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Abstract: The goal of the present work was to conduct a meta-analysis comparing reboxetine and the selective serotonin reuptake inhibitors (SSRIs) for major depressive disorder (MDD). Medline/Pubmed was searched for double-blind, randomized trials comparing these two agents for MDD. The makers of reboxetine (Pfizer Inc.) were also contacted to provide missing data and/or unpublished studies. 9 trials (n =2641) were combined using a random effects model. Response rates were comparable between the SSRI (63.9%) and reboxetine (59.2%)-treated groups (p =0.118). There was no significant difference in the degree of improvement in psychosocial functioning, as measured by the social adaptation self-evaluation scale, between the two groups. Overall discontinuation rates (25.1% versus 32.0%; p =0.015), and the rate of discontinuation due to intolerance (8.5% versus 12.6%; p =0.007) favored SSRI treatment. The rate of discontinuation due to lack of efficacy did not differ significantly between the two groups. SSRI-treated patients were more likely to experience nausea, hypersomnia, and fatigue. Reboxetine-treated patients were more likely to experience constipation, difficulty urinating, and insomnia. These results suggest that the NRI reboxetine and the SSRIs differ with respect to their side-effect profile and overall tolerability but not their efficacy in treating MDD. [Copyright &y& Elsevier]

Background: We examined two previously published studies comparing a norepinephrine (NE) selective agent, reboxetine, and a serotonin (5-HT) selective agent, fluoxetine, to determine if these agents have different effects on individual depressive symptoms. Methods: Both studies were 8-week, double-blind, comparison studies of men and women with DSM III-R major depression. Within-group effect sizes for individual symptom change on the Hamilton Depression Rating Scale (HAMD) were determined in the observed case samples and in patients for whom the symptom was relatively severe at baseline. We required that any significant differences in one sample be cross-validated in the second. Results: Two hundred fifty-three subjects in study I and 168 subjects in study II were randomized to reboxetine or fluoxetine. In both samples, depressed mood, decreased interest, and psychic anxiety had the greatest change. Effect sizes for all HAMD symptoms were similar for the two drugs. No difference between groups in one sample was replicated in the second. Among subjects with severe symptoms, no significant differences were cross-validated. Conclusions: Reboxetine and fluoxetine appear to have similar effects on depressive symptoms. These data suggest that NE and 5-HT selective antidepressant drugs act through the same final common pathway and challenge the belief that symptom differences are useful for antidepressant selection. [Copyright &y& Elsevier]

: BackgroundAlthough several antidepressants are now available, all have limited efficacy and a delayed onset of action. The current study was undertaken as a proof of the concept that combining norepinephrine and serotonin reuptake inhibition would be more effective and act more rapidly than either drug alone.: MethodsInpatients with nonpsychotic unipolar major depression and a Hamilton Depression Rating Scale (HAMD) score of at least 18 after 1 week of hospitalization without antidepressant medication were randomized to 6 weeks of treatment with fluoxetine (FLX) 20 mg/day, desipramine (DMI) adjusted to an adequate plasma level, or the combination of FLX 20 mg/day and DMI, given under double-blind conditions. Twenty-four-hour DMI levels were used to rapidly adjust DMI dose to achieve a therapeutic level and to anticipate the enzyme-inhibiting effects of FLX. Treatment-resistant patients were stratified. Patients were rated with the HAMD and the Montgomery-Asberg Depression Rating Scale (MADRS).: ResultsThirty-nine patients began treatment. One patient withdrew consent. The DMI–FLX combination was significantly more likely to result in remission on the MADRS than either FLX or DMI alone [53.8% vs. 7.1% and 0%, respectively; χ2(2) = 13.49, p = .001]. The advantage for combined treatment was not explained by history of treatment resistance or by drug plasma concentrations. Rapid response, at 1 or 2 weeks, was neither statistically nor meaningfully greater with combined treatment.: ConclusionsThis study supports the hypothesis that the combination of a noradrenergic and serotonergic agent is more likely to result in remission than either selective agent alone during a 6-week treatment period. [Copyright &y& Elsevier]

Deals with the use of selective serotonin reuptake inhibitors in the treatment of depression. Studies which demonstrated that interruption of the synthesis of 5-HT or norepinephrine compromised the antidepressant effect of drugs; Effectiveness of antidepressants that combine noradrenergic and serotonergic mechanisms; Mechanism of action of the mirtazapine drug.

Background: Less than half of patients with major depressive disorder (MDD) respond to their first antidepressant trial. Our understanding of the underlying mechanisms of selective serotonin reuptake inhibitors (SSRIs) remains poor, and there is no reliable method of predicting treatment response.Methods: Thirty-seven MDD subjects and 41 healthy controls, somatically healthy and medication-free for at least six weeks, were recruited, and plasma serotonin (5-HT) levels were assessed at baseline. Twenty-six of the MDD subjects were then treated in an open-label manner with clinically appropriate doses of sertraline for 8 weeks, after which plasma 5-HT levels were again assessed. Response to treatment was defined as an improvement of 50% or more on the Hamilton Depression Rating Scale.Results: Non-responders to sertraline treatment had significantly lower pre-treatment 5-HT levels compared to both healthy controls and responders (F = 4.4, p = 0.004 and p = 0.036, respectively). There was a significant decrease in 5-HT levels over treatment in all MDD subjects (t = 6.2, p = 0.000003). The decrease was significantly more prominent in responders compared to non-responders (t = 2.1, p = 0.047). There was no significant difference in post-treatment 5-HT levels between responders and non-responders.Limitations: The study had a modest sample size. 5-HT levels in plasma may not reflect 5-HT levels in the brain.Conclusions: The results indicate that SSRI response may be facilitated by adequate baseline plasma 5-HT content and that successful SSRI treatment is associated with greater decreases in circulating 5-HT. Plasma 5-HT content may be a predictor of SSRI treatment outcome. Potential underlying mechanisms are discussed. [ABSTRACT FROM AUTHOR]

Background Randomised, placebo-controlled trials of treatments for depression typically collect outcomes data but traditionally only analyse data to demonstrate efficacy and safety. Additional post-hoc statistical techniques may reveal important insights about treatment variables useful when considering inter-individual differences amongst depressed patients. This paper aims to examine the Gradient Boosted Model (GBM), a statistical technique that uses regression tree analyses and can be applied to clinical trial data to identify and measure variables that may influence treatment outcomes. Methods GBM was applied to pooled data from 12 randomised clinical trials of 4987 participants experiencing an acute depressive episode who were treated with duloxetine, an SSRI or placebo to predict treatment remission. Additional analyses were conducted on the same dataset using the logistic regression model for comparison between these two methods. Results With GBM, there were noticeable differences between treatments when identifying which and to what extent variables were associated with remission. A single logistic regression only revealed a decreasing or increasing relationship between predictors and remission while GBM was able to reveal a complex relationship between predictors and remission. Limitations These analyses were conducted post-hoc utilising clinical trials databases. The criteria for constructing the analyses data were based on the characteristics of the clinical trials. Conclusions GBM can be used to identify and quantify patient variables that predict remission with specific treatments and has greater flexibility than the logistic regression model. GBM may provide new insights into inter-individual differences in treatment response that may be useful for selecting individualised treatments. Trial registration IMPACT clinical trial number 3327; IMPACT clinical trial number 4091; IMPACT clinical trial number 4689; IMPACT clinical trial number 4298; NCT00071695; NCT00062673; NCT00036335; NCT00067912; NCT00073411; NCT00489775; NCT00536471; NCT00666757 (note that trials with IMPACT numbers predate mandatory clinical trial registration requirements) [ABSTRACT FROM AUTHOR]

Abstract: Objectives: The “neurotrophin hypothesis” of depression posits a role of brain-derived neurotrophic factor (BDNF) in depression, although it is unknown whether BDNF is more involved in the etiology of depression or in the mechanism of action of antidepressants. It is also unknown whether pre-treatment serum BDNF levels predict antidepressant response. Methods: Thirty un-medicated depressed subjects were treated with escitalopram (N=16) or sertraline (N=14) for 8weeks. Twenty-five of the depressed subjects completed 8weeks of antidepressant treatment and had analyzable data. Twenty-eight healthy controls were also studied. Serum for BDNF assay was obtained at baseline in all subjects and after 8weeks of treatment in the depressed subjects. Depression ratings were obtained at baseline and after 8weeks of treatment in the depressed subjects. Results: Pre-treatment BDNF levels were lower in the depressed subjects than the controls (p=0.001) but were not significantly correlated with pre-treatment depression severity. Depression ratings improved with SSRI treatment (p<0.001), and BDNF levels increased with treatment (p=0.005). Changes in BDNF levels were not significantly correlated with changes in depression ratings. However, pre-treatment BDNF levels were directly correlated with antidepressant responses (p<0.01), and “Responders” to treatment (≥50% improvement in depression ratings) had higher pre-treatment BDNF levels than did “Non-responders” (p<0.05). Conclusions: These results confirm low serum BDNF levels in un-medicated depressed subjects and confirm antidepressant-induced increases in BDNF levels, but they suggest that antidepressants do not work simply by correcting BDNF insufficiency. Rather, these findings are consistent with a permissive or facilitatory role of BDNF in the mechanism of action of antidepressants. [Copyright &y& Elsevier]

Background: Recent studies suggest that the treatment of major depressive disorder (MDD) with newer antidepressant drugs that simultaneously enhance norepinephrine and serotonin neurotransmission might result in higher response and remission rates than the selective serotonin reuptake inhibitors (SSRIs). The goal of our work was to compare response rates among patients with MDD treated with either of these two broad categories of antidepressant drugs. Methods: Medline/Pubmed, EMBase, clinical trial registries, program syllabi from major psychiatric meetings held since 1995, and documents from relevant pharmaceutical companies were searched for double-blind, randomized trials comparing a newer serotonergic-noradrenergic antidepressant drug (venlafaxine, duloxetine, milnacipran, mirtazapine, mianserin, or moclobemide) with an SSRI for MDD. Results: Ninety-three trials (n = 17,036) were combined using a random-effects model. Treatment with serotonergic + noradrenergic antidepressant drugs was more likely to result in clinical response than the SSRIs (risk ratio [RR] = 1.059; response rates 63.6% versus 59.3%; p = .003). There was no evidence for heterogeneity among studies combined (p = 1.0). Excluding each individual agent did not significantly alter the pooled RR. With the exception of duloxetine (.985), RRs for response for each individual serotonergic + noradrenergic antidepressant drug were within the 95% confidence interval of the pooled RR (1.019–1.101). Conclusions: Serotonergic-noradrenergic antidepressant drugs seem to have a modest efficacy advantage compared with SSRIs in MDD. With the Number Needed to Treat (NNT) statistic as one indicator of clinical significance, nearly 24 patients would need to be treated with dual-action antidepressant drugs instead of SSRIs in order to obtain one additional responder. This difference falls well below the mark of NNT = 10 suggested by the United Kingdom’s National Institute of Clinical Excellence but nonetheless might be of public health relevance given the large number of depressed patients treated with SSRI /serotonin-norepinephrine reuptake inhibitor (SNRI) antidepressant drugs. Further research is needed to examine whether larger differences between classes of antidepressant drugs might exist in specific MDD sub-populations or for specific MDD symptoms. [Copyright &y& Elsevier]