Genetic predictors of response to treatment with citalopram in depression secondary to traumatic brain injury

Brain-Derived Neurotrophic Factor (BDNF) as a Predictor of Treatment Response in Major Depressive Disorder (MDD): A Systematic Review

Brain-derived neurotrophic factor (BDNF) has been studied as a biomarker of major depressive disorder (MDD). Besides diagnostic biomarkers, clinically useful biomarkers can inform response to treatment. We aimed to review all studies that sought to relate BDNF baseline levels, or BDNF polymorphisms, with response to treatment in MDD. In order to achieve this, we performed a systematic review of studies that explored the relation of BDNF with both pharmacological and non-pharmacological treatment. Finally, we reviewed the evidence that relates peripheral levels of BDNF and BDNF polymorphisms with the development and management of treatment-resistant depression.

Effectiveness of Pharmacotherapy for Depression after Adult Traumatic Brain Injury: an Umbrella Review

Symptoms of depression are common following traumatic brain injury (TBI), impacting survivors' ability to return to work, participate in leisure activities, and placing strain on relationships. Depression symptoms post TBI are often managed with pharmacotherapy, however, there is little research evidence to guide clinical practice. There have been a number of recent systematic reviews examining pharmacotherapy for post TBI depression. The aim of this umbrella review was to synthesize systematic reviews and meta-analyses of the effectiveness of pharmacotherapy for the management of post TBI depression in adults. Eligible reviews examined any pharmacotherapy against any comparators, for the treatment of depression in adults who had sustained TBI. Seven databases were searched, with additional searching of online journals, Research Gate, Google Scholar and the TRIP Medical Database to identify published and unpublished systematic reviews and meta-analyses in English up to May 2020. A systematic review of primary studies available between March 2018 and May 2020 was also conducted. Evidence quality was assessed using Joanna Briggs Institute Critical Appraisal Instruments. The results are presented as a narrative synthesis. Twenty-two systematic reviews were identified, of which ten reviews contained a meta-analysis. No new primary studies were identified in the systematic review. There was insufficient high quality and methodologically rigorous evidence to recommend prescribing any specific drug or drug class for post TBI depression. The findings do show, however, that depression post TBI is responsive to pharmacotherapy in at least some individuals. Recommendations for primary studies, systematic reviews and advice for prescribers is provided. Review Registration PROSPERO (CRD42020184915).

Rehabilitation for Impaired Attention in the Acute and Post-Acute Phase After Traumatic Brain Injury: A Narrative Review

Impaired attention is the most common and debilitating cognitive deficit following a traumatic brain injury (TBI). Attention is a fundamental function that profoundly influences the performance of other cognitive components such as memory and execution. Intriguingly, attention can be improved through cognitive rehabilitation. This narrative review summarizes the essential elements of rehabilitation for attention problems in acute and post-acute TBI. In the acute phase of mild TBI, investigations into the medical history and daily life performance, neurological examination, screening and management of concomitant sleep-wake disorders or neuropsychiatric disorders, and support and education on the natural course of concussion are covered. Rehabilitation for patients with moderate-to-severe TBI consists of serial assessment for patients with disorders of consciousness and a post-traumatic confusion state. In the post-acute phase after TBI, components of rehabilitation include investigating medical history; neurological, imaging, and electrophysiological tests; evaluation and treatment of factors that may impact attention, including sleep-wake, emotional, and behavioral disorders; evaluation of attention function; and cognitive rehabilitation as a matter of course. We summarized metacognitive strategy, direct attention training, computer-based cognitive interventions, medication, and environmental control as interventions to enhance attention.

The α2-adrenergic receptor pathway modulating depression influences the risk of arterial thrombosis associated with BDNFVal66Met polymorphism

Depression is associated with thrombotic risk and arterial events, its proper management is strongly recommended in coronary artery disease (CAD) patients. We have previously shown that the Brain-Derived Neurotrophic Factor (BDNF)Val66Met polymorphism, related to depression, is associated with arterial thrombosis in mice, and with an increased risk of acute myocardial infarction in humans. Herein, expanding the previous findings on BDNFVal66Met polymorphism, we show that desipramine, a norepinephrine reuptake-inhibitor, rescues behavioral impairments, reduces the arterial thrombosis risk, abolishes pathological coagulation and platelet hyper-reactivity, normalizes leukocyte, platelet, and bone marrow megakaryocyte number and restores physiological norepinephrine levels in homozygous knock-in BDNF Val66Met (BDNF^Met/Met) mice. The in vitro data confirm the enhanced procoagulant activity and the alpha_2A-adrenergic receptor (α_2A-ADR) overexpression found in BDNF^Met/Met mice and we provide evidence that, in presence of Met variant, norepinephrine is crucial to up-regulate procoagulant activity and to enhance platelet generation. The α₂-ADR antagonist rauwolscine rescues the prothrombotic phenotype in BDNF^Met/Met mice and reduces procoagulant activity and platelet generation in cells transfected with BDNF^Met plasmid or exposed to pro-BDNF^Met peptide. Finally, we show that homozygous BDNF^Met/Met CAD patients have hyper-reactive platelets overexpressing abundant α_2A-ADR. The great proplatelet release from their megakaryocytes well reflects their higher circulating platelet number compared to BDNF^Val/Val patients. These data reveal an unprecedented described role of Met allele in the dysregulation of norepinephrine/α_2A-ADR pathway that may explain the predisposition to arterial thrombosis. Overall, the development of α_2A-ADR inhibitors might represent a pharmacological treatment for depression-associated thrombotic conditions in this specific subgroup of CAD patients.

Moderators of gene-outcome associations following traumatic brain injury

The field of genomics is the principal avenue in the ongoing development of precision/personalised medicine for a variety of health conditions. However, relating genes to outcomes is notoriously complex, especially when considering that other variables can change, or moderate, gene-outcome associations. Here, we comprehensively discuss moderation of gene-outcome associations in the context of traumatic brain injury (TBI), a common, chronically debilitating, and costly neurological condition that is under complex polygenic influence. We focus our narrative review on single nucleotide polymorphisms (SNPs) of three of the most studied genes (apolipoprotein E, brain-derived neurotrophic factor, and catechol-O-methyltransferase) and on three demographic variables believed to moderate associations between these SNPs and TBI outcomes (age, biological sex, and ethnicity). We speculate on the mechanisms which may underlie these moderating effects, drawing widely from biomolecular and behavioural research (n = 175 scientific reports) within the TBI population (n = 72) and other neurological, healthy, ageing, and psychiatric populations (n = 103). We conclude with methodological recommendations for improved exploration of moderators in future genetics research in TBI and other populations.

The Role of BDNF in Experimental and Clinical Traumatic Brain Injury

Traumatic brain injury is one of the leading causes of mortality and morbidity in the world with no current pharmacological treatment. The role of BDNF in neural repair and regeneration is well established and has also been the focus of TBI research. Here, we review experimental animal models assessing BDNF expression following injury as well as clinical studies in humans including the role of BDNF polymorphism in TBI. There is a large heterogeneity in experimental setups and hence the results with different regional and temporal changes in BDNF expression. Several studies have also assessed different interventions to affect the BDNF expression following injury. Clinical studies highlight the importance of BDNF polymorphism in the outcome and indicate a protective role of BDNF polymorphism following injury. Considering the possibility of affecting the BDNF pathway with available substances, we discuss future studies using transgenic mice as well as iPSC in order to understand the underlying mechanism of BDNF polymorphism in TBI and develop a possible pharmacological treatment.

Depression following traumatic brain injury: a comprehensive overview

Traumatic brain injury (TBI) represents a major health concern affecting the neuropsychological health; TBI is accompanied by drastic long-term adverse complications that can influence many aspects of the life of affected individuals. A substantial number of studies have shown that mood disorders, particularly depression, are the most frequent complications encountered in individuals with TBI. Post-traumatic depression (P-TD) is present in approximately 30% of individuals with TBI, with the majority of individuals experiencing symptoms of depression during the first year following head injury. To date, the mechanisms of P-TD are far from being fully understood, and effective treatments that completely halt this condition are still lacking. The aim of this review is to outline the current state of knowledge on the prevalence and risk factors of P-TD, to discuss the accompanying brain changes at the anatomical, molecular and functional levels, and to discuss current approaches used for the treatment of P-TD.

Efficacy and Harms of Pharmacological Interventions for Anxiety after Traumatic Brain Injury: Systematic Review

After a traumatic brain injury (TBI), many persons experience significant and debilitating problems with anxiety. The aim of this systematic review was to critically evaluate the evidence regarding efficacy of pharmacological interventions for anxiety after TBI. We reviewed studies published in English before July 2020 and included original research on pharmacological interventions for anxiety after TBI in adults ≥16 years of age. MEDLINE, PubMed, CINAHL, EMBASE, PsycINFO, and CENTRAL databases were searched, with additional searching of key journals, clinical trials registries, and international drug regulators. The primary outcomes of interest were reduction in symptoms of anxiety and occurrence of harms. The secondary outcomes of interest were changes in depression, cognition, quality of life, and participation. Data were summarized in a narrative synthesis, and evidence quality was assessed using the Cochrane Risk of Bias tool. Only a single non-peer-reviewed, randomized controlled trial of 19 male military service members with mild TBI met inclusion criteria. This study found no significant effect of citalopram on anxiety symptoms over a 12-week intervention. The trial was stopped early because of poor recruitment, and much of the study detail was not included in the report. The methodological quality of the study was difficult to assess because of the lack of detail. No recommendations could be drawn from this review. There is a critical need for adequately powered and controlled studies of pharmacological interventions for anxiety after TBI across all severities that examine side-effect profiles and consider issues of comorbidity and effects of long-term pharmacotherapy.

The management of depression following traumatic brain injury: A systematic review with meta-analysis

BACKGROUND

Traumatic brain injury (TBI) is prevalent. Declining mortality has led to increasing survivors with chronic sequalae, including depression. With a lack of guidelines, this review aims to provide a comprehensive, evidence-based summary of the management of depression following TBI.

METHODS

Systematic searches were conducted for quasi-experimental and randomized controlled trials (RCTs) assessing pharmacotherapy, psychological interventions, and transcranial magnetic stimulation (TMS). Databases searched CENTRAL, Medline, Embase, CINAHL, PsycINFO, Web of Science, and ProQuest dissertations. Data extraction and risk-of-bias tools were used. Where possible, outcomes were combined into meta-analyses.

RESULTS

2719 studies were identified. After abstract screening and full-text reading, 34 remained. Prophylactic sertraline significantly reduced the odds of depression (OR (odds ratio) = 0.31 [95%CI (confidence interval) = 0.12 to 0.82]). Meta-analysis of RCT's showed TMS to have the greatest reduction in depression severity (SMD (Standardized-Mean-Difference) = 2.43 [95%CI = 1.24 to 3.61]). Stimulants were the only treatment superior to control (SMD = -1.03 [95%CI = - 1.6 to -0.47]).

CONCLUSION

Methylphenidate was the most effective pharmacotherapy. Sertraline appears effective for prevention. The efficacy of psychological interventions is unclear. TMS as a combination therapy appears promising. Heterogeneity of study populations and dearth of evidence means results should be interpreted cautiously.

Influence of genetic polymorphisms in homocysteine and lipid metabolism systems on antidepressant drug response

BACKGROUND

Variation in genes implicated in homocysteine and lipid metabolism systems may influence antidepressant response for patients with major depressive disorder (MDD). This study aimed to investigate whether association of polymorphisms on the MTHFR, ApoE and ApoA4 genes with the treatment response in MDD subjects.

METHODS

A total of 281 Han Chinese MDD patients received a single antidepressant drug (SSRI or SNRI) for at least 6 weeks, among whom 275 were followed up for 8 weeks. Their response to 6 weeks' treatment and remission to 8 weeks' treatment with antidepressant drugs was determined by changes in the 17-item Hamilton Depression Rating Scale (HARS-17) score. Single SNP and haplotype associations with treatment response were analyzed by UNPHASED 3.0.13. Logistic regression analysis was used to explore the interactions between genotypes and gender or drug type on treatment outcome, only those SNPs that had interactional association with gender or drug type were subjected to further stratified analysis.

RESULTS

In total group, the haplotype (C-A) in MTHFR (rsl801133 and rs1801131) and the ApoE rs405509 AA genotype were significantly associated with better efficacy of antidepressants; In gender subgroups, only haplotype (C-A) in MTHFR (rsl801133 and rs1801131) was significantly associated with better efficacy of antidepressants in male subgroup; In drug type subgroup, the haplotype (C-A) in MTHFR (rsl801133 and rs1801131) and haplotype (G-C) in ApoE (rs7412 and rs405509) were associated with better efficacy of antidepressants in SNRI treated subgroup; The ApoA4 rs5092 G allele and GG genotype were associated with worse efficacy of antidepressants in SNRI treated subgroup.

CONCLUSIONS

Genetic polymorphisms in homocysteine and lipid metabolism systems are associated with antidepressant response, particularly for the interactions of the certain genetic with gender or drug type.

Treatment of Depression After Traumatic Brain Injury: A Systematic Review Focused on Pharmacological and Neuromodulatory Interventions

BACKGROUND

Depression is the most common psychiatric sequela after traumatic brain injury (TBI) and poses a variety of treatment challenges. There is a lack of clinical trials focused on biological interventions used to manage TBI depression.

OBJECTIVE

The aim of this systematic review is to summarize the current evidence of psychotropic and neuromodulatory interventions used to treat TBI depression and to provide directions for future research.

METHODS

Key words were used to describe the following search terms: "traumatic brain injury", "depression", "pharmacological/drug therapy", and "neuromodulation". Studies focused on pharmacotherapy or neuromodulation in TBI depression were identified in 5 databases: Medline (PubMed), EMBASE (Embase.com), the Cochrane Library (Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Cochrane Methodology Register), PsycINFO (EbscoHost), and Web of Science. Article inclusion/exclusion using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-based systematic protocol of extraction and evaluation was applied. Level of evidence for each study was determined using the American Academy of Neurology criteria.

RESULTS

The initial search provided 1473 citations. Twenty-two studies met inclusion criteria. Sixteen studies explored pharmacological interventions with emphasis on serotonergic agents. Results between studies were conflicting, and interventions did not always outperform placebos, although sertraline provided the highest level of evidence for treatment of TBI depression. Six studies examining neuromodulatory interventions show preliminary evidence of efficacy with a range of interventions and modes of delivery used.

CONCLUSIONS

Additional research including large-sample randomized-controlled trials using pharmacological, neuromodulation, or combination treatment is needed. These studies should incorporate premorbid psychosocial functioning, preinjury psychiatric disease, cognitive deficits, and functional recovery when examining outcomes.

The Influence of the Val66Met Polymorphism of Brain-Derived Neurotrophic Factor on Neurological Function after Traumatic Brain Injury

Functional outcomes after traumatic brain injury (TBI) vary widely across patients with apparently similar injuries. This variability hinders prognosis, therapy, and clinical innovation. Recently, single nucleotide polymorphism (SNPs) that influence outcome after TBI have been identified. These discoveries create opportunities to personalize therapy and stratify clinical trials. Both of these changes would propel clinical innovation in the field. This review focuses on one of most well-characterized of these SNPs, the Val66Met SNP in the brain-derived neurotrophic factor (BDNF) gene. This SNP influences neurological function in healthy subjects as well as TBI patients and patients with similar acute insults to the central nervous system. A host of other patient-specific factors including ethnicity, age, gender, injury severity, and post-injury time point modulate this influence. These interactions confound efforts to define a simple relationship between this SNP and TBI outcomes. The opportunities and challenges associated with personalizing TBI therapy around this SNP and other similar SNPs are discussed in light of these results.

Genetic Influences on Patient-Oriented Outcomes in Traumatic Brain Injury: A Living Systematic Review of Non-Apolipoprotein E Single-Nucleotide Polymorphisms

There is a growing literature on the impact of genetic variation on outcome in traumatic brain injury (TBI). Whereas a substantial proportion of these publications have focused on the apolipoprotein E (APOE) gene, several have explored the influence of other polymorphisms. We undertook a systematic review of the impact of single-nucleotide polymorphisms (SNPs) in non–apolipoprotein E (non-APOE) genes associated with patient outcomes in adult TBI). We searched EMBASE, MEDLINE, CINAHL, and gray literature from inception to the beginning of August 2017 for studies of genetic variance in relation to patient outcomes in adult TBI. Sixty-eight articles were deemed eligible for inclusion into the systematic review. The SNPs described were in the following categories: neurotransmitter (NT) in 23, cytokine in nine, brain-derived neurotrophic factor (BDNF) in 12, mitochondrial genes in three, and miscellaneous SNPs in 21. All studies were based on small patient cohorts and suffered from potential bias. A range of SNPs associated with genes coding for monoamine NTs, BDNF, cytokines, and mitochondrial proteins have been reported to be associated with variation in global, neuropsychiatric, and behavioral outcomes. An analysis of the tissue, cellular, and subcellular location of the genes that harbored the SNPs studied showed that they could be clustered into blood–brain barrier associated, neuroprotective/regulatory, and neuropsychiatric/degenerative groups. Several small studies report that various NT, cytokine, and BDNF-related SNPs are associated with variations in global outcome at 6–12 months post-TBI. The association of these SNPs with neuropsychiatric and behavioral outcomes is less clear. A definitive assessment of role and effect size of genetic variation in these genes on outcome remains uncertain, but could be clarified by an adequately powered genome-wide association study with appropriate recording of outcomes.

5-HTTLPR and MTHFR 677C>T polymorphisms and response to yoga-based lifestyle intervention in major depressive disorder: A randomized active-controlled trial

BACKGROUND

There is growing evidence suggesting that both genetic and environmental factors modulate treatment outcome in, a highly heterogeneous, major depressive disorder (MDD). 5-HTTLPR variant of the serotonin transporter gene (SLC6A4) and MTHFR 677C>T polymorphisms have been linked to the pathogenesis of MDD, and antidepressant treatment response. The evidence is lacking on the clinical utility of yoga in patients with MDD who have 5-HTTLPR and MTHFR 677C>T polymorphisms and less likely to respond to medications (SSRIs).

AIMS

We aimed to examine the impact of YBLI in those who have susceptible 5-HTTLPR and MTHFR 677C>T polymorphisms and are less likely to drug therapy with SSRIs.

SETTINGS AND DESIGN

In a 12 week randomized active-controlled trial, MDD patients (n = 178) were randomized to receive YBLI or drug therapy.

METHODS

Genotyping was conducted using PCR-based methods. The clinical remission was defined as BDI-II score ≤ 9.

STATISTICAL ANALYSIS USED

An intent-to-treat analysis was performed, and the association of genotype with treatment remission consisted of the logistic regression model. A P value of <0.05 was considered statistically significant.

RESULTS

Multivariate logistic regression models for remission including either 5-HTTLPR or MTHFR 677C>T genotypes showed statistically significant odds of remission in YOGA arm vs. DRUG arm. Neither 5-HTTLPR nor MTHFR 677C>T genotype showed any influence on remission to YBLI (P = 0.73 and P = 0.64, respectively). Further analysis showed childhood adversity interact with 5-HTTLPR and MTHFR 677C>T polymorphisms to decrease treatment response in DRUG treatment arm, but not in YOGA arm.

CONCLUSIONS

YBLI provides MDD remission in those who have susceptible 5-HTTLPR and MTHFR 677C>T polymorphisms and are resistant to SSRIs treatment. YBLI may be therapeutic for MDD independent of heterogeneity in its etiopathogenesis.

Effects of Depression and Antidepressant Use on Cognitive Deficits and Functional Cognition Following Severe Traumatic Brain Injury

OBJECTIVE

To use a Rehabilomics framework to evaluate relations hips between post-traumatic brain injury (TBI) depression (PTD) and potential associated factors, including antidepressant use, on cognitive recovery following severe TBI.

PARTICIPANTS

Severe TBI survivors (n = 154), recruited from a level 1 trauma center.

DESIGN

Prospective cohort study with assessments at 6 and 12 months postinjury.

MAIN MEASURES

Patient Health Questionnaire-9 (PTD symptoms); cognitive composite score from a neuropsychological assessment battery (cognitive impairment); and Functional Independence Measure-Cognition (FIM-Cog, self-reported functional cognition).

RESULTS

Individuals with and without PTD did not differ with respect to cognitive impairment. However, antidepressant use, regardless of PTD status, was associated with cognitive impairment. Individuals with PTD reported lower FIM-Cog scores at both time points compared with those without PTD. In a post hoc longitudinal analysis, individuals with late-onset PTD had worse cognitive impairment.

CONCLUSION

These results suggest that antidepressant use impairs cognition among individuals without PTD. Also, PTD did not directly affect cognitive impairment but may affect functional cognitive limitations through self-evaluation and apathy/motivation factors.

Evaluating the Psychometric Properties of 3 Depression Measures in a Sample of Persons With Traumatic Brain Injury and Major Depressive Disorder

OBJECTIVES

To explore the psychometric properties of 3 widely used measures of depression in a sample of individuals with traumatic brain injury (TBI) and major depressive disorder and refine them to maximize efficiency.

DESIGN

Secondary analysis of data from a randomized controlled trial of cognitive-behavioral therapy for depression after TBI.

SETTING

Nationwide recruitment from community and clinical settings.

PARTICIPANTS

One hundred adults within 10 years of complicated mild to severe TBI.

INTERVENTION

Telephone and in-person cognitive-behavioral therapy.

MAIN MEASURES

Patient Health Questionnaire-9 (PHQ-9), Symptom Checklist-20, and Hamilton Depression Rating Scale.

RESULTS

We used Rasch rating scale analysis and multilevel modeling to investigate the 3 measures. Measurement properties of each of the depression measures were strong. We explored modifications to the rating scales to improve efficiency while retaining strong psychometric characteristics. Correlations among these revised measures were high. Treatment effects of each revised depression measure were compared using a multilevel model, and effect size estimates were comparable among the revised PHQ-9, Symptom Checklist-20, and Hamilton Depression Rating Scale.

CONCLUSIONS

Although each of the 3 measures demonstrated adequate reliability, the efficiency of all 3 instruments was improved with rating scale analysis. The PHQ-9 required the fewest modifications and functions well as a measure of depression among those with TBI.

Selective Serotonin Reuptake Inhibitors for Treating Neurocognitive and Neuropsychiatric Disorders Following Traumatic Brain Injury: An Evaluation of Current Evidence

The prevalence of neuropsychiatric disorders following traumatic brain injury (TBI) is 20%-50%, and disorders of mood and cognition may remain even after recovery of neurologic function is achieved. Selective serotonin reuptake inhibitors (SSRI) block the reuptake of serotonin in presynaptic cells to lead to increased serotonergic activity in the synaptic cleft, constituting first-line treatment for a variety of neurocognitive and neuropsychiatric disorders. This review investigates the utility of SSRIs in treating post-TBI disorders. In total, 37 unique reports were consolidated from the Cochrane Central Register and PubMed (eight randomized-controlled trials (RCTs), nine open-label studies, 11 case reports, nine review articles). SSRIs are associated with improvement of depressive but not cognitive symptoms. Pooled analysis using the Hamilton Depression Rating Scale demonstrate a significant mean decrease of depression severity following sertraline compared to placebo-a result supported by several other RCTs with similar endpoints. Evidence from smaller studies demonstrates mood improvement following SSRI administration with absent or negative effects on cognitive and functional recovery. Notably, studies on SSRI treatment effects for post-traumatic stress disorder after TBI remain absent, and this represents an important direction of future research. Furthermore, placebo-controlled studies with extended follow-up periods and concurrent biomarker, neuroimaging and behavioral data are necessary to delineate the attributable pharmacological effects of SSRIs in the TBI population.

A narrative literature review of depression following traumatic brain injury: prevalence, impact, and management challenges

Depression is one of the most common conditions to emerge after traumatic brain injury (TBI), and despite its potentially serious consequences it remains undertreated. Treatment for post-traumatic depression (PTD) is complicated due to the multifactorial etiology of PTD, ranging from biological pathways to psychosocial adjustment. Identifying the unique, personalized factors contributing to the development of PTD could improve long-term treatment and management for individuals with TBI. The purpose of this narrative literature review was to summarize the prevalence and impact of PTD among those with moderate to severe TBI and to discuss current challenges in its management. Overall, PTD has an estimated point prevalence of 30%, with 50% of individuals with moderate to severe TBI experiencing an episode of PTD in the first year after injury alone. PTD has significant implications for health, leading to more hospitalizations and greater caregiver burden, for participation, reducing rates of return to work and affecting social relationships, and for quality of life. PTD may develop directly or indirectly as a result of biological changes after injury, most notably post-injury inflammation, or through psychological and psychosocial factors, including pre injury personal characteristics and post-injury adjustment to disability. Current evidence for effective treatments is limited, although the strongest evidence supports antidepressants and cognitive behavioral interventions. More personalized approaches to treatment and further research into unique therapy combinations may improve the management of PTD and improve the health, functioning, and quality of life for individuals with TBI.

What are the complications and emerging strategies for preventing depression following traumatic brain injury?

INTRODUCTION

Depression is a common and disabling complication of traumatic brain injury (TBI). The high rates of post-TBI depression (PTBID) make this condition an important candidate for selective preventive interventions. Areas covered: The authors recently reported on the efficacy of sertraline, a selective serotonin reuptake inhibitor (SSRI), for the prevention of new cases of depression in the first six months after TBI. The authors review this and other studies on preventive strategies in PTBID as ascertained from a PubMed and citation search. The potential complications and barriers to the implementation of pharmacological prevention in patients with TBI are also discussed. Expert commentary: The prevention of depression in patients with TBI has received little attention relative to other medical conditions. Future studies are needed to confirm the benefit of SSRIs and investigate other pharmacological and non-pharmacological interventions, including in special groups of patients at greater risk of developing PTBID.

MTHFR: Genetic variants, expression analysis and COMT interaction in major depressive disorder

BACKGROUND

Methylenetetrahydrofolate reductase (MTHFR) genetic variations have been widely studied in major depressive disorder (MDD) and antidepressants outcome. An interaction with catechol-O-methyltransferase (COMT) has also been proved affecting depression. The aim of this study was to clarify the role of the most commonly studied single nucleotide polymorphisms (SNPs) of MTHFR gene in MDD and in treatment response mechanisms, along with the impact of the interaction with COMT.

METHODS

A total of 613 MDD patients, of whom 389 were classified as having treatment resistant depression (TRD), and 463 controls were enrolled. The A1298C, C677T and COMT Val158Met were genotyped. Genetic data were integrated with a transcriptional level analysis in peripheral blood cells (PBCs) and fibroblasts.

RESULTS

The A1298C CC homozygotes were more frequent in MDD patients compared to controls in women, increasing twice the genetic risk to develop depression. Moreover this genotype resulted in epistasis with COMT Met carriers in association with MDD. No significant effects were obtained concerning response to treatment. Transcriptional analyses highlighted a strong correlation between the mRNA levels of MTHFR in fibroblasts and COMT genotypes whereas no significant association with MDD was found. PBCs results revealed relevant influences of environmental factors.

LIMITATION

We did not measure folate and homocisteine levels.

CONCLUSION

This study showed the involvement of A1298C, Val158Met and their interaction in MDD. The transcriptional analyses supported the participation of COMT in the folate pathway, which partakes in the complex network of gene×gene and gene×environment interactions of MDD etiopathogenesis.

BDNF/TRKB/P75NTR polymorphisms and their consequences on antidepressant efficacy in depressed patients

We propose an extensive review of the literature about BDNF/TRKB/P75NTR polymorphisms and their consequences on antidepressant efficacy in depressed patients. Five genome-wide association studies and 30 association studies were included. Twenty seven studies focused on the Val66Met polymorphism (rs6265), the Met allele being associated with a higher antidepressant efficacy only in Asian patients. Other BDNF/TRKB/P75NTR polymorphisms (BDNF: rs7103411, rs7124442, rs908867, rs2049046, rs61888800, rs10501087, rs1491850; TRKB: rs10868223, rs11140778, rs1565445, rs1659412; P75NTR: rs2072446) were reported to be associated with antidepressant efficacy but these results were not replicated. Finally, there are 15 positive studies among 30 studies regarding BDNF/TRKB/P75NTR polymorphisms. The only SNP which benefits of at least three positive studies is the BDNF Val66Met polymorphism (rs6265). Consequently, with a lack of good and consistent studies, the clinical utility of BDNF in treatment selection is far from clear. We propose several recommendations for further studies.

Brain-derived neurotrophic factor Val66Met polymorphism and 6-month antidepressant remission in depressed Caucasian patients

BACKGROUND

Whether the Brain Derived Neurotrophic Factor (BDNF) Val66Met polymorphism can predict antidepressant drug efficacy in depressed patients remains unclear, suggesting that it may depend on antidepressant classes. We assessed the impact of Val66Met polymorphism on antidepressant response and remission depending on antidepressant classes.

METHODS

In a 6-month prospective, real-world setting, treatment study, 345 Caucasian depressed patients requiring a new or different drug treatment with a selective serotonin reuptake inhibitor (SSRI), a serotonin and noradrenalin reuptake inhibitor (SNRI) or a tricyclic antidepressant (TCA), were genotyped and assessed for response and remission.

RESULTS

231 (67%) patients were homozygous for the Val66 allele (Val/Val) and 114 (33%) were carriers of Met allele (Met). 152 (44.1%) patients were treated with SSRI, the others with SNRI/TCA. Both response and remission were explained by interactions between the Val66Met polymorphism and antidepressant drug classes (multivariate models adjusted for propensity-scores: p=0.02 and p=0.03 respectively). With SSRI, Val/Val patients had a higher response rate 3 months post-treatment than Met patients (68.1% versus 44%; adjusted-OR: 3.04, IC95% [1.05; 9.37], p=0.04). With SNRI/TCA, Val/Val patients had a lower remission rate 6 months post-treatment than Met patients (33.3% versus 60.9%, adjusted-OR: 0.27, IC95% [0.09; 0.76], p=0.02).

LIMITATIONS

Limited sample size.

CONCLUSIONS

This study argues for a personalized prescription of antidepressants in Caucasian patients with major depressive disorder, based on the BDNF Val66Met polymorphism: SSRI should be preferred for Val/Val patients and SNRI/TCA for Met patients. Further studies are required to confirm these data.

B vitamin polymorphisms and behavior: evidence of associations with neurodevelopment, depression, schizophrenia, bipolar disorder and cognitive decline

The B vitamins folic acid, vitamin B12 and B6 are essential for neuronal function, and severe deficiencies have been linked to increased risk of neurodevelopmental disorders, psychiatric disease and dementia. Polymorphisms of genes involved in B vitamin absorption, metabolism and function, such as methylene tetrahydrofolate reductase (MTHFR), cystathionine β synthase (CβS), transcobalamin 2 receptor (TCN2) and methionine synthase reductase (MTRR), have also been linked to increased incidence of psychiatric and cognitive disorders. However, the effects of these polymorphisms are often quite small and many studies failed to show any meaningful or consistent associations. This review discusses previous findings from clinical studies and highlights gaps in knowledge. Future studies assessing B vitamin-associated polymorphisms must take into account not just traditional demographics, but subjects' overall diet, relevant biomarkers of nutritional status and also analyze related genetic factors that may exacerbate behavioral effects or nutritional status.

Mood disorders after TBI

In this article, we examine the epidemiology and risk factors for the development of the most common mood disorders observed in the aftermath of TBI: depressive disorders and bipolar spectrum disorders. We describe the classification approach and diagnostic criteria proposed in the fifth edition of the Diagnostic and Statistical Manual for Mental Disorders. We also examine the differential diagnosis of post-TBI mood disorders and describe the mainstay of the evaluation process. Finally, we place a special emphasis on the analysis of the different therapeutic options and provide guidelines for the appropriate management of these conditions.

Systematic review and meta-analysis of serotonin transporter genotype and discontinuation from antidepressant treatment

There is evidence that 5-HTTLPR is associated with response following treatment from selective serotonin reuptake inhibitors (SSRIs). The short (S) allele has reduced serotonin transporter expression, compared to the long (L) allele, and has been reported to be associated with poorer response in Europeans, with the effect in other populations unclear. However the published literature is inconsistent. A systematic review and meta-analysis was performed to investigate the effect of 5-HTTLPR on discontinuation from antidepressant treatment. Data were obtained from 17 studies including 4309 participants. The principal outcome measure was the allelic odds ratio (OR) for the 5-HTTLPR S allele and discontinuation status. A random effects meta-analysis provided no evidence that the S allele was associated with increased odds of discontinuation from SSRIs in Europeans (OR 1.09, 95% CI 0.83-1.42, p=0.53; 10 studies, n=2504) but in East Asians there was evidence of a reduced odds of discontinuation (OR 0.28, 95% CI 0.12-0.64, p=0.002; 2 studies, n=136). There was a suggestion of small study bias (p=0.05). This meta-analysis provides no evidence of an association between 5-HTTLPR and discontinuation from antidepressant treatment in Europeans. The low number of studies in East Asian samples using SSRIs reduces confidence in our evidence that the S allele decreases the odds of discontinuation in this population. At present, there is no evidence of an association between 5-HTTLPR and discontinuation from SSRI treatment in a European population with further studies required to investigate its effects in different populations.

Folate metabolism genes, dietary folate and response to antidepressant medications in late-life depression

OBJECTIVE

The primary aims of this study were to (i) determine whether folate metabolism genetic polymorphisms predict age of onset and occurrence of late life depression; and (ii) determine whether folate metabolism genetic polymorphisms predict response to antidepressant medications in late-life depression.

METHODS

This study used the Conte Center for the Neuroscience of Depression and the Neurocognitive Outcomes of Depression in the Elderly Study database, which includes individuals aged ≥60. The folate nutrition assessment was determined by the Block Food Frequency Questionnaire. Genotype was evaluated for 15 single nucleotide polymorphisms from 10 folate metabolism genes. Logistic regression models were used to examine genetic polymorphisms and folate estimates with association with depression age of onset and remission status.

RESULTS

There were 304 Caucasians in the database, 106 of these were not depressed and 198 had a diagnosis of depression. There were no significant differences between remitters and non-remitters in age, sex or estimated folate intakes. There were no folate estimates or folate metabolism gene single nucleotide polymorphisms that significantly predicted age of onset of depression or occurrence of depression. Methionine synthase reductase (MTRR) A66G (rs1801394) was significantly associated with remission status (p = 0.0077) such that those with the AA genotype were 3.2 times as likely as those with the GG genotype to be in remission (p = 0.0020). Methylenetetrahydrofolate reductase A1298C (rs1801131) achieved a borderline significance for association with remission status (p = 0.0313).

CONCLUSION

The major finding from this study is that the MTRR A66G genotype predicts response to selective serotonin reuptake inhibitor antidepressants in late life depression.

Treatment for depression following mild traumatic brain injury in adults: a meta-analysis

PRIMARY OBJECTIVE

Development of depression after TBI is linked to poorer outcomes. The aim of this manuscript is to review evidence for the effectiveness of current treatments.

RESEARCH DESIGN

Two meta-analyses were undertaken to examine the effectiveness of both pharmacological and non-pharmacological interventions for depression after mild TBI.

METHOD AND PROCEDURES

PubMed, Medline, PsychInfo, Web of Science and Digital Dissertations were searched and 13 studies located. Meta Analyst Beta 3.13 was used to conduct analyses of pre- vs post-effects then to examine treatment group vs control group effects.

MAIN OUTCOMES AND RESULTS

Studies using a pre-post design produced an overall effect size of 1.89 (95% CI = 1.20-2.58, p < 0.001), suggesting that treatments were effective; however, the overall effect for controlled trials was 0.46 (95% CI = -0.44-1.36, p < 0.001), which favoured the control rather than treatment groups.

CONCLUSIONS

This study highlights the need for additional large well-controlled trials of effective treatments for depression post-TBI.

Peptidergic drugs for the treatment of traumatic brain injury

Traumatic brain injury (TBI) is a devastating medical condition that has an enormous socioeconomic impact because it affects more than 10 million people annually worldwide and is associated with high rates of hospitalization, mortality and disability. Although TBI survival has improved continuously for decades, particularly in developing countries, implementation of an effective drug therapy for TBI represents an unmet clinical need. All confirmatory trials conducted to date with drugs targeting a single TBI pathological pathway failed to show clinical efficacy, probably because TBI pathophysiology involves multiple cellular and molecular mechanisms of secondary brain damage. According to current scientific evidence of the participation of peptide-mediated mechanisms in the processes of brain injury and repair after TBI, peptidergic drugs represent a multimodal therapy alternative to improve acute outcome and long-term recovery in TBI patients. Preliminary randomized-controlled clinical trials and open-label studies conducted to date with the peptidergic drug Cerebrolysin® (Ever Neuro Pharma GmbH, Unterach, Austria) and with the endogenous neuropeptides progesterone and erythropoietin, showed positive clinical results. Cerebrolysin-treated patients had a faster clinical recovery, a shorter hospitalization time and a better long-term outcome. Treatment with progesterone showed advantages over placebo regarding TBI mortality and clinical outcome, whereas erythropoietin only reduced mortality. Further validation of these promising findings in confirmatory randomized-controlled clinical trials is warranted. This article reviews the scientific basis and clinical evidence on the development of multimodal peptidergic drugs as a therapeutic option for the effective treatment of TBI patients.

Aripiprazole improves various cognitive and behavioral impairments after traumatic brain injury: a case report

Various types of cognitive and behavioral impairments occur after traumatic brain injury. We present a case exhibiting psychotic symptoms such as irritability, dysphoria, anxiety and insomnia with severe brain dysfunction due to a right temporal lobe contusion incurred in a traffic accident. The patient did not sufficiently respond to rehabilitation or treatment with any pharmacotherapy. In the present case, aripiprazole dramatically improved the patient's symptoms and cognitive function. We evaluated the case using the Wechsler Adult Intelligence Scale-Revised and the Wechsler Memory Scale Revised between baseline and 5 years later.

Folates and S-adenosylmethionine for major depressive disorder

Interest in nonpharmaceutical supplements for treating major depressive disorder (MDD) has increased significantly, both among patients and among clinicians during the past decades. Despite the large array of antidepressants (ADs) available, many patients continue to experience relatively modest response and remission rates, in addition to a burden of side effects that can hinder treatment compliance and acceptability. In this article, we review the literature on folates and S-adenosylmethionine (SAMe), 2 natural compounds linked in the 1-carbon cycle metabolic pathway, for which substantial evidence supports their involvement in mood disorders. Background information, efficacy data, proposed mechanisms of action, and side effects are reviewed. Based on existing data, supplementation with SAMe, as well as with various formulations of folates, appears to be efficacious and well tolerated in reducing depressive symptoms. Compared with other forms of folates, 5-methyltetrahydrofolate (L-methylfolate or 5-MTHF) may represent a preferable treatment option for MDD given its greater bioavailability in patients with a genetic polymorphism, and the lower risk of specific side effects associated with folic acid. Although further randomized controlled trials in this area appear warranted, SAMe and L-methylfolate may represent a useful addition to the AD armamentarium.

A Rehabilomics focused perspective on molecular mechanisms underlying neurological injury, complications, and recovery after severe TBI

The molecular mechanisms underlying TBI pathophysiology and recovery are both complex and varied. Further, the pathology underlying many of the clinical sequelae observed in this population evolve over the acute injury period and encompass the subacute and chronic phases of recovery, supporting the contemporary concept that TBI is a chronic disease rather than a static insult from which limited recovery occurs. TBI related complications can also span from acute care to the very chronic stages of recovery that occur years after the initial trauma. Despite ongoing neurodegeneration, the TBI recovery period is also characterized by a propensity for neuroplasticity and rewiring through multiple mechanisms. This review summarizes key elements of acute pathophysiology, how they link to structural damage and ongoing degeneration, and how this process coincides with a permissive neuroplastic environment. The pathophysiology of selected TBI related complications is also discussed. Each of these concepts is studied through the lens of Rehabilomics, wherein an emphasis is placed on biomarker studies characterizing these pathophysiological mechanisms, and biomarker profiles are assessed in relation to multi-modal outcomes and susceptibility to rehabilitation relevant complications. In reviewing these concepts, implications for future research and theranostic principles for patient care are presented.

Depression following traumatic brain injury: epidemiology, risk factors and management

It is important for clinicians to recognize major depression following traumatic brain injury (TBI) because of its association with poor global and psychosocial outcome, postconcussive symptoms and cognitive deficits. The purpose of this review is to provide an up-to-date selective review of the current understanding of epidemiology, risk factors and management of major depression following TBI. Many studies of prevalence of depression following TBI have not used accepted structured criteria for the diagnoses, but those that did found wide ranges of rates, from 17% to 61%. The risk factors for development of depression following TBI are poorly understood, but past psychiatric history, frontal lesions and atrophy, and family dysfunction have been shown in more than one study to play important roles. There are few controlled trials of the treatment of major depression in patients with TBI using accepted diagnostic criteria for major depression, as well as defined criteria for response and remission. As such, it is important for clinicians to use best practice guidelines for the treatment of major depression in the absence of TBI.

Genetics and outcomes after traumatic brain injury (TBI): what do we know about pediatric TBI?

Human genetic association studies in individuals with traumatic brain injury (TBI) have increased rapidly over the past few years. Recently, several review articles evaluated the association of genetics with outcomes after TBI. However, almost all of the articles discussed in these reviews focused on adult TBI. The primary objective of this review is to gain a better understanding of which genes and/or genetic polymorphisms have been evaluated in pediatric TBI. Our initial search identified 113 articles. After review of these articles only 5 genetic association studies specific to pediatric TBI were identified. All five of these studies evaluated the apolipoprotein (APOE) gene. The study design and methods of these identified papers will be discussed. An additional search was then performed to evaluate genes beyond APOE that have been evaluated in adult TBI; findings from these studies are highlighted. Larger genetic studies will need to be performed in the future to better elucidate the association of APOE and other genes with outcomes after TBI in children. There is great potential to utilized genetic information to inform prognosis and management after TBI in children; however, we have much work ahead of us to reach the goal of individualized management.

Disturbed neurotransmitter transporter expression in Alzheimer's disease brain

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by memory loss and behavioral and psychological symptoms of dementia. An imbalance of different neurotransmitters--glutamate, acetylcholine, dopamine, and serotonin--has been proposed as the neurobiological basis of behavioral symptoms in AD. The molecular changes associated with neurotransmission imbalance in AD are not clear. We hypothesized that altered reuptake of neurotransmitters by vesicular glutamate transporters (VGLUTs), excitatory amino acid transporters (EAATs), the vesicular acetylcholine transporter (VAChT), the serotonin reuptake transporter (SERT), or the dopamine reuptake transporter (DAT) are involved in the neurotransmission imbalance in AD. We tested this hypothesis by examining protein and mRNA levels of these transporters in postmortem prefrontal cortex from 10 AD patients and 10 matched non-AD controls. Compared with controls, protein and mRNA levels of VGLUTs, EAAT1-3, VAChT, and SERT were reduced significantly in AD. Expression of DAT and catechol O-methyltransferase was unchanged. Reduced VGLUTs and EAATs may contribute to an alteration in glutamatergic recycling, and reduced SERT could exacerbate depressive symptoms in AD. The reduced VAChT expression could contribute to the recognized cholinergic deficit in AD. Altered neurotransmitter transporters could contribute to the pathophysiology of AD and are potential targets for therapy.