Functioning in patients with major depressive disorder in remission: A systematic review and meta-analysis.

BACKGROUND: Major depressive disorder (MDD) is one of the leading causes of burden of disease globally. We aimed to investigate whether global functioning is impaired in patients with MDD in full or partial remission compared to healthy control individuals (HC). METHODS: We conducted a systematic review and meta-analysis according to the PRISMA guideline. We searched the databases PubMed, EMBASE and PsycINFO from January 1st 1980 to February 1st 2023. We included studies of adults with a diagnosis/former diagnosis of MDD with assessment of global functioning performed during a state of full or partial remission. The methodological quality was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist. Standardised mean differences (SMD) using random-effects models were calculated as the summary measure. We further performed meta-analyses of the mean raw score in patients with MDD for individual functioning scales. RESULTS: Forty-two studies, comprising 17,999 patients with MDD and 35,550 HC, were included, 14 of which included both patients with MDD in full or partial remission and HC. Global functioning was lower in patients with MDD in full or partial remission compared with HC (SMD -2.00, 95 % CI: -0.9 to -3.03, 15 comparisons, I2: 99.8 %). LIMITATIONS: Important information about the study participants and setting was not reported for most studies, or the reporting was unclear. CONCLUSION: Patients with MDD have lower levels of functioning compared with HC also when in full or partial remission. Assessment of functioning should be an essential component of managing patients with MDD, also during remission.

Inflammatory and oxidative stress biomarkers in children and adolescents with bipolar disorder - A systematic review and meta-analysis.

Evidence suggests a role for low-grade inflammation and oxidative stress in the pathophysiology of bipolar disorder. We conducted a systematic review and meta-analysis of peripheral markers of inflammation and oxidative stress in children and adolescents under 20 years of age with bipolar disorder. We searched PubMed, Embase and psycINFO and performed random effects meta-analysis calculating standardized mean differences (SMD) of marker levels between patients with bipolar disorder and healthy control individuals. Ten studies comprising a total of 418 patients with bipolar disorder and 3017 healthy control individuals were included. The levels of C-Reactive Protein were higher in patients with bipolar disorder compared with healthy individuals (SMD 0.53; 95 %CI: 0.33-0.74; I2 = 0 %). For other biomarkers there were no statistically significant differences between groups. Findings were limited by a low number of studies and participants and methodological issues in the included studies. More and larger studies using rigorous methodology are needed to establish the role of inflammation and oxidative stress in children and adolescents with bipolar disorder.

Early specialised treatment for bipolar disorder: Long-term follow-up from the early intervention in affective disorders (EIA) randomised controlled trial.

BACKGROUND: It is unclear whether treatment early after onset in bipolar disorder may improve the long-term illness course. The early intervention in affective disorders (EIA) randomised controlled trial found that 2-years treatment in a specialised mood disorder clinic combining evidence-based pharmacological treatment with group psychoeducation improved clinical outcomes compared with standard treatment in patients with bipolar disorder discharged after their 1st, 2nd, or 3rd hospital admission. We aimed to assess the 16 years long-term outcomes after randomisation of the participants in the EIA trial. METHODS: Data were obtained by linking nation-wide Danish population-based registers. All 158 participants of the EIA trial (Trial Registration Number NCT00253071) were followed from time of randomisation (2005-2009) to end of study (31 December 2021). The primary outcome was risk of psychiatric readmission. Secondary outcomes were total admissions and costs, medication use, intentional self-harm or suicide attempt or suicide, and socio-economic measures. RESULTS: The absolute mean risk of psychiatric readmission was 49.3% in the intervention group and 59.8% in the control group, with no statistically significant difference between the groups (b = -0.10, 95% CI: -0.26 to 0.047, p = 0.18). Compared with the control group, patients in the intervention group had numerically fewer total admission days (mean (SD) 44 (77) versus 62 (109)), lower total cost of psychiatric hospital admissions and hospital-based outpatient visits (mean (SD) 22,001 (36793) euros versus 29,822 (52671) euros) and higher use of lithium and antipsychotics, but the differences were not statistically significant. Fewer patients in the intervention group had an event of intentional self-harm or suicide attempt or suicide during follow-up (OR 0.25, 95% CI: 0.15-0.40, p < 0.001) compared with the control group and more patients in the intervention group used antiepileptics (OR 2.21, 95% CI: 1.08-4.60, p = 0.031). CONCLUSION: Analyses of very long-term outcomes of the EIA trial may potentially indicate a beneficial effect of the intervention at the long term but were likely underpowered to detect a more subtle effect and for most outcomes the differences between groups were not statistically significant.

A composite immune and vascular stress marker in patients newly diagnosed with bipolar disorder and their unaffected first-degree relatives.

AIMS: Substantial evidence emphasizes immune dysregulation in patients with bipolar disorder (BD). However, whether immune dysregulation is present already in the early illness stages of BD or even precedes development of BD is largely unknown. In this study we compared immune and vascular stress markers in patients newly diagnosed with BD, their unaffected first-degree relatives (UR) and healthy control individuals (HC) and investigated the ability a composite immune and vascular stress marker to discriminate between the three groups of participants. METHODS: In a unique sample including 373 patients newly diagnosed with BD, 95 UR and 190 HC, we compared 47 immune and vascular stress markers at the baseline visit in the ongoing longitudinal Bipolar Illness Onset study. For comparison of individual immune and vascular stress markers between groups, we applied linear mixed models, whereas the composite immune and vascular stress marker was investigated using the SuperLearner ensemble-method. RESULTS: Compared with HC, patients newly diagnosed with BD had higher levels of the anti-inflammatory interleukin-1 receptor antagonist (IL-1RA) and IL-10, and of the pro-inflammatory IL-6, eotaxin, monocyte chemoattractant protein-1 (MCP-1), MCP-4, Macrophage Derived Chemokine (MDC), and Thymus and Activation-Regulated Chemokine (TARC) in analyses adjusted for sex and age ranging from 26 % higher levels of IL-6 (1.26, 95 %CI: [1.12-1.43], p < 0.001, adjusted p = 0.009) and IL-10 (1.26, 95 %CI: [1.09-1.46], p = 0.002, adjusted p = 0.049), respectively, to 9 % higher eotaxin levels (1.09, 95 %CI: [1.04-1.15], p = 0.001, adjusted p = 0.024). Of these, MDC levels were 12 % higher in BD compared with UR (1.12, 95 %CI: [1.02-1.22], p = 0.001, adjusted p = 0.024). For all other markers, UR showed no difference from patients with BD or HC. Based on a data-driven model, a composite marker including all 47 immune and vascular stress markers, sex, age, BMI, smoking status, and alcohol intake, discriminated patients with BD from HC with a with an area under the receiver operating curve (AUC) of 0.76 (95 % CI: 0.75-0.77) CONCLUSIONS: Higher levels of pro-inflammatory and anti-inflammatory immune markers are present in patients newly diagnosed with BD but not in UR compared with HC, supporting immune dysregulation playing a role in the pathophysiology of BD.

Minor tranquillizers for short-term treatment of newly onset symptoms of anxiety and distress: a systematic review with network meta-analysis of randomized trials.

Unspecific symptoms of anxiety and distress are frequently encountered in patients in both general practice and acute psychiatric services. Minor tranquillizers may be a treatment option when non-pharmacological interventions are insufficient or unavailable. We conducted a systematic review with network meta-analysis of the evidence for short-term (1-4 weeks) pharmacological treatment of newly onset symptoms of anxiety and distress. We searched the PsycInfo, MEDLINE, EMBASE and Cochrane Library databases and extracted data following a predefined hierarchy of outcomes. We assessed risk of bias using the Cochrane Risk of Bias tool and the certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluation framework (GRADE). We included 34 randomized trials comprising a total of 7044 patients with adjustment disorders or anxiety spectrum disorders. The network meta-analysis showed that regarding the critical outcome symptoms of anxiety within 1-4 weeks benzodiazepines (SMD - 0.58, 95% CI - 0.77 to - 0.40), quetiapine (SMD - 0.51, 95% CI - 0.90 to - 0.13) and pregabalin (SMD - 0.58, 95% CI - 0.87 to - 0.28) all performed better than placebo with no statistically significant difference between the drugs. Data on other important outcomes were inconsistently reported. Adverse effects varied, but overall, it was uncertain whether adverse effects differed between interventions. The evidence regarding the risk of dependence was uncertain, but dependence may be a concern in susceptible individuals even with short-term treatment. Overall, the certainty of the evidence according to GRADE was rated as low to very low across outcomes. Despite the limitations in the evidence, the results of this review can inform treatment guidelines, supporting clinicians in the choice of minor tranquillizer in this prevalent and help-seeking, clinically heterogeneous population.

Ferritin as a potential disease marker in patients with bipolar disorder.

BACKGROUND: Low-grade inflammation and oxidative stress have been implicated as potential pathophysiological processes in bipolar disorder, but the underlying mechanism is unknown. Ferritin is a marker of iron stores and involved in redox processes and inflammation but its role in bipolar disorder is unclear. METHODS: We investigated the possible association of increased plasma ferritin levels and bipolar disorder. We pooled two studies using similar longitudinal repeated measures designs and included 330 blood- and urinary samples from 95 patients with bipolar disorder across all affective states and 84 samples from 84 healthy control individuals. Plasma ferritin was measured along with multiple blood inflammatory markers and urinary markers of oxidatively generated damage to DNA and RNA. RESULTS: Plasma ferritin levels, adjusting for multiple demographical- and lifestyle variables, did not differ between patients with bipolar disorder compared with healthy control individuals (b = 1.09, 95 % CI: 0.86 to 1.39, p = 0.49). Within patients with bipolar disorder ferritin levels were higher in a depressed state compared with euthymia (b = 1.12, 95 % CI: 1.01 to 1.24, p < 0.04), and ferritin levels were positively associated with Interleukin-18 blood levels and urinary levels of 8-oxodG. LIMITATIONS: Patients with bipolar disorder received medication which could potentially influence iron metabolism. CONCLUSION: Elevated ferritin levels in depressed patients with bipolar disorder may point to a role for iron metabolism in bipolar disorder pathophysiology, and potentially as a biomarker, linking low-grade inflammation with redox biology and the well-known increased risk of medical comorbidity and reduced life expectancy.

The risks of adverse events with venlafaxine and mirtazapine versus 'active placebo', placebo, or no intervention for adults with major depressive disorder: a protocol for two separate systematic reviews with meta-analysis and Trial Sequential Analysis.

BACKGROUND: Major depressive disorder causes a great burden on patients and societies. Venlafaxine and mirtazapine are commonly prescribed as second-line treatment for patients with major depressive disorder worldwide. Previous systematic reviews have concluded that venlafaxine and mirtazapine reduce depressive symptoms, but the effects seem small and may not be important to the average patient. Moreover, previous reviews have not systematically assessed the occurrence of adverse events. Therefore, we aim to investigate the risks of adverse events with venlafaxine or mirtazapine versus 'active placebo', placebo, or no intervention for adults with major depressive disorder in two separate systematic reviews. METHODS: This is a protocol for two systematic reviews with meta-analysis and Trial Sequential Analysis. The assessments of the effects of venlafaxine or mirtazapine will be reported in two separate reviews. The protocol is reported as recommended by Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols, risk of bias will be assessed with the Cochrane risk-of-bias tool version 2, clinical significance will be assessed using our eight-step procedure, and the certainty of the evidence will be assessed with the Grading of Recommendations Assessment, Development and Evaluation approach. We will search for published and unpublished trials in major medical databases and trial registers. Two review authors will independently screen the results from the literature searches, extract data, and assess risk of bias. We will include published or unpublished randomised clinical trial comparing venlafaxine or mirtazapine with 'active placebo', placebo, or no intervention for adults with major depressive disorder. The primary outcomes will be suicides or suicide attempts, serious adverse events, and non-serious adverse events. Exploratory outcomes will include depressive symptoms, quality of life, and individual adverse events. If feasible, we will assess the intervention effects using random-effects and fixed-effect meta-analyses. DISCUSSION: Venlafaxine and mirtazapine are frequently used as second-line treatment of major depressive disorder worldwide. There is a need for a thorough systematic review to provide the necessary background for weighing the benefits against the harms. This review will ultimately inform best practice in the treatment of major depressive disorder. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42022315395.

Robustness of reported postacute health outcomes in children with SARS-CoV-2 infection: a systematic review.

OBJECTIVE: To systematically assess the robustness of reported postacute SARS-CoV-2 infection health outcomes in children. METHODS: A search on PubMed and Web of Science was conducted to identify studies published up to 22 January 2022 that reported on postacute SARS-CoV-2 infection health outcomes in children (<18 years) with follow-up of ≥2 months since detection of infection or ≥1 month since recovery from acute illness. We assessed the consideration of confounding bias and causality, as well as the risk of bias. RESULTS: 21 studies including 81 896 children reported up to 97 symptoms with follow-up periods of 2.0-11.5 months. Fifteen studies had no control group. The reported proportion of children with post-COVID syndrome was between 0% and 66.5% in children with SARS-CoV-2 infection (n=16 986) and between 2.0% and 53.3% in children without SARS-CoV-2 infection (n=64 910). Only two studies made a clear causal interpretation of an association between SARS-CoV-2 infection and the main outcome of 'post-COVID syndrome' and provided recommendations regarding prevention measures. The robustness of all 21 studies was seriously limited due to an overall critical risk of bias. CONCLUSIONS: The robustness of reported postacute SARS-CoV-2 infection health outcomes in children is seriously limited, at least in all the published articles we could identify. None of the studies provided evidence with reasonable certainty on whether SARS-CoV-2 infection has an impact on postacute health outcomes, let alone to what extent. Children and their families urgently need much more reliable and methodologically robust evidence to address their concerns and improve care.

Description of antidepressant withdrawal symptoms in clinical practice guidelines on depression: A systematic review.

BACKGROUND: Antidepressant withdrawal symptoms may mimic symptoms of depression relapse and can be challenging for patients when tapering or discontinuing antidepressants. We aimed to assess how withdrawal symptoms are described in major clinical practice guidelines on depression. METHODS: Systematic review of major clinical practice guidelines on depression from the United Kingdom, the United States, Canada, Australia, Singapore, Ireland, and New Zealand. We searched PubMed, 14 guideline registries, and the websites of relevant organisations (last search 10 July 2022). The guidelines were assessed for information and descriptions of antidepressant withdrawal symptoms regarding their type, incidence, duration, severity, onset, and presumed mechanism. RESULTS: We included 21 guidelines, 15 (71 %) of which stated that withdrawal or discontinuation symptoms can occur. None of the guidelines provided an exhaustive list of potential withdrawal symptoms; ten (48 %) guidelines mentioned at least one specific symptom, ranging between four and 39 symptoms. The symptomatic overlap between withdrawal and relapse was mentioned in four (19 %) guidelines. Withdrawal symptoms were generally described as mild, brief, and self-limiting; and severe in a minority of cases. Estimates of the duration, incidence, or expected onset were reported in five (24 %) guidelines, and were in all cases lower than those reported in systematic reviews. LIMITATIONS: We included clinical practice guidelines from English-speaking countries only; our findings may not be generalizable to non-English-speaking countries. CONCLUSIONS: Clinical practice guidelines provide scarce and inadequate information on antidepressant withdrawal symptoms and limited guidance for distinguishing withdrawal symptoms from symptoms of relapse.

Substantial delays in clinical data published by the European Medicines Agency - a cross sectional study.

BACKGROUND: Reporting bias poses a fundamental threat to the transparency and validity of interpretations of clinical trials, which may, in part, be mitigated through access Clinical Study Reports (CSRs). The European Medicines Agency (EMA), under their Policy 0070, prospectively publishes clinical data, including CSRs, submitted as part of marketing authorization applications or post-authorization procedures, although this practice is currently suspended for non-COVID-19 medicines, and have set out planned timelines for publication. METHODS: We conducted a cross-sectional study assessing the content and characteristics of all clinical data packages released by the EMA under Policy 0070 and the time to their publication. We extracted the number and characteristics of trials included in the clinical packages, assessed the delay to publication relative to the EMAs planned timeline and whether it differed between the EMAs various transparency measures and types of application procedures. RESULTS: We identified 148 clinical data packages that contained data on a total of 1,005 clinical trials, of which 261 (26%) were labelled as phase 3 trials. Full CSRs were available for 913 (90•8%) of the trials. The median time to publication was 511 (IQR 411 to 574) days. Only 2 (1•4%) of the clinical data packages were published within the EMA's planned timeline. The delay was shorter for clinical data packages released under the EMAs transparency measures for COVID.19 medicines compared with their standard transparency measure. CONCLUSION: The clinical data packages released by the EMA under Policy 0070 contained CSRs on many trials but were published with considerable delays relative to the timeline set forth by the EMA, reducing their potential impact on reporting bias.

Clinical practice guideline recommendations on tapering and discontinuing antidepressants for depression: a systematic review.

BACKGROUND: Tapering and discontinuing antidepressants are important aspects of the management of patients with depression and should therefore be considered in clinical practice guidelines. OBJECTIVES: We aimed to assess the extent and content, and appraise the quality, of guidance on tapering and discontinuing antidepressants in major clinical practice guidelines on depression. METHODS: Systematic review of clinical practice guidelines on depression issued by national health authorities and major national or international professional organisations in the United Kingdom, the United States, Canada, Australia, Singapore, Ireland and New Zealand (PROSPERO CRD42020220682). We searched PubMed, 14 guideline registries and the websites of relevant organisations (last search 25 May 2021). The clinical practice guidelines were assessed for recommendations and information relevant to tapering and discontinuing antidepressants. The quality of the clinical practice guidelines as they pertained to tapering and discontinuation was assessed using the AGREE II tool. RESULTS: Of the 21 included clinical practice guidelines, 15 (71%) recommended that antidepressants are tapered gradually or slowly, but none provided guidance on dose reductions, how to distinguish withdrawal symptoms from relapse or how to manage withdrawal symptoms. Psychological challenges were not addressed in any clinical practice guideline, and the treatment algorithms and flow charts did not include discontinuation. The quality of the clinical practice guidelines was overall low. CONCLUSION: Current major clinical practice guidelines provide little support for clinicians wishing to help patients discontinue or taper antidepressants in terms of mitigating and managing withdrawal symptoms. Patients who have deteriorated upon following current guidance on tapering and discontinuing antidepressants thus cannot be concluded to have experienced a relapse. Better guidance requires better randomised trials investigating interventions for discontinuing or tapering antidepressants.

The relationship between dose and serotonin transporter occupancy of antidepressants-a systematic review.

Brain imaging techniques enable the visualization of serotonin transporter (SERT) occupancy as a measure of the proportion of SERT blocked by an antidepressant at a given dose. We aimed to systematically review the evidence on the relationship between antidepressant dose and SERT occupancy. We searched PubMed and Embase (last search 20 May 2021) for human in vivo, within-subject PET, or SPECT studies measuring SERT occupancy at any dose of any antidepressant with highly selective radioligands ([11C]-DASB, [123I]-ADAM, and [11C]-MADAM). We summarized and visualized the dose-occupancy relationship for antidepressants across studies, overlaying the plots with a curve based on predicted values of a standard 2-parameter Michaelis-Menten model fitted using the observed data. We included seventeen studies of 10 different SSRIs, SNRIs, and serotonin modulators comprising a total of 294 participants, involving 309 unique occupancy measures. Overall, following the Michaelis-Menten equation, SERT occupancy increased with a higher dose in a hyperbolic relationship, with occupancy increasing rapidly at lower doses and reaching a plateau at approximately 80% at the usual minimum recommended dose. All the studies were small, only a few investigated the same antidepressant, dose, and brain region, and few reported information on factors that may influence SERT occupancy. The hyperbolic dose-occupancy relationship may provide mechanistic insight of relevance to the limited clinical benefit of dose-escalation in antidepressant treatment and the potential emergence of withdrawal symptoms. The evidence is limited by non-transparent reporting, lack of standardized methods, small sample sizes, and short treatment duration. Future studies should standardize the imaging and reporting procedures, measure occupancy at lower antidepressant doses, and investigate the moderators of the dose-occupancy relationship.

Protocol: Benefits and harms of remdesivir for COVID-19 in adults: A systematic review with meta-analysis.

BACKGROUND: Effective drug treatments for Covid-19 are needed to decrease morbidity and mortality for the individual and to alleviate pressure on health care systems. Remdesivir showed promising results in early randomised trials but subsequently a large publicly funded trial has shown less favourable results and the evidence is interpreted differently in clinical guidelines. Systematic reviews of remdesivir have been published, but none have systematically searched for unpublished data, including regulatory documents, and assessed the risk of bias due to missing evidence. METHODS: We will conduct a systematic review of randomised trials comparing remdesivir to placebo or standard of care in any setting. We will include trials regardless of the severity of disease and we will include trials examining remdesivir for indications other than Covid-19 for harms analyses. We will search websites of regulatory agencies, trial registries, bibliographic databases, preprint servers and contact trial sponsors to obtain all available data, including unpublished clinical data, for all eligible trials. Our primary outcomes will be all-cause mortality and serious adverse events. Our secondary outcomes will be length of hospital stay, time to death, severe disease, and adverse events. We will assess the risk of bias using the Cochranes Risk of Bias 2 tool and the risk of bias due to missing evidence (e.g. publication bias, selective reporting bias) using the ROB-ME tool. Where appropriate we will synthesise study results by conducting random-effects meta-analysis. We will present our findings in a Summary of Findings table and rate the certainty of the evidence using the GRADE approach. DISCUSSION: By conducting a comprehensive systematic review including unpublished data (where available), we expect to be able to provide valuable information for patients and clinicians about the benefits and harms of remdesivir for the treatment of Covid-19. This will help to ensure optimal treatment for individual patients and optimal utilisation of health care resources. SYSTEMATIC REVIEW REGISTRATION: CRD42021255915.

Tricyclic antidepressants versus 'active placebo', placebo or no intervention for adults with major depressive disorder: a protocol for a systematic review with meta-analysis and Trial Sequential Analysis.

BACKGROUND: Major depressive disorder is a common psychiatric disorder causing great burden on patients and societies. Tricyclic antidepressants are frequently used worldwide to treat patients with major depressive disorder. It has repeatedly been shown that tricyclic antidepressants reduce depressive symptoms with a statistically significant effect, but the effect is small and of questionable clinical importance. Moreover, the beneficial and harmful effects of all types of tricyclic antidepressants have not previously been systematically assessed. Therefore, we aim to investigate the beneficial and harmful effects of tricyclic antidepressants versus 'active placebo', placebo or no intervention for adults with major depressive disorder. METHODS: This is a protocol for a systematic review with meta-analysis that will be reported as recommended by Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols, bias will be assessed with the Cochrane Risk of Bias tool-version 2, our eight-step procedure will be used to assess if the thresholds for clinical significance are crossed, Trial Sequential Analysis will be conducted to control random errors and the certainty of the evidence will be assessed with the Grading of Recommendations Assessment, Development and Evaluation approach. To identify relevant trials, we will search both for published and unpublished trials in major medical databases and trial registers, such as CENTRAL, MEDLINE, EMBASE and ClinicalTrials.gov from their inception to 12 May 2021. Clinical study reports will be applied for from regulatory authorities and pharmaceutical companies. Two review authors will independently screen the results from the literature searches, extract data and perform risk of bias assessment. We will include any published or unpublished randomised clinical trial comparing tricyclic antidepressants with 'active placebo', placebo or no intervention for adults with major depressive disorder. The following interventions will be assessed: amineptine, amitriptyline, amoxapine, butriptyline, cianopramine, clomipramine, desipramine, demexiptiline, dibenzepin, dosulepin, dothiepin, doxepin, imipramine, iprindole, lofepramine, maprotiline, melitracen, metapramine, nortriptyline, noxiptiline, opipramol, protriptyline, tianeptine, trimipramine and quinupramine. Primary outcomes will be depressive symptoms, serious adverse events and quality of life. Secondary outcomes will be suicide or suicide-attempts and non-serious adverse events. If feasible, we will assess the intervention effects using random-effects and fixed-effect meta-analyses. DISCUSSION: Tricyclic antidepressants are recommended by clinical guidelines and frequently used worldwide in the treatment of major depressive disorder. There is a need for a thorough systematic review to provide the necessary background for weighing the benefits against the harms. This review will ultimately inform best practice in the treatment of major depressive disorder. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42021226161 .

Duloxetine versus 'active' placebo, placebo or no intervention for major depressive disorder; a protocol for a systematic review of randomised clinical trials with meta-analysis and trial sequential analysis.

BACKGROUND: Major depression significantly impairs quality of life, increases the risk of suicide, and poses tremendous economic burden on individuals and societies. Duloxetine, a serotonin norepinephrine reuptake inhibitor, is a widely prescribed antidepressant. The effects of duloxetine have, however, not been sufficiently assessed in earlier systematic reviews and meta-analyses. METHODS/DESIGN: A systematic review will be performed including randomised clinical trials comparing duloxetine with 'active' placebo, placebo or no intervention for adults with major depressive disorder. Bias domains will be assessed, an eight-step procedure will be used to assess if the thresholds for clinical significance are crossed. We will conduct meta-analyses. Trial sequential analysis will be conducted to control random errors, and the certainty of the evidence will be assessed using GRADE. To identify relevant trials, we will search Cochrane Central Register of Controlled Trials, Medical Literature Analysis and Retrieval System Online, Excerpta Medica database, PsycINFO, Science Citation Index Expanded, Social Sciences Citation Index, Conference Proceedings Citation Index-Science and Conference Proceedings Citation Index-Social Science & Humanities. We will also search Chinese databases and Google Scholar. We will search all databases from their inception to the present. Two review authors will independently extract data and perform risk of bias assessment. Primary outcomes will be the difference in mean depression scores on Hamilton Depression Rating Scale between the intervention and control groups and serious adverse events. Secondary outcomes will be suicide, suicide-attempts, suicidal ideation, quality of life and non-serious adverse events. DISCUSSION: No former systematic review has systematically assessed the beneficial and harmful effects of duloxetine taking into account both the risks of random errors and the risks of systematic errors. Our review will help clinicians weigh the benefits of prescribing duloxetine against its adverse effects and make informed decisions. SYSTEMATIC REVIEW REGISTRATION: PROSPERO 2016 CRD42016053931.