymorphisms. By contrast, polygenic risk scores (PRSs) derived from genome-wide association studies (GWAS) can quantify the influence of thousands of common alleles of small effect in a single measure. The authors examined whether PRSs for schizophrenia were predictive of antipsychotic efficacy in four independent cohorts of patients with first-episode psychosis (total N=510).

METHOD

All study subjects received initial treatment with antipsychotic medication for first-episode psychosis, and all were genotyped on standard single-nucleotide polymorphism (SNP) arrays imputed to the 1000 Genomes Project reference panel. PRS was computed based on the results of the large-scale schizophrenia GWAS reported by the Psychiatric Genomics Consortium. Symptoms were measured by using total symptom rating scales at baseline and at week 12 or at the last follow-up visit before dropout.

RESULTS

In the discovery cohort, higher PRS significantly predicted higher symptom scores at the 12-week follow-up (controlling for baseline symptoms, sex, age, and ethnicity). The PRS threshold set at a p value <0.01 gave the strongest result in the discovery cohort and was used to replicate the findings in the other three cohorts. Higher PRS significantly predicted greater posttreatment symptoms in the combined replication analysis and was individually significant in two of the three replication cohorts. Across the four cohorts, PRS was significantly predictive of adjusted 12-week symptom scores (pooled partial r=0.18; 3.24% of variance explained). Patients with low PRS were more likely to be treatment responders than patients with high PRS (odds ratio=1.91 in the two Caucasian samples).

CONCLUSIONS

Patients with higher PRS for schizophrenia tended to have less improvement with antipsychotic drug treatment. PRS burden may have potential utility as a prognostic biomarker.

DNA methylation of ANKK1 and response to aripiprazole in patients with acute schizophrenia: A preliminary study

Epigenetic modification including DNA methylation may affect pathophysiology and the response to antipsychotic drugs in patients with schizophrenia. The objective of the present study was to investigate the effect of the DNA methylation of ANKK1 (ankyrin repeat and kinase domain containing 1) on the response to aripiprazole and plasma levels of monoamine metabolites in antipsychotic-free acute schizophrenia patients. The subjects were 34 Japanese patients with schizophrenia who had been treated with aripiprazole for 6 weeks. Comprehensive DNA methylation of ANKK1 was determined using a next-generation sequencer. DNA methylation levels at CpG site 387 of ANKK1 were higher in responders to treatment with aripiprazole and correlated with the changes in Positive and Negative Syndrome Scale scores, although the associations did not remain significant after Bonferroni correction. In responders, methylation at all CpG sites was significantly correlated with plasma levels of homovanillic acid (r = 0.587, p = 0.035) and 3-methoxy-4hydroxyphenylglycol (r = 0.684, p = 0.010) at baseline. Despite our non-significant results after multiple correction, our preliminary findings suggest that methylation levels at CpG site 387 of ANKK1 may be associated with treatment response to aripiprazole. Furthermore, methylation of ANKK1 may affect dopaminergic neural transmission in the treatment of schizophrenia, and may influence treatment response. Caution is needed in interpreting these findings because of the small sample size, and further studies are needed to confirm and expand our preliminary results.

SLC6A3 polymorphism and response to methylphenidate in children with ADHD: A systematic review and meta-analysis

Methylphenidate (MPH) is the most commonly used treatment for attention-deficit hyperactivity disorder (ADHD) in children. However, the response to MPH is not similar in all patients. This meta-analysis investigated the potential role of SLC6A3 polymorphisms in response to MPH in children with ADHD. Clinical trials or naturalistic studies were selected from electronic databases. A meta-analysis was conducted using a random-effects model. Cohen's d effect size and 95% confidence intervals (CIs) were determined. Sensitivity analysis and meta-regression were performed. Q-statistic and Egger's tests were conducted to evaluate heterogeneity and publication bias, respectively. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to assess the quality of evidence. Sixteen studies with follow-up periods of 1-28 weeks were eligible. The mean treatment acceptability of MPH was 97.2%. In contrast to clinical trials, the meta-analysis of naturalistic studies indicated that children without 10/10 repeat carriers had better response to MPH (Cohen's d: -0.09 and 0.44, respectively). The 9/9 repeat polymorphism had no effect on the response rate (Cohen's d: -0.43). In the meta-regression, a significant association was observed between baseline severity of ADHD, MPH dosage, and combined type of ADHD in some genetic models. Sensitivity analysis indicated the robustness of our findings. No publication bias was observed in our meta-analysis. The GRADE evaluations revealed very low levels of confidence for each outcome of response to MPH. The results of clinical trials and naturalistic studies regarding the effect size between different polymorphisms of SLC6A3 were contradictory. Therefore, further research is recommended.

New Targets for Schizophrenia Treatment beyond the Dopamine Hypothesis

Schizophrenia has been primarily associated with dopamine dysfunction, and treatments have been developed that target the dopamine pathway in the central nervous system. However, accumulating evidence has shown that the core pathophysiology of schizophrenia might involve dysfunction in dopaminergic, glutamatergic, serotonergic, and gamma-aminobutyric acid (GABA) signaling, which may lead to aberrant functioning of interneurons that manifest as cognitive, behavioral, and social dysfunction through altered functioning of a broad range of macro- and microcircuits. The interactions between neurotransmitters can be modeled as nodes and edges by using graph theory, and oxidative balance, immune, and glutamatergic systems may represent multiple nodes interlocking at a central hub; imbalance within any of these nodes might affect the entire system. Therefore, this review attempts to address novel treatment targets beyond the dopamine hypothesis, including glutamate, serotonin, acetylcholine, GABA, and inflammatory cytokines. Furthermore, we outline that these treatment targets can be possibly integrated with novel treatment strategies aimed at different symptoms or phases of the illness. We anticipate that reversing anomalous activity in these novel treatment targets or combinations between these strategies might be beneficial in the treatment of schizophrenia.

Development of a Diverse Learning Experience for Diverse Psychiatry Resident Needs: A Four-Year Biological Psychiatry Curriculum Incorporating Principles of Neurobiology, Psychopharmacology, and Evidence-Based Practice

OBJECTIVE

A clinically relevant approach to patient care grounded in neurobiological constructs and evidence based practice which emphasizes a relevant psychopharmacology is needed to optimally train psychiatry residents.

METHODS

We implemented a biological psychiatry course that now incorporates neurobiology, psychopharmacology, and evidence-based practice in conjunction with a Research Domain Criteria (RDoC) perspective. A survey launched prior to course implementation and following each class session, served as the outcome metric of residents' attitudes toward the new curriculum and followed a baseline attitudinal survey designed to evaluate the program.

RESULTS

Greater than 90% of the psychiatry residents at Duke University who took the attitudinal survey agreed or strongly agreed with needing a course that helped them develop an understanding of neurobiology, psychopharmacology, and evidence-based practice concepts. Most residents also indicated a less than adequate understanding of the neurobiology and psychopharmacology of psychiatric disorders prior to sessions.

CONCLUSION

Our biological psychiatry curriculum was associated with enthusiasm among residents regarding the incorporation of neurobiology, psychopharmacology, and evidence-based practice into course topics and discussions. A biological psychiatry curriculum with integrated neurobiology and psychopharmacology built on an evidence base approach is possible, well-received, and needed in training of future psychiatrists.

New Clinically Relevant Findings about Violence by People with Schizophrenia

OBJECTIVE

To review findings with clinical relevance that add to knowledge about antisocial and aggressive behaviour among persons with schizophrenia.

METHOD

Nonsystematic literature review.

RESULTS

Recent evidence shows that individuals who develop schizophrenia present cognitive deficits, psychotic-like experiences, and internalizing and externalizing problems from childhood onwards. Many of their relatives present not only schizophrenia-related disorders but also antisocial behaviour. While the increased risk of aggressive behaviour among persons with schizophrenia has been robustly established, recent findings show that by first contact with clinical services for psychosis, most people with schizophrenia who will engage in aggressive behaviour may be identified. At first episode, 2 distinct types are distinguishable: those who present a history of antisocial and aggressive behaviour since childhood and those who began engaging in aggressive behaviour as illness onsets. Antipsychotic medications and other treatments shown to be effective for schizophrenia are needed by both types of patients. Additionally, those with a history of antisocial and aggressive behaviour since childhood require cognitive-behavioural programs aimed at reducing these behaviours and promoting prosocial behaviour. Reducing physical victimisation and cannabis use will likely reduce aggressive behaviour. Evidence suggests that threats to hurt others often precede assaults.

CONCLUSIONS

At first contact with services, patients with schizophrenia who have engaged in aggressive behaviour should be identified and treated for schizophrenia and for aggression. Research is needed to identify interactions between genotypes and environmental factors, from conception onwards, that promote and that protect against the development of aggressive behaviour among persons with schizophrenia.

Personalized medicine in psychiatry

BACKGROUND

Personalized medicine is a model in which a patient's unique clinical, genetic, and environmental characteristics are the basis for treatment and prevention. Aim, method, and results: This review aims to describe the current tools, phenomenological features, clinical risk factors, and biomarkers used to provide personalized medicine. Furthermore, this study describes the target areas in which they can be applied including diagnostics, treatment selection and response, assessment of risk of side-effects, and prevention.

DISCUSSION AND CONCLUSION

Personalized medicine in psychiatry is challenged by the current taxonomy, where the diagnostic categories are broad and great biological heterogeneity exists within each category. There is, thus, a gap between the current advanced research prospects and clinical practice, and the current taxonomy is, thus, a poor basis for biological research. The discussion proposes possible solutions to narrow this gap and to move psychiatric research forward towards personalized medicine.

Treatment-resistant schizophrenia: current insights on the pharmacogenomics of antipsychotics

Up to 30% of people with schizophrenia do not respond to two (or more) trials of dopaminergic antipsychotics. They are said to have treatment-resistant schizophrenia (TRS). Clozapine is still the only effective treatment for TRS, although it is underused in clinical practice. Initial use is delayed, it can be hard for patients to tolerate, and clinicians can be uncertain as to when to use it. What if, at the start of treatment, we could identify those patients likely to respond to clozapine - and those likely to suffer adverse effects? It is likely that clinicians would feel less inhibited about using it, allowing clozapine to be used earlier and more appropriately. Genetic testing holds out the tantalizing possibility of being able to do just this, and hence the vital importance of pharmacogenomic studies. These can potentially identify genetic markers for both tolerance of and vulnerability to clozapine. We aim to summarize progress so far, possible clinical applications, limitations to the evidence, and problems in applying these findings to the management of TRS. Pharmacogenomic studies of clozapine response and tolerability have produced conflicting results. These are due, at least in part, to significant differences in the patient groups studied. The use of clinical pharmacogenomic testing - to personalize clozapine treatment and identify patients at high risk of treatment failure or of adverse events - has moved closer over the last 20 years. However, to develop such testing that could be used clinically will require larger, multicenter, prospective studies.

Pharmacogenetic Associations of Antipsychotic Drug-Related Weight Gain: A Systematic Review and Meta-analysis

Although weight gain is a serious but variable adverse effect of antipsychotics that has genetic underpinnings, a comprehensive meta-analysis of pharmacogenetics of antipsychotic-related weight gain is missing. In this review, random effects meta-analyses were conducted for dominant and recessive models on associations of specific single nucleotide polymorphisms (SNP) with prospectively assessed antipsychotic-related weight or body mass index (BMI) changes (primary outcome), or categorical increases in weight or BMI (≥7%; secondary outcome). Published studies, identified via systematic database search (last search: December 31, 2014), plus 3 additional cohorts, including 222 antipsychotic-naïve youth, and 81 and 141 first-episode schizophrenia adults, each with patient-level data at 3 or 4 months treatment, were meta-analyzed. Altogether, 72 articles reporting on 46 non-duplicated samples (n = 6700, mean follow-up = 25.1wk) with 38 SNPs from 20 genes/genomic regions were meta-analyzed (for each meta-analysis, studies = 2-20, n = 81-2082). Eleven SNPs from 8 genes were significantly associated with weight or BMI change, and 4 SNPs from 2 genes were significantly associated with categorical weight or BMI increase. Combined, 13 SNPs from 9 genes (Adrenoceptor Alpha-2A [ADRA2A], Adrenoceptor Beta 3 [ADRB3], Brain-Derived Neurotrophic Factor [BDNF], Dopamine Receptor D2 [DRD2], Guanine Nucleotide Binding Protein [GNB3], 5-Hydroxytryptamine (Serotonin) Receptor 2C [HTR2C], Insulin-induced gene 2 [INSIG2], Melanocortin-4 Receptor [MC4R], and Synaptosomal-associated protein, 25kDa [SNAP25]) were significantly associated with antipsychotic-related weight gain (P-values < .05-.001). SNPs in ADRA2A, DRD2, HTR2C, and MC4R had the largest effect sizes (Hedges' g's = 0.30-0.80, ORs = 1.47-1.96). Less prior antipsychotic exposure (pediatric or first episode patients) and short follow-up (1-2 mo) were associated with larger effect sizes. Individual antipsychotics did not significantly moderate effect sizes. In conclusion, antipsychotic-related weight gain is polygenic and associated with specific genetic variants, especially in genes coding for antipsychotic pharmacodynamic targets.

GADL1 variant and medication adherence in predicting response to lithium maintenance treatment in bipolar I disorder

BACKGROUND

Genetic variants and medication adherence have been identified to be the main factors contributing to lithium treatment response in bipolar disorders.

AIMS

To simultaneously examine effects of variant glutamate decarboxylase-like protein 1 (GADL1) and medication adherence on response to lithium maintenance treatment in Han Chinese patients with bipolar I (BPI) disorder.

METHOD

Frequencies of manic and depressive episodes between carriers and non-carriers of the effective GADL1 rs17026688 T allele during the cumulative periods of off-lithium, poor adherence to lithium treatment and good adherence to lithium treatment were compared in Han Chinese patients with BPI disorder (n=215).

RESULTS

GADL1 rs17026688 T carriers had significantly lower frequencies of recurrent affective episodes than non-T carriers during the cumulative period of good adherence, but not during those of poor adherence.

CONCLUSIONS

GADL1 rs17026688 and medication adherence jointly predict response to lithium maintenance treatment in Han Chinese BPI patients.

DECLARATION OF INTEREST

None.

COPYRIGHT AND USAGE

© The Royal College of Psychiatrists 2016. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) license.

Pharmacogenetics and pharmacogenomics in psoriasis treatment: current challenges and future prospects

INTRODUCTION

Topical, systemic, oral disease modifying, and biologic agents are part of the armamentarium to manage psoriatic disease. The choice of therapy depends upon disease severity, relevant co-morbidities and patient preference. There is great variability in patient response with these agents, and there is still no clear method of selecting the preferred therapeutic agent for efficacy or lack of adverse events.

AREAS COVERED

This article will review the pharmacogenetic and pharmacogenomic targets that are currently known with respect to psoriasis vulgaris, and the most frequent co-morbidity of psoriasis, psoriatic arthritis.

EXPERT OPINION

Presently, no clinically actionable biomarker exists for any therapeutic agent used to treat psoriasis or psoriatic arthritis. The lack of validated outcome measures and conflicting results of open-label studies conducted may be attributed to a multitude of issues that confound discovery. Consequently, studies have been underpowered to identify genes or genetic variants worth translating to clinical practice. In order to achieve a pharmacogenetic/pharmacogenomic signature, improvements in study design of future investigations are required, including carefully designed prospective studies. It is imperative to combine known clinical, serological, and molecular markers with consistent outcomes and an adequate health economic evaluation before they can be adopted widely in clinical practice.

Pharmacogenetic Testing: Application in Mental Health Prescribing

BACKGROUND

Despite extensive scholastic and professional training, medication management in psychiatry is often relegated to trial-and-error prescribing. Pharmacogenetic testing (PGT) may expedite identification of medications with maximal efficacy and minimal side effects by recognizing individual genetic variability in drug response.

OBJECTIVES

This article outlines the background of PGT, explains drug metabolism, and evaluates the impact of PGT.

DESIGN

A review of the literature since 2010 found 42 articles regarding PGT in clinical nursing settings on PubMed and ProQuest.

RESULTS

Despite continuing rises in health care costs, new biotechnology has led to a decrease in the cost of genetic sequencing and application of PGT to practice.

CONCLUSION

As PGT becomes increasingly prevalent, nurses should be knowledgeable of its purpose, possibilities, and potential limitations to provide accurate and up-to-date patient information.

Association of a Schizophrenia Risk Variant at the DRD2 Locus With Antipsychotic Treatment Response in First-Episode Psychosis

Findings from the Psychiatric Genomics Consortium genome-wide association study (GWAS) showed that variation at the DRD2 locus is associated with schizophrenia risk. However, the functional significance of rs2514218, the top DRD2 single nucleotide polymorphism in the GWAS, is unknown. Dopamine D2 receptor binding is a common mechanism of action for all antipsychotic drugs, and DRD2 variants were related to antipsychotic response in previous studies. The present study examined whether rs2514218 genotype could predict antipsychotic response, including efficacy and adverse events, in a cohort of patients with first episode of psychosis treated with either risperidone or aripiprazole for 12 weeks. Subjects were genotyped using the Illumina Infinium HumanOmniExpressExome array platform. After standard quality control, data from 100 subjects (49 randomly assigned to treatment with aripiprazole and 51 assigned to risperidone) was available for analysis. Subjects were assessed for psychotic symptomatology and medication-related adverse events weekly for 4 weeks, then biweekly for 8 weeks. Linear mixed model analysis revealed that the homozygotes for the risk (C) allele at rs2514218 had significantly greater reduction in positive symptoms during 12 weeks of treatment compared to the T allele carriers. In the aripiprazole group, C/C homozygotes also reported more akathisia than the T allele carriers, while in the risperidone group, male T allele carriers demonstrated greater prolactin elevations compared to male C/C homozygotes. These findings suggest that the schizophrenia risk variant at the DRD2 locus (or another variant in close proximity) is associated with observable differences in response to treatments which reduce striatal dopamine signaling.

"Getting off the Bus Closer to Your Destination": Patients' Views about Pharmacogenetic Testing

The authors conducted focus groups with patients prescribed antidepressants (pilot session plus 2 focus groups, n = 27); patients prescribed carbamazepine (2 focus groups, n = 17); and healthy patients (2 focus groups, n = 17). Although participants understood the potential advantages of pharmacogenetic testing, many felt that the risks (discrimination, stigmatization, physician overreliance on genomic results, and denial of certain medications) may outweigh the benefits. These concerns were shared across groups but were more strongly expressed among participants with chronic mental health diagnoses.

Genetics in child and adolescent psychiatry: methodological advances and conceptual issues

Discovering the genetic basis of early-onset psychiatric disorders has been the aim of intensive research during the last decade. We will first selectively summarize results of genetic research in child and adolescent psychiatry by using examples from different disorders and discuss methodological issues, emerging questions and future directions. In the second part of this review, we will focus on how to link genetic causes of disorders with physiological pathways, discuss the impact of genetic findings on diagnostic systems, prevention and therapeutic interventions. Finally we will highlight some ethical aspects connected to genetic research in child and adolescent psychiatry. Advances in molecular genetic methods have led to insights into the genetic architecture of psychiatric disorders, but not yet provided definite pathways to pathophysiology. If replicated, promising findings from genetic studies might in some cases lead to personalized treatments. On the one hand, knowledge of the genetic basis of disorders may influence diagnostic categories. On the other hand, models also suggest studying the genetic architecture of psychiatric disorders across diagnoses and clinical groups.

Should we keep on? Looking into pharmacogenomics of ADHD in adulthood from a different perspective

A considerable proportion of adults with attention-deficit/hyperactivity disorder (ADHD) do not respond to the treatment with methylphenidate. This scenario could be due to inherited interindividual differences that may alter pharmacologic treatment response. In this sense, in 2012 we conducted a systematic search on PUBMED-indexed literature for articles containing information about pharmacogenomics of ADHD in adults. Five studies were found on methylphenidate pharmacogenomics and the only significant association was reported by one particular study. However, this single association with the SLC6A3 gene was not replicated in two subsequent reports. In the present review, although we could not find additional pharmacogenomics studies, we discuss these up-to-date findings and suggest new approaches for this field. Additionally, using systeomic-oriented databases, we provide a broad picture of new possible candidate genes as well as potential gene-gene interactions to be investigated in pharmacogenomics of persistent ADHD.

Allelic variation in 5-HTTLPR and the effects of citalopram on the emotional neural network

BACKGROUND

Selective serotonin reuptake inhibitors (SSRIs), such as citalopram, which selectively block serotonin transporter (5-HTT) activity, are widely used in the treatment of depression and anxiety disorders. Numerous neuroimaging studies have examined the effects of SSRIs on emotional processes. However, there are considerable inter-individual differences in SSRI effect, and a recent meta-analysis further revealed discrepant effects of acute SSRI administration on neural responses to negative emotions in healthy adults.

AIMS

We examined how a variant of the serotonin-transporter polymorphism (5-HTTLPR), which affects the expression and function of 5-HTT, influenced the acute effects of an SSRI (citalopram) on emotion-related brain activity in healthy adults.

METHOD

Combining genetic neuroimaging, pharmacological technique and a psychological paradigm of emotion recognition, we scanned the short/short (s/s) and long/long (l/l) variants of 5-HTTLPR during perception of fearful, happy and neutral facial expressions after the acute administration of an SSRI (i.e. 30 mg citalopram administered orally) or placebo administration.

RESULTS

We found that 5-HTTLPR modulated the acute effects of citalopram on neural responses to negative emotions. Specifically, relative to placebo, citalopram increased amygdala and insula activity in l/l but not s/s homozygotes during perception of fearful faces. Similar analyses of brain activity in response to happy faces did not show any significant effects.

CONCLUSIONS

Our combined pharmacogenetic and functional imaging results provide a neurogenetic mechanism for discrepant acute effects of SSRIs.

The current and potential impact of genetics and genomics on neuropsychopharmacology

One justification for the major scientific and financial investments in genetic and genomic studies in medicine is their therapeutic potential, both for revealing novel targets for drugs which treat the disease process, as well as allowing for more effective and safe use of existing medications. This review considers the extent to which this promise has yet been realised within psychopharmacology, how things are likely to develop in the foreseeable future, and the key issues involved. It draws primarily on examples from schizophrenia and its treatments. One observation is that there is evidence for a range of genetic influences on different aspects of psychopharmacology in terms of discovery science, but far less evidence that meets the standards required before such discoveries impact upon clinical practice. One reason is that results reveal complex genetic influences that are hard to replicate and usually of very small effect. Similarly, the slow progress being made in revealing the genes that underlie the major psychiatric syndromes hampers attempts to apply the findings to identify novel drug targets. Nevertheless, there are some intriguing positive findings of various kinds, and clear potential for genetics and genomics to play an increasing and major role in psychiatric drug discovery.

Pharmacogenomic testing for neuropsychiatric drugs: current status of drug labeling, guidelines for using genetic information, and test options

Advancements in pharmacogenomics have introduced an increasing number of opportunities to bring personalized medicine into clinical practice. Understanding how and when to use this technology to guide pharmacotherapy used to treat psychiatric and neurological (neuropsychiatric) conditions remains a challenge for many clinicians. Currently, guidelines exist to assist clinicians in the use of existing genetic information for drug selection and/or dosing for the tricyclic antidepressants, carbamazepine, and phenytoin. Additional language in the product labeling suggests that genetic information may also be useful for determining the starting and target doses, as well as drug interaction potential, for a number of other drugs. In this review, we outline the current status of pharmacogenomic testing for neuropsychiatric drugs as it pertains to information contained in drug labeling, consensus guidelines, and test panels, as well as considerations related to obtaining tests for patients.

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.

Genome-wide association study of medication adherence in chronic diseases in the korean population

Medication adherence is generally defined as the extent of voluntary cooperation of a patient in taking medicine as prescribed. Adherence to long-term treatment with chronic disease is essential for reducing disease comorbidity and mortality. However, medication non-adherence in chronic disease averages 50%. This study was conducted a genome-wide association study to identify the genetic basis of medication adherence. A total of 235 medication non-adherents and 1,067 medication adherents with hypertension or diabetes were used from the Korean Association Resource project data according to the self-reported treatment status of each chronic disease, respectively. We identified four single nucleotide polymorphisms with suggestive genome-wide association. The most significant single nucleotide polymorphism was rs6978712 (chromosome 7, p = 4.87 × 10^-7), which is located proximal to the GCC1 gene, which was previously implicated in decision-making capability in drug abusers. Two suggestive single nucleotide polymorphisms were in strong linkage disequilibrium (r² > 0.8) with rs6978712. Thus, in the aspect of decision-making in adherence behavior, the association between medication adherence and three loci proximal to the GCC1 gene seems worthy of further research. However, to overcome a few limitations in this study, defining the standardized phenotype criteria for self-reported adherence should be performed before replicating association studies.

Behavior genetics: past, present, future

The disciplines of developmental psychopathology and behavior genetics are concerned with many of the same questions about the etiology and course of normal and abnormal behavior and about the factors that promote typical development despite the presence of risk. The goal of this paper is to summarize how research in behavior genetics has shed light on questions that are central to developmental psychopathology. We briefly review the origins of behavior genetics, summarize the findings that have been gleaned from several decades of quantitative and molecular genetics research, and describe future directions for research that will delineate gene function as well as pathways from genes to brain to behavior. The importance of environmental contributions, at both genetic and epigenetic levels, will be discussed. We conclude that behavior genetics has made significant contributions to developmental psychopathology by documenting the interplay among risk and protective factors at multiple levels of the organism, by clarifying the causal status of risk exposures, and by identifying factors that account for change and stability in psychopathology. As the tools to identify gene function become increasingly sophisticated, and as behavioral geneticists become increasingly interdisciplinary in their scope, the field is poised to make ever greater contributions to our understanding of typical and atypical development.

Identification of candidate single-nucleotide polymorphisms in NRXN1 related to antipsychotic treatment response in patients with schizophrenia

Neurexins are presynaptic neuronal adhesion molecules that interact with postsynaptic neuroligins to form an inter-synaptic complex required for synaptic specification and efficient neurotransmission. Deletions and point mutations in the neurexin 1 (NRXN1) gene are associated with a broad spectrum of neuropsychiatric and neurodevelopmental disorders, including autism, intellectual disability, epilepsy, developmental delay, and schizophrenia. Recently, small nucleotide polymorphisms in NRXN1 have been associated with antipsychotic drug response in patients with schizophrenia. Based on previous suggestive evidence of an impact on clozapine response in patients with schizophrenia, we conducted an association study of NRXN1 polymorphisms (rs12467557 and rs10490162) with antipsychotic treatment response in 54 patients with schizophrenia in a double blind, placebo-controlled NIMH inpatient crossover trial and examined for association with risk for schizophrenia in independent case-control and family-based clinical cohorts. Pharmacogenetic analysis in the placebo controlled trial revealed significant association of rs12467557and rs10490162 with drug response, whereby individuals homozygous for the A allele, at either SNP, showed significant improvement in positive symptoms, general psychopathology, thought disturbance, and negative symptoms, whereas patients carrying the G allele showed no overall response. Although we did not find evidence of the same NRXN1 SNPs being associated with results of the NIMH sponsored CATIE trial, other SNPs showed weakly positive signals. The family and case-control analyses for schizophrenia risk were negative. Our results provide confirmatory evidence of genetically determined differences in drug response in patients with schizophrenia related to NRXN1 variation. Furthermore, these findings potentially implicate NRXN1 in the therapeutic actions of antipsychotic drugs.

5-HTTLPR moderates naltrexone and psychosocial treatment responses in heavy drinking men who have sex with men

BACKGROUND

A functional polymorphism (5-HTTLPR) in the promoter region of the serotonin transporter gene has been widely studied as a risk factor and moderator of treatment for a variety of psychopathologic conditions. To evaluate whether 5-HTTLPR moderates the effects of treatment to reduce heavy drinking, we studied 112 high-functioning European-American men who have sex with men (MSM). Subjects participated in a randomized clinical trial of naltrexone (NTX) and cognitive behavioral therapy (CBT) for problem drinking.

METHODS

Subjects were treated for 12 weeks with 100 mg/d of oral NTX or placebo (PBO). All participants received medical management with adjusted brief behavioral compliance enhancement treatment (BBCET) alone or in combination with modified behavioral self-control therapy (MBSCT; an amalgam of motivational interviewing and CBT). Participants were genotyped for the tri-allelic 5-HTTLPR polymorphism (i.e., low-activity S' or high-activity L' alleles).

RESULTS

During treatment, the number of weekly heavy drinking days (HDD; defined as 5 or more standard drinks per day) was significantly lower in subjects with the L'L' (N = 26, p = 0.015) or L'S' (N = 52, p = 0.016) genotype than those with the S'S' (N = 34) genotype regardless of treatment type. There was a significant interaction of genotype with treatment: For subjects with the S'S' genotype, the effects of MBSCT or NTX on HDD were significantly greater than the minimal intervention (i.e., BBCET or PBO, p = 0.007 and p = 0.049, respectively). In contrast, for subjects with 1 or 2 L' alleles, the effects of the more intensive psychosocial treatment (MBSCT) or NTX did not significantly differ from BBCET or PBO.

CONCLUSIONS

These preliminary findings support the utility of the 5-HTTLPR polymorphism for personalizing treatment selection in problem drinkers.

Pharmacogenetics in schizophrenia: a review of clozapine studies

OBJECTIVES

Clozapine is quite effective to treat schizophrenia, but its use is complicated by several factors. Although many patients respond to antipsychotic therapy, about 50% of them exhibit inadequate response, and ineffective medication trials may entail weeks of unremitted illness, potential adverse drug reactions, and treatment nonadherence. This review of the literature sought to describe the main pharmacogenetic studies of clozapine and the genes that potentially influence response to treatment with this medication in schizophrenics.

METHODS

We searched the PubMed database for studies published in English in the last 20 years using keywords related to the topic.

RESULTS AND CONCLUSIONS

Our search yielded 145 studies that met the search and selection criteria. Of these, 21 review articles were excluded. The 124 studies included for analysis showed controversial results. Therefore, efforts to identify key gene mechanisms that will be useful in predicting clozapine response and side effects have not been fully successful. Further studies with new analysis approaches and larger sample sizes are still required.

Variant GADL1 and response to lithium therapy in bipolar I disorder

BACKGROUND

Lithium has been a first-line choice for maintenance treatment of bipolar disorders to prevent relapse of mania and depression, but many patients do not have a response to lithium treatment.

METHODS

We selected subgroups from a sample of 1761 patients of Han Chinese descent with bipolar I disorder who were recruited by the Taiwan Bipolar Consortium. We assessed their response to lithium treatment using the Alda scale and performed a genomewide association study on samples from one subgroup of 294 patients with bipolar I disorder who were receiving lithium treatment. We then tested the single-nucleotide polymorphisms (SNPs) that showed the strongest association with a response to lithium for association in a replication sample of 100 patients and tested them further in a follow-up sample of 24 patients. We sequenced the exons, exon-intron boundaries, and part of the promoter of the gene encoding glutamate decarboxylase-like protein 1 (GADL1) in 94 patients who had a response to lithium and in 94 patients who did not have a response in the genomewide association sample.

RESULTS

Two SNPs in high linkage disequilibrium, rs17026688 and rs17026651, that are located in the introns of GADL1 showed the strongest associations in the genomewide association study (P=5.50×10(-37) and P=2.52×10(-37), respectively) and in the replication sample of 100 patients (P=9.19×10(-15) for each SNP). These two SNPs had a sensitivity of 93% for predicting a response to lithium and differentiated between patients with a good response and those with a poor response in the follow-up cohort. Resequencing of GADL1 revealed a novel variant, IVS8+48delG, which lies in intron 8 of the gene, is in complete linkage disequilibrium with rs17026688 and is predicted to affect splicing.

CONCLUSIONS

Genetic variations in GADL1 are associated with the response to lithium maintenance treatment for bipolar I disorder in patients of Han Chinese descent. (Funded by Academia Sinica and others.).

The Personalized Advantage Index: translating research on prediction into individualized treatment recommendations. A demonstration

Background

Advances in personalized medicine require the identification of variables that predict differential response to treatments as well as the development and refinement of methods to transform predictive information into actionable recommendations.

Objective

To illustrate and test a new method for integrating predictive information to aid in treatment selection, using data from a randomized treatment comparison.

Method

Data from a trial of antidepressant medications (N = 104) versus cognitive behavioral therapy (N = 50) for Major Depressive Disorder were used to produce predictions of post-treatment scores on the Hamilton Rating Scale for Depression (HRSD) in each of the two treatments for each of the 154 patients. The patient's own data were not used in the models that yielded these predictions. Five pre-randomization variables that predicted differential response (marital status, employment status, life events, comorbid personality disorder, and prior medication trials) were included in regression models, permitting the calculation of each patient's Personalized Advantage Index (PAI), in HRSD units.

Results

For 60% of the sample a clinically meaningful advantage (PAI≥3) was predicted for one of the treatments, relative to the other. When these patients were divided into those randomly assigned to their “Optimal” treatment versus those assigned to their “Non-optimal” treatment, outcomes in the former group were superior (d = 0.58, 95% CI .17—1.01).

Conclusions

This approach to treatment selection, implemented in the context of two equally effective treatments, yielded effects that, if obtained prospectively, would rival those routinely observed in comparisons of active versus control treatments.

Application of personalized medicine to chronic disease: a feasibility assessment

Personalized Medicine has the potential to improve health outcomes and reduce the cost of care; however its adoption has been slow in Canada. Bridgepoint Health is a complex continuous care provider striving to reduce the burden of polypharmacy in chronic patients. The main goal of the study was to explore the feasibility of utilizing personalized medicine in the treatment of chronic complex patients as a preliminary institutional health technology assessment. We analyzed stroke treatment optimization as a clinical indication that could serve as a "proof of concept" for the widespread implementation of pharmacogenetics. The objectives of the study were three-fold:1. Review current practice in medication administration for stroke treatment at Bridgepoint Health2. Critically analyze evidence that pharmacogenetic testing could (or could not) enhance drug selection and treatment efficacy for stroke patients;3. Assess the cost-benefit potential of a pharmacogenetic intervention for stroke.Review current practice in medication administration for stroke treatment at Bridgepoint HealthCritically analyze evidence that pharmacogenetic testing could (or could not) enhance drug selection and treatment efficacy for stroke patients;Assess the cost-benefit potential of a pharmacogenetic intervention for stroke.We conducted a review of stroke treatment practices at Bridgepoint Health, scanned the literature for drug-gene and drug-outcome interactions, and evaluated the potential consequences of pharmacogenetic testing using the ACCE model.There is a substantial body of evidence suggesting that pharmacogenetic stratification of stroke treatment can improve patient outcomes in the long-term, and provide substantial efficiencies for the healthcare system in the short-term. Specifically, pharmacogenetic stratification of antiplatelet and anticoagulant therapies for stroke patients may have a major impact on the risk of disease recurrence, and thus should be explored further for clinical application. Bridgepoint Health, and other healthcare institutions taking this path, should consider launching pilot projects to assess the practical impact of pharmacogenetics to optimize treatment for chronic continuous care.

Safety profile of iloperidone in the treatment of schizophrenia

INTRODUCTION

Iloperidone is a novel antipsychotic medication approved for the treatment of schizophrenia in adults with efficacy similar to its class counterparts. The purpose of this article is to describe the safety profile of iloperidone and its clinical implications.

AREAS COVERED

A PubMed search was undertaken on May 10, 2013, using the keyword iloperidone. Of the 121 articles that resulted, those with primary sources of information, along with secondary sources with an emphasis on drug safety, were included in this article. Iloperidone was found to have lower extrapyramidal symptom (EPS) and akathisia rates compared to haloperidol and risperidone. Twelve percent of patients experienced clinically significant weight gain, largely during initiation phase of treatment. No other clinically significant metabolic abnormalities were observed. QTc interval was increased by 10 ms, comparable to the effect observed with ziprasidone. QTc prolongation was heightened under inhibition of CYP2D6 and CYP3A4. Orthostatic hypotension was a common effect seen in the first week of treatment.

EXPERT OPINION

The favorable EPS and akathisia profile of iloperidone makes it an attractive choice for patients whose compliance is limited by these effects. However, the slow titration schedule adapted to reduce orthostasis may limit the use of this agent in an acute setting.

Issues surrounding the health economic evaluation of genomic technologies

AIM

Genomic interventions could enable improved disease stratification and individually tailored therapies. However, they have had a limited impact on clinical practice to date due to a lack of evidence, particularly economic evidence. This is partly because health economists are yet to reach consensus on whether existing methods are sufficient to evaluate genomic technologies. As different approaches may produce conflicting adoption decisions, clarification is urgently required. This article summarizes the methodological issues associated with conducting economic evaluations of genomic interventions.

MATERIALS & METHODS

A structured literature review was conducted to identify references that considered the methodological challenges faced when conducting economic evaluations of genomic interventions.

RESULTS

Methodological challenges related to the analytical approach included the choice of comparator, perspective and timeframe. Challenges in costing centered around the need to collect a broad range of costs, frequently, in a data-limited environment. Measuring outcomes is problematic as standard measures have limited applicability, however, alternative metrics (e.g., personal utility) are underdeveloped and alternative approaches (e.g., cost-benefit analysis) underused. Effectiveness data quality is weak and challenging to incorporate into standard economic analyses, while little is known about patient and clinician behavior in this context. Comprehensive value of information analyses are likely to be helpful.

CONCLUSION

Economic evaluations of genomic technologies present a particular challenge for health economists. New methods may be required to resolve these issues, but the evidence to justify alternative approaches is yet to be produced. This should be the focus of future work in this field.

Opening Pandora’s box in the UK: a hypothetical pharmacogenetic test for clozapine

Clozapine is a uniquely efficacious antipsychotic drug in treatment-resistant schizophrenia. Its use is restricted due to adverse effects including a rare but dangerous reduction in neutrophils (agranulocytosis) and the mandatory hematological monitoring this entails in many countries. We review the statistical, ethical and legal issues arising from a hypothetical pharmacogenetic test for clozapine, using the UK as an exemplary case for consideration. Our key findings include: a consideration of the probabilistic results that a pharmacogenetic test may return; the impact on drug licensing; and the potential for pharmacogenetic tests for clozapine being used without consent under the UK’s legal framework. We make recommendations regarding regulatory changes applicable to the special case of pharmacogenetic testing in clozapine treatment.

Neuroimaging in psychiatric pharmacogenetics research: the promise and pitfalls

The integration of research on neuroimaging and pharmacogenetics holds promise for improving treatment for neuropsychiatric conditions. Neuroimaging may provide a more sensitive early measure of treatment response in genetically defined patient groups, and could facilitate development of novel therapies based on an improved understanding of pathogenic mechanisms underlying pharmacogenetic associations. This review summarizes progress in efforts to incorporate neuroimaging into genetics and treatment research on major psychiatric disorders, such as schizophrenia, major depressive disorder, bipolar disorder, attention-deficit/hyperactivity disorder, and addiction. Methodological challenges include: performing genetic analyses in small study populations used in imaging studies; inclusion of patients with psychiatric comorbidities; and the extensive variability across studies in neuroimaging protocols, neurobehavioral task probes, and analytic strategies. Moreover, few studies use pharmacogenetic designs that permit testing of genotype × drug effects. As a result of these limitations, few findings have been fully replicated. Future studies that pre-screen participants for genetic variants selected a priori based on drug metabolism and targets have the greatest potential to advance the science and practice of psychiatric treatment.

The genetics of eating disorders

Over the past decade, considerable advances have been made in understanding genetic influences on eating pathology. Eating disorders aggregate in families, and twin studies reveal that additive genetic factors account for approximately 40% to 60% of liability to anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED). Molecular genetics studies have been undertaken to identify alterations in deoxyribonucleic acid sequence and/or gene expression that may be involved in the pathogenesis of disordered eating behaviors, symptoms, and related disorders and to uncover potential genetic variants that may contribute to variability of treatment response. This article provides an in-depth review of the scientific literature on the genetics of AN, BN, and BED including extant studies, emerging hypotheses, future directions, and clinical implications.

A genome-wide association study of a sustained pattern of antidepressant response

Genome-wide association studies (GWAS) have failed to replicate common genetic variants associated with antidepressant response, as defined using a single endpoint. Genetic influences may be discernible by examining individual variation between sustained versus unsustained patterns of response, which may distinguish medication effects from non-specific, or placebo responses to active medication. We conducted a GWAS among 1116 subjects with Major Depressive Disorder from the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) trial who were characterized using Growth Mixture Modeling as showing a sustained versus unsustained pattern of clinical response over 12 weeks of treatment with citalopram. Replication analyses examined 585 subjects from the Genome-based Therapeutic Drugs for Depression (GENDEP) trial. The strongest association with sustained as opposed to unsustained response in STAR*D involved a single nucleotide polymorphism (SNP; rs10492002) within the acyl-CoA synthetase short-chain family member 3 gene (ACSS3, p-value=4.5×10(-6), odds ratio=0.61). No SNPs met our threshold for genome-wide significance. SNP data were available in GENDEP for 18 of the top 25 SNPs in STAR*D. The most replicable association was with SNP rs7816924 (p=0.008, OR=1.58); no SNP met the replication p-value threshold of 0.003. Joint analysis of these 18 SNPs resulted in the strongest signal coming from rs7816924 (p=2.11×10(-7)), which resides in chondroitin sulfate N-acetylgalactosaminyltransferase 1 gene (CSGALNACT1). An exploratory genetic pathway analysis revealed evidence for an involvement of the KEGG pathway of long-term potentiation (FDR=.02). Results suggest novel genetic associations to sustained response.

Strengths and weaknesses of pharmacogenetic studies of antipsychotic drugs: the potential value of the PEPs study

The successful application of pharmacogenetics in routine clinical practice is still a long way from becoming a reality. In order to favor the transfer of pharmacogenetic results to clinical practice, especially in psychiatry, these studies must be optimized. This article reviews the strengths and weaknesses that characterize pharmacogenetic studies in psychiatry and condition their implementation in clinical practice. We also include recommendations for improving the design of pharmacogenetic studies, which may convert their limitations into strengths and facilitate the implementation of their results into clinical practice. Finally, we discuss the potential value of naturalistic, prospective, multicenter and coordinated projects such as the 'Phenotype-genotype and environmental interaction. Application of a predictive model in first psychotic episodes' (known as the PEPs study, from the Spanish abbreviation) in pharmacogenetic studies.