Gender differences in the efficacy of fluoxetine and maprotiline in depressed patients: a double-blind trial of antidepressants with serotonergic or norepinephrinergic reuptake inhibition profile

A multicenter retrospective study of antidepressant use in outpatient clinics in China pre- and post-COVID

BACKGROUND

Analyzing antidepressant prescribing in real-world settings can provide clinicians and health policymakers valuable information.

AIM

This epidemiological study examined the status and trends in antidepressant prescribing among the Chinese population from July 1, 2017, to June 30, 2022.

METHOD

A retrospective study was conducted in three hospitals. Data were collected 2.5 years before and 2.5 years after the onset of the COVID-19 pandemic. We analyzed the number of patients diagnosed with depression and their corresponding antidepressant prescriptions. Using the chi-square test, stratified analyses were performed to explore the characteristics of these prescriptions in different ages and sexes.

RESULTS

The study included 124,355 patients and 400,840 antidepressant prescriptions. We observed fluctuating upward trends in the number of patients and antidepressant prescriptions. Post-COVID-19, the number of patients increased by 37.1% compared to the pre-pandemic period, and the number of antidepressant prescriptions rose by 88.3%. The three most frequently prescribed antidepressants for adolescents were sertraline, citalopram, and escitalopram. Among adults, citalopram, escitalopram, and sertraline were most common, while in older adults, citalopram, escitalopram, and mirtazapine were predominant. Male patients used mirtazapine, venlafaxine, paroxetine, bupropion, fluvoxamine, vortioxetine, and clomipramine more frequently compared to female patients, who were more likely to be prescribed citalopram, flupentixol/melitracen, agomelatine, and fluoxetine. Antidepressant monotherapy represented 76.6% of prescriptions, with the most common combination being antidepressants and anxiolytics.

CONCLUSION

Over the past 5 years, both the number of patients and antidepressant prescriptions have shown upward trends, and the COVID-19 pandemic has impacted prescribing. Understanding the changes in antidepressant prescriptions can identify adherence to national guidelines.

Fluoxetine Rescues Excessive Myelin Formation and Psychological Behaviors in a Murine PTSD Model

Posttraumatic stress disorder (PTSD) is a complex mental disorder notable for traumatic experience memory. Although current first-line treatments are linked with clinically important symptom reduction, a large proportion of patients retained to experience considerable residual symptoms, indicating pathogenic mechanism should be illustrated further. Recent studies reported that newly formed myelin could shape neural circuit function and be implicated in fear memory preservation. However, its role in PTSD remains to be elucidated. In this study, we adopted a restraint stress-induced PTSD mouse model and found that PTSD-related neuropsychiatric symptoms were accompanied by increased myelination in the posterior parietal cortex and hippocampus. Fluoxetine, but not risperidone or sertraline, has a more profound rescue effect on neuropsychological behaviors and myelin abnormalities. Further mechanistic experiments revealed that fluoxetine could directly interfere with oligodendroglial differentiation by upregulating Wnt signaling. Our data demonstrated the correlation between PTSD and abnormal myelination, suggesting that the oligodendroglial lineage could be a target for PTSD treatment.

The neural basis underlying female vulnerability to depressive disorders

Depressive disorders are more prevalent and severe in women; however, our knowledge of the underlying factors contributing to female vulnerability to depression remains limited. Additionally, females are notably underrepresented in studies seeking to understand the mechanisms of depression. Various animal models of depression have been devised, but only recently have females been included in research. In this comprehensive review, we aim to describe the sex differences in the prevalence, pathophysiology, and responses to drug treatment in patients with depression. Subsequently, we highlight animal models of depression in which both sexes have been studied, in the pursuit of identifying models that accurately reflect female vulnerability to depression. We also introduce explanations for the neural basis of sex differences in depression. Notably, the medial prefrontal cortex and the nucleus accumbens have exhibited sex differences in previous studies. Furthermore, other brain circuits involving the dopaminergic center (ventral tegmental area) and the serotonergic center (dorsal raphe nucleus), along with their respective projections, have shown sex differences in relation to depression. In conclusion, our review covers the critical aspects of sex differences in depression, with a specific focus on female vulnerability in humans and its representation in animal models, including the potential underlying mechanisms. Employing suitable animal models that effectively represent female vulnerability would benefit our understanding of the sex-dependent pathophysiology of depression.

A sex-specific genome-wide association study of depression phenotypes in UK Biobank

There are marked sex differences in the prevalence, phenotypic presentation and treatment response for major depression. While genome-wide association studies (GWAS) adjust for sex differences, to date, no studies seek to identify sex-specific markers and pathways. In this study, we performed a sex-stratified genome-wide association analysis for broad depression with the UK Biobank total participants (N = 274,141), including only non-related participants, as well as with males (N = 127,867) and females (N = 146,274) separately. Bioinformatics analyses were performed to characterize common and sex-specific markers and associated processes/pathways. We identified 11 loci passing genome-level significance (P < 5 × 10-8) in females and one in males. In both males and females, genetic correlations were significant between the broad depression GWA and other psychopathologies; however, correlations with educational attainment and metabolic features including body fat, waist circumference, waist-to-hip ratio and triglycerides were significant only in females. Gene-based analysis showed 147 genes significantly associated with broad depression in the total sample, 64 in the females and 53 in the males. Gene-based analysis revealed "Regulation of Gene Expression" as a common biological process, but suggested sex-specific molecular mechanisms. Finally, sex-specific polygenic risk scores (PRSs) for broad depression outperformed total and the opposite sex PRSs in the prediction of broad major depressive disorder. These findings provide evidence for sex-dependent genetic pathways for clinical depression as well as for health conditions comorbid with depression.

The Serotonergic System and Bone Metabolism During Pregnancy and Lactation and the Implications of SSRI Use on the Maternal-Offspring Dyad

Lactation is a physiological adaptation of the class Mammalia and is a product of over 200 million years of evolution. During lactation, the mammary gland orchestrates bone metabolism via serotonin signaling in order to provide sufficient calcium for the offspring in milk. The role of serotonin in bone remodeling was first discovered over two decades ago, and the interplay between serotonin, lactation, and bone metabolism has been explored in the years following. It is estimated that postpartum depression affects 10-15% of the population, and selective serotonin reuptake inhibitors (SSRI) are often used as the first-line treatment. Studies conducted in humans, nonhuman primates, sheep, and rodents have provided evidence that there are consequences on both parent and offspring when serotonin signaling is disrupted during the peripartal period; however, the long-term consequences of disruption of serotonin signaling via SSRIs during the peripartal period on the maternal and offspring skeleton are not fully known. This review will focus on the relationship between the mammary gland, serotonin, and bone remodeling during the peripartal period and the skeletal consequences of the dysregulation of the serotonergic system in both human and animal studies.

Role of 5-HT1A-mediated upregulation of brain indoleamine 2,3 dioxygenase 1 in the reduced antidepressant and antihyperalgesic effects of fluoxetine during maintenance treatment

The reduced antidepressant and antihyperalgesic effects of selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine during maintenance treatment has been reported, but little is known about the molecular mechanism of this phenomenon. In three comorbid pain and depression animal models (genetic predisposition, chronic social stress, arthritis), we showed that the fluoxetine's antidepressant and antihyperalgesic effects were reduced during the maintenance treatment. Fluoxetine exposure induced upregulation of the 5-hydroxytryptamine 1A (5-HT1A) auto-receptor and indoleamine 2,3 dioxygenase 1 (IDO1, a rate-limiting enzyme of tryptophan metabolism) in the brainstem dorsal raphe nucleus (DRN), which shifted the tryptophan metabolism away from the 5-HT biosynthesis. Mechanistically, IDO1 upregulation was downstream to fluoxetine-induced 5-HT1A receptor expression because 1) antagonism of the 5-HT1A receptor with WAY100635 or 5-HT1A receptor knockout blocked the IDO1 upregulation, and 2) inhibition of IDO1 activity did not block the 5-HT1A receptor upregulation following fluoxetine exposure. Importantly, inhibition of either the 5-HT1A receptor or IDO1 activity sustained the fluoxetine's antidepressant and antihyperalgesic effects, indicating that 5-HT1A-mediated IDO1 upregulation in the brainstem DRN contributed to the reduced antidepressant and antihyperalgesic effects of fluoxetine. These results suggest a new strategy to improving the therapeutic efficacy of SSRI during maintenance treatment.

Antidepressant Prescription for Major Depressive Disorder: Results from a Population-Based Study in Italy

OBJECTIVES

There is limited evidence about the factors influencing antidepressant (AD) prescription for the treatment of major depressive disorder (MDD) in Real World clinical practice in Italy. In this retrospective, population-based study, we set out to describe a patient cohort initiated on AD treatment for MDD and investigate the possible predictors of different AD prescriptions in the primary care setting.

METHODS

Patients with a diagnosis of MDD who received an initial prescription of one of 11 selected ADs between 1-Apr-2017 and 31-Mar-2019 (index date) were identified from primary care electronic medical records in the Longitudinal Patient Database. Patients prescribed ≥1 AD in the 12 months before the index date were excluded. Results were stratified by AD molecule. Multivariable logistic regression models estimated the association between patients' demographic, clinical factors, and choice of AD molecule.

RESULTS

The study cohort comprised 8,823 patients (67.1% female; mean age 61.6 years). Previous AD treatments (prescribed in the 10 years before the index date) had been received by 46.6% of patients (non-naïve patients). The most commonly reported psychiatric and medical comorbidities reported in the 12 months before the index date were anxiety (8.4%) and hypertension (41.9%), respectively. Patients' age was a significant predictor of AD molecule prescribed at index date in eight of the 11 molecules investigated, while patients' gender influenced clinician prescribing bupropion, citalopram, fluoxetine, fluvoxamine, sertraline, and vortioxetine.

CONCLUSION

Results from this Real World study provide useful information for clinicians on the clinical factors influencing AD prescription in patients treated for MDD in primary care.

Sex-Related Differences in Pharmacological Response to CNS Drugs: A Narrative Review

In the last decades, both animal and human studies have neglected female subjects with the aim of evading a theorized intricacy of feminine hormonal status. However, clinical experience proves that pharmacological response may vary between the two sexes since pathophysiological dissimilarities between men and women significantly influence the pharmacokinetics and pharmacodynamics of drugs. Sex-related differences in central nervous system (CNS) medication are particularly challenging to assess due to the complexity of disease manifestation, drugs’ intricate mechanisms of action, and lack of trustworthy means of evaluating the clinical response to medication. Although many studies showed contrary results, it appears to be a general tendency towards a certain sex-related difference in each pharmacological class. Broadly, opioids seem to produce better analgesia in women especially when they are administered for a prolonged period of time. On the other hand, respiratory and gastrointestinal adverse drug reactions (ADRs) following morphine therapy are more prevalent among female patients. Regarding antidepressants, studies suggest that males might respond better to tricyclic antidepressants (TCAs), whereas females prefer selective serotonin reuptake inhibitors (SSRI), probably due to their tolerance to particular ADRs. In general, studies missed spotting any significant sex-related differences in the therapeutic effect of antiepileptic drugs (AED), but ADRs have sex variations in conjunction with sex hormones’ metabolism. On the subject of antipsychotic therapy, women appear to have a superior response to this pharmacological class, although there are also studies claiming the opposite. However, it seems that reported sex-related differences regarding ADRs are steadier: women are more at risk of developing various side effects, such as metabolic dysfunctions, cardiovascular disorders, and hyperprolactinemia. Taking all of the above into account, it seems that response to CNS drugs might be occasionally influenced by sex as a biological variable. Nonetheless, although for each pharmacological class, studies generally converge to a certain pattern, opposite outcomes are standing in the way of a clear consensus. Hence, the fact that so many studies are yielding conflicting results emphasizes once again the need to address sex-related differences in pharmacological response to drugs.

Large-Scale Transcriptomics Studies Provide Insight Into Sex Differences in Depression

Major depressive disorder (MDD) is a leading cause of disability, affecting more than 300 million people worldwide. We first review the well-known sex difference in incidence of MDD, with women being twice as likely to be diagnosed as men, and briefly summarize how the impact of MDD varies between men and women, with sex differences in symptoms, severity, and antidepressant drug response. We then attempt to deconstruct the biological bases for MDD and discuss implications for sex differences research. Next, we review findings from human postmortem studies, both from selected candidate gene studies and from well-powered, unbiased transcriptomics studies, which suggest distinct, and possibly opposite, molecular changes in the brains of depressed men and women. We then discuss inherent challenges of research on the human postmortem brain and suggest paths forward that rely on thoughtful cohort design. Although studies indicate that circulating gonadal hormones might underlie the observed sex differences in MDD, we discuss how additional sex-specific factors, such as genetic sex and developmental exposure to gonadal hormones, may also contribute to altered vulnerability, and we highlight various nuances that we believe should be considered when determining mechanisms underlying observed sex differences. Altogether, this review highlights not only how various sex-specific factors might influence susceptibility or resilience to depression, but also how those sex-specific factors might result in divergent pathology in men and women.

Sex differences in depressive symptoms and tolerability after treatment with selective serotonin reuptake inhibitor antidepressants: Secondary analyses of the GENPOD trial

BACKGROUND

Differences in serotonergic neurotransmission could lead to sex differences in depressive symptoms and tolerability after treatment with selective serotonin reuptake inhibitors (SSRIs).

AIMS

We investigated whether women have greater reductions in depressive symptoms than men after treatment with an SSRI (citalopram) compared with a noradrenaline reuptake inhibitor (reboxetine) control, and after antidepressant treatment irrespective of class. We also investigated tolerability and the influence of menopausal status.

METHODS

Secondary analyses of the GENPOD (GENetic and clinical Predictors Of treatment response in Depression) trial. Six hundred and one people with depression were recruited from UK primary care and randomized to citalopram or reboxetine. Beck Depression Inventory (BDI-II) score at 6 weeks was the primary outcome. Secondary outcomes included BDI-II score at 12 weeks, and physical symptoms and treatment discontinuation. We calculated main effects and interaction terms using linear and logistic regression models.

RESULTS

There was no evidence that women experienced greater reductions in depressive symptoms than men when treated with citalopram compared with reboxetine. We also found no evidence of sex differences at six or 12 weeks (irrespective of antidepressant class): men scored -0.31 (95% confidence interval (CI) -2.23 to 1.62) BDI-II points lower than women at six weeks and -0.44 (95% CI -2.62 to 1.74) points lower at 12 weeks. There was no evidence of sex differences in physical symptoms or treatment discontinuation and no evidence for an influence of menopausal status.

CONCLUSION

Citalopram was not more effective in women compared with men and there was no difference in tolerability. Women and men had similar prognosis after SSRI treatment and similar prognosis regardless of antidepressant class. Findings were unaltered by menopausal status.

Venlafaxine vs. fluoxetine in postmenopausal women with major depressive disorder: an 8-week, randomized, single-blind, active-controlled study

BACKGROUND

In the population of postmenopausal patients with major depressive disorder (MDD), the superiority of serotonin-norepinephrine reuptake inhibitors (SNRIs) over selective serotonin reuptake inhibitors (SSRIs) has not yet been definitively proven. Consequently, a direct comparison of the efficacy of SSRIs and SNRIs in the treatment of postmenopausal depression could provide relevant data. The aim of this study was to compare the efficacy and safety of venlafaxine vs. fluoxetine in the treatment of postmenopausal MDD.

METHODS

This was an 8-week, multicenter, randomized, single-blind, active-controlled trial conducted at a psychiatric hospital (Beijing Anding Hospital) and a general hospital (Beijing Chaoyang Hospital) between April 2013 and September 2017. The primary outcome measure was improving depressive symptoms (Hamilton Depression Rating Scale (HAMD-24) score). The secondary outcomes included the change of HAMD-24 anxiety/somatization factor score and Clinical Global Impressions-Improvement (CGI-I) response rate. Safety was assessed by treatment-emergent adverse events (TEAEs) and laboratory tests. Efficacy was analyzed by using the full analysis set (FAS) following the modified intention-to-treat (mITT) principle. The primary endpoint measurements were analyzed using a mixed-effect model for repeated measures (MMRM) model with patients as a random-effect factor, treatment group as the independent variable, time as a repeated measure, and baseline covariates, using a first-order ante dependence covariance matrix.

RESULTS

A total of 184 women were randomized. The full analysis set (FAS) included 172 patients (venlafaxine, n = 82; fluoxetine, n = 90). Over the 8-week study period, the reduction in HAMD-24 scores was significant (P < 0.001) in both groups, while a significantly greater decline from baseline was observed in the venlafaxine group compared with the fluoxetine group (least-squares mean difference [95% CI]: - 2.22 [- 7.08, - 0.41]), P = 0.001). The baseline-to-week-8 least-squares mean change of the anxiety/somatization factor scores, CGI-I response rate were greater in the venlafaxine group than in the fluoxetine group (all P < 0.05). The most frequent TEAEs (≥5%) in both groups were nausea, somnolence, dizziness, headache, and dry mouth. There was no significant difference in the incidence of adverse events between the two groups.

CONCLUSION

Venlafaxine was well tolerated and compared to fluoxetine, it led to a greater improvement in the treatment of postmenopausal MDD.

TRIAL REGISTRATION

Clinical Trials. gov #NCT01824433 . The trial was registered on April 4, 2013.

Involvement of dorsal raphe nucleus serotonergic systems in social approach-avoidance behaviour and in the response to fluoxetine treatment in peri-adolescent female BALB/c mice

Serotonergic systems are involved in the development and regulation of social behaviour, and drugs that target serotonin neurotransmission, such as selective serotonin reuptake inhibitors (SSRIs), also alter aspects of social approach-avoidance. The midbrain dorsal raphe nucleus (DR), which is a major serotonergic nucleus and main source of serotonergic innervation of the forebrain, has been proposed as an important target for SSRIs, although evidence in females is lacking. In this study, we examined the involvement of the DR serotonergic systems in social behaviour and in response to SSRI treatment, using peri-adolescent female BALB/c mice. Mice were exposed to the SSRI fluoxetine either chronically (18 mg/kg/day, in drinking water, for 12 days) or acutely (18 mg/kg, i.p.), or to vehicle control condition (0.9 % saline, i.p.), prior to being exposed to the three-chambered sociability test. Activation of serotonergic neurons across subregions of the DR were subsequently measured, using dual-label immunohistochemistry for TPH2 and c-Fos. Acute fluoxetine administration increased generalised and social avoidance, while mice exposed to chronic fluoxetine treatment showed levels of social approach behaviour that were comparable to controls. Serotonergic populations across the DR showed reduced activity following acute fluoxetine treatment. Further, activation of serotonergic neurons in the ventral DR correlated with social approach behaviour in vehicle-treated control mice. These data provide some support for the involvement of discrete populations of DR serotonergic neurons in the regulation of social approach-avoidance, although more research is needed to understand the effects and mechanisms of chronic SSRI treatment in females.

Xanthotoxin affects depression-related behavior and neurotransmitters content in a sex-dependent manner in mice

The present study aimed to evaluate xanthotoxin's influence on male and female Swiss mice's depression-like behaviors and investigate the potential mechanism of this effect. Naturally derived furanocoumarin (the Apiaceae family), xanthotoxin, administered acutely (12.5 mg/kg), diminished the immobility level in the forced swim test only in males. The immobility level was lower in females than males, which may be associated with a higher serotonin level in the female prefrontal cortex. A dose-dependent increase of serotonin and noradrenaline was reported in the reverse-phase ion-pair liquid chromatography in the female prefrontal cortex but not in the hippocampus. We suggest that xanthotoxin may exert antidepressant properties and affect males and females differently. The increasing level of serotonin in the male and female prefrontal cortex may underlie this effect.

Effects of adolescent administration of fluoxetine on novel object recognition memory, anxiety-like behaviors, and hippocampal brain-derived neurotrophic factor level

AIMS

Fluoxetine (FLX) is a common selective serotonin reuptake inhibitor, which is used in adolescents with psychiatric disorders. Controversial results have been obtained in different studies about the effects of FLX on cognitive functions. The present study was designed to examine the effects of chronic FLX exposure during adolescence on cognitive function, anxiety-like behaviors, and hippocampal brain-derived neurotrophic factor (BDNF) mRNA expression among adult male and female rats.

MAIN METHODS

The sex-dependent effects of FLX chronic administration during adolescence (5 mg/kg/day, gavage) on short-term novel object recognition memory (NORM), anxiety-like behaviors, and BDNF mRNA expression in the hippocampus were examined. NORM and anxiety-like behaviors were assessed by novel object recognition, open field, and elevated plus-maze (EPM) tests, respectively. The expression of BDNF mRNA was also evaluated by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR).

KEY FINDINGS

The present findings revealed the dysfunction of short-term NORM among the adolescent male and female rats exposed to FLX, while the mRNA expression of BDNF was significantly higher among the males. Moreover, adolescent FLX administration had different effects on the anxiety-like behaviors of the male and female rats. Adolescent FLX treatment also decreased the body weight of the male animals.

SIGNIFICANCE

In conclusion, adolescent FLX treatment impairs cognitive functions in both sexes and increases BDNF mRNA expression in the hippocampus of the male animals. FLX administration during adolescence has sex-dependent effects on anxiety-like behaviors. These findings indicate that the impairment of cognitive functions can occur following the adolescent manipulation of the serotonergic system. Therefore, the side effects of chronic FLX administration during adolescence should be more considered.

A functional variant in the serotonin receptor 7 gene (HTR7), rs7905446, is associated with good response to SSRIs in bipolar and unipolar depression

Predicting antidepressant response has been a clinical challenge for mood disorder. Although several genome-wide association studies have suggested a number of genetic variants to be associated with antidepressant response, the sample sizes are small and the results are difficult to replicate. Previous animal studies have shown that knockout of the serotonin receptor 7 gene (HTR7) resulted in an antidepressant-like phenotype, suggesting it was important to antidepressant action. In this report, in the first stage, we used a cost-effective pooled-sequencing strategy to sequence the entire HTR7 gene and its regulatory regions to investigate the association of common variants in HTR7 and clinical response to four selective serotonin reuptake inhibitors (SSRIs: citalopram, paroxetine, fluoxetine and sertraline) in a retrospective cohort mainly consisting of subjects with bipolar disorder (n = 359). We found 80 single-nucleotide polymorphisms (SNPs) with false discovery rate < 0.05 associated with response to paroxetine. Among the significant SNPs, rs7905446 (T/G), which is located at the promoter region, also showed nominal significance (P < 0.05) in fluoxetine group. GG/TG genotypes for rs7905446 and female gender were associated with better response to two SSRIs (paroxetine and fluoxetine). In the second stage, we replicated this association in two independent prospective samples of SSRI-treated patients with major depressive disorder: the MARS (n = 253, P = 0.0169) and GENDEP studies (n = 432, P = 0.008). The GG/TG genotypes were consistently associated with response in all three samples. Functional study of rs7905446 showed greater activity of the G allele in regulating expression of HTR7. The G allele displayed higher luciferase activity in two neuronal-related cell lines, and estrogen treatment decreased the activity of only the G allele. Electrophoretic mobility shift assay suggested that the G allele interacted with CCAAT/enhancer-binding protein beta transcription factor (TF), while the T allele did not show any interaction with any TFs. Our results provided novel pharmacogenomic evidence to support the role of HTR7 in association with antidepressant response.

A comparative study of fluoxetine, moclobemide, and tianeptine in the treatment of posttraumatic stress disorder following an earthquake

Purpose

Although antidepressant drugs have been proven as an effective treatment for posttraumatic stress disorder (PTSD), there are few comparative studies of antidepressants that are acting on different neurotransmitters. The main aim of this study is to compare the efficacy of different class of antidepressant drugs on the PTSD.

Subjects/materials and methods. –

In this open label study, the patients who met DSM-IV criteria for PTSD were randomly assigned to flexible doses of fluoxetine, moclobemide, or tianeptine. After the first assessment, consecutive assessments were performed at the end of weeks 2, 4, 8, and 12 using clinician administered PTSD scale (CAPS) and Clinical Global Impression of Severity (CGI-S). Changes in the total score of CAPS and sub-scale scores of symptom clusters (re-experience, avoidance, and hyperarousal) were the main output of efficacy. All statistics were based on intention-to-treat and last-observation-carried-forward (LOCF) principles.

Results.

Thirty-eight patients were assigned to fluoxetine, 35 patients were assigned to moclobemide, and 30 patients were assigned to tianeptine group. Gender distributions and mean ages of the treatment groups were not significantly different. Drop-out rates due to an adverse events or unknown reasons were not significantly different among fluoxetine (18.4%), moclobemide (14.3%), and tianeptine (20.0%) groups. All three treatments has led to a significant improvement in PTSD severity assessed with CAPS total score (ANOVA P < 0.001). Similarly, total scores of re-experiencing, avoidance, and hyperarousal clusters that are subscales of CAPS were significantly reduced by all three treatments (with ANOVA all P values < 0.001). There was not significant difference in terms of treatment effect between three groups.

Discussion. –

Treatment groups showed very similar improvement on all ratings scales. The findings support that fluoxetine, moclobemide, and tianeptine are all effective in the treatment of PTSD. Different mechanisms of action for these antidepressant drugs might result in the same common neurochemical end point. However, further studies using different classes of antidepressant drugs are needed.

Guidelines for the evaluation and treatment of perimenopausal depression: summary and recommendations

There is a new appreciation of the perimenopause - defined as the early and late menopause transition stages as well as the early postmenopause - as a window of vulnerability for the development of both depressive symptoms and major depressive episodes. However, clinical recommendations on how to identify, characterize and treat clinical depression are lacking. To address this gap, an expert panel was convened to systematically review the published literature and develop guidelines on the evaluation and management of perimenopausal depression. The areas addressed included: 1) epidemiology; 2) clinical presentation; 3) therapeutic effects of antidepressants; 4) effects of hormone therapy; and 5) efficacy of other therapies (eg, psychotherapy, exercise, and natural health products). Overall, evidence generally suggests that most midlife women who experience a major depressive episode during the perimenopause have experienced a prior episode of depression. Midlife depression presents with classic depressive symptoms commonly in combination with menopause symptoms (ie, vasomotor symptoms, sleep disturbance), and psychosocial challenges. Menopause symptoms complicate, co-occur, and overlap with the presentation of depression. Diagnosis involves identification of menopausal stage, assessment of co-occurring psychiatric and menopause symptoms, appreciation of the psychosocial factors common in midlife, differential diagnoses, and the use of validated screening instruments. Proven therapeutic options for depression (ie, antidepressants, psychotherapy) are the front-line treatments for perimenopausal depression. Although estrogen therapy is not approved to treat perimenopausal depression, there is evidence that it has antidepressant effects in perimenopausal women, particularly those with concomitant vasomotor symptoms. Data on estrogen plus progestin are sparse and inconclusive.

Selective Depletion of CREB in Serotonergic Neurons Affects the Upregulation of Brain-Derived Neurotrophic Factor Evoked by Chronic Fluoxetine Treatment

Neurotrophic factors are regarded as crucial regulatory components in neuronal plasticity and are postulated to play an important role in depression pathology. The abundant expression of brain-derived neurotrophic factor (BDNF) in various brain structures seems to be of particular interest in this context, as downregulation of BDNF is postulated to be correlated with depression and its upregulation is often observed after chronic treatment with common antidepressants. It is well-known that BDNF expression is regulated by cyclic AMP response element-binding protein (CREB). In our previous study using mice lacking CREB in serotonergic neurons (Creb1^TPH2CreERT2 mice), we showed that selective CREB ablation in these particular neuronal populations is crucial for drug-resistant phenotypes in the tail suspension test observed after fluoxetine administration in Creb1^TPH2CreERT2 mice. The aim of this study was to investigate the molecular changes in the expression of neurotrophins in Creb1^TPH2CreERT2 mice after chronic fluoxetine treatment, restricted to the brain structures implicated in depression pathology with profound serotonergic innervation including the prefrontal cortex (PFC) and hippocampus. Here, we show for the first time that BDNF upregulation observed after fluoxetine in the hippocampus or PFC might be dependent on the transcription factor CREB residing, not within these particular structures targeted by serotonergic projections, but exclusively in serotonergic neurons. This observation may shed new light on the neurotrophic hypothesis of depression, where the effects of BDNF observed after antidepressants in the hippocampus and other brain structures were rather thought to be regulated by CREB residing within the same brain structures. Overall, these results provide further evidence for the pivotal role of CREB in serotonergic neurons in maintaining mechanisms of antidepressant drug action by regulation of BDNF levels.

Social Defeat Stress, Sex, and Addiction-Like Behaviors

Social confrontation is a form of social interaction in animals where two conspecific individuals confront each other in dispute over territory, during the formation of hierarchies, and during breeding seasons. Typically, a social confrontation involves a prevailing individual and a yielding individual. The prevailing individual often exhibits aggressive postures and launches attacks, whereas the yielding individual often adopts postures of defeat. The yielding or defeated animals experience a phenomenon known as social defeat stress, in which they show exaggerated stress as well as autonomic and endocrine responses that cause impairment of both the brain and body. In laboratory settings, one can reliably generate social defeat stress by allowing a naïve (or already defeated) animal to intrude into a home cage in which its resident has already established a territory or is nursing. This resident-intruder paradigm has been widely used in both males and females to study mechanisms in the brain that underlie the stress responses. Stress has profound effects on drug reward for cocaine, methamphetamine, alcohol, and opioids. Particularly, previous experiences with social defeat can exaggerate subsequent addiction-like behaviors. The extent of these addiction-like behaviors depends on the intensity, duration, frequency, and intermittency of the confrontation episodes. This chapter describes four types of social defeat stress: acute, repeated, intermittent, and chronic. Specifically, it focuses on social defeat stress models used in laboratories to study individual, sex, and animal strain differences in addiction-like behaviors.

Medication for Behavior Modification in Birds

The use of behavior modifying drugs may be considered in birds with behavior problems, especially those refractory to behavior modification therapy and environmental management. To accomplish behavior change, a variety of drugs can be used, including psychoactive drugs, hormones, antihistamines, analgesics, and anticonvulsants. Because their prescription to birds is off-label, these drugs are considered appropriate only when a sound rationale can be provided for their use. This requires a (correct) behavioral diagnosis to be established. In addition, regular monitoring and follow-up are warranted to determine the efficacy of the treatment and evaluate the occurrence of potential adverse side effects.

Sex differences in the psychopharmacological treatment of depression

Although a number of studies have observed that females respond better to serotonergic antidepressants than males and that postmenopausal females have a diminished response to antidepressants compared with younger females, there are also studies that conflict with both of these findings, making any generalizations regarding sex differences difficult to make. Sex variance in antidepressant efficacy and pharmacokinetics profiles have been attributed to sex-based physiological differences, behavioral differences, related disorders, and sex-specific conditions, including pregnancy and menopause. This paper will review the history and current research on sex effects of antidepressant treatment.

Sex-dependent mental illnesses and mitochondria

The prevalence of some mental illnesses, including major depression, anxiety-, trauma-, and stress-related disorders, some substance use disorders, and later onset of schizophrenia, is higher in women than men. While the higher prevalence in women could simply be explained by socioeconomic determinants, such as income, social status, or cultural background, extensive studies show sex differences in biological, pharmacokinetic, and pharmacological factors contribute to females' vulnerability to these mental illnesses. In this review, we focus on estrogens, chronic stress, and neurotoxicity from behavioral, pharmacological, biological, and molecular perspectives to delineate the sex differences in these mental illnesses. Particularly, we investigate a possible role of mitochondrial function, including biosynthesis, bioenergetics, and signaling, on mediating the sex differences in psychiatric disorders.

Sex-specific transcriptional signatures in human depression

Major depressive disorder (MDD) is a leading cause of disease burden worldwide. While the incidence, symptoms and treatment of MDD all point toward major sex differences, the molecular mechanisms underlying this sexual dimorphism remain largely unknown. Here, combining differential expression and gene coexpression network analyses, we provide a comprehensive characterization of male and female transcriptional profiles associated with MDD across six brain regions. We overlap our human profiles with those from a mouse model, chronic variable stress, and capitalize on converging pathways to define molecular and physiological mechanisms underlying the expression of stress susceptibility in males and females. Our results show a major rearrangement of transcriptional patterns in MDD, with limited overlap between males and females, an effect seen in both depressed humans and stressed mice. We identify key regulators of sex-specific gene networks underlying MDD and confirm their sex-specific impact as mediators of stress susceptibility. For example, downregulation of the female-specific hub gene Dusp6 in mouse prefrontal cortex mimicked stress susceptibility in females, but not males, by increasing ERK signaling and pyramidal neuron excitability. Such Dusp6 downregulation also recapitulated the transcriptional remodeling that occurs in prefrontal cortex of depressed females. Together our findings reveal marked sexual dimorphism at the transcriptional level in MDD and highlight the importance of studying sex-specific treatments for this disorder.

Lurasidone in post-menopausal females with major depressive disorder with mixed features: Post-hoc analysis of a placebo-controlled trial

BACKGROUND

Several studies have found that depressed, post-menopausal females may respond differently to antidepressants compared to pre-menopausal females. The atypical antipsychotic lurasidone, whose mechanism of action differs from SSRIs and other standard antidepressants, was shown in a 6-week randomized, flexible-dose, placebo-controlled study (n=209), to be effective in treating major depressive disorder (MDD) with mixed features (subthreshold hypomanic symptoms). This post-hoc analysis assessed the efficacy of lurasidone in this study by menopausal status.

METHODS

The main outcome measure for this post-hoc analysis was change in MADRS score from baseline to week 6 endpoint for two lurasidone-treated subgroups: presumptive pre-menopausal (<52years) and presumptive post-menopausal (≥52years) patients, compared to placebo treatment, using a mixed-model for repeated-measures analysis, and calculation of the effect size for each subgroup. Additional efficacy assessments included the CGI-S, HAM-A and YMRS. An exploratory analysis was also conducted removing presumptive peri-menopausal women (ages 45-51years) to allow for clearer definition of pre- and post-menopausal status.

RESULTS

A total of 56 lurasidone-treated and 47 placebo-treated pre-menopausal females, and 17 lurasidone-treated and 25 placebo-treated post-menopausal females were available from the larger study for comparison on key outcome measures. The pre- and post-menopausal subgroups had similar demographic and clinical characteristics at study baseline (other than age), including number of past major depressive episodes as well as depressive and manic symptom severity. Mean daily lurasidone dose was similar for each subgroup during the study. Both the primary and exploratory analyses showed that both lurasidone-treated post-menopausal and pre-menopausal females responded significantly compared to placebo (p=0.016 or less) on the MADRS, and that post-menopausal patients had a numerically larger response (effect size=0.96) than pre-menopausal patients (effect size=0.64). All other secondary outcome measures for lurasidone compared with placebo treatment were significant (p=0.045 or less) for both subgroups.

CONCLUSIONS

In this post-hoc analysis, lurasidone was found to be effective in treating post-menopausal MDD patients with mixed features (subthreshold hypomanic symptoms).

EEG connectivity between the subgenual anterior cingulate and prefrontal cortices in response to antidepressant medication

Antidepressant medication is the most common treatment for major depressive disorder (MDD), however, the precise working mechanism underlying these treatments remains unclear. Recent neuromodulation treatments demonstrate that direct stimulation of the dorsolateral prefrontal cortex (DLPFC), dorsomedial prefrontal cortex (DMPFC), and subgenual anterior cingulate (sgACC) relate to clinical improvement, suggesting connectivity alterations of the DLPFC-DMPFC-sgACC network to mediate antidepressant response. The international Study to Predict Optimized Treatment in Depression (iSPOT-D) is an international multicentre study that collected EEG data for 1008 MDD patients, randomized to 3 different antidepressant medications (N=447 MDD with complete pre- and post-treatment data and N=336 non-MDD). Treatment response was defined by a decline of >50% on the Hamilton Rating Score for Depression (HRSD₁₇). We investigated whether connectivity in alpha and theta frequencies of the DLPFC-DMPFC-sgACC network changed from pre- to post-treatment between: (i) patients and controls, and (ii) responders (R) and non-responders (NR). Women exhibited higher alpha and theta connectivity compared to males, both pre- and post-treatment. Furthermore, theta, but not alpha, hypo-connectivity was found for MDD patients. A decreased alpha connectivity after treatment was found only for male responders, while non-responders and females exhibited no changes in alpha connectivity. Decreasing alpha connectivity could potentially serve as a treatment emergent biomarker, in males only. Furthermore, it could be useful to a priori stratify by gender for future MDD studies.

Why are women so vulnerable to anxiety, trauma-related and stress-related disorders? The potential role of sex hormones

Increased prevalence, severity, and burden of anxiety, trauma-related and stress-related disorders in women compared with men has been well documented. Evidence from a variety of fields has emerged suggesting that sex hormones, particularly oestradiol and progesterone, play a significant part in generation of these sex differences. In this Series paper, we aim to integrate the literature reporting on the effects of sex hormones on biological, behavioural, and cognitive pathways, to propose two broad mechanisms by which oestradiol and progesterone influence sex differences in anxiety disorders: augmentation of vulnerability factors associated with anxiety disorder development; and facilitation of the maintenance of anxious symptoms post-development. The implications for future research, along with novel approaches to psychological and pharmacological treatment of anxiety disorders, are also considered.

Integrative Analysis of Sex-Specific microRNA Networks Following Stress in Mouse Nucleus Accumbens

Adult women are twice as likely as men to suffer from affective and anxiety disorders, although the mechanisms underlying heightened female stress susceptibility are incompletely understood. Recent findings in mouse Nucleus Accumbens (NAc) suggest a role for DNA methylation-driven sex differences in genome-wide transcriptional profiles. However, the role of another epigenetic process-microRNA (miR) regulation-has yet to be explored. We exposed male and female mice to Subchronic Variable Stress (SCVS), a stress paradigm that produces depression-like behavior in female, but not male, mice, and performed next generation mRNA and miR sequencing on NAc tissue. We applied a combination of differential expression, miR-mRNA network and functional enrichment analyses to characterize the transcriptional and post-transcriptional landscape of sex differences in NAc stress response. We find that male and female mice exhibit largely non-overlapping miR and mRNA profiles following SCVS. The two sexes also show enrichment of different molecular pathways and functions. Collectively, our results suggest that males and females mount fundamentally different transcriptional and post-transcriptional responses to SCVS and engage sex-specific molecular processes following stress. These findings have implications for the pathophysiology and treatment of stress-related disorders in women.

Disruption of the Glutamate-Glutamine Cycle Involving Astrocytes in an Animal Model of Depression for Males and Females

Background: Women are twice as likely as men to develop major depression. The brain mechanisms underlying this sex disparity are not clear. Disruption of the glutamate–glutamine cycle has been implicated in psychiatric disturbances. This study identifies sex-based impairments in the glutamate–glutamine cycle involving astrocytes using an animal model of depression.

Methods: Male and female adult Long-Evans rats were exposed to chronic social defeat stress (CSDS) for 21 days, using a modified resident-intruder paradigm. Territorial aggression was used for males and maternal aggression was used for females to induce depressive-like deficits for intruders. The depressive-like phenotype was assessed with intake for saccharin solution, weight gain, estrous cycle, and corticosterone (CORT). Behaviors displayed by the intruders during daily encounters with residents were characterized. Rats with daily handling were used as controls for each sex. Ten days after the last encounter, both the intruders and controls were subjected to a no-net-flux in vivo microdialysis to assess glutamate accumulation and extracellular glutamine in the nucleus accumbens (NAc). The contralateral hemispheres were used for determining changes in astrocytic markers, including glial fibrillary acidic protein (GFAP) and glutamate transporter-1 (GLT-1).

Results: Both male and female intruders reduced saccharin intake over the course of CSDS, compared to their pre-stress period and to their respective controls. Male intruders exhibited submissive/defensive behaviors to territorial aggression by receiving sideways threats and bites. These males showed reductions in striatal GLT-1 and spontaneous glutamine in the NAc, compared to controls. Female intruders exhibited isolated behaviors to maternal aggression, including immobility, rearing, and selfgrooming. Their non-reproductive days were extended. Also, they showed reductions in prefrontal and accumbal GFAP⁺ cells and prefrontal GLT-1, compared to controls. When 10 μM of glutamate was infused, these females showed a significant accumulation of glutamate compared to controls. Infusions of glutamate reduced extracellular glutamine for both male and female intruders compared to their respective controls.

Conclusion: Twenty-one days of territorial or maternal aggression produced a depressive-like phenotype and impaired astrocytes in both male and female intruders. Disruption of the glutamate–glutamine cycle in the PFC-striatal network may be linked to depressive-like deficits more in females than in males.

Serotonin and arginine-vasopressin mediate sex differences in the regulation of dominance and aggression by the social brain

There are profound sex differences in the incidence of many psychiatric disorders. Although these disorders are frequently linked to social stress and to deficits in social engagement, little is known about sex differences in the neural mechanisms that underlie these phenomena. Phenotypes characterized by dominance, competitive aggression, and active coping strategies appear to be more resilient to psychiatric disorders such as posttraumatic stress disorder (PTSD) compared with those characterized by subordinate status and the lack of aggressiveness. Here, we report that serotonin (5-HT) and arginine-vasopressin (AVP) act in opposite ways in the hypothalamus to regulate dominance and aggression in females and males. Hypothalamic injection of a 5-HT1a agonist stimulated aggression in female hamsters and inhibited aggression in males, whereas injection of AVP inhibited aggression in females and stimulated aggression in males. Striking sex differences were also identified in the neural mechanisms regulating dominance. Acquisition of dominance was associated with activation of 5-HT neurons within the dorsal raphe in females and activation of hypothalamic AVP neurons in males. These data strongly indicate that there are fundamental sex differences in the neural regulation of dominance and aggression. Further, because systemically administered fluoxetine increased aggression in females and substantially reduced aggression in males, there may be substantial gender differences in the clinical efficacy of commonly prescribed 5-HT-active drugs such as selective 5-HT reuptake inhibitors. These data suggest that the treatment of psychiatric disorders such as PTSD may be more effective with the use of 5-HT-targeted drugs in females and AVP-targeted drugs in males.

Association of treatment response with obesity and other metabolic risk factors in adults with depressive disorders: Results from a National Depression Cohort study in Korea (the CRESCEND study)

BACKGROUND

Available studies indicate that obesity may exert a moderational effect on antidepressant treatment response. The aim of this study was to investigate the relationship between treatment response and metabolic abnormalities amongst patients with depressive disorders in a large naturalistic clinical setting.

METHODS

A nationwide prospective study was conducted in 18 hospitals in South Korea; 541 depressive patients meeting DSM-IV criteria were recruited. After baseline evaluation, subjects received naturalistic clinician-determined antidepressant interventions. Assessment was performed at baseline and weeks 1, 2, 4, 8, 12, 24 and 52. Treatment response was defined as a ≥50% reduction from baseline on at least one evaluation point.

RESULTS

In univariate comparison, the patients who showed insufficient response to antidepressant therapy were more likely to be male, unmarried, unemployed, and obese. After adjusting for baseline variables, male sex (OR=1.82) and obesity (OR=1.55) remained as were significant variables. Stratification of the subjects into one of three groups, i.e. male, pre-menopausal female and post-menopausal female, revealed that males with concurrent metabolic problems, (i.e. the presence of one or more of hypertension, hyperglycemia, or hypercholesterolemia) had significantly higher risk for insufficient response (OR=2.32) and, after adjusting for baseline variables, obesity predicted insufficient response in post-menopausal female (OR=2.41).

CONCLUSIONS

The presence of metabolic abnormalities in patients with depressive disorders was associated with decreased treatment response to antidepressants. These results underscore the neurobiological relationship between obesity and the central nervous system, and provide empiric evidence supporting stratification of treatment response in depression.

Gender Differences in Depression

Depression is among the most prevalent and debilitating psychiatric disorders in the world. A striking feature of this disorder is that women are twice as likely to experience depression compared with men. Research indicates that genetic, biological and environmental factors contribute to the gender differences noted in depression. Women are more likely to suffer a greater number of and more severe stressful life events compared with men, although no gender difference has been found to explain the genetic vulnerability. As individuals with depression most frequently present to general practitioners, healthcare providers should consider screening for depression and using rigorous treatment strategies for depressed patients with comorbid medical illnesses.

Anxiolytic effects of fluoxetine and nicotine exposure on exploratory behavior in zebrafish

Zebrafish (Danio rerio) have emerged as a popular model for studying the pharmacology and behavior of anxiety. While there have been numerous studies documenting the anxiolytic and anxiogenic effects of common drugs in zebrafish, many do not report or test for behavioral differences between the sexes. Previous studies have indicated that males and females differ in their baseline level of anxiety. In this study, we test for a sex interaction with fluoxetine and nicotine. We exposed fish to system water (control), 10 mg/L fluoxetine, or 1 mg/L nicotine for three minutes prior to being subjected to four minutes in an open-field drop test. Video recordings were tracked using ProAnalyst. Fish from both drug treatments reduced swimming speed, increased vertical position, and increased use of the top half of the open field when compared with the control, though fluoxetine had a larger effect on depth related behaviors while nicotine mostly affected swimming speed. A significant sex effect was observed where females swam at a slower and more constant speed than males, however neither drug produced a sex-dependent response.

Chronic fluoxetine treatment induces anxiolytic responses and altered social behaviors in medaka, Oryzias latipes

Medaka (Oryzias latipes) is a small freshwater teleost that is an emerging model system for neurobehavioral research and toxicological testing. The selective serotonin reuptake inhibitor class of antidepressants such as fluoxetine is one of the widely prescribed drugs, but little is known about the effects of these drugs on medaka behaviors. To assess the behavioral effects of fluoxetine, we chronically administrated fluoxetine to medaka adult fish and analyzed the anxiety-related and social behaviors using five behavioral paradigms (diving, open-field, light-dark transition, mirror-biting, and social interaction) with an automated behavioral testing system. Fish chronically treated with fluoxetine exhibited anxiolytic responses such as an overall increased time spent in the top area in the diving test and an increased time spent in center area in the open-field test. Analysis of socially evoked behavior showed that chronic fluoxetine administration decreased the number of mirror biting times in the mirror-biting test and increased latency to first contact in the social interaction test. Additionally, chronic fluoxetine administration reduced the horizontal locomotor activity in the open-field test but not the vertical activity in the diving test. These investigations are mostly consistent with previous reports in the other teleost species and rodent models. These results indicate that behavioral assessment in medaka adult fish will become useful for screening of effects of pharmaceutical and toxicological compounds in animal behaviors.

5-HTTLPR and gender differences in affective disorders: A systematic review

BACKGROUND

Serotonin transporter-linked polymorphic region (5-HTTLPR) variants have been extensively studied in psychiatric disorders. Although gender effects have been reported, they have not been comprehensively reviewed. The aim of our study was to summarize literature findings on 5-HTTLPR and gender differences in affective disorders.

METHODS

A systematic search of PubMed, ISI Web of Knowledge, and PsycINFO databases was performed for dates until January 2015. The included articles (n=78) analyzed the association between 5-HTTLPR and affective spectrum disorders, taking into account gender. The quality of each study was assessed through STROBE and CONSORT.

RESULTS

5-HTTLPR modulation of affective disorders varied by gender. The S allele (or SS genotype) seemed to be differently associated with an increased risk of depression, depressive symptoms, anxiety traits and symptoms, and symptoms of internalizing behavior among women and an increased risk of aggressiveness, conduct disorder and symptom counts of externalizing behavior among men. Moreover, the presence of stressful life events reinforced the association. Interestingly, these differences seemed to begin with adolescence and were not consistent among the elderly, suggesting a plausible role of hormonal fluctuations.

LIMITATIONS

The review is limited by the small number of included papers, due to the paucity of information in the literature regarding 5-HTTLPR and gender.

CONCLUSIONS

5-HTTLPR variants may exert a differential modulation on a number of features depending on gender. Further studies are needed to more deeply investigate the effect of 5-HTTLPR×gender on the modulation of affective disorders.

Obesity and Its Potential Effects on Antidepressant Treatment Outcomes in Patients with Depressive Disorders: A Literature Review

Accumulating evidence regarding clinical, neurobiological, genetic, and environmental factors suggests a bidirectional link between obesity and depressive disorders. Although a few studies have investigated the link between obesity/excess body weight and the response to antidepressants in depressive disorders, the effect of weight on treatment response remains poorly understood. In this review, we summarized recent data regarding the relationship between the response to antidepressants and obesity/excess body weight in clinical studies of patients with depressive disorders. Although several studies indicated an association between obesity/excess body weight and poor antidepressant responses, it is difficult to draw definitive conclusions due to the variability of subject composition and methodological differences among studies. Especially, differences in sex, age and menopausal status, depressive symptom subtypes, and antidepressants administered may have caused inconsistencies in the results among studies. The relationship between obesity/excess body weight and antidepressant responses should be investigated further in high-powered studies addressing the differential effects on subject characteristics and treatment. Moreover, future research should focus on the roles of mediating factors, such as inflammatory markers and neurocognitive performance, which may alter the antidepressant treatment outcome in patients with comorbid obesity and depressive disorder.

Sex-Specific and Estrous Cycle-Dependent Antidepressant-Like Effects and Hippocampal Akt Signaling of Leptin

Sex differences in the incidence of depression and antidepressant treatment responses are well documented. Depression is twice as common in women as in men. Recent studies indicate that low levels of leptin, an adipocyte-derived hormone, are associated with increased symptoms of depression in women. Leptin has been shown to produce antidepressant-like effects in male rodents. In the present study, we examined sex differences and estrous cycle variations in antidepressant-like responses to leptin. Leptin administration significantly reduced immobility, a putative measure of behavioral despair, in the forced swim test in intact female mice in the proestrus phase but not in the diestrus phase of the estrous cycle. Moreover, leptin administration stimulated Akt phosphorylation in the hippocampus of female mice in proestrus but not in diestrus, in correlation with its differential behavioral effects in these two phases of the cycle. Leptin-induced behavioral responses and stimulation of hippocampal Akt phosphorylation in female mice were abolished by ovariectomy. By contrast, the antidepressant-like effect of leptin in male mice was not affected by gonadectomy (castration). Pretreatment with 17β-estradiol restored sensitivity to the effects of leptin on behavior and hippocampal Akt phosphorylation in ovariectomized female mice. These results suggest leptin regulates depression-like behavior and hippocampal Akt signaling in a sex-specific and estrous cycle-dependent manner.

A pooled analysis of the efficacy of desvenlafaxine for the treatment of major depressive disorder in perimenopausal and postmenopausal women

BACKGROUND

Few studies in the literature have examined the efficacy of antidepressant drugs in perimenopausal and postmenopausal women. The objective of the current study was to assess the efficacy of desvenlafaxine (administered as desvenlafaxine succinate) separately in perimenopausal and postmenopausal women with major depressive disorder (MDD).

METHODS

Data were pooled from two double-blind, placebo-controlled clinical trials enrolling perimenopausal and postmenopausal women (40-70 years old) diagnosed with MDD. Patients were randomly assigned to receive desvenlafaxine 100 to 200 mg/day or placebo (8 weeks) or desvenlafaxine 50 mg/day or placebo (10 weeks). The primary efficacy end point for each trial was change from baseline in Hamilton Rating Scale for Depression (HAM-D17) total score at week 8. Secondary end points included change from baseline in Sheehan Disability Scale (SDS) and Menopause Rating Scale (MRS) scores. Changes from baseline in continuous variables were analyzed using analysis of covariance with treatment, region, and baseline in the model. All treatment comparisons were carried out separately in perimenopausal or postmenopausal women, in individual studies, and in the pooled population, adjusting for menopausal status and study.

RESULTS

A total of 798 patients were included in the full analysis set (perimenopausal, n=252; postmenopausal, n=546). Desvenlafaxine significantly reduced HAM-D17 total scores versus placebo at week 8 in both perimenopausal (-10.3 vs. -6.5; p<0.001) and postmenopausal women (-10.1 vs. -7.6; p<0.001). Significant improvements in SDS and MRS total scores were also observed for desvenlafaxine versus placebo in perimenopausal (p ≤ 0.024) and postmenopausal women (p ≤ 0.009). A significant treatment by menopausal status interaction was observed for SDS only (p=0.036).

CONCLUSIONS

Desvenlafaxine demonstrated antidepressant efficacy in both perimenopausal and postmenopausal subgroups of women with MDD.

DISCLAIMER

In September 2011, Pfizer received a Complete Response Letter from the United States Food and Drug Administration on its application for approval to market desvenlafaxine for the treatment of moderate to severe vasomotor symptoms associated with menopause. The Complete Response Letter states that the data included in the application are not sufficient to establish an acceptable risk/benefit profile for the treatment of vasomotor symptoms in the general population of postmenopausal women, and therefore desvenlafaxine is not approved for the treatment of vasomotor symptoms in the United States at this time. This decision does not impact desvenlafaxine's approval for the treatment of MDD in adults.

Evidence-based guidelines for treating depressive disorders with antidepressants: A revision of the 2008 British Association for Psychopharmacology guidelines

A revision of the 2008 British Association for Psychopharmacology evidence-based guidelines for treating depressive disorders with antidepressants was undertaken in order to incorporate new evidence and to update the recommendations where appropriate. A consensus meeting involving experts in depressive disorders and their management was held in September 2012. Key areas in treating depression were reviewed and the strength of evidence and clinical implications were considered. The guidelines were then revised after extensive feedback from participants and interested parties. A literature review is provided which identifies the quality of evidence upon which the recommendations are made. These guidelines cover the nature and detection of depressive disorders, acute treatment with antidepressant drugs, choice of drug versus alternative treatment, practical issues in prescribing and management, next-step treatment, relapse prevention, treatment of relapse and stopping treatment. Significant changes since the last guidelines were published in 2008 include the availability of new antidepressant treatment options, improved evidence supporting certain augmentation strategies (drug and non-drug), management of potential long-term side effects, updated guidance for prescribing in elderly and adolescent populations and updated guidance for optimal prescribing. Suggestions for future research priorities are also made.

Sex differences in the pharmacokinetics of antidepressants: influence of female sex hormones and oral contraceptives

Women are twice as likely to develop depression as men. Moreover, the symptoms they experience also show sex differences: women tend to develop depression at an earlier age and show more severe symptoms than men. Likewise, the response to antidepressant pharmacotherapy appears to have sex differences. These differences can partially be explained by differences in pharmacokinetic properties (i.e., absorption, distribution, metabolism, and excretion) of drugs in males and females. More recent research has shown that sex hormones may influence all these previously named pharmacokinetic processes. As concentrations of sex hormones vary throughout the female lifespan, these hormonal variations can have effects on therapeutic responses to antidepressants as well as the occurrence of adverse events. The purpose of this paper is therefore to review the literature reporting on the effects of female sex hormones on the pharmacokinetics of antidepressants and to discuss and evaluate the implications of changes in levels of sex hormones throughout life for the treatment of depression.

Drug-, dose- and sex-dependent effects of chronic fluoxetine, reboxetine and venlafaxine on open-field behavior and spatial memory in rats

In an effort to address the need to include both sexes in studies of effects of the SSRI fluoxetine, the NRI reboxetine and the SNRI venlafaxine on anxiety-related behavior and memory along with the use of chronic drug administration, male and female PVG/c rats were fed diets containing two doses of each drug for 21 days. The rats' anxiety level was then assessed in an open field. Short-term spatial memory for a brightness change in a Y maze was also measured. While there was little evidence of anxiolytic effects of any of the drugs, both fluoxetine and, to a lesser extent, venlafaxine appeared to be mainly anxiogenic in their action depending on both dose and sex. Reboxetine was relatively ineffective in this respect. Ability to locate the Y-maze arm that had changed (from white to black) seemed to be impaired for male (but not female) rats by both fluoxetine and venlafaxine and, to a much lesser extent, by reboxetine. Given the relative ineffectiveness of reboxetine in either test, it is possible that the effects of the other two drugs on both anxiety and memory were mainly due to their serotonin reuptake inhibiting properties. The differences that occurred between males and females in responsiveness to all three drugs supported the long-held view that both sexes should be investigated in studies of this sort, especially in view of reports of sex differences in effects of clinically prescribed antidepressants.

Gender differences in genetic mouse models evaluated for depressive-like and antidepressant behavior

Depression is a mental disease that affects complex cognitive and emotional functions. It is believed that depression is twice as prevalent in women as in men. This phenomenon may influence the response to various antidepressant therapies, and these differences are still underestimated in clinical treatment. Nevertheless, most of the current findings are based on studies on male animal models, and relatively few of these studies take possible gender differences into consideration. Advancements in genetic engineering over the last two decades have introduced many transgenic lines that have been screened to study the pathomechanisms of depression. In this mini-review, we provide a compendious list of genetically altered mice that underwent tests for depressive-like or antidepressant behavior and determine if and how the gender factor was analyzed in their evaluation. Furthermore, we compile the gender differences in response to antidepressant treatment. On the basis of these analyses, we conclude that in many cases, gender variability is neglected or not taken into consideration in the presented results. We note the necessity of discussing this issue in the phenotypic characterization of transgenic mice, which seems to be particularly important while modeling mental diseases.

Baseline vitamin B12 and folate levels do not predict improvement in depression after a single infusion of ketamine

INTRODUCTION

Deficiencies in both vitamin B12 and folate have been associated with depression. Recently, higher baseline vitamin B12 levels were observed in individuals with bipolar depression who responded to the antidepressant ketamine at 7 days post-infusion. This study sought to -replicate this result by correlating peripheral vitamin levels with ketamine's antidepressant efficacy in bipolar depression and major depressive disorder (MDD).

METHODS

Baseline vitamin B12 and folate levels were obtained in 49 inpatients with treatment-resistant MDD and 34 inpatients with treatment-resistant bipolar depression currently experiencing a major depressive episode. All subjects received a single intravenous ketamine infusion. Post-hoc Pearson correlations were performed between baseline vitamin B12 and folate levels, as well as antidepressant response assessed by percent change in Hamilton Depression Rating Scale (HDRS) scores from baseline to 230 min, 1 day, and 7 days post-infusion.

RESULTS

No significant correlation was observed between baseline vitamin B12 or folate and percent change in HDRS for any of the 3 time points in either MDD or bipolar depression.

DISCUSSION

Ketamine's antidepressant efficacy may occur independently of baseline peripheral vitamin levels.

A gender analysis of the study of pharmacotherapy of psychotic depression (STOP-PD): gender and age as predictors of response and treatment-associated changes in body mass index and metabolic measures

BACKGROUND

Gender differences exist in psychiatric disorders; however, gender has not been well studied in psychotic depression. This analysis of the largest clinical trial in psychotic depression examined the effects of age and gender on clinical characteristics and predictors of treatment outcome and treatment-associated changes in body mass index (BMI) and metabolic measures.

METHOD

Secondary analyses were performed on data from 259 subjects with major depressive disorder with psychotic features (DSM-IV-TR) aged 18-93 years in the double-blind randomized controlled trial of olanzapine plus sertraline versus olanzapine plus placebo for psychotic depression (Study of Pharmacotherapy of Psychotic Depression). Sociodemographic factors, clinical characteristics, treatment outcome, and treatment-associated changes in BMI and metabolic measures were analyzed by gender and age. Subjects were enrolled from December 2002 to June 2007.

RESULTS

Female gender was associated with divorced (χ(2)(1) = 5.3, P = .03) or widowed (χ(2)(1) = 8.1, P ≤ .01) marital status. Comorbid anxiety disorders were more common in women than in men (χ(2)(1) = 4.9, P = .03). Hallucinations (χ(2)(1) = 7.8, P = .005) and delusions with disorganization (t(257) = -2.10, P = .04) were significantly associated with female gender, as were higher cholesterol measures (χ(2)(1) = 7.15, P = .008). There were no significant interactions between treatment and gender in terms of change in BMI. Gender was not associated with treatment response.

DISCUSSION

This study is the first analysis of gender and age as predictors of treatment outcome and treatment-associated changes in BMI and metabolic adverse effects in psychotic depression. Gender differences exist in patients with psychotic depression, most notably with regard to the presence of hallucinations. Female gender was associated with metabolic measures. Future studies with larger sample sizes may detect small gender differences in treatment outcome and treatment-associated changes in BMI and metabolic measures in psychotic depression.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00056472.

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.