Statins for major depressive disorder: A systematic review and meta-analysis of randomized controlled trials

Cryostructuring of Polymeric Systems: 68. Evaluation of Poly(vinyl alcohol) Composite Cryogels Filled with Poly(3-hydroxybutyric acid)-Based Microspheres of Different Porous Morphology as Potential Delivery Systems for Drugs of Various Water-Solubility

Poly(3-hydroxybutyric acid)-based microspheres of two types, with and without macropores, were prepared; their morphology and particle size were evaluated. These microspheres were entrapped as disperse fillers into the bulk of macroporous cryogels based on poly(vinyl alcohol) (PVA). It was found that the rigidity of the resultant composite cryogels increased markedly as compared to that of unfilled cryogels of the same PVA concentration. The resulting composites were further tested for their potential to act as drug carriers. With that, simvastatin was included into the filler particles directly in the course of their preparation, followed by entrapment of such drug-loaded microspheres into the PVA cryogel. In turn, ibuprofen sodium salt was introduced into the preliminary prepared cryogels filled with the drug-free microspheres. The experimental study of drug release kinetics showed that due to the non-covalent interactions of both simvastatin and ibuprofen sodium salt with the particles of discrete phase, prolongation of the release processes was observed.

Delayed simvastatin treatment improves neurological recovery after cryogenic traumatic brain injury through downregulation of ELOVL1 by inhibiting mTOR signaling

Statins are well-tolerated and widely available lipid-lowering medications with neuroprotective effects against traumatic brain injury (TBI). However, whether delayed statin therapy starting in the subacute phase promotes recovery after TBI is unknown. Elongation of the very long-chain fatty acid protein 1 (ELOVL1) is involved in astrocyte-mediated neurotoxicity, but its role in TBI and the relationship between ELOVL1 and statins are unclear. We hypothesized that delayed simvastatin treatment promotes neurological functional recovery after TBI by regulating the ELOVL1-mediated production of very long-chain fatty acids (VLCFAs). ICR male mice received daily intragastric administration of 1, 2 or 5 mg/kg simvastatin on Days 1-14, 3-14, 5-14, or 7-14 after cryogenic TBI (cTBI). The results showed that simvastatin promoted motor functional recovery in a dose-dependent manner, with a wide therapeutic window of at least 7 days postinjury. Meanwhile, simvastatin inhibited astrocyte and microglial overactivation and glial scar formation, and increased total dendritic length, neuronal complexity and spine density on day 14 after cTBI. The up-regulation of ELOVL1 expression and saturated VLCFAs concentrations in the cortex surrounding the lesion caused by cTBI was inhibited by simvastatin, which was related to the inhibition of the mTOR signaling. Overexpression of ELOVL1 in astrocytes surrounding the lesion using HBAAV2/9-GFAP-m-ELOVL1-3xFlag-EGFP partially attenuated the benefits of simvastatin. These results showed that delayed simvastatin treatment promoted functional recovery and brain tissue repair after TBI through the downregulation of ELOVL1 expression by inhibiting mTOR signaling. Astrocytic ELOVL1 may be a potential target for rehabilitation after TBI.

The Role of Inflammation in Depression and Beyond: A Primer for Clinicians

PURPOSE OF REVIEW

We evaluate available evidence for the role of inflammation in depression. We reappraise literature involving systemic inflammation, neuroinflammation and neurotransmission and their association with depression. We review the connection between depression, autoimmunity and infectious diseases. We revise anti-inflammatory treatments used in depression.

RECENT FINDINGS

Peripheral inflammatory markers are present in a subset of patients with depression and can alter common neurotransmitters in this population but there is no clear causality between depression and systemic inflammation. Infectious conditions and autoimmune illnesses do not have a clear correlation with depression. Certain medications have positive evidence as adjunctive treatments in depression but studies are heterogenic, hence they are sparsely used in clinical settings. The current evidence does not fully support inflammation, infections or autoimmunity as possible etiologies of depression. The available studies have numerous confounders that obscure the findings. Anti-inflammatory agents may have potential for treatment of depression, but further research is needed to clarify their usefulness in routine clinical practice.

"Inflamed" depression: A review of the interactions between depression and inflammation and current anti-inflammatory strategies for depression

Depression is a common mental disorder, the effective treatment of which remains a challenging issue worldwide. The clinical pathogenesis of depression has been deeply explored, leading to the formulation of various pathogenic hypotheses. Among these, the monoamine neurotransmitter hypothesis holds a prominent position, yet it has significant limitations as more than one-third of patients do not respond to conventional treatments targeting monoamine transmission disturbances. Over the past few decades, a growing body of research has highlighted the link between inflammation and depression as a potential key factor in the pathophysiology of depression. In this review, we first summarize the relationship between inflammation and depression, with a focus on the pathophysiological changes mediated by inflammation in depression. The mechanisms linking inflammation to depression as well as multiple anti-inflammatory strategies are also discussed, and their efficacy and safety are assessed. This review broadens the perspective on specific aspects of using anti-inflammatory strategies for treating depression, laying the groundwork for advancing precision medicine for individuals suffering from "inflamed" depression.

Efficacy and acceptability of anti-inflammatory agents in major depressive disorder: a systematic review and meta-analysis

Background

Anti-inflammatory agents have emerged as a potential new therapy for major depressive disorder (MDD). In this meta-analysis, our aim was to evaluate the antidepressant effect of anti-inflammatory agents and compare their efficacy.

Methods

We conducted a comprehensive search across multiple databases, including PubMed, Embase, Web of Science, Cochrane Review, Cochrane Trial, and ClinicalTrials.gov, to identify eligible randomized clinical trials. The primary outcome measures of our meta-analysis were efficacy and acceptability, while the secondary outcome measures focused on remission rate and dropout rate due to adverse events. We used odds ratio (OR) and 95% confidence interval (95% CI) to present our results.

Results

A total of 48 studies were included in our analysis. In terms of efficacy, anti-inflammatory agents demonstrated a significant antidepressant effect compared to placebo (OR = 2.04, 95% CI: 1.41-2.97, p = 0.0002). Subgroup analyses revealed that anti-inflammatory agents also exhibited significant antidepressant effects in the adjunctive therapy subgroup (OR = 2.17, 95% CI: 1.39-3.37, p = 0.0006) and in MDD patients without treatment-resistant depression subgroup (OR = 2.33, 95% CI: 1.53-3.54, p < 0.0001). Based on the surface under the cumulative ranking curve (SUCRA) value of network meta-analysis, nonsteroidal anti-inflammatory drugs (NSAIDs) (SUCRA value = 81.6) demonstrated the highest acceptability among the included anti-inflammatory agents.

Conclusion

In summary, our meta-analysis demonstrates that anti-inflammatory agents have significant antidepressant effects and are well-accepted. Furthermore, adjunctive therapy with anti-inflammatory agents proved effective in treating MDD. Among the evaluated anti-inflammatory agents, NSAIDs exhibited the highest acceptability, although its efficacy is comparable to placebo.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=422004), identifier CRD42023422004.

Major depressive disorder as a neuro-immune disorder: Origin, mechanisms, and therapeutic opportunities

Notwithstanding advances in understanding the pathophysiology of major depressive disorder (MDD), no single mechanism can explain all facets of this disorder. An expanding body of evidence indicates a putative role for the inflammatory response. Several meta-analyses showed an increase in systemic peripheral inflammatory markers in individuals with MDD. Numerous conditions and circumstances in the modern world may promote chronic systemic inflammation through mechanisms, including alterations in the gut microbiota. Peripheral cytokines may reach the brain and contribute to neuroinflammation through cellular, humoral, and neural pathways. On the other hand, antidepressant drugs may decrease peripheral levels of inflammatory markers. Anti-inflammatory drugs and nutritional strategies that reduce inflammation also could improve depressive symptoms. The present study provides a critical review of recent advances in the role of inflammation in the pathophysiology of MDD. Furthermore, this review discusses the role of glial cells and the main drivers of changes associated with neuroinflammation. Finally, we highlight possible novel neurotherapeutic targets for MDD that could exert antidepressant effects by modulating inflammation.

Statin for mood and inflammation among adult patients with major depressive disorder: an updated meta-analysis

Introduction

Several small sample-sized clinical trials have demonstrated a beneficial effect of statin on depressive mood among major depressive disorder (MDD) patients. However, observational studies have showed the increased risk of anxiety/depression with statin treatment. Therefore, we aimed to evaluate the effects of statin on depressive mood and inflammation status among MDD patients.

Methods

We performed an updated meta-analysis RCTs identified in systematic searches of PubMed, Cochrane library, Embase, ClinicalTrials.gov, CNKI, Wan fang, VIP, and SinoMed database (up to August 2023). The primary endpoint was the Hamilton depression rating scale (HDRS). The secondary endpoints were rate of response to treatment, remission rate, levels of C-reactive protein (CRP), cognition and blood lipid. We evaluated the certainty of the evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

Results

The search identified seven RCTs involving 448 patients with a median follow-up of 10.4 weeks (range, 6-12 weeks). Compared with selective serotonin reuptake inhibitors (SSRIs) alone, treatment with statin plus SSRIs was associated with a significantly decreased HDRS [mean difference (MD) = -2.79; 95% confidence interval (CI): -3.83 to -1.76] and C-reactive protein (MD = -0.42 mg/L; 95% CI: -0.53 to -0.12 mg/L), and decreased levels of lipid profiles (P < 0.05). Moreover, statin plus SSRIs was associated with a comparable rate of treatment response [relative risk (RR) = 1.26; 95% CI: 0.98 to 1.62], remission rate (RR = 1.33; 95% CI: 0.89 to 1.99). Meta-regression indicated that the follow-up period was a source of heterogeneity regarding the HDRS (r = 0.302, P = 0.041). The quality of evidence was rated as moderate for HDRS and response rate according to the GRADE.

Conclusion

Statin could safely and effectively improve the symptoms of depression and inflammation status among MDD patients.

Systematic review registration

https://inplasy.com/inplasy-2022-3-0016/, identifier INPLASY2022230016.

Real-world outcomes of concomitant antidepressant and statin use in primary care patients with depression: a population-based cohort study

BACKGROUND

Antidepressants are licensed for use in depressive disorders, but non-response and poor adherence to treatment affect a considerable number of patients. Pre-clinical and clinical evidence suggest that statins can augment the effects of antidepressants. However, the acceptability and tolerability of combining statins with antidepressants are unclear, and their add-on efficacy has only been shown in small, short-term clinical trials. Observational data can provide complementary information about treatment effects on larger samples over longer follow-ups. In this study, we therefore assessed the real-world acceptability, tolerability, and efficacy of concomitant antidepressant and statin treatment in depression.

METHODS

We conducted a population-based cohort study investigating QResearch primary care research database, which comprises the anonymised electronic healthcare records of 35 + million patients over 1574 English general practices. Patients aged 18-100 years, registered between January 1998 and August 2020, diagnosed with a new episode of depression, and commencing an antidepressant were included. Using a between-subject design, we identified two study groups: antidepressant + statin versus antidepressant-only prescriptions. Outcomes of interest included the following: antidepressant treatment discontinuations due to any cause (acceptability) and due to any adverse event (tolerability) and effects on depressive symptoms (efficacy) measured as response, remission, and change in depression score on the Patient Health Questionnaire-9. All outcomes were assessed at 2, 6, and 12 months using multivariable regression analyses, adjusted for relevant confounders, to calculate adjusted odds ratios (aORs) or mean differences (aMDs) with 99% confidence intervals (99% CIs).

RESULTS

Compared to antidepressant-only (N 626,335), antidepressant + statin (N 46,482) was associated with higher antidepressant treatment acceptability (aOR2months 0.88, 99% CI 0.85 to 0.91; aOR6months 0.81, 99% CI 0.79 to 0.84; aOR12months 0.78, 99% CI 0.75 to 0.81) and tolerability (aOR2months 0.92, 99% CI 0.87 to 0.98; aOR6months 0.94, 99% CI 0.89 to 0.99, though not long term aOR12 months 1.02, 99% CI 0.97 to 1.06). Efficacy did not differ between groups (range aOR2-12 months 1.00 and 1.02 for response and remission, range aOR2-12 months - 0.01 and - 0.02 for change in depression score).

CONCLUSIONS

On real-world data, there is a positive correlation between antidepressant treatment adherence and statin use, partly explained by fewer dropouts due to adverse events. The main limitation of our study is its observational design, which restricts the potential to make causal inferences.

The Possible Role of NLRP3 Inflammasome in Depression and Myocardial Infarction Comorbidity

It is well-established that cardiovascular disease and depression are highly comorbid. This study aimed to assess the possible role of the NOD-like receptor protein 3 (NLRP3) inflammasome pathway and the high-sensitivity C-reactive protein (hsCRP) in patients with incident myocardial infarction in the presence or absence of depression. Sixty-eight consecutive patients with incident ST-elevation myocardial infarction and twenty healthy subjects were included. The patients were assessed using the Structured Clinical Interview for DSM-5 Disorders-Clinician Version during their 1-4-day-long hospitalization and were divided into two groups: with and without comorbid depression. Blood samples for the determination of NLRP3, interleukin-18 (IL-18), interleukin-1β (IL-1β), and hsCRP levels were analyzed using ELISA. NLRP3, IL-1β, IL-18, and hsCRP levels were significantly higher in myocardial infarction patients compared to the healthy group (p = 0.02, p < 0.001, p < 0.001, and p < 0.001, respectively). No significant difference was found between the myocardial groups with and without depression. However, in the logistic regression analysis, the NLRP3 variable in myocardial infarction patients was found to have a significant contribution to the likelihood of depression (p = 0.015, OR = 1.72, and CI = 1.11-2.66). The likelihood of depression is associated with increasing NLRP3 levels in myocardial infarction patients. However, this potential role should be further explored in a larger sample.

Lipids in major depressive disorder: new kids on the block or old friends revisited?

Major depressive disorder (MDD) is a psychiatric mood disorder that results in substantial functional impairment and is characterized by symptoms such as depressed mood, diminished interest, impaired cognitive function, and vegetative symptoms such as disturbed sleep. Although the exact etiology of MDD is unclear, several underlying mechanisms (disturbances in immune response and/or stress response) have been associated with its development, with no single mechanism able to account for all aspects of the disorder. Currently, about 1 in 3 patients are resistant to current antidepressant therapies. Providing an alternative perspective on MDD could therefore pave the way for new, unexplored diagnostic and therapeutic solutions. The central nervous system harbors an enormous pool of lipids and lipid intermediates that have been linked to a plethora of its physiological functions. The aim of this review is therefore to provide an overview of the implications of lipids in MDD and highlight certain MDD-related underlying mechanisms that involve lipids and/or their intermediates. Furthermore, we will also focus on the bidirectional relationship between MDD and the lipid-related disorders obesity and type 2 diabetes.

The pharmacological bases for repurposing statins in depression: a review of mechanistic studies

Statins are commonly prescribed medications widely investigated for their potential actions on the brain and mental health. Pre-clinical and clinical evidence suggests that statins may play a role in the treatment of depressive disorders, but only the latter has been systematically assessed. Thus, the physiopathological mechanisms underlying statins' putative antidepressant or depressogenic effects have not been established. This review aims to gather available evidence from mechanistic studies to strengthen the pharmacological basis for repurposing statins in depression. We used a broad, well-validated search strategy over three major databases (Pubmed/MEDLINE, Embase, PsychINFO) to retrieve any mechanistic study investigating statins' effects on depression. The systematic search yielded 8068 records, which were narrowed down to 77 relevant papers. The selected studies (some dealing with more than one bodily system) described several neuropsychopharmacological (44 studies), endocrine-metabolic (17 studies), cardiovascular (6 studies) and immunological (15 studies) mechanisms potentially contributing to the effects of statins on mood. Numerous articles highlighted the beneficial effect of statins on depression, particularly through positive actions on serotonergic neurotransmission, neurogenesis and neuroplasticity, hypothalamic-pituitary axis regulation and modulation of inflammation. The role of other mechanisms, especially the association between statins, lipid metabolism and worsening of depressive symptoms, appears more controversial. Overall, most mechanistic evidence supports an antidepressant activity for statins, likely mediated by a variety of intertwined processes involving several bodily systems. Further research in this area can benefit from measuring relevant biomarkers to inform the selection of patients most likely to respond to statins' antidepressant effects while also improving our understanding of the physiopathological basis of depression.

The Potential Therapeutic Application of Simvastatin for Brain Complications and Mechanisms of Action

Statins are common drugs that are clinically used to reduce elevated plasma cholesterol levels. Based on their solubility, statins are considered to be either hydrophilic or lipophilic. Amongst them, simvastatin has the highest lipophilicity to facilitate its ability to cross the blood-brain barrier. Recent studies have suggested that simvastatin could be a promising therapeutic option for different brain complications and diseases ranging from brain tumors (i.e., medulloblastoma and glioblastoma) to neurological disorders (i.e., Alzheimer's disease, Parkinson's disease, and Huntington's disease). Specific mechanisms of disease amelioration, however, are still unclear. Independent studies suggest that simvastatin may reduce the risk of developing certain neurodegenerative disorders. Meanwhile, other studies point towards inducing cell death in brain tumor cell lines. In this review, we outline the potential therapeutic effects of simvastatin on brain complications and review the clinically relevant molecular mechanisms in different cases.

An online experimental medicine trial on the effect of 28-day simvastatin administration on emotional processing, reward learning, working memory and salivary cortisol in healthy volunteers at risk for depression: OxSTEP protocol

BACKGROUND

Evidence suggests inflammation may be a key mechanism by which psychosocial stress, including loneliness, predisposes to depression. Observational and clinical studies have suggested simvastatin, with its anti-inflammatory properties, may have a potential use in the treatment of depression. Previous experimental medicine trials investigating 7-day use of statins showed conflicting results, with simvastatin displaying a more positive effect on emotional processing compared with atorvastatin. It is possible that statins require longer administration in predisposed individuals before showing the expected positive effects on emotional processing.

AIMS

Here, we aim to test the neuropsychological effects of 28-day simvastatin administration versus placebo, in healthy volunteers at risk for depression owing to loneliness.

METHOD

This is a remote experimental medicine study. One hundred participants across the UK will be recruited and randomised to either 28-day 20 mg simvastatin or placebo in a double-blind fashion. Before and after administration, participants will complete an online testing session involving tasks of emotional processing and reward learning, processes related to vulnerability to depression. Working memory will also be assessed and waking salivary cortisol samples will be collected. The primary outcome will be accuracy in identifying emotions in a facial expression recognition task, comparing the two groups across time.

Chronic stress, neuroinflammation, and depression: an overview of pathophysiological mechanisms and emerging anti-inflammatories

In a subset of patients, chronic exposure to stress is an etiological risk factor for neuroinflammation and depression. Neuroinflammation affects up to 27% of patients with MDD and is associated with a more severe, chronic, and treatment-resistant trajectory. Inflammation is not unique to depression and has transdiagnostic effects suggesting a shared etiological risk factor underlying psychopathologies and metabolic disorders. Research supports an association but not necessarily a causation with depression. Putative mechanisms link chronic stress to dysregulation of the HPA axis and immune cell glucocorticoid resistance resulting in hyperactivation of the peripheral immune system. The chronic extracellular release of DAMPs and immune cell DAMP-PRR signaling creates a feed forward loop that accelerates peripheral and central inflammation. Higher plasma levels of inflammatory cytokines, most consistently interleukin IL-1β, IL-6, and TNF-α, are correlated with greater depressive symptomatology. Cytokines sensitize the HPA axis, disrupt the negative feedback loop, and further propagate inflammatory reactions. Peripheral inflammation exacerbates central inflammation (neuroinflammation) through several mechanisms including disruption of the blood-brain barrier, immune cellular trafficking, and activation of glial cells. Activated glial cells release cytokines, chemokines, and reactive oxygen and nitrogen species into the extra-synaptic space dysregulating neurotransmitter systems, imbalancing the excitatory to inhibitory ratio, and disrupting neural circuitry plasticity and adaptation. In particular, microglial activation and toxicity plays a central role in the pathophysiology of neuroinflammation. Magnetic resonance imaging (MRI) studies most consistently show reduced hippocampal volumes. Neural circuitry dysfunction such as hypoactivation between the ventral striatum and the ventromedial prefrontal cortex underlies the melancholic phenotype of depression. Chronic administration of monoamine-based antidepressants counters the inflammatory response, but with a delayed therapeutic onset. Therapeutics targeting cell mediated immunity, generalized and specific inflammatory signaling pathways, and nitro-oxidative stress have enormous potential to advance the treatment landscape. Future clinical trials will need to include immune system perturbations as biomarker outcome measures to facilitate novel antidepressant development. In this overview, we explore the inflammatory correlates of depression and elucidate pathomechanisms to facilitate the development of novel biomarkers and therapeutics.

Systematic reviews and meta-analyses on major depressive disorder: a bibliometric perspective

Background

There is a vast amount of evidence-based medicine research on the major depressive disorder (MDD) available in the literature, however, no studies on the overall performance, productivity and impact of such research have been published to date. This study explored and mapped the research outputs of MDD-related systematic reviews and meta-analyses (SR/MA) from a bibliometric perspective.

Methods

Relevant data were retrieved with search terms on MDD, systematic review and meta-analysis.

Results

A total of 4,870 papers with 365,402 citations published from 1983 to 2022 were included in the analysis. The publication output has grown steadily over time with the most publications originating from the USA (1,020; 20.94%), the UK (516; 10.60%) and China (448; 9.20%). The research collaborations between countries were most frequent between the USA and UK (266; 5.46%). Journal of Affective Disorders (379; 7.78%) was the most productive journal, while Cuijpers P was the most productive author (121; 2.48%), and University of Toronto (569; 11.78%) was the most productive institution. The top 10 most cited articles on MDD-related SR/MA had citations ranging from 1,806 to 3,448. The high-frequency keywords were mainly clustered into four themes, including psychiatric comorbidities, clinical trials, treatment, and brain stimulation in MDD.

Conclusion

The rapid increase in the number of SR/MA of MDD in recent years highlights the importance of this research field. Psychiatric comorbidities, clinical interventions, and treatment of MDD have been identified as hot topics, while biological mechanisms in MDD are likely to be an emerging research priority.

Investigating the potential anti-depressive mechanisms of statins: a transcriptomic and Mendelian randomization analysis

Observational studies and randomized controlled trials presented inconsistent findings on the effects of cholesterol-lowering statins on depression. It therefore remains unclear whether statins have any beneficial effects on depression, and if so, what the underlying molecular mechanisms are. Here, we aimed to use genomic approaches to investigate this further. Using Connectivity Map (CMap), we first investigated whether statins and antidepressants shared pharmacological effects by interrogating gene expression responses to drug exposure in human cell lines. Second, using Mendelian randomization analysis, we investigated both on-target (through HMGCR inhibition) and potential off-target (through ITGAL and HDAC2 inhibition) causal effects of statins on depression risk and depressive symptoms, and traits related to the shared biological pathways identified from CMap analysis. Compounds inducing highly similar gene expression responses to statins in HA1E cells (indicated by an average connectivity score with statins > 90) were found to be enriched for antidepressants (12 out of 38 antidepressants; p = 9E-08). Genes perturbed in the same direction by both statins and antidepressants were significantly enriched for diverse cellular and metabolic pathways, and various immune activation, development and response processes. MR analysis did not identify any significant associations between statin exposure and depression risk or symptoms after multiple testing correction. However, genetically proxied HMGCR inhibition was strongly associated with alterations in platelets (a prominent serotonin reservoir) and monocyte percentage, which have previously been implicated in depression. Genetically proxied ITGAL inhibition was strongly associated with basophil, monocyte and neutrophil counts. We identified biological pathways that are commonly perturbed by both statins and antidepressants, and haematological biomarkers genetically associated with statin targets. Our findings warrant pre-clinical investigation of the causal role of these shared pathways in depression and potential as therapeutic targets, and investigation of whether blood biomarkers may be important considerations in clinical trials investigating effects of statins on depression.

Effect of Adjunctive Simvastatin on Depressive Symptoms Among Adults With Treatment-Resistant Depression: A Randomized Clinical Trial

Importance

Immune-metabolic disturbances have been implicated in the pathophysiology of major depressive disorder and may be more prominent in individuals with treatment-resistant depression (TRD). Preliminary trials suggest that lipid-lowering agents, including statins, may be useful adjunctive treatments for major depressive disorder. However, no adequately powered clinical trials have assessed the antidepressant efficacy of these agents in TRD.

Objective

To assess the efficacy and tolerability of adjunctive simvastatin compared with placebo for reduction of depressive symptoms in TRD.

Design, Setting, and Participants

This 12-week, double-blind, placebo-controlled randomized clinical trial was conducted in 5 centers in Pakistan. The study involved adults (aged 18-75 years) with a Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) major depressive episode that had failed to respond to at least 2 adequate trials of antidepressants. Participants were enrolled between March 1, 2019, and February 28, 2021; statistical analysis was performed from February 1 to June 15, 2022, using mixed models.

Intervention

Participants were randomized to receive standard care plus 20 mg/d of simvastatin or placebo.

Main Outcomes and Measures

The primary outcome was the difference between the 2 groups in change in Montgomery-Åsberg Depression Rating Scale total scores at week 12. Secondary outcomes included changes in scores on the 24-item Hamilton Rating Scale for Depression, the Clinical Global Impression scale, and the 7-item Generalized Anxiety Disorder scale and change in body mass index from baseline to week 12. C-reactive protein and plasma lipids were measured at baseline and week 12.

Results

A total of 150 participants were randomized to simvastatin (n = 77; median [IQR] age, 40 [30-45] years; 43 [56%] female) or placebo (n = 73; median [IQR] age, 35 [31-41] years; 40 [55%] female). A significant baseline to end point reduction in Montgomery-Åsberg Depression Rating Scale total score was observed in both groups and did not differ significantly between groups (estimated mean difference for simvastatin vs placebo, -0.61; 95% CI, -3.69 to 2.46; P = .70). Similarly, there were no significant group differences in any of the secondary outcomes or evidence for differences in adverse effects between groups. A planned secondary analysis indicated that changes in plasma C-reactive protein and lipids from baseline to end point did not mediate response to simvastatin.

Conclusions and Relevance

In this randomized clinical trial, simvastatin provided no additional therapeutic benefit for depressive symptoms in TRD compared with standard care.

Trial Registration

ClinicalTrials.gov Identifier: NCT03435744.

Comparative efficacy, acceptability, and tolerability of adjunctive anti-inflammatory agents on bipolar disorder: A systemic review and network meta-analysis

OBJECTIVES

We performed a network meta-analysis (NMA) with up-to-date evidence to compare different anti-inflammatory agents to improve the treatment of bipolar disorder (BD) patients.

METHODS

Four databases (i.e., the Cochrane Library, Web of Science, PubMed, and Embase) were searched for randomized controlled trials (RCTs) published between 1995 and 2022 on the use of anti-inflammatory agents in the treatment of BD. A systematic review and NMA were conducted.

RESULTS

Adjunctive N-acetylcysteine (NAC) was superior to placebo for the treatment of BD according to the endpoint scale score (SMD -0.65, 95% confidence interval (CI): - 0.99 to - 0.31), response rate (odds ratio (OR) 3.42, 95% CI: 1.23-9.52), remission rate (OR 4.94, 95% CI: 1.03-41.38) and surface under the cumulative ranking curve (SUCRA) value of the endpoint scale score (0.84). Adjunctive nonsteroidal anti-inflammatory drugs (NSAIDs) were more favorable than placebo based on the remission rate (OR 3.93, 95% CI: 1.15-13.43) and were significantly more acceptable than other treatments (OR 0.60, 95% CI: 0.36-0.99). Adjunctive coenzyme Q10 (CoQ10) was superior to other agents in terms of the response rate (OR 18.85, 95% CI: 2.63-135.00), with a SUCRA value for the response rate of 0.90 and that for the remission rate of 0.71.

CONCLUSION

Adjunctive NAC is recommended for the treatment of BD. Adjunctive NSAIDs and CoQ10 are still seen as effective, but more high-quality clinical studies are needed to verify their efficacy. Other anti-inflammatory agents may not be recommended for clinical use at present. All anti-inflammatory agents demonstrated a good safety profile. We call for further research on the combined treatment of BD with different anti-inflammatory agents to be included in future trials.

The Anti-Depressant Effects of Statins in Patients With Major Depression Post-Myocardial Infarction: An Updated Review 2022

Statins are the most commonly prescribed lipid-lowering agents in patients with cardiovascular disease, and more than half of the patients with cardiovascular disease have associated depressive symptoms, particularly post-myocardial infarction, which is a major trigger for depression. In our research, we tried to understand the anti-depressant effects of statins, the mechanisms, risks and benefits, and potential drug-drug interactions with anti-depressant medications. We reviewed all the relevant information from inception up to September 2022 regarding the anti-depressant effects of statins. The database used was PubMed, and the keywords were statins, major depression, post-myocardial infarction, and hydroxy methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors. We have screened each of the articles carefully, including both human and animal studies, and found a positive correlation between reduction in depressive symptoms with statin therapy as adjunctive treatment with conventional anti-depressants. In conclusion, statins as a monotherapy are not an effective treatment for depression post-myocardial infarction but are good add-on options along with standard therapy such as selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs). Statins are safe and have no serious drug-drug interactions with anti-depressants. We would like to encourage large-scale observational studies and further post-marketing surveillance to improve our knowledge regarding the effectiveness of statins in the treatment of depression.

Statins in depression: a repurposed medical treatment can provide novel insights in mental health

Depression has a large burden, but the development of new drugs for its treatment has proved difficult. Progresses in neuroscience have highlighted several physiopathological pathways, notably inflammatory and metabolic ones, likely involved in the genesis of depressive symptoms. A novel strategy proposes to repurpose established medical treatments of known safety and to investigate their potential antidepressant activity. Among numerous candidates, growing evidence suggests that statins may have a positive role in the treatment of depressive disorders, although some have raised concerns about possible depressogenic effects of these widely prescribed medications. This narrative review summarises relevant findings from translational studies implicating many interconnected neurobiological and neuropsychological, cardiovascular, endocrine-metabolic, and immunological mechanisms by which statins could influence mood. Also, the most recent clinical investigations on the effects of statins in depression are presented. Overall, the use of statins for the treatment of depressive symptoms cannot be recommended based on the available literature, though this might change as several larger, methodologically robust studies are being conducted. Nevertheless, statins can already be acknowledged as a driver of innovation in mental health, as they provide a novel perspective to the physical health of people with depression and for the development of more precise antidepressant treatments.

Current Perspectives on Pharmacological and Non-Pharmacological Interventions for the Inflammatory Mechanism of Unipolar Depression

Since depression remains a major public health issue there is a constant need for new and more efficient therapeutic strategies based on the mechanisms involved in the aetiology of depression. Thus, the pathogenic link between depression and inflammation is considered to play a potential key role in the development of such therapies. This review summarizes the results of various pharmacological (non-steroidal anti-inflammatory drugs, aspirin, cyclooxygenase inhibitors, cytokine inhibitors, corticosteroids, statins, minocycline, N-acetyl cysteine, omega-3 fatty acids and probiotics) and non-pharmacological interventions (electroconvulsive therapy, physical exercise and psychological therapy) and outlines their efficacy and discusses potential challenges. Both conventional and non-conventional anti-inflammatory drugs showed promising results according to the specific group of patients. The pre-existing pro-inflammatory status was, in most cases, a predictor for clinical efficacy and, in some cases, a correlation between clinical improvement and changes in various biomarkers was found. Some of the non-pharmacological interventions (physical exercise and electroconvulsive therapy) have also showed beneficial effects for depressive patients with elevated inflammatory markers. Treatments with anti-inflammatory action may improve clinical outcomes in depression, at least for some categories of patients, thus opening the way for a future personalised approach to patients with unipolar depression regarding the inflammation-related mechanism.

The effects of statin monotherapy on depressive symptoms: A systematic review and meta-analysis

INTRODUCTION

Statins have been proposed as a strategy for treating depression, but their benefit in the absence of concurrent antidepressant treatment is unclear. This meta-analysis investigated the antidepressant effects of statin monotherapy in the general population.

METHODS

We conducted a literature search of randomised controlled trials using any statin monotherapy versus any control condition for depressive symptoms. Our primary efficacy outcome was the mean value on any standardised scale for depression at study endpoint. We also measured efficacy at three further timepoints (<6 months, 6-12 months, >12 months), as well as acceptability, tolerability, and safety. Respectively, continuous and dichotomous outcomes were computed using standardised mean difference (SMD) or relative risk (RR) with 95% confidence intervals (CI) using a random-effect model.

RESULTS

Pooled analyses did not show that statin monotherapy improves depressive symptoms at endpoint (N = 2712 SMD = -0.18; 95% CI = -0.41 to 0.04), nor at any other specific timepoint. No difference between statins and control was identified for any of the other outcome measures.

DISCUSSION

These results differ from those of previous meta-analyses and, compounded by more recently available evidence, suggest that statins may not have intrinsic antidepressant properties, but may be useful for the management of depression in add-on to antidepressants.

LIMITATIONS

Data from heterogeneous populations and using different statins were pooled, though several sensitivity and subgroup analyses were performed to account for that. PROSPERO registration: CRD42022306653. https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=306653.

An experimental medicine study of the effects of simvastatin on emotional processing, reward learning, verbal memory, and inflammation in healthy volunteers

RATIONALE

Clinical studies suggest that the highly lipophilic, anti-inflammatory molecule, simvastatin, might be an ideal candidate for drug repurposing in the treatment of depression. The neuropsychological effects of simvastatin are not known, but their ascertainment would have significant translational value about simvastatin's influence on mood and cognition.

OBJECTIVES

We aimed to investigate the effects of simvastatin on a battery of psychological tests and inflammatory markers in healthy volunteers.

METHODS

Fifty-three healthy subjects were randomly assigned to 7 days of either simvastatin (N = 27) or sucrose-based placebo (N = 26) given in a double-blind fashion. Then, participants were administered questionnaires measuring subjective rates of mood and anxiety, and a battery of tasks assessing emotional processing, reward learning, and verbal memory. Blood samples for C-reactive protein were also collected.

RESULTS

Compared to placebo, participants on simvastatin showed a higher number of positively valenced intrusions in the emotional recall task (F1,51 = 4.99, p = 0.03), but also an increase in anxiety scores (F1,51 = 5.37, p = 0.02). An exploratory analysis of the females' subgroup (N = 27) showed lower number of misclassifications as sad facial expression in the simvastatin arm (F1,25 = 6.60, p = 0.02). No further statistically significant changes could be observed on any of the other outcomes measured.

CONCLUSIONS

We found limited evidence that 7-day simvastatin use in healthy volunteer induces a positive emotional bias while also being associated with an increase in anxiety, potentially reflecting the early effects of antidepressants in clinical practice. Such effect might be more evident in female subjects. Different drug dosages, treatment lengths, and sample selection need consideration in further experimental medicine and clinical studies.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT04652089.

Hypolipidemic Activity of Olive Oil-Based Nanostructured Lipid Carrier Containing Atorvastatin

Currently, hyperlipidemia is a growing health issue that is considered a risk factor for obesity. Controlling body weight and modifying life style in most of cases are not adequate and the condition requires medical treatment. Statin drugs (mainly Atorvastatin (ATO)), have been used broadly and for long time as medications for handling higher levels of lipid, especially bad cholesterol, which accordingly controls the prevalence of obesity. Still, the obstacle that stands in front of any formulation is the poor solubility of the drug. Low solubility of ATO came up with poor absorption as well as poor bioavailability. This paved the way for the present study, which aimed to exploit nanotechnology and develop certain nanolipid carriers that could accommodate hydrophobic drugs, such as ATO. Nanostructured lipid carrier (NLC) containing ATO was fabricated using olive oil. Olive oil is natural plant oil possessing confirmed hypolipidemic activity that would help in improving the efficacy of the formulation. Via applying the Quality by Design (QbD) approach, one NLC formula was selected to be optimized based on appropriate size and higher entrapment. Optimized ATO-NLC was scrutinized for zeta potential, in vitro study and kinetic profile. Moreover, stability testing and in vivo hypolipidemic behavior was conducted. The optimized NLC formulation seemed to show particle size (254.23 nm) with neutral zeta potential (−1.77 mV) and entrapment efficiency (69.56%). The formulation could be prolonged for 12 h and provided higher % of release (97.17%). Stability testing confirmed the role of modifying the surface of the formulation with PEG-DSPE in providing a highly stable formulation that could withstand three months storage in two altered conditions. Ultimately, optimized ATO-NLC could successfully lower total cholesterol level in rats induced with obesity and fed a high-fat diet. Remarkably, ATO-NLC prepared with olive oil, in addition to shielding its surface, would provide a stable formulation that holds up the synergistic action between olive oil and ATO.

An assessment of sensory sensitivity in women suffering from depression using transcutaneous electrical nerve stimulation

Background

Perception is the process or result of the process arising from the mental interpretation of the phenomena occurring, therefore it depends not only on physiology, but is also psychologically and socially conditioned. The aim of this study was to assess if there is a difference in the sensory sensitivity to an electrical stimulus in women suffering from depression and what the hedonic rating is of the lived experience of transcutaneous electrical nerve stimulation.

Methods

The depression group: 44 women, who were inpatients treated for depression at the Psychiatric Ward in the Clinical Hospital, and the control group: 41 women, matched by the age, height and weight, with no mental illness. Measures: threshold for sensing current, type of sensation evoked, hedonic rating.

Results

Median sensing threshold of electric current (depression vs. control: 7.75 mA vs. 8.35 mA; no significant), type of sensation evoked (depression vs. control: tingling 90.9% vs. 92.7%, no significant), hedonic rating (depression vs. control: unpleasant 11.4% vs. 2.4%; p = 0.003), hedonic rating (mildly ill vs. moderately ill vs. markedly ill: unpleasant 5.3% vs. 6.3% vs. 33.3%; p = 0.066).

Conclusions

Women suffering from depression exhibit a similar threshold of sensitivity to an electrical stimulus as mentally healthy women, however the hedonic rating of the stimulus acting on the skin in the group of clinically depressed women was more negative than in the mentally healthy subjects. The stimulus was described as 'unpleasant' for many of the mentally unhealthy women. The most negative sensations related to the electrical stimulus were experienced by women with the highest severity of mental illness according to The Clinical Global Impression - Severity Scale.

Lipophilic vs. hydrophilic statins and psychiatric hospitalizations and emergency room visits in US Veterans with schizophrenia and bipolar disorder

Objective –

Psychiatric hospitalizations and emergency department (ED) visits are costly, stigmatizing, and often ineffective. Given the immune and kynurenine activation in bipolar disorder (BD) and schizophrenia, as well as the immune-modulatory effects of statins, we aimed to compare the relative risk (RRs) of psychiatric hospitalizations and ED visits between individuals prescribed lipophilic vs. hydrophilic statins vs. no statins. We hypothesized (a) reduced rates of hospitalization and ER utilization with statins versus no statins and (b) differences in outcomes between statins, as lipophilia increases the capability to penetrate the blood–brain barrier with potentially beneficial neuroimmune, antioxidant, neuroprotective, neurotrophic, and endothelial stabilizing effects, and, in contrast, potentially detrimental decreases in brain cholesterol concentrations leading to serotoninergic dysfunction, changes in membrane lipid composition, thus affecting ion channels and receptors.

Methods –

We used VA service utilization data from October 1, 2010 to September 30, 2015. The RRs for psychiatric hospitalization and ED visits, were estimated using robust Poisson regression analyses. The number of individuals analyzed was 683,129.

Results –

Individuals with schizophrenia and BD who received prescriptions for either lipophilic or hydrophilic statins had a lower RR of psychiatric hospitalization or ED visits relative to nonstatin controls. Hydrophilic statins were significantly associated with lower RRs of psychiatric hospitalization but not of ED visits, compared to lipophilic statins.

Conclusion –

The reduction in psychiatric hospitalizations in statin users (vs. nonusers) should be interpreted cautiously, as it carries a high risk of confounding by indication. While the lower RR of psychiatric hospitalizations in hydrophilic statins relative to the lipophilic statins is relatively bias free, the finding bears replication in a specifically designed study. If replicated, important clinical implications for personalizing statin treatment in patients with mental illness, investigating add-on statins for improved therapeutic control, and mechanistic exploration for identifying new treatment targets are natural next steps.

The effects of atorvastatin on emotional processing, reward learning, verbal memory and inflammation in healthy volunteers: An experimental medicine study

BACKGROUND

Growing evidence from clinical trials and epidemiological studies suggests that statins can have clinically significant antidepressant effects, potentially related to anti-inflammatory action on several neurobiological structures. However, the underlying neuropsychological mechanisms of these effects remain unexplored.

AIMS

In this experimental medicine trial, we investigated the 7-day effects of the lipophilic statin, atorvastatin on a battery of neuropsychological tests and inflammation in healthy volunteers.

METHODS

Fifty healthy volunteers were randomised to either 7 days of atorvastatin 20 mg or placebo in a double-blind design. Participants were assessed with psychological questionnaires and a battery of well-validated behavioural tasks assessing emotional processing, which is sensitive to putative antidepressant effects, reward learning and verbal memory, as well as the inflammatory marker, C-reactive protein.

RESULTS

Compared to placebo, 7-day atorvastatin increased the recognition (p = 0.006), discriminability (p = 0.03) and misclassifications (p = 0.04) of fearful facial expression, independently from subjective states of mood and anxiety, and C-reactive protein levels. Otherwise, atorvastatin did not significantly affect any other psychological and behavioural measure, nor peripheral C-reactive protein.

CONCLUSIONS

Our results reveal for the first time the early influence of atorvastatin on emotional cognition by increasing the processing of anxiety-related stimuli (i.e. increased recognition, discriminability and misclassifications of fearful facial expression) in healthy volunteers, in the absence of more general effects on negative affective bias. Further studies exploring the effects of statins in depressed patients, especially with raised inflammatory markers, may clarify this finding and inform future clinical trials.

Targeting Metabolic Dysfunction for the Treatment of Mood Disorders: Review of the Evidence

Major depressive disorder (MDD) and bipolar disorder (BD) are often chronic with many patients not responding to available treatments. As these mood disorders are frequently associated with metabolic dysfunction, there has been increased interest in novel treatments that would target metabolic pathways. The objectives of this scoping review were to synthesize evidence on the impact on mood symptoms of lipid lowering agents and anti-diabetics drugs, while also reviewing current knowledge on the association between mood disorders and dyslipidemia or hyperglycemia. We propose that metabolic dysfunction is prevalent in both MDD and BD and it may contribute to the development of these disorders through a variety of pathophysiological processes including inflammation, brain structural changes, hormonal alterations, neurotransmitter disruptions, alteration on brain cholesterol, central insulin resistance, and changes in gut microbiota. Current evidence is conflicting on the use of statins, polyunsaturated fatty acids, thiazolidinediones, glucagon-like peptide agonists, metformin, or insulin for the treatment of MDD and BD. Given the paucity of high-quality randomized controlled trials, additional studies are needed before any of these medications can be repurposed in routine clinical practice. Future trials need to enrich patient recruitment, include evaluations of mechanism of action, and explore differential effects on specific symptom domains such as anhedonia, suicidality, and cognition.

Statins in Depression: An Evidence-Based Overview of Mechanisms and Clinical Studies

Background: Depression is a leading cause of disability, burdened by high levels of non-response to conventional antidepressants. Novel therapeutic strategies targeting non-monoaminergic pathways are sorely needed. The widely available and safe statins have several putative mechanisms of action, especially anti-inflammatory, which make them ideal candidates for repurposing in the treatment of depression. A large number of articles has been published on this topic. The aim of this study is to assess this literature according to evidence-based medicine principles to inform clinical practise and research. Methods: We performed a systematic review of the electronic databases MEDLINE, CENTRAL, Web of Science, CINAHL, and ClinicalTrials.gov, and an unstructured Google Scholar and manual search, until the 9th of April 2021, for all types of clinical studies assessing the effects of statins in depression. Results: Seventy-two studies were retrieved that investigated the effects of statins on the risk of developing depression or on depressive symptoms in both depressed and non-depressed populations. Fifteen studies specifically addressed the effects of statins on inflammatory-related symptoms of anhedonia, psychomotor retardation, anxiety, and sleep disturbances in depression. Most studies suggested a positive effect of statins on the occurrence and severity of depression, with fewer studies showing no effect, while a minority indicated some negative effects. Limitations: We provide a narrative report on all the included studies but did not perform any quantitative analysis, which limits the strength of our conclusions. Conclusions: Robust evidence indicates that statins are unlikely to lead to depressive symptoms in the general population. Promising data suggest a potential role for statins in the treatment of depression. Further clinical studies are needed, especially in specific subgroups of patients identified by pre-treatment assessments of inflammatory and lipid profiles.