AmpliChip CYP450 Test: personalized medicine has arrived in psychiatry

Challenges and opportunities for SERS in the infrared: materials and methods

In the wake of a global, heightened interest towards biomarker and disease detection prompted by the SARS-CoV-2 pandemic, surface enhanced Raman spectroscopy (SERS) positions itself again at the forefront of biosensing innovation. But is it ready to move from the laboratory to the clinic? This review presents the challenges associated with the application of SERS to the biomedical field, and thus, to the use of excitation sources in the near infrared, where biological windows allow for cell and through-tissue measurements. Two main tackling strategies will be discussed: (1) acting on the design of the enhancing substrate, which includes manipulation of nanoparticle shape, material, and supramolecular architecture, and (2) acting on the spectral collection set-up. A final perspective highlights the upcoming scientific and technological bets that need to be won in order for SERS to stably transition from benchtop to bedside.

Case Report: Pharmacogenetics Applied to Precision Psychiatry Could Explain the Outcome of a Patient With a New CYP2D6 Genotype

Precision medicine applied to psychiatry provides new insight into the promising field of precision psychiatry. Psychotic disorders are heterogeneous, complex, chronic, and severe mental disorders. Not only does the prognosis and the course of the disease vary among patients suffering from psychotic disorders, but the treatment response varies as well. Although antipsychotic drugs are the cornerstone of the treatment of schizophrenia, many patients only partially respond to these drugs. Furthermore, patients often experience adverse events which can lead to poor treatment adherence. Interindividual variability in drug response could be related to age, gender, ethnicity, lifestyle factors, pharmacological interactions, obesity, and genetics, all of which influence the process of drug metabolism. Commonly prescribed antipsychotics are metabolized by cytochrome P450 (CYP450) enzymes, and CYP450 genes are highly polymorphic. Pharmacogenetic testing is increasingly being used to predict a patient's drug response and could help to find the most appropriate therapy for an individual patient. In this report, we describe a psychotic patient who did not receive adequate clinical follow-up and subsequently presented adverse events, which could be explained by his pharmacogenetic profile and the drug interactions resulting from the polypharmacy prescribed.

Four Actionable Bottlenecks and Potential Solutions to Translating Psychiatric Genetics Research: An Expert Review

BACKGROUND

Psychiatric genetics has had limited success in translational efforts. A thorough understanding of the present state of translation in this field will be useful in the facilitation and assessment of future translational progress.

PURPOSE

A narrative literature review was conducted. Combinations of 3 groups of terms were searched in EBSCOhost, Google Scholar, and PubMed. The review occurred in multiple steps, including abstract collection, inclusion/exclusion criteria review, coding, and analysis of included papers.

RESULTS

One hundred and fourteen articles were analyzed for the narrative review. Across those, 4 bottlenecks were noted that, if addressed, may provide insights and help improve and increase translation in the field of psychiatric genetics. These 4 bottlenecks are emphasizing linear translational frameworks, relying on molecular genomic findings, prioritizing certain psychiatric disorders, and publishing more reviews than experiments.

CONCLUSIONS

These entwined bottlenecks are examined with one another. Awareness of these bottlenecks can inform stakeholders who work to translate and/or utilize psychiatric genetic information. Potential solutions include utilizing nonlinear translational frameworks as well as a wider array of psychiatric genetic information (e.g., family history and gene-environment interplay) in this area of research, expanding which psychiatric disorders are considered for translation, and when possible, conducting original research. Researchers are urged to consider how their research is translational in the context of the frameworks, genetic information, and psychiatric disorders discussed in this review. At a broader level, these efforts should be supported with translational efforts in funding and policy shifts.

The Impact of Pharmacogenomics in Personalized Medicine

Recent advances in Pharmacogenomics have made it possible to understand the reasons behind the different response of a drug. Discovery of genetic variants and its association with the varying response of drug provide the basis for recommending a drug and its dose to an individual patient. Genetic makeup-based prescription, design, and implementation of therapy not only improve the outcome of treatments but also reduce the risk of toxicity and other adverse effects. A better understanding of individual variations and their effect on drug response, metabolism excretion, and toxicity will replace the trial-and-error approach of treatment. Evidence of the clinical utility of pharmacogenetics testing is only available for a few medications, and FDA labels only require pharmacogenetics testing for a small number of drugs. Although there is a great promise, there are not many examples where Pharmacogenomics impacts clinical utility. Some genetic variants related to different diseases have been reported, and many have not been studied yet. The information related to the outcome of treatment with a particular drug and a genetic variant can be used to release a warning/label for the use of that drug. There are many limitations in the way of implementing the goal of personalized medicine. Future advances in the field of genomics, diagnosis approaches, data analysis, clinical decision-making, and sustainable business model for personalization of therapy can speed up the individualization of therapy based on genetic makeup.

Prolactin levels: sex differences in the effects of risperidone, 9-hydroxyrisperidone levels, CYP2D6 and ABCB1 variants

AIM

The role of sex on the association of plasma prolactin levels with risperidone (R) and 9-hydroxyrisperidone (9-OHR) concentrations is investigated.

METHODS

Plasma R and prolactin concentrations, CYP2D6 and exon 21 and 26 ABCB1 gene variants were studied in 110 patients.

RESULTS

In females, a 1 ng/ml increase in R levels was associated with a significant 1.02% increase in prolactin levels. In males, a 1 ng/ml increase in 9-OHR levels was associated with a significant 1.18% increase in prolactin levels. ABCB1 haplotype 12 had significant but opposite effects in males and females. In the combined sample, 9-OHR, but not R levels had significant effects on prolactin levels.

CONCLUSION

Genes had sex-specific effects on risperidone-associated prolactin elevations.

CYP2C19*2 and CYP2C19*17 variants and effect of tamoxifen on breast cancer recurrence: Analysis of the International Tamoxifen Pharmacogenomics Consortium dataset

The role of cytochrome P450 drug metabolizing enzymes in the efficacy of tamoxifen treatment of breast cancer is subject to substantial interest and controversy. CYP2D6 have been intensively studied, but the role of CYP2C19 is less elucidated, and we studied the association of CYPC19 genotype and recurrence of breast cancer. We used outcome and genotyping data from the large publicly available International Tamoxifen Pharmacogenomics Consortium (ITPC) dataset. Cox regression was used to compute the hazard ratios (HRs) for recurrence. CYP2C19 genotype data was available for 2 423 patients and the final sample cohort comprised 2 102 patients. CYP2C19*2 or *19 alleles did not influence DFS. For the CYP2C19*2 allele, the HR was 1.05 (CI 0.78–1.42) and 0.79 (CI 0.32–1.94) for hetero- and homozygote carriers, respectively. The corresponding HR for hetero- and homozygote carriers of the CYP2C19*17 allele were 1.02 (CI 0.71–1.46) and 0.57 (CI 0.26–1.24), respectively. Accounting for CYP2D6 genotype status did not change these estimates. We found no evidence to support a clinically meaningful role of CYP2C19 polymorphisms and response to tamoxifen in breast cancer patients and, consequently, CYP2C19 genotype status should not be included in clinical decisions on tamoxifen treatment.

CYP2D6 ultra-rapid metabolizer phenotype not associated with attempted suicide in a large sample of psychiatric inpatients

AIM

Suicide accounts for over 800,000 deaths per year worldwide and is the tenth-leading cause of mortality in USA. Several studies have investigated cytochrome P450 CYP2D6 ultra-rapid metabolizer (UM) phenotype in relation to suicidality, with mixed results. This study tested the hypothesis of increased suicide risk among CYP2D6 UMs.

PATIENTS & METHODS

Among the 4264 state psychiatric hospital inpatients included, 2435 (57%) reported a prior suicide attempt.

RESULTS

No association between UM status and attempted suicide was observed in bivariate (odds ratio: 0.87; 95% CI: 0.53-1.25), multivariate (adjusted odds ratio: 0.89; 95% CI: 0.55-1.46), or risk-stratified analyses.

CONCLUSION

These results contrast with prior reports of increased suicidality among CYP2D6 UMs and highlight the pressing need to identify reliable screening methods to better address this persistent public health problem.

Precision medicine for psychopharmacology: a general introduction

INTRODUCTION

Precision medicine is an emerging medical model that can provide accurate diagnoses and tailored therapeutic strategies for patients based on data pertaining to genes, microbiomes, environment, family history and lifestyle.

AREAS COVERED

Here, we provide basic information about precision medicine and newly introduced concepts, such as the precision medicine ecosystem and big data processing, and omics technologies including pharmacogenomics, pharamacometabolomics, pharmacoproteomics, pharmacoepigenomics, connectomics and exposomics. The authors review the current state of omics in psychiatry and the future direction of psychopharmacology as it moves towards precision medicine. Expert commentary: Advances in precision medicine have been facilitated by achievements in multiple fields, including large-scale biological databases, powerful methods for characterizing patients (such as genomics, proteomics, metabolomics, diverse cellular assays, and even social networks and mobile health technologies), and computer-based tools for analyzing large amounts of data.

Exploring the role of drug-metabolising enzymes in antidepressant side effects

RATIONALE

Cytochrome P450 enzymes are important in the metabolism of antidepressants. The highly polymorphic nature of these enzymes has been linked to variability in antidepressant metabolism rates, leading to hope regarding the use of P450 genotyping to guide treatment. However, evidence that P450 genotypic differences underlie the variation in treatment outcomes is inconclusive.

OBJECTIVES

We explored the links between both P450 genotype and serum concentrations of antidepressant with antidepressant side effects, using data from the Genome-Based Therapeutic Drugs for Depression Project (GENDEP), which is a large (n = 868), pharmacogenetic study of depressed individuals treated with escitalopram or nortriptyline.

METHODS

Patients were genotyped for the enzymes CYP2C19 and CYP2D6, and serum concentrations of both antidepressant and primary metabolite were measured after 8 weeks of treatment. Side effects were assessed weekly. We investigated associations between P450 genotypes, serum concentrations of antidepressants and side effects, as well as the relationship between P450 genotype and study discontinuation.

RESULTS

P450 genotype did not predict total side effect burden (nortriptyline: n = 251, p = 0.5638, β = -0.133, standard error (SE) = 0.229; escitalopram: n = 340, p = 0.9627, β = -0.004, SE = 0.085), study discontinuation (nortriptyline n = 284, hazard ratio (HR) = 1.300, p = 0.174; escitalopram n = 376, HR = 0.870, p = 0.118) or specific side effects. Serum concentrations of antidepressant were only related to a minority of the specific side effects measured: dry mouth, dizziness and diarrhoea.

CONCLUSIONS

In this sample where antidepressant dosage is titrated using clinical judgement, P450 genotypes do not explain differences between patients in side effects with antidepressants. Serum drug concentrations appear to only explain variability in the occurrence of a minority of specific side effects.

Pharmacogenomics of neuropsychiatric disorders: analysis of genetic variability in 162 identified neuroreceptors using 1000 Genomes Project data

BACKGROUND

Neuroreceptors are considered to be primary drug targets and their abrupt signaling is a notable cause of interindividual drug response variability and treatment failure for complex neuropsychiatric diseases. In view of recent evidence, it is believed that common genetic risk factors mainly highly polymorphic neuroreceptors are being shared among neuropsychiatric disorders.

MATERIALS & METHODS

We identified 162 neuroreceptors from the 639 known receptors in Homo sapiens and investigated 231,683 SNPs using 1000 Genomes Project data and evaluated their biological effect using in silico tools including RegulomeDB, SIFT, PolyPhen-2 and CAROL. Furthermore, data from the 1000 Genomes Project was utilized to retrieve minor allele frequency and calculate pairwise logartithm of the odds score among these SNPs for African, American, Asian and European populations separately as well as when combined together using Haploview v4.2. LRTag was used to identify tagSNPs in populations.

RESULTS

A total of 52,381 (22.60%) SNPs were predicted as functionally important genetic variations. We identified sets of 603, 495, 450, 453 and 646 informative tagSNPs for African, American, Asian, European and combined populations, respectively. We propose construction of a 'neuroreceptor variants array' with these informative SNPs for future pharmacogenomic studies of neuropsychiatric disorders.

CONCLUSION

Such an approach might improve genotype-phenotype correlation across different populations and lead to identification of reliable genetic markers and novel drug targets. Integration of these SNPs in literature would further provide evidence relevant to underlying mechanisms of genetics based nosology, pathophysiology and development of new drugs for the treatment of neuropsychiatric disorders.

Molecular mechanisms of the microsomal mixed function oxidases and biological and pathological implications

The cytochrome P450 mixed function oxidase enzymes play a major role in the metabolism of important endogenous substrates as well as in the biotransformation of xenobiotics. The liver P450 system is the most active in metabolism of exogenous substrates. This review briefly describes the liver P450 (CYP) mixed function oxidase system with respect to its enzymatic components and functions. Electron transfer by the NADPH-P450 oxidoreductase is required for reduction of the heme of P450, necessary for binding of molecular oxygen. Binding of substrates to P450 produce substrate binding spectra. The P450 catalytic cycle is complex and rate-limiting steps are not clear. Many types of chemical reactions can be catalyzed by P450 enzymes, making this family among the most diverse catalysts known. There are multiple forms of P450s arranged into families based on structural homology. The major drug metabolizing CYPs are discussed with respect to typical substrates, inducers and inhibitors and their polymorphic forms. The composition of CYPs in humans varies considerably among individuals because of sex and age differences, the influence of diet, liver disease, presence of potential inducers and/or inhibitors. Because of such factors and CYP polymorphisms, and overlapping drug specificity, there is a large variability in the content and composition of P450 enzymes among individuals. This can result in large variations in drug metabolism by humans and often can contribute to drug–drug interactions and adverse drug reactions. Because of many of the above factors, especially CYP polymorphisms, there has been much interest in personalized medicine especially with respect to which CYPs and which of their polymorphic forms are present in order to attempt to determine what drug therapy and what dosage would reflect the best therapeutic strategy in treating individual patients.

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The CYP P450 system is important in metabolism of endogenous substrates and drugs.

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About 150 forms of CYPs have been identified and they are grouped into families.

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CYPs catalyze a wide variety of reactions and are among the most diverse catalysts known.

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Electrons are passed to the CYP via NADPH+NADPH-cytochrome P450 reductase.

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Metabolism of certain compounds by CYPs generate reactive intermediates which are toxic.

Towards the clinical implementation of pharmacogenetics in bipolar disorder

BACKGROUND

Bipolar disorder (BD) is a psychiatric illness defined by pathological alterations between the mood states of mania and depression, causing disability, imposing healthcare costs and elevating the risk of suicide. Although effective treatments for BD exist, variability in outcomes leads to a large number of treatment failures, typically followed by a trial and error process of medication switches that can take years. Pharmacogenetic testing (PGT), by tailoring drug choice to an individual, may personalize and expedite treatment so as to identify more rapidly medications well suited to individual BD patients.

DISCUSSION

A number of associations have been made in BD between medication response phenotypes and specific genetic markers. However, to date clinical adoption of PGT has been limited, often citing questions that must be answered before it can be widely utilized. These include: What are the requirements of supporting evidence? How large is a clinically relevant effect? What degree of specificity and sensitivity are required? Does a given marker influence decision making and have clinical utility? In many cases, the answers to these questions remain unknown, and ultimately, the question of whether PGT is valid and useful must be determined empirically. Towards this aim, we have reviewed the literature and selected drug-genotype associations with the strongest evidence for utility in BD.

SUMMARY

Based upon these findings, we propose a preliminary panel for use in PGT, and a method by which the results of a PGT panel can be integrated for clinical interpretation. Finally, we argue that based on the sufficiency of accumulated evidence, PGT implementation studies are now warranted. We propose and discuss the design for a randomized clinical trial to test the use of PGT in the treatment of BD.

Problems and solutions to filling the drying drug pipeline for psychiatric disorders: a report from the inaugural 2012 CINP Think Tank

The inaugural Collegium Internationale Neuro-Psychopharmacologicum (CINP) Think Tank, a small open meeting sponsored by the CINP, discussed impediments to developing new drugs for psychiatric disorders and approaches to overcome these impediments. Whilst neuropsycharmacology has a rich pharmacopeia (current treatments benefiting many individuals), issues of treatment resistance, sub-optimal response and unwanted side effects remain problematic. Many scientific, economic and social issues are impeding the development of drugs (e.g. higher risk of failure, placebo effects, problematic regulatory environments, pressures imposed by patent protection, downward pressure on reimbursements and financial, legal and social risk aversion). A consensus of the meeting was that efforts to understanding the core pathophysiology of psychiatric disorders are fundamental to increasing the chance of developing new drugs. However, findings from disorders such as Huntington's chorea, have shown that knowing the cause of a disorder may not reveal new drug targets. By contrast, clinically useful biomarkers that define target populations for new drugs and models that allow findings to be accurately translated from animals to humans will increase the likelihood of developing new drugs. In addition, a greater accent on experimental medicine, creative clinical investigations and improved communication between preclinical neuropsychopharmacologists, clinicians committed to neuropsychopharmacological research, industry and the regulators would also be a driver to the development of new treatments. Finally, it was agreed that the CINP must continue its role as a conduit facilitating vibrant interactions between industry and academia as such communications are a central component in identifying new drug targets, developing new drugs and transitioning new drugs into the clinic.

A systematically combined genotype and functional combination analysis of CYP2E1, CYP2D6, CYP2C9, CYP2C19 in different geographic areas of mainland China--a basis for personalized therapy

The cytochrome P450 is the major enzyme involved in drug metabolism. Single CYP genotypes and metabolic phenotypes have been widely studied, but no combination analysis has been conducted in the context of specific populations and geographical areas. This study is the first to systematically analyze the combined genotypes and functional combinations of 400 samples of major CYP genes—CYP2E1, CYP2D6, CYP2C9, and CYP2C19 in four geographical areas of mainland China. 167 different genotype combinations were identified, of which 25 had a greater than 1% frequency in the Chinese Han population. In addition, phenotypes of the four genes for each sample were in line with the predictions of previous studies of the four geographical areas. On the basis of the genotype classification, we were able to produce a systemic functional combinations analysis for the population. 25 of the combinations detected had at least two non-wild phenotypes and four showed a frequency above 1%. A bioinformatics analysis of the relationship between particular drugs and multi-genes was conducted. This is the first systematic study to analyze genotype combinations and functional combinations across whole Chinese population and could make a significant contribution in the field of personalized medicine and therapy.

Rethinking psychiatry with OMICS science in the age of personalized P5 medicine: ready for psychiatome?

The Diagnostic and Statistical Manual of Mental Disorders (DSM) is universally acknowledged as the prominent reference textbook for the diagnosis and assessment of psychiatric diseases. However, since the publication of its first version in 1952, controversies have been raised concerning its reliability and validity and the need for other novel clinical tools has emerged. Currently the DSM is in its fourth edition and a new fifth edition is expected for release in 2013, in an intense intellectual debate and in a call for new proposals. Since 1952, psychiatry has undergone many changes and is emerging as unique field in the medical area in which a novel approach is being demanded for properly treating patients: not the classical “one-size-fits-all” approach, but a more targeted and tailored diagnosis and therapeutics, taking into account the complex interactions among genes and their products, environment, culture and the psychological apparatus of the subject. OMICS sciences, being based on high-throughput technologies, are systems biology related fields (like genomics, proteomics, transcriptomics and so on). In the frame of the P5 medicine (personalized, participatory, predictive, preventive, psycho-cognitive), they could establish links between psychiatric diseases, which are disorders with a final common symptomatology with vastly heterogeneous biological, environmental and sociological underpinnings, and by understanding the psychiatric diseases beyond their classic symptomatic or syndromal definitions using OMICS research, one can have a broader picture and unprecedented links and reclassification of psychiatric nosology. Importantly, by understanding the basis of heterogeneity in diseases through OMICS research, one could also personalize treatment of psychiatric illnesses. In this manuscript, we discuss a gap in the current psychiatric research, namely the missing logical link among OMICS, personalized medicine and reclassification of diseases. Moreover, we explore the importance of incorporating OMICS-based quantitative dimensional criteria, besides the classical qualitative and categorical approach.

Applications of CYP450 testing in the clinical setting

Interindividual variability in drug response is a major clinical problem. Polymedication and genetic polymorphisms modulating drug-metabolising enzyme activities (cytochromes P450, CYP) are identified sources of variability in drug responses. We present here the relevant data on the clinical impact of the major CYP polymorphisms (CYP2D6, CYP2C19 and CYP2C9) on drug therapy where genotyping and phenotyping may be considered, and the guidelines developed when available. CYP2D6 is responsible for the oxidative metabolism of up to 25% of commonly prescribed drugs such as antidepressants, antipsychotics, opioids, antiarrythmics and tamoxifen. The ultrarapid metaboliser (UM) phenotype is recognised as a cause of therapeutic inefficacy of antidepressant, whereas an increased risk of toxicity has been reported in poor metabolisers (PMs) with several psychotropics (desipramine, venlafaxine, amitriptyline, haloperidol). CYP2D6 polymorphism influences the analgesic response to prodrug opioids (codeine, tramadol and oxycodone). In PMs for CYP2D6, reduced analgesic effects have been observed, whereas in UMs cases of life-threatening toxicity have been reported with tramadol and codeine. CYP2D6 PM phenotype has been associated with an increased risk of toxicity of metoprolol, timolol, carvedilol and propafenone. Although conflicting results have been reported regarding the association between CYP2D6 genotype and tamoxifen effects, CYP2D6 genotyping may be useful in selecting adjuvant hormonal therapy in postmenopausal women. CYP2C19 is responsible for metabolising clopidogrel, proton pump inhibitors (PPIs) and some antidepressants. Carriers of CYP2C19 variant alleles exhibit a reduced capacity to produce the active metabolite of clopidogrel, and are at increased risk of adverse cardiovascular events. For PPIs, it has been shown that the mean intragastric pH values and the Helicobacter pylori eradication rates were higher in carriers of CYP2C19 variant alleles. CYP2C19 is involved in the metabolism of several antidepressants. As a result of an increased risk of adverse effects in CYP2C19 PMs, dose reductions are recommended for some agents (imipramine, sertraline). CYP2C9 is responsible for metabolising vitamin K antagonists (VKAs), non-steroidal anti-inflammatory drugs (NSAIDs), sulfonylureas, angiotensin II receptor antagonists and phenytoin. For VKAs, CYP2C9 polymorphism has been associated with lower doses, longer time to reach treatment stability and higher frequencies of supratherapeutic international normalised ratios (INRs). Prescribing algorithms are available in order to adapt dosing to genotype. Although the existing data are controversial, some studies have suggested an increased risk of NSAID-associated gastrointestinal bleeding in carriers of CYP2C9 variant alleles. A relationship between CYP2C9 polymorphisms and the pharmacokinetics of sulfonylureas and angiotensin II receptor antagonists has also been observed. The clinical impact in terms of hypoglycaemia and blood pressure was, however, modest. Finally, homozygous and heterozygous carriers of CYP2C9 variant alleles require lower doses of phenytoin to reach therapeutic plasma concentrations, and are at increased risk of toxicity. New diagnostic techniques made safer and easier should allow quicker diagnosis of metabolic variations. Genotyping and phenotyping may therefore be considered where dosing guidelines according to CYP genotype have been published, and help identify the right molecule for the right patient.

Towards personalizing treatment for depression : developing treatment values markers

BACKGROUND

While 'personalized medicine' commonly refers to genetic markers or profiles associated with pharmacological treatment response, tailoring treatments to patient preferences and values is equally important.

OBJECTIVE

To describe and demonstrate a method to develop 'values markers,' or profiles based on the relative importance of attributes of depression treatment.

STUDY DESIGN

Discrete choice analysis was used to assess individuals' relative preferences for features of depression treatment. Preference profiles were developed using latent profile analysis.

PATIENTS OR OTHER PARTICIPANTS

Eighty-six adults participating in an internet-based discrete choice questionnaire.

MAIN OUTCOME MEASURE

Participants were presented with two depression scenarios representing mild and severe depression. For each scenario, they were asked to compare 18 choice sets based on the type of medication side effect (nausea, dizziness, and sexual dysfunction) and severity (mild, moderate, and severe); and for counseling frequency (once per week or every other week) and provider setting (the office of a mental health professional, primary care doctor, or spiritual counselor).

RESULTS

Three profiles were identified: profile 1 was associated with a preference for counseling and an avoidance of medication side effects; profile 2 with an avoidance of strong medication side effects and for receiving counseling in medical settings; and profile 3 with a preference for medication over counseling. When presented with a severe depression scenario, there was a higher prevalence for profile 1 and patients were more likely to prefer mental health over primary care and spiritual settings.

CONCLUSIONS

Values markers may provide a foundation for personalized medicine, and reflect current initiatives emphasizing patient-centered care. Next steps should assess whether values markers are predictive of treatment initiation and adherence.

Personalized medicine in psychiatry: new technologies and approaches

Psychiatric patients tend to exhibit significant interindividual variability in their responses to psychoactive drugs, as well as an irregular clinical course. For these (and other) reasons, increasing numbers of psychiatrists are turning to genotyping for help in selecting the psychopharmacologic agents best suited to an individual patient's distinctive metabolic characteristics and clinical presentation. Fortunately, routine genotyping is already available for gene variations that code for proteins involved in neurotransmission, and for drug-metabolizing enzymes involved in the elimination of many medications. Thus, genotyping-based personalized psychiatry is now in sight. Increasing numbers of clinically useful DNA microarrays are in the development stage, including a simplified procedure for genotyping patients for CYP2D6, which metabolizes a high proportion of the currently prescribed antidepressants and antipsychotics. It has been pointed out that psychiatric disease is rarely a consequence of an abnormality in a single gene, but reflects the perturbations of complex intracellular networks in the brain. Thus, analysis of functional neuronal networks is becoming an essential component of drug development strategies. The integrated use of technologies such as electroencephalography, magnetoencephalography, functional magnetic resonance imaging (fMRI), and diffusion tensor imaging (DTI), in combination with pharmacogenetics, promises to transform our understanding of the mechanisms of psychiatric disorders and their treatment. The concept of network medicine envisions a time to come when drugs will be used to target a neural network rather than simply components within the network. Personalized medicine in psychiatry is still at an early stage, but it has a very promising future.

Biomarkers: symptoms, survivorship, and quality of life

OBJECTIVES

To review the evidence on a number of biomarkers that show potential clinical utility in the prediction of and treatment responsiveness for the four most common symptoms associated with cancer and its treatment (ie, pain, fatigue, sleep disturbance, depression).

DATA SOURCES

Review and synthesis of review articles and data-based publications.

CONCLUSION

A growing body of evidence suggests that sensitive and specific biomarkers will be available to assist clinicians with the assessment and management of symptoms.

IMPLICATIONS FOR NURSING PRACTICE

Nurses will play a critical role in educating patients about their risk for specific symptoms based on an evaluation of specific biomarkers. Nurses will be involved in using biomarker data to titrate medications based on patient's responses to symptom management interventions.

Clinical Application of Pharmacogenomics

The purpose of this review is to discuss the clinical application of pharmacogenomics for select drug therapies (eg, proton pump inhibitors [PPIs], codeine, and carbamazepine) and to highlight limitations and challenges that preclude implementation of pharmacogenomics into clinical practice. Genetic polymorphisms of cytochrome P450 (CYP) enzymes and the presence of the human leukocyte antigen ( HLA) -B*1502 allele influence drug disposition and/or response. A portion of PPI pharmacokinetic and pharmacodynamic variability can be explained by CYP2C19 genotype. However, conflicting evidence exists related to Helicobacter pylori cure rates based on CYP2C19 genotype. For codeine, adverse drug reactions in neonates through breast-feeding from CYP2D6 ultra-rapid metabolizers have been reported. However, there is lack of conclusive evidence regarding the overall influence of CYP2D6 polymorphisms on codeine efficacy and toxicity. Although CYP2C19 and CYP2D6 genotyping tests are available, clinical utility remains low. The presence of the HLA-B*1502 allele is associated with carbamazepine-induced Stevens-Johnson syndrome (SJS) and/or toxic epidermal necrolysis (TEN). Pharmacogenomic testing is required prior to initiating carbamazepine in high-risk patients. Lack of sufficient resources, provider knowledge, and ethical, legal, and social issues are several limitations and challenges to implementing pharmacogenomic testing in clinical practice.

Ecstasy (MDMA)-induced hyponatraemia is associated with genetic variants in CYP2D6 and COMT

We hypothesised that genetically determined poor metabolism of 3,4-methylene dioxymetamphetamine (MDMA) due either to the presence of CYP2D6 genotypes giving absent or low CYP2D6 enzyme activity, or a COMT genotype predicting low COMT enzyme activity would be associated with a greater degree of MDMA-induced reduction in plasma sodium and osmolality than other genotypes at these genes following consumption of 'ecstasy' tablets by clubbers. Of the 48 subjects who returned to the test site post-clubbing, 30 provided samples for measurement of vasopressin (AVP), plasma sodium, urea and plasma and urine osmolality. Genotyping was performed for functional variants in CYP2D6 (n = 29) and COMT (Val158Met, n = 30). In subjects with urinary MDMA detected post-clubbing, there was a significant association between change in plasma osmolality (p = 0.009) and in plasma sodium (p = 0.012) and CYP2D6 genotypic category. Individuals with the low-activity but readily inhibitable CYP2D6 extensive metaboliser/intermediate metaboliser (EM/IM) genotype showed greater reductions in these measures than all other CYP2D6 genotypic categories. COMT low-activity genotypes (Met/Met and Val/Met) were also significantly associated with reductions in plasma osmolality (p = 0.028) and in plasma sodium (p = 0.003). On conservative Bonferroni correction for two independent genes, the CYP2D6 and COMT plasma sodium findings remain significant. The relatively high frequency of the low-activity CYP2D6 and COMT genotypes in the population warrants further attention, since consumption of free water following ingestion of MDMA in these individuals may trigger dilutational hyponatraemia and increased risk of syndrome of inappropriate antidiuretic hormone secretion.

CYP2C19 genotype predicts steady state escitalopram concentration in GENDEP

In vitro work shows CYP2C19 and CYP2D6 contribute to the metabolism of escitalopram to its primary metabolite, N-desmethylescitalopram. We report the effect of CYP2C19 and CYP2D6 genotypes on steady state morning concentrations of escitalopram and N-desmethylescitalopram and the ratio of this metabolite to the parent drug in 196 adult patients with depression in GENDEP, a clinical pharmacogenomic trial. Subjects who had one CYP2D6 allele associated with intermediate metabolizer phenotype and one associated with poor metabolizer (i.e. IM/PM genotypic category) had a higher mean logarithm escitalopram concentration than CYP2D6 extensive metabolizers (EMs) (p = 0.004). Older age was also associated with higher concentrations of escitalopram. Covarying for CYP2D6 and age, we found those homozygous for the CYP2C19*17 allele associated with ultrarapid metabolizer (UM) phenotype had a significantly lower mean escitalopram concentration (2-fold, p = 0.0001) and a higher mean metabolic ratio (p = 0.0003) than EMs, while those homozygous for alleles conferring the PM phenotype had a higher mean escitalopram concentration than EMs (1.55-fold, p = 0.008). There was a significant overall association between CYP2C19 genotypic category and escitalopram concentration (p = 0.0003; p = 0.0012 Bonferroni corrected). In conclusion, we have demonstrated an association between CYP2C19 genotype, including the CYP2C19*17 allele, and steady state escitalopram concentration.

Pharmacogenetics and the pharmacological management of depression

Depression is a chronic disease seen in many healthcare settings. Current pharmacological treatment options are successful in two-thirds of patients. One CYP450 enzyme, CYP2D6, is responsible for the metabolism of 30% of all drugs including many antidepressants. Phenotypes of metabolizer status affect antidepressant treatment outcomes and adverse drug reactions.

Genetic polymorphisms of cytochrome P450 enzymes and antidepressant metabolism

INTRODUCTION

The cytochrome P450 (CYP) enzymes are the major enzymes responsible for Phase I reactions in the metabolism of several substances, including antidepressant medications. Thus, it has been hypothesized that variants in the CYP network may influence antidepressant efficacy and safety. Nonetheless, data on this field are still contradictory. The authors aim to give an overview of the published studies analyzing the influence of CYP highly polymorphic loci on antidepressant treatment in order to translate the acquired knowledge to a clinical level.

AREAS COVERED

The authors collected and compared experimental works and reviews published from the 1980s to the present and included in the Medline database. The included studies pertain to the effects of CYP gene polymorphisms on antidepressant pharmacokinetic parameters and clinical outcomes (response and drug-related adverse effects), with a focus on applications in clinical practice. The authors focused mainly on in vivo studies in humans (patients or healthy volunteers).

EXPERT OPINION

Great variability in antidepressant metabolism among individuals has been demonstrated. Thus, with the current interest in individualized medicine, several genetic tests to detect CYP variants have been produced. They provide a potentially useful way to anticipate some clinical outcomes of antidepressant treatment, although they will only be extensively used in clinical practice if precise and specific treatment options and guidelines based on genetic tests can be provided.

The promise and reality of pharmacogenetics in psychiatry

Existing psychotropic medications for the treatment of mental illnesses, including antidepressants, mood stabilizers, and antipsychotics, are clinically suboptimal. They are effective in only a subset of patients or produce partial responses, and they are often associated with debilitating side effects that discourage adherence. There is growing enthusiasm in the promise of pharmacogenetics to personalize the use of these treatments to maximize their efficacy and tolerability; however, there is still a long way to go before this promise becomes a reality. This article reviews the progress that has been made in research toward understanding how genetic factors influence psychotropic drug responses and the challenges that lie ahead in translating the research findings into clinical practices that yield tangible benefits for patients with mental illnesses.

CYP2D6 genotyping in breast cancer patients by liquid chromatography-electrospray ionization mass spectrometry

The application of cytochrome P450 2D6 (CYP2D6) genotyping to allow a personalized treatment approach for breast cancer patients undergoing endocrine therapy has been repeatedly discussed. However, the actual clinical relevance of the CYP2D6 genotype in the endocrine treatment of breast cancer still remains to be elucidated. A major prerequisite for the successful and valid evaluation of the CYP2D6 genotype with regard to its pharmacokinetic and clinical relevance is the availability of a comprehensive, accurate and cost-effective CYP2D6 genotyping strategy. Herein we present a CYP2D6 genotyping assay employing polymerase chain reaction (PCR)-ion pair reversed-phase high-performance liquid chromatography-electrospray ionization time-of-flight mass spectrometry (ICEMS). The genotyping strategy involves the simultaneous amplification of nine variable regions within the CYP2D6 gene by a two-step PCR protocol and the direct analysis of the generated PCR amplicons by ICEMS. The nucleotide composition profiles generated by ICEMS enable the differentiation of 37 of the 80 reported CYP2D6 alleles. The assay was applied to type the CYP2D6 gene in 199 Austrian individuals including 106 breast cancer patients undergoing tamoxifen treatment. The developed method turned out to be a highly applicable, robust and cost-effective approach, enabling an economical CYP2D6 testing for large patient cohorts.

Genetics of tardive dyskinesia

Tardive dyskinesia (TD) is one of the most serious adverse side effects of antipsychotic drugs and is an important topic of pharmacogenetic studies. Since there is a genetic susceptibility for developing this adverse reaction, and given that it is hard to predict its development prior to or during the early period of medication, the genetic study of TD is a promising research topic that has a direct clinical application. Moreover, such studies would improve our understanding of the genetic mechanism(s) underlying abnormal dyskinetic movement. A substantial number of case-control association studies of TD have been performed, with numbers of studies focusing on the genes involved in antipsychotic drug metabolism, such as those for cytochrome P450 (CYP) and oxidative stress related genes as well as various neurotransmitter related genes. These studies have produced relatively consistent though controversial findings for certain polymorphisms such as CYP2D6*10, DRD2 Taq1A, DRD3 Ser9Gly, HTR2A T102C, and MnSOD Ala9Val. Moreover, the application of the genome-wide association study (GWAS) to the susceptibility of TD has revealed certain associated genes that previously were never considered to be associated with TD, such as the rs7669317 on 4q24, GLI2 gene, GABA pathway genes, and HSPG2 gene. Although a substantial number of genetic studies have investigated TD, many of the positive findings have not been replicated or are inconsistent, which could be due to differences in study design, sample size, and/or subject ethnicity. We expect that more refined research will be performed in the future to resolve these issues, which will then enable the genetic prediction of TD and clinical application thereof.

Genome-wide pharmacogenomic analysis of response to treatment with antipsychotics

Schizophrenia is an often devastating neuropsychiatric illness. Understanding the genetic variation affecting response to antipsychotics is important to develop novel diagnostic tests to match individual schizophrenia patients to the most effective and safe medication. In this study, we use a genome-wide approach to detect genetic variation underlying individual differences in response to treatment with the antipsychotics olanzapine, quetiapine, risperidone, ziprasidone and perphenazine. Our sample consisted of 738 subjects with DSM-IV schizophrenia who took part in the Clinical Antipsychotic Trials of Intervention Effectiveness. Subjects were genotyped using the Affymetrix 500 K genotyping platform plus a custom 164 K chip to improve genome-wide coverage. Treatment outcome was measured using the Positive and Negative Syndrome Scale. Our criterion for genome-wide significance was a prespecified threshold that ensures that, on an average, only 10% of the significant findings are false discoveries. The top statistical result reached significance at our prespecified threshold and involved a single-nucleotide polymorphism (SNP) in an intergenic region on chromosome 4p15. In addition, SNPs in Ankyrin Repeat and Sterile Alpha Motif Domain-Containing Protein 1B (ANKS1B) and in the Contactin-Associated Protein-Like 5 gene (CNTNAP5), which mediated the effects of olanzapine and risperidone on Negative symptoms, were very close to our threshold for declaring significance. The most significant SNP in CNTNAP5 is nonsynonymous, giving rise to an amino-acid substitution. In addition to highlighting our top results, we provide all P-values for download as a resource for investigators with the requisite samples to carry out replication. This study demonstrates the potential of genome-wide association studies to discover novel genes that mediate the effects of antipsychotics, which could eventually help to tailor drug treatment to schizophrenic patients.

Personalized psychopharmacology for the affective disorders and schizophrenia: where is the evidence?

Individualized medicine is the ultimate aim of many medical specialties. Attempts to individualize psychopharmacology have focused on the genetic polymorphisms of neurotransmitter- and CNS-related genes. While there have been numerous reports on the discovery of possible genetic differences in various psychiatric disorders, clinical psychopharmacology has not yet significantly benefited from such data. At present, individualized psychopharmacology in practice is still largely the choice of drugs with the least side effects for a particular patient.

Shared decision making in mental health: prospects for personalized medicine

This paper describes the shared decision-making model, reviews its current status in the mental health field, and discusses its potential impact on personalized medicine. Shared decision making denotes a structured process that encourages full participation by patient and provider. Current research shows that shared decision making can improve the participation of mental health patients and the quality of decisions in terms of knowledge and values. The impact of shared decision making on adherence, illness self-management, and health outcomes remains to be studied. Implementing shared decision making broadly will require re-engineering the flow of clinical care in routine practice settings and much greater use of information technology Similar changes will be needed to combine genomic and other biological data with patients' values and preferences and with clinicians' expertise. The future of personalized medicine is dearly linked with our ability to create the infrastructure and cultural receptivity to these changes.

The promise and reality of pharmacogenetics in psychiatry

Existing psychotropic medications for the treatment of mental illnesses, including antidepressants, mood stabilizers, and antipsychotics, are clinically suboptimal. They are effective in only a subset of patients or produce partial responses, and they are often associated with debilitating side effects that discourage adherence. There is growing enthusiasm in the promise of pharmacogenetics to personalize the use of these treatments to maximize their efficacy and tolerability; however, there is still a long way to go before this promise becomes a reality. This article reviews the progress that has been made in research toward understanding how genetic factors influence psychotropic drug responses and the challenges that lie ahead in translating the research findings into clinical practices that yield tangible benefits for patients with mental illnesses.

Molecular diversity at the CYP2D6 locus in healthy and schizophrenic southern Brazilians

Aims: The delineation of allele distribution and frequency is required to effectively translate pharmacogenetics to the clinic and given the paucity of CYP2D6 data in the Brazilian population, the purpose of this research was to characterize CYP2D6 alleles and genotype frequencies in Brazilians of European and African ancestries. Moreover, since it is suggested in the literature that CYP2D6 poor metabolism might be involved with susceptibility to schizophrenia, we included data from Brazilian schizophrenic patients to verify if CYP2D6 poor metabolism phenotypes are associated with susceptibility to schizophrenia. Materials & methods: We investigated 24 CYP2D6 polymorphisms, gene deletions and gene multiplications in 179 healthy individuals from Brazil, 92 of European descent and 87 African Brazilians. CYP2D6 gene polymorphisms were genotyped by a MassARRAY® SNP genotyping system. Results: A total of 19 different alleles and five allele duplications were identified in African and European Brazilians. No significant differences in CYP2D6 allele function or poor metabolizer predicted phenotype frequencies were observed between healthy controls and schizophrenic patients, but the predicted metabolic phenotype distribution showed a significant higher frequency of intermediate metabolizers in African Brazilians than in European Brazilians (p = 0.001). Conclusions: CYP2D6 poor metabolizer genotype seems not to be a determining factor of schizophrenia susceptibility in Brazilians. The characterization of CYP2D6 variability will be very useful for future pharmacogenetic studies in the Brazilian population.

Practical guidelines for the use of new generation antipsychotic drugs (except clozapine) in adult individuals with intellectual disabilities

New generation antipsychotic (NGA) drugs introduced to the US market after clozapine (aripiprazole, olanzapine, paliperidone, quetiapine, risperidone, and ziprasidone) are frequently used in individuals with intellectual disabilities (ID). However, there is very limited research to fully establish evidence-based or personalized medicine approaches for their use in this population. These guidelines take a pragmatic approach to establishing frameworks for their use by utilizing the prescribing information and reviewing the available literature on other relevant neuropsychiatric disorders. In the absence of expert consensus guidance and well-controlled comparison trials, we present a set of guidelines to inform initiation, dosing and monitoring of use in adults. Further, in these guidelines we provide practical information on drug-drug interactions and adverse drug reactions, and a brief review of discontinuation syndromes, potential for abuse, use during pregnancy and cost considerations. We also provide drug utilization review forms for each NGA to facilitate implementation of these guidelines, these guidelines provide a practical and necessary resource for practitioners treating psychiatric disorders and challenging behaviors in adult individuals with ID.

CYP2D6 genotyping for psychiatric patients treated with risperidone: considerations for cost–effectiveness studies

In order to ascertain data availability and feasibility for conducting cost–effectiveness studies in pharmacogenetics, and as part of a European Commission Joint Research Center, Institute for Prospective Technological Studies (JRC-IPTS) study, data concerning risperidone use and cytochrome P450 (CYP2D6) genotyping in medical care was collected in Germany, Spain and the USA, and are summarized in this perspective. The gene coding for CYP2D6 is highly polymorphic, resulting in a significant part of the population being poor metabolizers and ultrarapid metabolizers. Individuals who are CYP2D6 poor metabolizers, have an increased risk of adverse drug reactions (ADRs) when treated with CYP2D6-metabolized drugs, suggesting that CYP2D6 genotyping might be beneficial for patient care. This might be especially important in psychiatry, where approximately 50% of the patients use at least one drug primarily metabolized by CYP2D6. In particular, ADRs and poor response to treatment are major problems for some antipsychotics, including risperidone. However, there are no published cost–effectiveness studies on CYP2D6 genotyping, and the benefit that pharmacogenetic testing might represent by identifying problematic patients is still unclear. The present European Commission study found that current clinical and economical data concerning the frequency and direct healthcare costs of risperidone-related ADRs, the relation of such ADRs with the patients CYP2D6 genotypes, and costs for CYP2D6 genotyping, are not sufficient for determining if routine CYP2D6 genotyping might be cost beneficial for patients treated with risperidone. Therefore, efforts should be put on performing prospective cost–benefit studies with randomized treatment according to the CYP2D6 genotype to establish the utility of CYP2D6 genotyping for personalizing antipsychotic treatment.

Pharmacogenetic testing in psychiatry: a review of features and clinical realities

This article focuses on the first generation of pharmacogenetic tests that are potentially useful in psychiatry. All pharmacogenetic tests currently on the market, or soon to be marketed in psychiatry, for which some information has been published in peer-reviewed journal articles (or abstracts), were selected. Five pharmacogenetic tests are reviewed in detail: the Roche AmpliChip CYP450 Test, the Luminex Tag-It Mutation Detection Kit, the LGC clozapine response test, the PGxPredict: Clozapine test, and the Genomas PhyzioType system. After reviewing these tests, three practical aspects of implementing pharmacogenetic testing in psychiatric clinical practice are briefly reviewed: (1) the evaluation of these tests in clinical practice, (2) cost-effectiveness, and (3) regulatory oversight. Finally, the future of these and other pharmacogenetic tests in psychiatry is discussed.

DNA microarray technology in the clinical environment: the AmpliChip CYP450 test for CYP2D6 and CYP2C19 genotyping

INTRODUCTION

An important technological advance in genetic testing is the DNA microarray, which allows for the simultaneous testing of thousands of DNA sequences. The AmpliChip CYP450 Test employs this microarray technology for cytochrome P450 (CYP) 2D6 and CYP2C19 genotyping. Isoenzymes encoded by these genes are responsible for the metabolism of many widely prescribed drugs. The objectives of this study were to identify CYP2D6 and CYP2C19 alleles and phenotypes in a psychiatric patient population in Kentucky, and to describe practical issues associated with DNA microarray technology.

METHODS

A total of 4,532 psychiatric patients were recruited from three state hospitals in Kentucky. Whole blood, buccal swabs, or saliva samples were genotyped with the AmpliChip CYP450 Test to derive a predicted phenotype.

RESULTS

In this cohort, the overall prevalence of CYP2D6 poor metabolizers was 7.6% (95% CI 7%, 8.3%), 8.2% in the Caucasians (95% CI 7.4%, 9.%) and 1.8% in the African Americans (95% CI 0.9%, 3.5%). The overall prevalence of CYP2D6 ultrarapid metabolizers was 1.5% (95% CI 1.2%, 1.9%), 1.5% in the Caucasians (95% CI 1.1%, 1.9%) and 2.0% in the African Americans (95% CI 1.1%, 3.7%). The overall prevalence of CYP2C19 poor metabolizers was 2.0% (95% CI 1.8%, 2.7%), 2.2% in Caucasians (95% CI 1.6%, 2.5%) and 4.0% in African Americans (95% CI 2.6%, 6.1%).

CONCLUSION

We also propose a numeric system for expression of CYP2D6 and CYP2C19 enzyme activity to aid clinicians in determining treatment strategy for patients receiving therapeutics that are metabolized by the CYP2D6 or CYP2C19 gene products.

Evolution of child mental health services in primary care

OBJECTIVE

Although the importance of mental health assessment and treatment in primary care is increasingly recognized, the research that underlies current practices largely stems from a considerable body of non-mental health primary care studies. Our purpose was to describe trends in research over the past 2 decades and to suggest further key items for the research agenda.

METHODS

We reviewed the literature broadly on health services research in pediatrics, especially studies of changes in primary care practice, and examined recent articles in primary care mental health services.

RESULTS

The evolution of primary care mental health services for children has been slow, but the focus of research has changed with the development of clinical improvements. Proposals to deliver more effective services have evolved over the past 40 years in a series of approaches that paralleled initiatives in the broader fields of medicine and pediatrics. Current trends in electronic technology, practice consolidation and coordination, and personalized medicine are likely to increase the pace of change in mental health services for primary care.

CONCLUSIONS

The evolution of pediatric mental health services in primary care suggests a continuing expansion from a focus initially on provider behavior and quality to a growing attention to patient and systems' behavior over time and within communities.

Pharmacogenomics: the promise of personalized medicine for CNS disorders

This review focuses first on the concept of pharmacogenomics and its related concepts (biomarkers and personalized prescription). Next, the first generation of five DNA pharmacogenomic tests used in the clinical practice of psychiatry is briefly reviewed. Then the possible involvement of these pharmacogenomic tests in the exploration of early clinical proof of mechanism is described by using two of the tests and one example from the pharmaceutical industry (iloperidone clinical trials). The initial attempts to use other microarray tests (measuring RNA expression) as peripheral biomarkers for CNS disorders are briefly described. Then the challenge of taking pharmacogenomic tests (compared to drugs) into clinical practice is explained by focusing on regulatory oversight, the methodological/scientific issues concerning diagnostic tests, and cost-effectiveness issues. Current information on medicine-based evidence and cost-effectiveness usually focuses on average patients and not the outliers who are most likely to benefit from personalized prescription. Finally, future research directions are suggested. The future of 'personalized prescription' in psychiatry requires consideration of pharmacogenomic testing and environmental and personal variables that influence pharmacokinetic and pharmacodynamic drug response for each individual drug used by each patient.

Pharmacogenetics in psychiatry: are we ready for widespread clinical use?

There are high expectations about the capabilities of pharmacogenetics to tailor psychotropic treatment and "personalize" treatment. While a large number of associations, with generally small effect size, have been discovered, a "test" with widespread use and adoption is still missing. A more realistic picture, recognizing the important contribution of clinical and environmental factors toward overall clinical outcome has emerged. In this emerging view, genetic findings, if considered individually, may have limited clinical applications. Thus, in recent years, combinations of information in several genes have been used for the selection of appropriate therapeutic doses and for the prediction of agranulocytosis, hyperlipidemia, and response to antipsychotic and antidepressant medications. While these tests based on multiple genes show greater predictive ability than individual allele tests, their net impact on clinical consequence and costs is limited, thus leading to limited penetration into widespread clinical use. As one looks at other branches of medicine, there are successful examples of pharmacogenetic tests guiding treatment, and thus, it is reasonable to hope that with the incorporation of clinical and environmental information and the identification of new genes drawn from genome-wide analysis, will improve the predictive utility of these tests leading to their increased use by clinicians.