Differences in efficacy and safety of pharmaceutical treatments between men and women: an umbrella review

Sex-dependent astrocyte reactivity: Unveiling chronic stress-induced morphological changes across multiple brain regions

Chronic stress is a major precursor to various neuropsychiatric disorders and is linked with increased inflammation in the brain. However, the bidirectional association between inflammation and chronic stress has yet to be fully understood. Astrocytes are one of the key inflammatory regulators in the brain, and the morphological change in reactive astrocytes serves as an important indicator of inflammation. In this study, we evaluated the sex-specific astrocyte response to chronic stress or systemic inflammation in key brain regions associated with mood disorders. We conducted the unpredictable chronic mild stress (UCMS) paradigm to model chronic stress, or lipopolysaccharide (LPS) injection to model systemic inflammation. To evaluate stress-induced morphological changes in astrocyte complexity, we measured GFAP fluorescent intensity for astrocyte expression, branch bifurcation by quantifying branch points and terminal points, branch arborization by conducting Sholl analysis, and calculated the ramification index. Our analysis indicated that chronic stress-induced morphological changes in astrocytes in all brain regions investigated. The effects of chronic stress were region and sex specific. Notably, females had greater stress or inflammation-induced astrocyte activation in the hypothalamus (HYPO), CA1, CA3, and amygdala (AMY) than males. These findings indicate that chronic stress induces astrocyte activation that may drive sex and region-specific effects in females, potentially contributing to sex-dependent mechanisms of disease.

Gender differences in the association between body mass index and recent suicide attempts in Chinese patients with first-episode drug-naïve major depressive disorder

Controversial evidence exists on the relationship between body mass index (BMI) and suicide attempts (SA) in patients with major depressive disorder (MDD). This cross-sectional study aimed to explore the association between BMI and SA in first-episode drug-naïve (FEDN) MDD patients in China. The study was conducted from 2016 to 2018 in Taiyuan, China. Univariate and multivariate logistic regression analyzed the BMI-SA association, with subgroup analysis for gender. Threshold effects were examined using two-piecewise regression. In males, BMI was significantly associated with SA (OR = 0.84, 95% CI 0.74-0.94, P = 0.003) after full adjustment, but not in females (OR = 0.97, 95% CI 0.89-1.06, P = 0.541). The interaction with gender was significant (P for interaction < 0.05). Smoothing plots revealed an L-shaped BMI-SA relationship in both genders, with BMI inflection points at 27.3 kg/m2 in males and 21.4 kg/m2 in females. Below the inflection points, BMI is negatively associated with SA in males (OR = 0.75, 95% CI 0.66-0.86, P < 0.001) and females (OR = 0.48, 95% CI 0.32-0.72, P < 0.001). Above the inflection points, no association existed for both genders (all P > 0.05). Results showed an L-shaped nonlinear BMI-SA relationship in FEDN MDD patients but differing BMI inflection points between genders, thus contributing to effective prevention programs for suicide.

Sex blind: bridging the gap between drug exposure and sex-related gene expression in Danio rerio using next-generation sequencing (NGS) data and a literature review to find the missing links in pharmaceutical and environmental toxicology studies

The sex of both humans and Danio rerio has previously been shown to affect the way individuals respond to drug exposure. Genes which allow identification of sex in juvenile zebrafish show potential to reveal these confounding variables between sex in toxicological and preclinical trials but the link between these is so far missing. These sex-specific, early expressed genes where expression is not altered by drug exposure must be carefully selected for this purpose. We aimed to discover genes which can be used in pharmaceutical trials and environmental toxicology studies to uncover sex-related variations in gene expression with drug application using the model organism Danio rerio. Previously published early sex determining genes from King et al. were evaluated as well as additional genes selected from our zebrafish Next-generation sequencing (NGS) data which are known from previously published works not to be susceptible to changes in expression with drug exposure. NGS revealed a further ten female-specific genes (vtg1, cyp17a1, cyp19a1a, igf3, ftz-f1, gdf9, foxl2a, Nr0b1, ipo4, lhcgr) and five male related candidate genes (FKBP5, apobb1, hbaa1, dmrt1, spata6) which are also expressed in juvenile zebrafish, 28 days post fertilisation (dpf). Following this, a literature review was performed to classify which of these early-expressed sex specific genes are already known to be affected by drug exposure in order to determine candidate genes to be used in pharmaceutical trials or environmental toxicology testing studies. Discovery of these early sex-determining genes in Danio rerio will allow identification of sex-related responses to drug testing to improve sex-specific healthcare and the medical treatment of human patients.

Considering Sex as a Biological Variable in Basic and Clinical Studies: An Endocrine Society Scientific Statement

In May 2014, the National Institutes of Health (NIH) stated its intent to "require applicants to consider sex as a biological variable (SABV) in the design and analysis of NIH-funded research involving animals and cells." Since then, proposed research plans that include animals routinely state that both sexes/genders will be used; however, in many instances, researchers and reviewers are at a loss about the issue of sex differences. Moreover, the terms sex and gender are used interchangeably by many researchers, further complicating the issue. In addition, the sex or gender of the researcher might influence study outcomes, especially those concerning behavioral studies, in both animals and humans. The act of observation may change the outcome (the "observer effect") and any experimental manipulation, no matter how well-controlled, is subject to it. This is nowhere more applicable than in physiology and behavior. The sex of established cultured cell lines is another issue, in addition to aneuploidy; chromosomal numbers can change as cells are passaged. Additionally, culture medium contains steroids, growth hormone, and insulin that might influence expression of various genes. These issues often are not taken into account, determined, or even considered. Issues pertaining to the "sex" of cultured cells are beyond the scope of this Statement. However, we will discuss the factors that influence sex and gender in both basic research (that using animal models) and clinical research (that involving human subjects), as well as in some areas of science where sex differences are routinely studied. Sex differences in baseline physiology and associated mechanisms form the foundation for understanding sex differences in diseases pathology, treatments, and outcomes. The purpose of this Statement is to highlight lessons learned, caveats, and what to consider when evaluating data pertaining to sex differences, using 3 areas of research as examples; it is not intended to serve as a guideline for research design.

Sex-Related Differences in Pharmacokinetics and Pharmacodynamics of Frequently Prescribed Drugs: A Review of the Literature

While there is considerable evidence about sex-related differences between men and women in drug metabolism, efficacy and safety of frequently prescribed drugs such as analgesics, tranquillizers, statins and beta-blockers, clinicians' awareness of the implications on dosing and adverse event monitoring in routine practice is inadequate. Some drugs are more effective in men than women (e.g. ibuprofen) or vice versa (e.g. opioids, benzodiazepine), typically owing to pharmacodynamic causes. The 5-hydroxytryptamine (5-HT) receptor 3 antagonist alosetron is approved for women only since it largely lacks efficacy in men. For statins, equal efficacy was demonstrated in secondary prevention of cardiovascular events, but primary prevention is still under debate. For some drugs (e.g. paracetamol, metoprolol), women are at significantly higher risk of adverse effects. Therefore, considering sex-specific features in clinical trials and therapeutic guidelines is warranted to ensure efficacy and safety of medicines.

Sex-Gender Variable: Methodological Recommendations for Increasing Scientific Value of Clinical Studies

There is a clear sex-gender gap in the prevention and occurrence of diseases, and in the outcomes and treatments, which is relevant to women in the majority of cases. Attitudes concerning the enrollment of women in randomized clinical trials have changed over recent years. Despite this change, a gap still exists. This gap is linked to biological factors (sex) and psycho-social, cultural, and environmental factors (gender). These multidimensional, entangled, and interactive factors may influence the pharmacological response. Despite the fact that regulatory authorities recognize the importance of sex and gender, there is a paucity of research focusing on the racial/ethnic, socio-economic, psycho-social, and environmental factors that perpetuate disparities. Research and clinical practice must incorporate all of these factors to arrive at an intersectional and system-scenario perspective. We advocate for scientifically rigorous evaluations of the interplay between sex and gender as key factors in performing clinical trials, which are more adherent to real-life. This review proposes a set of 12 rules to improve clinical research for integrating sex-gender into clinical trials.

Sex-Divergent Clinical Outcomes and Precision Medicine: An Important New Role for Institutional Review Boards and Research Ethics Committees

The efforts toward individualized medicine have constantly increased in an attempt to improve treatment options. These efforts have led to the development of small molecules which target specific molecular pathways involved in cancer progression. We have reviewed preclinical studies of sunitinib that incorporate sex as a covariate to explore possible sex-based differences in pharmacokinetics and drug–drug interactions (DDI) to attempt a relationship with published clinical outputs. We observed that covariate sex is lacking in most clinical outcome reports and suggest a series of ethic-based proposals to improve research activities and identify relevant different sex outcomes. We propose a deeper integration of preclinical, clinical, and translational research addressing statistical and clinical significance jointly; to embed specific sex-divergent endpoints to evaluate possible gender differences objectively during all stages of research; to pay greater attention to sex-divergent outcomes in polypharmacy scenarios, DDI and bioequivalence studies; the clear reporting of preclinical and clinical findings regarding sex-divergent outcomes; as well as to encourage the active role of scientists and the pharmaceutical industry to foster a new scientific culture through their research programs, practice, and participation in editorial boards and Institutional Ethics Review Boards (IRBs) and Research Ethics Committees (RECs). We establish the IRB/REC as the centerpiece for the implementation of these proposals. We suggest the expansion of its competence to follow up clinical trials to ensure that sex differences are addressed and recognized; to engage in data monitoring committees to improve clinical research cooperation and ethically address those potential clinical outcome differences between male and female patients to analyze their social and clinical implications in research and healthcare policies.

Evidence for curricular and instructional design approaches in undergraduate medical education: An umbrella review

INTRODUCTION

An umbrella review compiles evidence from multiple reviews into a single accessible document. This umbrella review synthesizes evidence from systematic reviews on curricular and instructional design approaches in undergraduate medical education, focusing on learning outcomes.

METHODS

We conducted bibliographic database searches in Medline, EMBASE and ERIC from database inception to May 2013 inclusive, and digital keyword searches of leading medical education journals. We identified 18,470 abstracts; 467 underwent duplicate full-text scrutiny.

RESULTS

Thirty-six articles met all eligibility criteria. Articles were abstracted independently by three authors, using a modified Kirkpatrick model for evaluating learning outcomes. Evidence for the effectiveness of diverse educational approaches is reported.

DISCUSSION

This review maps out empirical knowledge on the efficacy of a broad range of educational approaches in medical education. Critical knowledge gaps, and lapses in methodological rigour, are discussed, providing valuable insight for future research. The findings call attention to the need for adopting evaluative strategies that explore how contextual variabilities and individual (teacher/learner) differences influence efficacy of educational interventions. Additionally, the results underscore that extant empirical evidence does not always provide unequivocal answers about what approaches are most effective. Educators should incorporate best available empirical knowledge with experiential and contextual knowledge.

Relationship of cortisol levels and genetic polymorphisms to antidepressant response to placebo and fluoxetine in patients with major depressive disorder: a prospective study

BACKGROUND

Increased cortisol levels and genetic polymorphisms have been related to both major depressive disorder and antidepressant treatment outcome. The aim of this study is to evaluate the relationship between circadian salivary cortisol levels, cortisol suppression by dexamethasone and genetic polymorphisms in some HPA axis-related genes to the response to placebo and fluoxetine in depressed patients.

METHODS

The diagnosis and severity of depression were performed using the Mini International Neuropsychiatric Interview (M.I.N.I.) and Hamilton depression scale (HAM-D17), respectively. Euthyroid patients were treated with placebo (one week) followed by fluoxetine (20 mg) (two months). Severity of depression was re-evaluated after placebo, three weeks and two months of fluoxetine treatments. Placebo response was defined as HAM-D17 score reductions of at least 25% and to < 15. Early response and response were reductions of at least 50% after three weeks and two months, and remission with ≤ 7 after two months. Plasma TSH, free-T4, circadian salivary cortisol levels and cortisol suppression by dexamethasone were evaluated. Seven genetic polymorphisms located in the Corticotrophin-releasing-hormone-receptor-1 (rs242939, rs242941, rs1876828), Corticotrophin-releasing-hormone-receptor-2 (rs2270007), Glucocorticoid-receptor (rs41423247), FK506-binding-protein-5 (rs1360780), and Arginine-vasopressin (rs3729965) genes were determined. Association analyses between response to placebo/fluoxetine and polymorphism were performed by chi-square or Fisher exact test. Cortisol levels were compared by t-test, ANOVA and the general linear model for repeated measures.

RESULTS

208 depressed patients were recruited, 187 of whom were euthyroid. Placebo responders, fluoxetine responders and remitters exhibited significantly lower circadian cortisol levels than those who did not respond (p-values of 0.014, 0.008 and 0.021 respectively). Patients who abandoned treatment before the third week also exhibited a trend to low cortisol levels (p = 0.057). The polymorphisms rs242939 (CRHR1) and rs2270007 (CRHR2) were not in Hardy-Weinberg equilibrium. Only the rs242939 polymorphism (CRHR1) exhibited association with early response (three weeks) to fluoxetine (p-value = 0.043). No other association between outcomes and polymorphisms was observed.

CONCLUSIONS

These results support the clinical relevance of low salivary cortisol levels as a predictor of antidepressant response, either to placebo or to fluoxetine. Only one polymorphism in the CRHR1 gene was associated with the early response. Other factors may be involved in antidepressant response, although further studies are needed to identify them.

Fluoxetine versus other types of pharmacotherapy for depression

BACKGROUND

Depression is common in primary care and is associated with marked personal, social and economic morbidity, thus creating significant demands on service providers. The antidepressant fluoxetine has been studied in many randomised controlled trials (RCTs) in comparison with other conventional and unconventional antidepressants. However, these studies have produced conflicting findings.Other systematic reviews have considered selective serotonin reuptake inhibitor (SSRIs) as a group which limits the applicability of the indings for fluoxetine alone. Therefore, this review intends to provide specific and clinically useful information regarding the effects of fluoxetine for depression compared with tricyclics (TCAs), SSRIs, serotonin-noradrenaline reuptake inhibitors (SNRIs), monoamineoxidase inhibitors (MAOIs) and newer agents, and other conventional and unconventional agents.

OBJECTIVES

To assess the effects of fluoxetine in comparison with all other antidepressive agents for depression in adult individuals with unipolar major depressive disorder.

SEARCH METHODS

We searched the Cochrane Collaboration Depression, Anxiety and Neurosis Review Group Controlled Trials Register (CCDANCTR)to 11May 2012. This register includes relevant RCTs from the Cochrane Central Register of Controlled Trials (CENTRAL) (all years),MEDLINE (1950 to date), EMBASE (1974 to date) and PsycINFO (1967 to date). No language restriction was applied. Reference lists of relevant papers and previous systematic reviews were handsearched. The pharmaceutical company marketing fluoxetine and experts in this field were contacted for supplemental data.

SELECTION CRITERIA

All RCTs comparing fluoxetine with any other AD (including non-conventional agents such as hypericum) for patients with unipolar major depressive disorder (regardless of the diagnostic criteria used) were included. For trials that had a cross-over design only results from the first randomisation period were considered.

DATA COLLECTION AND ANALYSIS

Data were independently extracted by two review authors using a standard form. Responders to treatment were calculated on an intention-to-treat basis: dropouts were always included in this analysis. When data on dropouts were carried forward and included in the efficacy evaluation, they were analysed according to the primary studies; when dropouts were excluded from any assessment in the primary studies, they were considered as treatment failures. Scores from continuous outcomes were analysed by including patients with a final assessment or with the last observation carried forward. Tolerability data were analysed by calculating the proportion of patients who failed to complete the study due to any causes and due to side effects or inefficacy. For dichotomous data, odds ratios (ORs) were calculated with 95% confidence intervals (CI) using the random-effects model. Continuous data were analysed using standardised mean differences (SMD) with 95% CI.

MAIN RESULTS

A total of 171 studies were included in the analysis (24,868 participants). The included studies were undertaken between 1984 and 2012. Studies had homogenous characteristics in terms of design, intervention and outcome measures. The assessment of quality with the risk of bias tool revealed that the great majority of them failed to report methodological details, like the method of random sequence generation, the allocation concealment and blinding. Moreover, most of the included studies were sponsored by drug companies, so the potential for overestimation of treatment effect due to sponsorship bias should be considered in interpreting the results. Fluoxetine was as effective as the TCAs when considered as a group both on a dichotomous outcome (reduction of at least 50% on the Hamilton Depression Scale) (OR 0.97, 95% CI 0.77 to 1.22, 24 RCTs, 2124 participants) and a continuous outcome (mean scores at the end of the trial or change score on depression measures) (SMD 0.03, 95% CI -0.07 to 0.14, 50 RCTs, 3393 participants). On a dichotomousoutcome, fluoxetine was less effective than dothiepin or dosulepin (OR 2.13, 95% CI 1.08 to 4.20; number needed to treat (NNT) =6, 95% CI 3 to 50, 2 RCTs, 144 participants), sertraline (OR 1.37, 95% CI 1.08 to 1.74; NNT = 13, 95% CI 7 to 58, 6 RCTs, 1188 participants), mirtazapine (OR 1.46, 95% CI 1.04 to 2.04; NNT = 12, 95% CI 6 to 134, 4 RCTs, 600 participants) and venlafaxine(OR 1.29, 95% CI 1.10 to 1.51; NNT = 11, 95% CI 8 to 16, 12 RCTs, 3387 participants). On a continuous outcome, fluoxetine was more effective than ABT-200 (SMD -1.85, 95% CI -2.25 to -1.45, 1 RCT, 141 participants) and milnacipran (SMD -0.36, 95% CI-0.63 to -0.08, 2 RCTs, 213 participants); conversely, it was less effective than venlafaxine (SMD 0.10, 95% CI 0 to 0.19, 13 RCTs,3097 participants). Fluoxetine was better tolerated than TCAs considered as a group (total dropout OR 0.79, 95% CI 0.65 to 0.96;NNT = 20, 95% CI 13 to 48, 49 RCTs, 4194 participants) and was better tolerated in comparison with individual ADs, in particular amitriptyline (total dropout OR 0.62, 95% CI 0.46 to 0.85; NNT = 13, 95% CI 8 to 39, 18 RCTs, 1089 participants), and among the newer ADs ABT-200 (total dropout OR 0.18, 95% CI 0.08 to 0.39; NNT = 3, 95% CI 2 to 5, 1 RCT, 144 participants), pramipexole(total dropout OR 0.12, 95% CI 0.03 to 0.42, NNT = 3, 95% CI 2 to 5, 1 RCT, 105 participants), and reboxetine (total dropout OR0.60, 95% CI 0.44 to 0.82, NNT = 9, 95% CI 6 to 24, 4 RCTs, 764 participants).

AUTHORS' CONCLUSIONS

The present study detected differences in terms of efficacy and tolerability between fluoxetine and certain ADs, but the clinical meaning of these differences is uncertain.Moreover, the assessment of quality with the risk of bias tool showed that the great majority of included studies failed to report details on methodological procedures. Of consequence, no definitive implications can be drawn from the studies' results. The better efficacy profile of sertraline and venlafaxine (and possibly other ADs) over fluoxetine may be clinically meaningful,as already suggested by other systematic reviews. In addition to efficacy data, treatment decisions should also be based on considerations of drug toxicity, patient acceptability and cost.

Duloxetine versus other anti-depressive agents for depression

BACKGROUND

Although pharmacological and psychological interventions are both effective for major depression, in primary and secondary care settings antidepressant drugs remain the mainstay of treatment. Amongst antidepressants many different agents are available. Duloxetine hydrochloride is a dual reuptake inhibitor of serotonin and norepinephrine and has been licensed by the Food and Drug Administration in the US for major depressive disorder (MDD), generalised anxiety disorder, diabetic peripheral neuropathic pain, fibromyalgia and chronic musculoskeletal pain.

OBJECTIVES

To assess the evidence for the efficacy, acceptability and tolerability of duloxetine in comparison with all other antidepressant agents in the acute-phase treatment of major depression.

SEARCH METHODS

MEDLINE (1966 to 2012), EMBASE (1974 to 2012), the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register and the Cochrane Central Register of Controlled Trials up to March 2012. No language restriction was applied. Reference lists of relevant papers and previous systematic reviews were hand-searched. Pharmaceutical company marketing duloxetine and experts in this field were contacted for supplemental data.

SELECTION CRITERIA

Randomised controlled trials allocating patients with major depression to duloxetine versus any other antidepressive agent.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and a double-entry procedure was employed. Information extracted included study characteristics, participant characteristics, intervention details and outcome measures in terms of efficacy, acceptability and tolerability.

MAIN RESULTS

A total of 16 randomised controlled trials (overall 5735 participants) were included in this systematic review. Of these, three trials were unpublished. We found 11 studies (overall 3304 participants) comparing duloxetine with one selective serotonin reuptake inhibitor (SSRI) (six studies versus paroxetine, three studies versus escitalopram and two versus fluoxetine), four studies (overall 1978 participants) comparing duloxetine with a newer antidepressants (three with venlafaxine and one with desvenlafaxine, respectively) and one study (overall 453 participants) comparing duloxetine with an antipsychotic drug which is also used as an antidepressive agent, quetiapine. No studies were found comparing duloxetine with tricyclic antidepressants. The pooled confidence intervals were rather wide and there were no statistically significant differences in efficacy when comparing duloxetine with other antidepressants. However, when compared with escitalopram or venlafaxine, there was a higher rate of drop out due to any cause in the patients randomised to duloxetine (odds ratio (OR) 1.62; 95% confidence interval (CI) 1.01 to 2.62 and OR 1.56; 95% CI 1.14 to 2.15, respectively). There was also some weak evidence suggesting that patients taking duloxetine experienced more adverse events than paroxetine (OR 1.24; 95% CI 0.99 to 1.55).

AUTHORS' CONCLUSIONS

Duloxetine did not seem to provide a significant advantage in efficacy over other antidepressive agents for the acute-phase treatment of major depression. No differences in terms of efficacy were found, even though duloxetine was worse than some SSRIs (most of all, escitalopram) and newer antidepressants (like venlafaxine) in terms of acceptability and tolerability. Unfortunately, we only found evidence comparing duloxetine with a handful of other active antidepressive agents and only a few trials per comparison were found (in some cases we retrieved just one trial). This limited the power of the review to detect moderate, but clinically meaningful differences between the drugs. As many statistical tests have been used in the review, the findings from this review are better thought of as hypothesis forming rather than hypothesis testing and it would be very comforting to see the conclusions replicated in future trials. Most of included studies were sponsored by the drug industry manufacturing duloxetine. As for all other new investigational compounds, the potential for overestimation of treatment effect due to sponsorship bias should be borne in mind. In the present review no trials reported economic outcomes. Given that several SSRIs and the great majority of antidepressants are now available as generic formulation (only escitalopram, desvenlafaxine and duloxetine are still on patent), more comprehensive economic estimates of antidepressant treatment effect should be considered to better inform healthcare policy.

Citalopram versus other anti-depressive agents for depression

BACKGROUND

Recent US and UK clinical practice guidelines recommend that second-generation antidepressants should be considered amongst the best first-line options when drug therapy is indicated for a depressive episode. Systematic reviews have already highlighted some differences in efficacy between second-generation antidepressants. Citalopram, one of the first selective serotonin reuptake inhibitors (SSRI) introduced in the market, is one of these antidepressant drugs that clinicians use for routine depression care.

OBJECTIVES

To assess the evidence for the efficacy, acceptability and tolerability of citalopram in comparison with tricyclics, heterocyclics, other SSRIs and other conventional and non-conventional antidepressants in the acute-phase treatment of major depression.

SEARCH METHODS

We searched The Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register and the Cochrane Central Register of Controlled Trials up to February 2012. No language restriction was applied. We contacted pharmaceutical companies and experts in this field for supplemental data.

SELECTION CRITERIA

Randomised controlled trials allocating patients with major depression to citalopram versus any other antidepressants.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data. Information extracted included study characteristics, participant characteristics, intervention details and outcome measures in terms of efficacy (the number of patients who responded or remitted), patient acceptability (the number of patients who failed to complete the study) and tolerability (side-effects).

MAIN RESULTS

Thirty-seven trials compared citalopram with other antidepressants (such as tricyclics, heterocyclics, SSRIs and other antidepressants, either conventional ones, such as mirtazapine, venlafaxine and reboxetine, or non-conventional, like hypericum). Citalopram was shown to be significantly less effective than escitalopram in achieving acute response (odds ratio (OR) 1.47, 95% confidence interval (CI) 1.08 to 2.02), but more effective than paroxetine (OR 0.65, 95% CI 0.44 to 0.96) and reboxetine (OR 0.63, 95% CI 0.43 to 0.91). Significantly fewer patients allocated to citalopram withdrew from trials due to adverse events compared with patients allocated to tricyclics (OR 0.54, 95% CI 0.38 to 0.78) and fewer patients allocated to citalopram reported at least one side effect than reboxetine or venlafaxine (OR 0.64, 95% CI 0.42 to 0.97 and OR 0.46, 95% CI 0.24 to 0.88, respectively).

AUTHORS' CONCLUSIONS

Some statistically significant differences between citalopram and other antidepressants for the acute phase treatment of major depression were found in terms of efficacy, tolerability and acceptability. Citalopram was more efficacious than paroxetine and reboxetine and more acceptable than tricyclics, reboxetine and venlafaxine, however, it seemed to be less efficacious than escitalopram. As with most systematic reviews in psychopharmacology, the potential for overestimation of treatment effect due to sponsorship bias and publication bias should be borne in mind when interpreting review findings. Economic analyses were not reported in the included studies, however, cost effectiveness information is needed in the field of antidepressant trials.

Sex Differences in the Expression of Drug-Metabolizing and Transporter Genes in Human Liver

Human sex differences in the gene expression of drug metabolizing enzymes and transporters (DMETs) introduce differences in drug absorption, distribution, metabolism and excretion, possibly affecting drug efficacy and adverse reactions. However, existing studies aimed at identifying dimorphic expression differences of DMET genes are limited by sample size and the number of genes profiled. Focusing on a list of 374 DMET genes, we analyzed a previously published gene expression data set consisting of human male (n=234) and female (n=193) liver samples, and identified 77 genes showing differential expression due to sex. To delineate the biological functionalities and regulatory mechanisms for the differentially expressed DMET genes, we conducted a co-expression network analysis. Moreover, clinical implications of sex differences in the expression of human hepatic DMETs are discussed. This study may contribute to the realization of personalized medicine by better understanding the inter-individual differences between males and females in drug/xenobiotic responses and human disease susceptibilities.

Paroxetine for the treatment of depression: a critical update

INTRODUCTION

A growth in the market for antidepressants, paired with an ever-increasing population affected from depressive disorder, requires a critical re-evaluation of most prescribed antidepressants, in order to provide up-to-date practical prescribing information for clinicians. Paroxetine represents a widely prescribed and reliable antidepressant for the expert clinician, but the latest data do not rank it amongst the most effective and tolerable newer antidepressants.

AREAS COVERED

This paper reviews latest data on paroxetine and investigates its clinical efficacy and safety in different groups of patients.

EXPERT OPINION

In previous subanalysis and metaregression analysis, paroxetine failed to show clear differences in terms of efficacy across clinical subgroups. Thus, nowadays the pharmacokinetic and pharmacodynamic properties of the molecule are fundamental to guiding its prescription, both for efficacy and tolerability issues, for example, it can have a high impact on sexual function and weight should also be considered at the beginning of treatment. Since prescription is still based mainly on its side-effect profile, newer and more accurate directions for an individualized prescription are needed.

Gene-environment interactions and construct validity in preclinical models of psychiatric disorders

The contributions of genetic risk factors to susceptibility for brain disorders are often so closely intertwined with environmental factors that studying genes in isolation cannot provide the full picture of pathogenesis. With recent advances in our understanding of psychiatric genetics and environmental modifiers we are now in a position to develop more accurate animal models of psychiatric disorders which exemplify the complex interaction of genes and environment. Here, we consider some of the insights that have emerged from studying the relationship between defined genetic alterations and environmental factors in rodent models. A key issue in such animal models is the optimization of construct validity, at both genetic and environmental levels. Standard housing of laboratory mice and rats generally includes ad libitum food access and limited opportunity for physical exercise, leading to metabolic dysfunction under control conditions, and thus reducing validity of animal models with respect to clinical populations. A related issue, of specific relevance to neuroscientists, is that most standard-housed rodents have limited opportunity for sensory and cognitive stimulation, which in turn provides reduced incentive for complex motor activity. Decades of research using environmental enrichment has demonstrated beneficial effects on brain and behavior in both wild-type and genetically modified rodent models, relative to standard-housed littermate controls. One interpretation of such studies is that environmentally enriched animals more closely approximate average human levels of cognitive and sensorimotor stimulation, whereas the standard housing currently used in most laboratories models a more sedentary state of reduced mental and physical activity and abnormal stress levels. The use of such standard housing as a single environmental variable may limit the capacity for preclinical models to translate into successful clinical trials. Therefore, there is a need to optimize 'environmental construct validity' in animal models, while maintaining comparability between laboratories, so as to ensure optimal scientific and medical outcomes. Utilizing more sophisticated models to elucidate the relative contributions of genetic and environmental factors will allow for improved construct, face and predictive validity, thus facilitating the identification of novel therapeutic targets.