Candidate genes for antidepressant response to selective serotonin reuptake inhibitors

Models for depression recognition and efficacy assessment based on clinical and sequencing data

Major depression is a complex psychiatric disorder that includes genetic, neurological, and cognitive factors. Early detection and intervention can prevent progression, and help select the best treatment. Traditional clinical diagnosis tends to be subjective and misdiagnosed. Based on this, this study leverages clinical scale assessments and sequencing data to construct disease prediction models. Firstly, data undergoes preprocessing involving normalization and other requisite procedures. Feature engineering is then applied to curate subsets of features, culminating in the construction of a model through the implementation of machine learning and deep learning algorithms. In this study, 18 features with significant differences between patients and healthy controls were selected. The depression recognition model was constructed by deep learning with an accuracy of 87.26 % and an AUC of 91.56 %, which can effectively distinguish patients with depression from healthy controls. In addition, 33 features selected by recursive feature elimination method were used to construct a prognostic effect model of patients after 2 weeks of treatment, with an accuracy of 75.94 % and an AUC of 83.33 %. The results show that the deep learning algorithm based on clinical and sequencing data has good accuracy and provides an objective and accurate method for the diagnosis and pharmacodynamic prediction of depression. Furthermore, the selected differential features can serve as candidate biomarkers to provide valuable clues for diagnosis and efficacy prediction.

Psychedelic Therapy: A Primer for Primary Care Clinicians-The Strengths, Weaknesses, Opportunities, and Threats of Psychedelic Therapeutics

The reviews in this special edition have presented a primer on the state of the literature for 7 different psychedelic compounds and their plausible roles in medicine. In a common format underscoring strengths, weakness, opportunities, and threats (SWOT), this article addresses how psychedelic compounds fit into the broader health care landscape for indicated conditions. Historically, psychiatric pathologies have been treated with small-molecule compounds that have limited effect sizes and carry a variety of adverse effect profiles. Psychedelic medicines offer the opportunity to provide more potent and rapidly acting treatments. It is crucial to note that this is an emerging field of medicine, and only one of these compounds (esketamine) is currently Food and Drug Administration-approved for depression. The other compounds discussed are investigational, and this discussion is both imaginative and prospective in nature.

Review on Surface-Modified Electrodes for the Enhanced Electrochemical Detection of Selective Serotonin Reuptake Inhibitors (SSRIs)

Selective serotonin re-uptake inhibitors (SSRIs) are one of the most commonly prescribed classes of antidepressants used for the treatment of moderate to severe depressive disorder, personality disorders and various phobias. This class of antidepressants was created with improved margins of safety. However, genetic polymorphism may be responsible for the high variability in patients' responses to treatment, ranging from failure to delayed therapeutic responses to severe adverse effects of treatment. It is crucial that the appropriate amount of SSRI drugs is administered to ensure the optimum therapeutic efficacy and intervention to minimise severe and toxic effects in patients, which may be the result of accidental and deliberate cases of poisoning. Determining SSRI concentration in human fluids and the environment with high sensitivity, specificity and reproducibility, and at a low cost and real-time monitoring, is imperative. Electrochemical sensors with advanced functional materials have drawn the attention of researchers as a result of these advantages over conventional techniques. This review article aims to present functional materials such as polymers, carbon nanomaterials, metal nanomaterials as well as composites for surface modification of electrodes for sensitive detection and quantification of SSRIs, including fluoxetine, citalopram, paroxetine, fluvoxamine and sertraline. Sensor fabrication, sensor/analyte interactions, design rationale and properties of functional material and the electrocatalytic effect of the modified electrode on SSRI detection are discussed.

Are the epigenetic changes predictive of therapeutic efficacy for psychiatric disorders? A translational approach towards novel drug targets

The etiopathogenesis of mental disorders is not fully understood and accumulating evidence support that clinical symptomatology cannot be assigned to a single gene mutation, but it involves several genetic factors. More specifically, a tight association between genes and environmental risk factors, which could be mediated by epigenetic mechanisms, may play a role in the development of mental disorders. Several data suggest that epigenetic modifications such as DNA methylation, post-translational histone modification and interference of microRNA (miRNA) or long non-coding RNA (lncRNA) may modify the severity of the disease and the outcome of the therapy. Indeed, the study of these mechanisms may help to identify patients particularly vulnerable to mental disorders and may have potential utility as biomarkers to facilitate diagnosis and treatment of psychiatric disorders. This article summarizes the most relevant preclinical and human data showing how epigenetic modifications can be central to the therapeutic efficacy of antidepressant and/or antipsychotic agents, as possible predictor of drugs response.

Serotonergic receptor gene polymorphism and response to selective serotonin reuptake inhibitors in ethnic Malay patients with first episode of major depressive disorder

The polymorphisms of the 5HTR1A and 5HTR2A receptor genes (rs6295C/G and rs6311G/A) have been evaluated for association with SSRI treatment outcome in various populations with different results. The present study was carried out to determine the association between genotypes of HTR1A-rs6295 and HTR2A-rs6311 with SSRI treatment outcome among the ethnic Malay patients diagnosed with first-episode major depressive disorder (MDD). The patients were recruited from four tertiary hospitals in the Klang Valley region of Malaysia. Predefined efficacy phenotypes based on 25% (partial early response) and 50% (clinical efficacy response) reduction in Montgomery Asberg Depression Rating Scale-self Rated score (MADRS-S) were adopted for assessment of treatment efficacy in this study. Self-reporting for adverse effects (AE) was documented using the Patient Rated Inventory of Side Effect (PRISE) after treatment with SSRI for up to 6 weeks. Adjusted binary logistic regression between genotypes of the polymorphism obtained using sequencing technique with the treatment outcome phenotypes was performed. The 142 patients recruited were made up of 96 females (67.6%) and 46 males (32.4%). Clinical efficacy and Partial early response phenotypes were not significantly associated with genotypes of HTR1A and HTR2A polymorphism. The GG genotype of HTR2A polymorphism has decreased odds for dizziness (CNS) and increased odds for poor concentration. The GA genotype increases the odd for excessive sweating, diarrhoea, constipation and blurred vision. The CC genotype of HTR1A-rs6295 decreases the odd for nausea/vomiting and increases the odd for anxiety. Thus, some genotypes of HTR1A and HTR2A polymorphism were associated with SSRI treatment outcomes in ethnic Malay MDD patients.

The Relationship between DNA Methylation and Antidepressant Medications: A Systematic Review

Major depressive disorder (MDD) is the leading cause of disability worldwide and is associated with high rates of suicide and medical comorbidities. Current antidepressant medications are suboptimal, as most MDD patients fail to achieve complete remission from symptoms. At present, clinicians are unable to predict which antidepressant is most effective for a particular patient, exposing patients to multiple medication trials and side effects. Since MDD’s etiology includes interactions between genes and environment, the epigenome is of interest for predictive utility and treatment monitoring. Epigenetic mechanisms of antidepressant medications are incompletely understood. Differences in epigenetic profiles may impact treatment response. A systematic literature search yielded 24 studies reporting the interaction between antidepressants and eight genes (BDNF, MAOA, SLC6A2, SLC6A4, HTR1A, HTR1B, IL6, IL11) and whole genome methylation. Methylation of certain sites within BDNF, SLC6A4, HTR1A, HTR1B, IL11, and the whole genome was predictive of antidepressant response. Comparing DNA methylation in patients during depressive episodes, during treatment, in remission, and after antidepressant cessation would help clarify the influence of antidepressant medications on DNA methylation. Individuals’ unique methylation profiles may be used clinically for personalization of antidepressant choice in the future.

Adenylyl cyclase 7 and neuropsychiatric disorders: A new target for depression?

Adenylyl cyclases (ACs) are enzymes that catalyze the production of cyclic adenosine monophosphate (cAMP) from adenosine triphosphate (ATP). Humans express nine isoforms of membranous ACs and a soluble AC. Studies with genetic knockout or overexpression rodent models have indicated that AC isoforms may be targeted to achieve specific therapeutic outcomes. AC1, for instance, has been suggested and pursued as a target for relieving pain. Notably, previous studies examining genetically modified mice as well as human genetic polymorphisms have suggested a link between AC7 activity and depressive disorders. In the present review we present an overview on AC function and discuss the most recent developments to target AC isoforms for drug therapies. We next focus on discussing the available literature on the molecular and animal pharmacology of AC7 highlighting the available studies on the role of AC7 in depressive disorders. In addition, we discuss other possible physiological functions of AC7 relating to ethanol effects and the immune system and conclude with considerations about pharmacological modulation of AC7.

HTR1A/1B DNA methylation may predict escitalopram treatment response in depressed Chinese Han patients

BACKGROUND

The serotonin receptor 1A and 1B (HTR1A/1B) gene have been suggested to be involved in the pathogenesis of major depressive disorder (MDD) and the antidepressant treatment response. Gene expression differences were partly mediated by genetic polymorphism and DNA methylation which might be affected by environmental factors. In the present study, we attempt to identify whether HTR1A/1B DNA methylation and genetic polymorphism could predict antidepressant treatment response.

METHODS

85 Chinese Han MDD patients were clinically assessed 8 weeks after of initiating escitalopram treatment for the first time. Antidepressant treatment response was assessed by changes in the Hamilton Depression Rating Scale-17 items (HAMD-17) score. The Life Events Scale (LES) and the Childhood Trauma Questionnaire (CTQ) were utilized as the assessment of previous life stress. The Illumina HiSeq platform was used to assess DNA methylation at 96 CpG sites located in HTR1A and HTR1B gene promoter regions. Six single nucleotide polymorphisms (SNPs) (HTR1A rs6294, rs116985176; HTR1B rs6296, rs6298, rs1228814, rs1778258) were genotype by using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) or PCR sequencing. Regression analyses were used to explore the relationship between DNA methylation and SNP and antidepressant response.

RESULTS

We identified two CpG sites predictor of antidepressant treatment response (CpG 668, amplicon HTR1A_1, NC_000005.10, P = 0.025; CpG 1401, amplicon HTR1B_4, NC_000006.12, P = 0.033). The interaction of four CpG sites hypomethylation of HTR1A/1B with high recent stress might result in impaired antidepressant treatment response. What's more, the present data indicated that age, environments and antidepressant treatment might affect DNA methylation status. It was found that DNA methylation status could be influenced by antidepressant treatment in turn. However, HTR1A and HTR1B genotypes did not influence antidepressant response and DNA methylation status.

CONCLUSIONS

The results suggest that HTR1A/1B DNA hypomethylation and its interaction with recent life stress might drive impaired antidepressant treatment response. Meanwhile, DNA methylation, in turn, was modified by antidepressant treatment and environments. Our results offer new evidence for the role of epigenetic and genetic polymorphism in pharmacological response to antidepressants.

Polymorphisms of 5-HTT LPR and GNβ3 825C>T and Response to Antidepressant Treatment in Functional Dyspepsia: A Study from The Functional Dyspepsia Treatment Trial

OBJECTIVES

The Functional Dyspepsia Treatment Trial reported that amitriptyline (AMI) was associated with adequate relief of functional dyspepsia (FD) symptoms, but the pharmacogenetics of antidepressant response in FD are not known. GNβ3 825C>T CC genotype has been previously linked to FD and TT genotype to antidepressant response in depression. The ss genotype of the 5-HTT LPR variant of the serotonin transporter gene (SLC6A4) has been linked to selective serotonin reuptake inhibitor (SSRI) response. We aimed to examine whether GNβ3 825C>T and 5-HTT LPR polymorphisms result in differential treatment effects in FD patients receiving antidepressant therapy.

METHODS

Participants were randomized to receive placebo, 50 mg AMI, or 10 mg escitalopram (ESC). The primary end point was adequate relief for ≥5 weeks of the last 10 weeks. Genotyping of GNβ3 825C>T and 5-HTT LPR was performed utilizing PCR-based methods.

RESULTS

GNβ3 825C>T and 5-HTT LPR genotype data were available for 256 (88%) and 246 (84%) patients, respectively. Both polymorphisms were in Hardy-Weinberg equilibrium. In tests for differential treatment, neither 5-HTT LPR nor GNβ3 825C>T genotype influenced response to therapy (P=0.89 and P=0.54, respectively). Although there was a tendency for a more favorable response to ESC in the SS/LS genotype compared to the LL genotype groups (40% vs. 31% reporting adequate relief of FD symptoms) among those in the ESC treatment arm, this was not significant (P=0.43).

CONCLUSIONS

GNβ3 825C>T and 5-HTT LPR genetic variants do not alter treatment response to tricyclic and SSRI antidepressants in FD.

Epigenetic and genetic variants in the HTR1B gene and clinical improvement in children and adolescents treated with fluoxetine

The serotonin 1B receptor (5-HT_1B) is important to both the pathogenesis of major depressive disorder and the antidepressant effects of selective serotonin reuptake inhibitors. Although fluoxetine has been shown to be effective and safe in children and adolescents, not all patients experience a proper clinical response, which has led to further study into the main factors involved in this inter-individual variability. Our aim was to study the effect of epigenetic and genetic factors that could affect 5-hydroxytryptamine receptor 1B (HTR1B) gene expression, and thereby response to fluoxetine. A total of 83 children and adolescents were clinically assessed 12weeks after of initiating an antidepressant treatment with fluoxetine for the first time. We evaluated the influence of single nucleotide polymorphisms (SNPs) specifically located in transcription factor binding sites (TFBSs) on their clinical improvement. A combined genetic analysis considering the significant SNPs together with the functional variant rs130058 previously associated in our population was also performed. Moreover, we assessed, for the first time in the literature, whether methylation levels of the HTR1B promoter region could be associated with the pharmacological response. Two, rs9361233 and rs9361235, were significantly associated with clinical improvement after treatment with fluoxetine. The heterozygous genotype combination analysis showed a negative correlation with clinical improvement. The lowest improvement was experienced by patients who were heterozygous for all three SNPs. Moreover, a negative correlation was found between clinical improvement and the average methylation level of the HTR1B promoter. These results give new evidence for the role of epigenetic and genetic factors which could modulate HTR1B expression in the pharmacological response to antidepressants.

Delineation of molecular pathway activities of the chronic antidepressant treatment response suggests important roles for glutamatergic and ubiquitin-proteasome systems

The aim of this study was to identify molecular pathways related to antidepressant response. We administered paroxetine to the DBA/2J mice for 28 days. Following the treatment, the mice were grouped into responders or non-responders depending on the time they spent immobile in the forced swim test. Hippocampal metabolomics and proteomics analyses revealed that chronic paroxetine treatment affects glutamate-related metabolite and protein levels differentially in the two groups. We found significant differences in the expression of N-methyl-d-aspartate receptor and neuronal nitric oxide synthase proteins between the two groups, without any significant alterations in the respective transcript levels. In addition, we found that chronic paroxetine treatment altered the levels of proteins associated with the ubiquitin-proteasome system (UPS). The soluble guanylate cyclase-β1, proteasome subunit α type-2 and ubiquitination levels were also affected in peripheral blood mononuclear cells from antidepressant responder and non-responder patients suffering from major depressive disorder. We submit that the glutamatergic system and UPS have a crucial role in the antidepressant treatment response in both mice and humans.

Common selective serotonin reuptake inhibitor side effects in older adults associated with genetic polymorphisms in the serotonin transporter and receptors: data from a randomized controlled trial

OBJECTIVE

Antidepressant side effects are a significant public health issue, associated with poor adherence, premature treatment discontinuation, and, rarely, significant harm. Older adults assume the largest and most serious burden of medication side effects. We investigated the association between antidepressant side effects and genetic variation in the serotonin system in anxious, older adults participating in a randomized, placebo-controlled trial of the selective serotonin reuptake inhibitor (SSRI) escitalopram.

METHODS

Adults (N = 177) aged ≥ 60 years were randomized to active treatment or placebo for 12 weeks. Side effects were assessed using the Udvalg fur Kliniske Undersøgelser side-effect rating scale. Genetic polymorphisms were putative functional variants in the promoters of the serotonin transporter and 1A and 2A receptors (5-HTTLPR [L/S + rs25531], HTR1A rs6295, HTR2A rs6311, respectively).

RESULTS

Four significant drug-placebo side-effect differences were found: increased duration of sleep, dry mouth, diarrhea, and diminished sexual desire. Analyses using putative high- versus low-transcription genotype groupings revealed six pharmacogenetic effects: greater dry mouth and decreased sexual desire for the low- and high-expressing serotonin transporter genotypes, respectively, and greater diarrhea with the 1A receptor low-transcription genotype. Diminished sexual desire was experienced significantly more by high-expressing genotypes in the serotonin transporter, 1A, or 2A receptors. There was not a significant relationship between drug concentration and side effects nor a mean difference in drug concentration between low- and high-expressing genotypes.

CONCLUSION

Genetic variation in the serotonin system may predict who develops common SSRI side effects and why. More work is needed to further characterize this genetic modulation and to translate research findings into strategies useful for more personalized patient care.

Concomitant interferon alpha stimulation and TLR3 activation induces neuronal expression of depression-related genes that are elevated in the brain of suicidal persons

We have previously identified 15 genes that are associated with the development of severe depressive side effects during the standard therapy with interferon alpha and ribavirin in the peripheral blood of hepatitis C virus infected patients. An enhanced expression of these genes was also found in the blood of psychiatric patients suffering severe depressive episode. Herein, we demonstrate that the same depression-related interferon-inducible genes (DRIIs) are also upregulated in post-mortem brains of suicidal individuals. Using cultured mouse hippocampal and prefrontal neurons we show that costimulation with murine IFN (mIFN) and the TLR3 agonist poly(I:C) promotes the expression of the described DRIIs, at the same time inducing pro-inflammatory cytokine expression through Stat1 and Stat3 activation, promoting neuronal apoptosis. Consequently, the upregulation of selective DRIIs, production of inflammatory cytokines and inhibition of neuronal plasticity may be involved in the pathogenesis of IFN-associated depression.

Aging and Clinical Pharmacology: Implications for Antidepressants

The elderly frequently have changes in pharmacokinetics, sensitivity to medications, homeostatic reserve (ability to tolerate physiological challenges), exposure to multiple medications, and adherence. All of these age-associated factors can potentially influence total exposure to medication, adverse effects, and subsequent treatment outcome. Most clinical trials are performed with healthy, younger adults. Extrapolating the results of these trials to the elderly may be inappropriate, particularly for the antidepressant treatment of depression. The authors review these age-associated differences and discuss their implications for antidepressant use in older adults.

Escitalopram reduces attentional performance in anxious older adults with high-expression genetic variants at serotonin 2A and 1B receptors

Older adults are among the most vulnerable to adverse cognitive effects of psychotropic medications and, therefore, the personalization of psychotropic treatment based on adverse drug reactions in this demographic is of great importance. We examined changes on neuropsychological tests of attention attributable to selective serotonin reuptake inhibitor (SSRI) treatment in anxious older adults. We also examined whether variation in serotonin receptor genes was associated with reduced attentional performance with SSRIs. We examined change from pre- to post-treatment in two attention measures - digit span and coding - in 133 adults aged ≥60 yr with generalized anxiety disorder in a 12-wk trial of escitalopram vs. placebo. We also examined attentional change in relation to genetic variability in four central serotonin receptors: the serotonin transporter and serotonin 1A, 2A and 1B receptors. Digit span scores were significantly lowered in patients receiving escitalopram relative to placebo, indicating reduced attentional performance attributable to the SSRI. Individuals with high-transcription variants in the receptors 5-HTR2A rs6311 and 5-HTR1B rs11568817 had greater reductions in attention with SSRI treatment compared to placebo. We conclude that SSRIs reduce attention in older adults, particularly in those with high-expression genetic variants at the serotonin 2A and 1B receptors. Analysing neuropsychological changes with SSRIs in relation to genetic variation in the serotonin system may be a useful strategy for detecting subgroups of older adults who are more susceptible to side-effects of SSRIs. These results, if confirmed, could lead to the personalization of SSRI use to reduce adverse neurocognitive effects.

Influence and interaction of genetic polymorphisms in the serotonin system and life stress on antidepressant drug response

Variation in genes implicated in serotonin neurotransmission may interact with environmental factors to influence antidepressant response. We aimed to determine how a range of polymorphisms in serotonergic genes determine this response to treatment and how they interact with childhood trauma and recent life stress in a Chinese sample. In total, 14 single nucleotide polymorphisms (SNPs) in coding regions of 10 serotonergic genes (HTR1A, HTR1B, HTR1D, HTR2A, HTR3A, HTR3C, HTR3D, HTR3E, HTR5A and TPH2) were genotyped in 308 Chinese Han patients with major depressive disorder. Response to 6 weeks' antidepressant treatment was determined by change in the 17-item Hamilton Depression Rating Scale (HDRS-17) score, and previous stressful events were evaluated by the Life Events Scale (LES) and Childhood Trauma Questionnaire-Short Form (CTQ-SF). Two 5-HT1B receptor SNPs (rs6296 and rs6298) and one tryptophan hydroxylase2 (rs7305115) SNP were significantly associated with antidepressant response in this Chinese sample, as was a haplotype in TPH2 (rs7305115 and rs4290270). A gene-gene interaction on antidepressant response was found between SNPs in HTR1B, HTR3A and HTR5A in female subjects. The HTR1B SNPs demonstrated interaction with recent stress, while that for TPH2 interacted with childhood trauma to influence antidepressant response.

Application of pharmacogenomics to clinical problems in depression

The goal of this article is to review the literature for evidence supporting an association between polymorphisms within drug target genes and clinical outcomes for treating depression, with a purpose to identify a research area having the most promising potential to be introduced into clinical settings, and thus, discussing the perspectives of genotyping in antidepressant therapy. A total of 67 articles were identified. Polymorphic sites within the serotonin transporter gene promoter, 5-HTTLPR, were the most studied polymorphisms. All except three articles were designed as cohort studies. The other three articles included two meta-analyses and one decision-analytic model. The main finding from these meta-analyses was that the l variant was associated with a better response to selective serotonin reuptake inhibitors. The main conclusion from the decision-analytic model study was that performing genetic testing before prescribing antidepressant treatment may lead to greater numbers of patients experiencing remission early in treatment. Clinical outcomes of genotyping this polymorphism were evaluated by improvement of depression score, odds ratio and absolute risk reduction.

Depression and antidepressants: molecular and cellular aspects

Clinical depression is viewed as a physical and psychic disease process having a neuropathological basis, although a clear understanding of its ethiopathology is still missing. The observation that depressive symptoms are influenced by pharmacological manipulation of monoamines led to the hypothesis that depression results from reduced availability or functional deficiency of monoaminergic transmitters in some cerebral regions. However, there are limitations to current monoamine theories related to mood disorders. Recently, a growing body of experimental data has showed that other classes of endogenous compounds, such as neuropeptides and amino acids, may play a significant role in the pathophysiology of affective disorders. With the development of neuroscience, neuronal networks and intracellular pathways have been identified and characterized, describing the existence of the interaction between monoamines and receptors in turn able to modulate the expression of intracellular proteins and neurotrophic factors, suggesting that depression/antidepressants may be intermingled with neurogenesis/neurodegenerative processes.

Pharmacogenetics and the serotonin transporter in late-life depression

BACKGROUND

The etiologies of variable antidepressant response remain elusive. Aging and age-related illness add to the complexity and heterogeneity of late-life depression. The serotonin transporter (5-HTT) is the principal site of initial action for several antidepressants, including serotonin re-uptake inhibitors (SSRIs). The serotonin transporter-linked polymorphic region (5-HTTLPR) is the most widely studied polymorphism of the 5-HTT gene, SLC6A4, and is suspected of conferring vulnerability to elderly depression and resistance to treatment.

OBJECTIVE

To present an up-to-date account of the influence of 5-HTT polymorphisms on elderly depression, antidepressant response and susceptibility to medication side effects.

METHOD

A Medline search (1993 - 2008) of 5-HTT gene variation studies and analyses that included elderly depressed subjects was performed using the terms: 'serotonin transporter'; '5-HTT'; 'SERT'; '5-HTTLPR'; 'late-life depression'; 'elderly depression'; 'geriatric depression'; 'antidepressants' and 'SSRIs'. Reference sections were gleaned for relevant articles that may have been overlooked by the search strategy.

CONCLUSION

5-HTTLPR may influence treatment response variability in late-life depression in a number of ways. Indirectly, 5-HTTLPR seems to influence the likelihood of adverse effects and non-adherence. Directly, the promoter region may contribute to response variability during the initial stages of treatment, which is explained, in part, by a gene-concentration interaction for paroxetine. Subjects with the S allele may be at an increased risk of adverse drug reactions and may require higher initial SSRI plasma concentrations to maximize response. Conversely, patients with the L/L genotype may respond even at lower concentrations.

Serotonin transporter genotype interacts with paroxetine plasma levels to influence depression treatment response in geriatric patients

OBJECTIVE

To investigate whether variable antidepressant response may be influenced by an interaction between the serotonin transporter promoter polymorphism (5-HTTLPR) and antidepressant concentration.

METHODS

Elderly subjects with depression treated with paroxetine (n = 110) were genotyped and assessed with the Hamilton Rating Scale for Depression (HAMD). A mixed-effect analysis of repeated measures was used.

RESULTS

There was an interaction between early paroxetine concentration and 5-HTTLPR genotype on symptomatic improvement over 12 weeks (F(18,59.5) = 1.8, p < 0.05), as well as main effects of both paroxetine concentration (F(68,55.3) = 2.4, p < 0.005) and genotype (F(2,74.2) = 5.7, p < 0.005). Paroxetine concentrations were correlated with change in HAMD scores after 2 weeks of treatment in subjects with the short (s) allele (r = 0.31, p < 0.05) but not in subjects homozygous for the long (l) allele.

CONCLUSION

The results demonstrate a concentration-response relation for paroxetine in late-life depression and support the hypothesis for both a direct main effect and a moderating influence of 5-HTTLPR alleles on this concentration-response relation.

Translational research in late-life mood disorders: implications for future intervention and prevention research

Clinical and epidemiological studies have consistently observed the heterogeneous symptomatology and course of geriatric depression. Given the importance of genetic and environmental risk factors, aging processes, neurodegenerative and cerebrovascular disease processes, and medical comorbidity, the integration of basic and clinical neuroscience research approaches is critical for the understanding of the variability in illness course, as well as the development of prevention and intervention strategies that are more effective. These considerations were the impetus for a workshop, sponsored by the Geriatrics Research Branch in the Division of Adult Translational Research and Treatment Development of the National Institute of Mental Health that was held on September 7-8, 2005. The primary goal of the workshop was to bring together investigators in geriatric psychiatry research with researchers in specific topic areas outside of geriatric mental health to identify priority areas to advance translational research in geriatric depression. As described in this report, the workshop focused on a discussion of the development and application of integrative approaches combining genetics and neuroimaging methods to understand such complex issues as treatment response variability, the role of medical comorbidity in depression, and the potential overlap between depression and dementia. Future directions for integrative research were identified. Understanding the nature of geriatric depression requires the application of translational research and interdisciplinary research approaches. Geriatric depression could serve as a model for translational research integrating basic and clinical neuroscience approaches that would have implications for the study of other neuropsychiatric disorders.

Potential cognitive enhancing and disease modification effects of SSRIs for Alzheimer's disease

OBJECTIVE

Selective serotonin reuptake inhibitors (SSRIs) have increased cognitive performance in some clinical studies of Alzheimer's disease (AD), but it is has been difficult to dissociate whether this is due to direct effects on cognition (neurochemical or disease-modifying) or a secondary effect of mood stabilization. We performed a systematic review for preclinical and human clinical trial evidence to support the use of SSRIs specifically for the management of cognitive decline in AD.

DATA SOURCES

(1) PUBMED without language restrictions from 1950s until 2004 and updated August 2006, terms: "serotonin uptake inhibitors"[MeSH] AND ("Alzheimer disease"[MeSH] OR "Cognition Disorders"[MeSH]) NOT "Parkinson disease"[MeSH] AND (Clinical Trial[ptyp] OR Letter[ptyp] OR Meta-Analysis[ptyp] OR Randomized Controlled Trial[ptyp]) AND "alzheimer disease" [MESH] OR "Alzheimer*" combined with AND to "ssri*" OR "serotonin reuptake inhibitors" [MESH] NOT Review[ptyp]. (2) Cochrane Database of Systematic Reviews, keywords "SSRI" and "Alzheimer's".

STUDY SELECTION

The PubMed search yielded 57 hits. Of these, 23 were included in this review for their specificity to SSRI use in AD or indications on efficacy beyond depressive symptoms. The other 34 citations were excluded because: (1) depression or other mood or behavioral disturbance severity was the reported outcome measure, (2) effects of SSRIs on cognition were confounded by concomitant use of other drugs, (3) subjects described were young adults, and/or (4) subjects had traumatic brain injury. The Cochrane Database of Systematic Reviews, 3rd Quarter 2006, yielded six citations related to SSRIs.

DATA EXTRACTION

Data extracted from clinical trials included name of SSRI tested, cognitive outcome measures, and adverse events reported, which could include cognitive worsening.

DATA SYNTHESIS

Preclinical evidence for use of SSRIs to enhance cognition in AD includes an effect at the hippocampus through carbonic anhydrase activation or stimulation of hippocampal neurogenesis. The chemical structure of paroxetine, and not intrinsic SSRI activity, may also affect APP ectodomain expression to reduce amyloid plaque formation. Clinical trials in AD generally have not assessed cognitive outcomes independently from mood or behavior stabilization. Currently, clinical studies in AD only indirectly support the use of SSRIs for disease modification by confirming a serotonergic deficit during the course of illness.

CONCLUSIONS

Lack of supportive evidence for SSRIs as cognition enhancers or disease modifiers in AD is the result of omissions in clinical trial design, as opposed to reporting of negative outcomes. The preclinical evidence warrants the study of SSRIs in AD using mood, behavior, cognition, neurochemistry, and possibly neuroimaging as outcome variables.

Sex steroid hormone gene polymorphisms and depressive symptoms in women at midlife

Single nucleotide polymorphism (SNP) genotype frequencies were examined to determine whether variation in 6 estrogen-related genes was associated with differences in self-reported depressive symptoms in women. In this substudy of the Study of Women's Health Across the Nation (SWAN), DNA from a multiracial/multiethnic sample of 1,538 African American, Caucasian, Chinese, and Japanese women aged 42 to 52 years participating in SWAN was genotyped. Depressive symptoms were measured with the Center for Epidemiologic Studies-Depression (CES-D) scale. After excluding data from women taking antidepressants (n=103), statistical models were fit using multivariate logistic regression to predict the association of estrogen-related polymorphisms with the dichotomized CES-D score. Among Caucasian women, those with the CYP1A1 rs2606345 CC and AC genotypes had approximately 2-fold greater odds of having depressive symptoms than did those with the AA genotype (95% confidence intervals [CIs], 1.33 to 4.66 and 1.25 to 3.14, respectively). African American women with the CC genotype of the same SNP had 10-fold greater odds of having more depressive symptoms than did women with the AA genotype (95% CI, 1.20 to 86.20). In Japanese women, the odds of depressive symptoms were nearly 5-fold higher among those with CYP 19 rs936306 TT genotype (95% CI, 1.10 to 22.17) than in women with the CC genotype and 9.6-fold higher (95% CI, 2.01 to 45.81) than in women with the CT genotype. The odds of depressive symptoms among Chinese women with the 17HSD rs615942 TT genotype were nearly 11-fold higher than in those with the GT genotype (95% CI, 1.94 to 60.84) and >7-fold higher than in those with the GG genotype (95% CI, 1.13 to 51.82). These data provide evidence that selected genes involved in estrogen synthesis and metabolism increase the odds of more depressive symptoms in women who are premenopausal or perimenopausal.

Multi-target strategies for the improved treatment of depressive states: Conceptual foundations and neuronal substrates, drug discovery and therapeutic application

Major depression is a debilitating and recurrent disorder with a substantial lifetime risk and a high social cost. Depressed patients generally display co-morbid symptoms, and depression frequently accompanies other serious disorders. Currently available drugs display limited efficacy and a pronounced delay to onset of action, and all provoke distressing side effects. Cloning of the human genome has fuelled expectations that symptomatic treatment may soon become more rapid and effective, and that depressive states may ultimately be "prevented" or "cured". In pursuing these objectives, in particular for genome-derived, non-monoaminergic targets, "specificity" of drug actions is often emphasized. That is, priority is afforded to agents that interact exclusively with a single site hypothesized as critically involved in the pathogenesis and/or control of depression. Certain highly selective drugs may prove effective, and they remain indispensable in the experimental (and clinical) evaluation of the significance of novel mechanisms. However, by analogy to other multifactorial disorders, "multi-target" agents may be better adapted to the improved treatment of depressive states. Support for this contention is garnered from a broad palette of observations, ranging from mechanisms of action of adjunctive drug combinations and electroconvulsive therapy to "network theory" analysis of the etiology and management of depressive states. The review also outlines opportunities to be exploited, and challenges to be addressed, in the discovery and characterization of drugs recognizing multiple targets. Finally, a diversity of multi-target strategies is proposed for the more efficacious and rapid control of core and co-morbid symptoms of depression, together with improved tolerance relative to currently available agents.