Serum BDNF levels in relation to illness severity, suicide attempts, and central serotonin activity in patients with major depressive disorder: a pilot study

Plasma Apo-E mediated corticospinal tract abnormalities and suicidality in patients with major depressive disorder

This study aims to explore the link between Apo-E, brain white matter, and suicide in patients with major depressive disorder (MDD) to investigate the potential neuroimmune mechanisms of Apo-E that may lead to suicide. Thirty-nine patients with MDD (22 patients with suicidality) and 57 age, gender, and education-matched healthy controls participated in this study, provided plasma Apo-E samples, and underwent diffusion tensor imaging scans. Plasma Apo-E levels and white matter microstructure were analyzed among the MDD with suicidality, MDD without suicidality, and HC groups using analysis of variance with post hoc Bonferroni correction and tract-based spatial statistics (TBSS) with threshold-free cluster enhancement correction. Mediation analysis investigated the relationship between Apo-E, brain white matter, and suicidality in MDD. The MDD with suicidality subgroup had higher depressive and suicide scores, longer disease course, and lower plasma Apo-E levels than MDD without suicidality. TBSS revealed that the MDD non-suicide subgroup showed significantly increased mean diffusivity in the left corticospinal tract and body of the left corpus callosum, as well as increased axial diffusivity in the left anterior corona radiata and the right posterior thalamic radiation compared to the suicidal MDD group. The main finding was that the increased MD of the left corticospinal tract contributed to the elevated suicide score, with Apo-E mediating the effect. Preliminary result that Apo-E's mediating role between the left corticospinal tract and the suicide factor suggests the neuroimmune mechanism of suicide in MDD. The study was registered on ClinicalTrials.gov (NCT03790085).

Electroconvulsive Therapy Modulates Loudness Dependence of Auditory Evoked Potentials: A Pilot MEG Study

Electroconvulsive therapy (ECT) remains a critical intervention for treatment-resistant depression (MDD), yet its neurobiological underpinnings are not fully understood. This pilot study utilizes high-resolution magnetoencephalography (MEG) in nine depressed patients receiving right unilateral ECT, to investigate the changes in loudness dependence of auditory evoked potentials (LDAEP), a proposed biomarker of serotonergic activity, following ECT. We hypothesized that ECT would reduce the LDAEP slope, reflecting enhanced serotonergic neurotransmission. Contrary to this, our findings indicated a significant increase in LDAEP post-ECT ( t 8 = 3.17, p = .013). The increase in LDAEP was not associated with changes in depression severity or cognitive performance, as assessed by the Hamilton Depression Rating Scale (HAMD-24) and Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). We discussed potential mechanisms for the observed increase, including ECT's impact on serotonergic, dopaminergic, glutamatergic, and GABAergic receptor activity, neuroplasticity involving brain-derived neurotrophic factor (BDNF), and inflammation modulators such as TNF- alpha . Our results suggest a complex interaction between ECT and these neurobiological systems, rather than a direct reflection of serotonergic neurotransmission.

Relationship between Loudness Dependence of Auditory-evoked Potentials and Suicidality

Objective

: Serotonin concentration is associated with suicide in patients with major depressive disorder. Loudness dependence of auditory-evoked potentials (LDAEPs), a representative neurophysiological indicator, is related to serotonin activity. Therefore, this study aimed to investigate the relationship between LDAEPs and suicidal ideation, suicide attempts, and the severity of depression.

Methods

: We evaluated the scalp N1, P2, and N1/P2 LDAEPs along with standardized low-resolution brain electromagnetic tomography (sLORETA)-localized N1, P2, and N1/P2 LDAEPs of 221 patients with major depressive disorder. The demographic and clinical data of the patients, including data on suicidal ideation and previous suicide attempts, were obtained from clinical interviews and medical records. The severity of depression was assessed using the Beck Depression Inventory and Hamilton Depression Rating Scale, whereas suicidal ideation was evaluated using the Beck Scale for Suicidal Ideation (BSS).

Results

: The total BSS score was associated with low N1/P2 LDAEP (p = 0.045), whereas P2 sLORETA-LDAEP was associated with lower previous suicide attempts (p = 0.043). In addition, suicide attempt was correlated with an elevated P2 left sLORETA-LDAEP (coefficient = 4.638, p = 0.038).

Conclusion

: These findings suggest that suicidal ideation is associated with decreased LDAEP, whereas suicide attempt is associated with increased LDAEP.

Elevated Plasma Levels of Mature Brain-Derived Neurotrophic Factor in Major Depressive Disorder Patients with Higher Suicidal Ideation

Several pieces of evidence show that signaling via brain-derived neurotrophic factor (BDNF) and its receptor, tropomycin receptor kinase B (TrkB), as well as inflammation, play a crucial part in the pathophysiology of depression. The purpose of our study was to evaluate plasma levels of BDNF-TrkB signaling, which are inflammatory factors in major depressive disorder (MDD) patients, and assess their associations with clinical performance. This study recruited a total sample of 83 MDD patients and 93 healthy controls (CON). All the participants were tested with the Hamilton Depression Scale (HAMD), the Beck Scale for Suicide Ideation, and the NEO Five-Factor Inventory. The plasma level of selected BDNF-TrkB signaling components (mature BDNF (mBDNF), precursor BDNF (proBDNF), tyrosine kinase B (TrkB), and tissue plasminogen activator (tPA)) and selected inflammatory factors (interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α)) were measured using an enzyme-linked immunosorbent assay (ELISA). Further, we performed correlation analysis to indicate the relationship between the plasma levels of the factors and clinical characteristics. Results: (i) A higher level of mBDNF and lower openness were observed in MDD patients with higher suicidal ideation than patients with lower suicidal ideation. (ii) In MDD patients, mBDNF was positively correlated with the sum score of the Beck Scale for Suicide Ideation (BSS). (iii) The levels of mBDNF, tPA, IL-1 β and IL-6 were significantly higher in all MDD subjects compared to the healthy controls, while the levels of TrkB and proBDNF were lower in MDD subjects. Conclusion: Our study provides novel insights regarding the potential role of mBDNF in the neurobiology of the association between depression and suicidal ideation and, in particular, the relationship between BDNF-TrkB signaling, inflammatory factors, and clinical characteristics in MDD.

The Effects of Walnuts and Academic Stress on Mental Health, General Well-Being and the Gut Microbiota in a Sample of University Students: A Randomised Clinical Trial

Poorer mental health is common in undergraduate students due to academic stress. An interplay between stress and diet exists, with stress influencing food choices. Nutritional interventions may be effective in preventing mental health decline due to complex bidirectional interactions between the brain, the gut and the gut microbiota. Previous studies have shown walnut consumption has a positive effect on mental health. Here, using a randomized clinical trial (Australian New Zealand Clinical Trials Registry, #ACTRN12619000972123), we aimed to investigate the effects of academic stress and daily walnut consumption in university students on mental health, biochemical markers of general health, and the gut microbiota. We found academic stress had a negative impact on self-reported mood and mental health status, while daily walnut consumption improved mental health indicators and protected against some of the negative effects of academic stress on metabolic and stress biomarkers. Academic stress was associated with lower gut microbial diversity in females, which was improved by walnut consumption. The effects of academic stress or walnut consumption in male participants could not be established due to small numbers of participants. Thus, walnut consumption may have a protective effect against some of the negative impacts of academic stress, however sex-dependent mechanisms require further study.

Interaction effects of diabetes and brain-derived neurotrophic factor on suicidal ideation in patients with acute coronary syndrome

Acute coronary syndrome (ACS) is related to an increased risk of suicide. Although both diabetes and the brain-derived neurotrophic factor (BDNF) pathway are closely associated with ACS and suicide, the effects of these factors on suicidal behavior in ACS patients have not been assessed. We investigated the individual and interaction effects of diabetes and BDNF-related markers, namely the serum BDNF (sBDNF) level and the BDNF Val66Met polymorphism, on suicidal ideation (SI) in ACS patients. The presence of diabetes was ascertained, and sBDNF levels and the presence of the BDNF Val66Met polymorphism were measured in 969 patients within 2 weeks after an ACS episode. 711 patients were followed up at 1 year after the ACS episode. SI was assessed using the relevant items of the Montgomery–Åsberg Depression Rating Scale at baseline (acute SI) and the 1-year follow-up (chronic SI). Significant individual effects of low sBDNF levels were found on acute SI. The presence of both diabetes and a low sBDNF level or the BDNF Met/Met genotype was associated with acute SI, with multivariate logistic regression analyses revealing significant interaction effects. The highest frequency of chronic SI was seen in diabetic patients with an sBDNF level in the lowest tertile or with the BDNF Met/Met genotype, although the interaction terms were not statistically significant. Our study suggests that the combination of diabetes and BDNF-related markers, such as the sBDNF level and the BDNF Val66Met polymorphism, might provide a useful predictor of acute SI in ACS patients.

Auditory evoked potentials and suicidal behaviors in patients with major depressive disorders

Loudness dependence of auditory evoked potentials (LDAEP) has been proposed as a biological marker of central serotonergic activity related to suicides. This study’s objective was to analyze the difference in LDAEP between depressed patients with suicide attempts (SA) and suicidal ideation (SI). It included 130 participants (45 depressed patients with SA, 49 depressed patients with SI, and 36 healthy controls) aged > 18 years who exhibited LDAEP during electroencephalography. Psychological characteristics and event-related potentials of the three groups were compared. There was no significant difference in LDAEP between major depressive disorder (MDD) patients with SA and SI (p = 0.59). MDD patients with SI, who attempted suicide had significantly lower LDAEP than healthy controls (p = 0.01 and p = 0.01, respectively). However, the significance disappeared when psychological characteristics were controlled. Our results suggest that LDAEP might not be possible biomarkers for suicidal behaviors in patients with MDD. Further studies to assess the biological basis of suicide and identify the underlying dimensions that mediate the relationship between the biological basis and suicidal behaviors will be needed.

Examining the underpinnings of loudness dependence of auditory evoked potentials with positron emission tomography

Loudness dependence of auditory evoked potentials (LDAEP) has long been considered to reflect central basal serotonin transmission. However, the relationship between LDAEP and individual serotonin receptors and transporters has not been fully explored in humans and may involve other neurotransmitter systems. To examine LDAEP's relationship with the serotonin system, we performed PET using serotonin-1A (5-HT_1A) imaging via [¹¹C]CUMI-101 and serotonin transporter (5-HTT) imaging via [¹¹C]DASB on a mixed sample of healthy controls (n ​= ​4: 4 females, 0 males), patients with unipolar (MDD, n ​= ​11: 4 females, 7 males) and bipolar depression (BD, n ​= ​8: 4 females, 4 males). On these same participants, we also performed electroencephalography (EEG) within a week of PET scanning, using 1000 ​Hz tones of varying intensity to evoke LDAEP. We then evaluated the relationship between LDAEP and 5-HT_1A or 5-HTT binding in both the raphe (5-HT_1A)/midbrain (5-HTT) areas and in the temporal cortex. We found that LDAEP was significantly correlated with 5-HT_1A positively and with 5-HTT negatively in the temporal cortex (p ​< ​0.05), but not correlated with either in midbrain or raphe. In males only, exploratory analysis showed multiple regions in which LDAEP significantly correlated with 5-HT_1A throughout the brain; we did not find this with 5-HTT. This multimodal study partially validates preclinical models of a serotonergic influence on LDAEP. Replication in larger samples is necessary to further clarify our understanding of the role of serotonin in perception of auditory tones.

Effect of Exercise on Major Depressive Disorder and Schizophrenia: A BDNF Focused Approach

Psychiatric disorders are remarkable health problems that cause a massive social and economic burden, and the issue of their long-term and effective treatment is subjected to discussion. The effect of physical activity and exercise is under investigation in the treatment of the major depressive disorder (MDD) and schizophrenia which are accompanied by cognitive dysfunctions. Scientists focus on the positive effects of exercise on learning, memory and attention parameters while investigating the regulatory role of brain-derived neurotrophic factor (BDNF). In this review, the effect of aerobic exercise on peripheral BDNF levels in MDD and schizophrenia is examined by including human studies in which acute and chronic aerobic exercise are applied. The results showed that aerobic exercise caused different responses on BDNF levels, and some of the studies were accompanied by the improvement in cognitive functions in BDNF changes. In order to comprehend the effect of aerobic exercise in MDD and schizophrenia, it is understood that applying studies on larger and paired participant groups with different exercise frequencies and tensions in necessary.

Genetic predictor of current suicidal ideation in US service members deployed to Iraq and Afghanistan

OBJECTIVE

Suicide is one of the ten leading causes of death in United States and the suicide rate in the military population has increased since the start of the Iraq and Afghanistan wars. However, few biomarkers for current suicidal ideation (CSI) have been identified. The current study examined the association of four candidate genes with CSI in active duty US Army Special Operations Command and National Guard units (n = 3,889) who served in Iraq and Afghanistan between November 2009 and July 2014.

METHODS

Current PTSD symptoms and CSI were assessed using the PTSD Checklist (PCL) and PHQ-9, respectively. Traumatic events were assessed using items from the Life Events Checklist (LEC) that met the DSM-IV PTSD criteria of a traumatic stressor. All genotypes of saliva DNA were discriminated using the TaqMan 5'-exonuclease assay.

RESULTS

The associations between CSI and brain-derived neurotrophic factor (BDNF), FK506 binding protein (FKBP5), catechol-O-methyltransferase (COMT), or S100A10 (p11) were examined. We found CSI was associated with BDNF (OR = 1.5, 95% CI = 1.5-1.8, P = 0.0002), but not FKBP5, COMT and p11. Female soldiers reported CSI more often than males (χ2 = 7.403, p = 0.0065), although gender did not affect CSI severity. In addition, associations were found between CSI and depression, PTSD, and BDNF, but not traumatic events. The BDNF Val66Met contributed to the severity of CSI even after adjusting to PTSD, depression and LEC.

CONCLUSIONS

The associations of BDNF with CSI and its severity suggest that BDNF may be a predictor of suicidal risk and present an opportunity to develop laboratory tools with clinical implications in suicide prevention and treatment.

Serum brain-derived neurotrophic factor levels in subjects with major depressive disorder with previous suicide attempt: A population-based study

Major depressive disorders (MDD) and suicide are significant public health concerns. Recent studies have been demonstrated that alterations in Brain Derived Neurotrophic Factor (BDNF) can be associated with this psychiatric disorders, MDD and suicide. Thus, the aim of this study was to evaluate differences in serum levels in individuals with MDD and with or without suicide attempt (SA), from a population-based sample. This was a paired cross-sectional study nested in a population-based study. The psychopathology screen was performed with the Mini-International Neuropsychiatric Interview (MINI). The total population of the sample consisted of 147 subjects distributed in three groups: 49 healthy controls, 49 subjects with MDD and 49 subjects with MDD and SA (MDD + SA). The BDNF serum levels were significantly reduced in subjects with MDD and MDD + SA compared to the healthy controls. However, there were no significant differences between the MDD and MDD + SA groups with respect to BDNF serum levels. These results suggest that SA did not interfere in the serum levels of BDNF, indicating that this neurotrophin may be related to the diagnosis of MDD and not to suicide attempt.

Heightened early-attentional stimulus orienting and impulsive action in men with antisocial personality disorder

We tested whether enhanced stimulus orienting operationalized as N1 and P2 auditory evoked potentials to increasing loudness (50-90 dB clicks) could be associated with trait impulsivity (Barratt Impulsiveness Scale, BIS-11), impulsive action (commission error on the Immediate Memory Task), or impulsive choice (immediate responses on temporal discounting tasks). We measured N1 and P2 loudness sensitivity in a passive listening task as linear intensity-sensitivity slopes in 36 men with antisocial personality disorder with a history of conviction for criminal conduct and 16 healthy control men. Across all subjects, regression analyses revealed that a steeper P2 slope predicted higher IMT commission error/correct detection ratio, and lower stimulus discriminability (A-prime). These associations were also found within both groups. These relationships suggest an association between enhanced early stimulus orienting (P2), impulsive action (response inhibition), and impaired signal-noise discriminability (A-prime).

Decrease in brain-derived neurotrophic factor at plasma level but not in serum concentrations in suicide behavior: A systematic review and meta-analysis

INTRODUCTION

Suicide is known as a major health concern worldwide. There is evidence for the role of brain-derived neurotrophic factor (BDNF) in suicide behavior. Therefore, this factor has been proposed as a biomarker for suicide behavior. Clinical studies have measured BDNF concentrations at central and peripheral levels. As a consequence, the aim of this study was to assess BDNF levels in blood plasma and serum to see whether there is a difference in concentrations in patients with suicide behavior when compared to those in controls, using a meta-analysis approach.

METHODS

We conducted a systematic review and meta-analysis. The search strategy was performed using three databases: PubMed, EBSCO and ScienceDirect. The meta-analysis included a total of nine case-control studies, six measured the BDNF level in serum and three in plasma in suicide behavior.

RESULTS

A decrease in BDNF levels in plasma was observed (d = -0.73, 95% CI -1.42 to -0.03 pg/ml). In the case of serum concentrations, no BDNF differences were encountered between cases and controls (d = 0.09, 95% CI -0.31 to 0.13 ng/ml, p(Q) = .92).

CONCLUSIONS

According to the results found in the present meta-analysis, the plasma BDNF level could be suggest as a potential biomarker in suicide behavior. However, since the number of studies included in the analysis is limited, a larger number is necessary to determine conclusively the role of BDNF as a biomarker in suicide behavior.

Exploring the Association between Serum BDNF and Attempted Suicide

Suicide is a leading cause of death and a significant public health concern. Brain-derived neurotrophic factor (BDNF), a protein important to nervous system function, has been implicated in psychiatric disorders and suicidal behaviour. We investigated the association between serum levels of BDNF and attempted suicide in a sample of 281 participants using a case-control study design. Participants were recruited from clinical and community settings between March 2011 and November 2014. Cases (individuals who had attempted suicide) (n = 84) were matched on sex and age (within five years) to both psychiatric controls (n = 104) and community controls (n = 93) with no history of suicide attempts. We collected fasting blood samples, socio-demographic information, physical measurements, and detailed descriptions of suicide attempts. We used linear regression analysis to determine the association between BDNF level (dependent variable) and attempted suicide (key exposure variable), adjusting for age, sex, body mass index, current smoking status, and antidepressant use. 250 participants were included in this analysis. In the linear regression model, attempted suicide was not significantly associated with BDNF level (β = 0.28, SE = 1.20, P = 0.82). Our findings suggest that no significant association exists between attempted suicide and BDNF level. However, the findings need to be replicated in a larger cohort study.

Plasma brain-derived neurotrophic factor levels are increased in patients with tinnitus and correlated with therapeutic effects

Tinnitus is the perception of sound without an external source and is known to be associated with altered neuronal excitability in the auditory system. Tinnitus severity can be assessed by various psychometric instruments and there is no objective measures developed to evaluate tinnitus severity and therapeutic effects so far. Brain-derived nerve growth factor (BDNF) is believed in playing a key role in regulating neuronal excitability in the brain. To determine whether BDNF correlates with tinnitus induction and severity, we described plasma BDNF levels in patients with tinnitus and healthy controls and evaluated the correlation between plasma BDNF levels and tinnitus severity measured by Tinnitus Handicap Inventory (THI) and Visual Analog Scale (VAS). Moreover, alteration of plasma BDNF levels before and after tinnitus retraining therapy (TRT) in patients with severe tinnitus was also analyzed. We found plasma BDNF levels were elevated in patients with tinnitus compared with healthy controls. In addition, plasma BDNF levels in patients with severe tinnitus were decreased significantly after effective TRT. However, plasma BDNF levels were not correlated with tinnitus loudness and tinnitus severity measured by THI and VAS. These findings support plasma BDNF as a marker for activity changes in the auditory system and could possibly evaluate therapeutic effects in patients with tinnitus.

[Biological basis of suicidal behavior]

Based on current clinical and classification concepts of suicidality, the biological parameters characteristic of suicidal behavior, completed and uncompleted suicides reported in the last few decades are discussed. The results obtained in the studies of neurotransmitter and other brain systems, immune system, lipid and other types of metabolism as well as data of neuroimaging brain studies and post-mortem investigation of brain structures are presented.

Association between BDNF levels and suicidal behaviour: a systematic review and meta-analysis

BACKGROUND

Suicidal behaviour is a complex phenomenon with a multitude of risk factors. Brain-derived neurotrophic factor (BDNF), a protein crucial to nervous system function, may be involved in suicide risk. The objective of this systematic review is to evaluate and summarize the literature examining the relationship between BDNF levels and suicidal behaviour.

METHODS

A predefined search strategy was used to search MEDLINE, EMBASE, PsychINFO, and CINAHL from inception to December 2015. Studies were included if they investigated the association between BDNF levels and suicidal behaviours (including completed suicide, attempted suicide, or suicidal ideation) by comparing BDNF levels in groups with and without suicidal behaviour. Only the following observational studies were included: case-control and cohort studies. Both clinical- and community-based samples were included. Screening, data extraction, and risk of bias assessment were conducted in duplicate.

RESULTS

Six-hundred thirty-one articles were screened, and 14 were included in the review. Three studies that assessed serum BDNF levels in individuals with suicide attempts and controls were combined in a meta-analysis that showed no significant association between serum BDNF and suicide attempts. The remaining 11 studies were not eligible for the meta-analysis and provided inconsistent findings regarding associations between BDNF and suicidal behaviour.

CONCLUSIONS

The findings of the meta-analysis indicate that there is no significant association between serum BDNF and attempted suicide. The qualitative review of the literature did not provide consistent support for an association between BDNF levels and suicidal behaviour. The evidence has significant methodological limitations.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015015871.

BDNF concentration and impulsiveness level in post-traumatic stress disorder

Among the symptoms of post-traumatic stress disorder (PTSD), impulsiveness has been observed in patients with high levels of hyperarousal. Recent literature reveals the importance of investigating the role of neurotrophins, such as brain-derived neurotrophic factor (BDNF), in several psychiatric disorders. Specifically, contrasting findings have been reported on the levels of serum BDNF in subjects with PTSD. The aim of the present study was to investigate the correlation between BDNF serum levels and impulsiveness in PTSD. To this end, we measured BDNF serum levels in 23 PTSD patients and a control group of 19 trauma-exposed non-PTSD subjects. Results indicate a positive correlation in the PTSD group; that is, the higher the BDNF levels the higher the impulsiveness score, as measured by the Barratt Impulsiveness Scale (BIS-11), suggesting that impulsiveness could be associated with greater BDNF production. Alternatively, it is also possible that high impulsiveness acts as a psychological mechanism that counteracts the negative effects exerted by the traumatic experience and the associated obsessive thoughts. The present paper discusses both hypotheses.

Relationship between Serotonergic Dysfunction Based on Loudness Dependence of Auditory-Evoked Potentials and Suicide in Patients with Major Depressive Disorder

The relationship between suicidality and the loudness dependence of auditory-evoked potentials (LDAEP) remains controversial. This article reviews the literature related to the LDAEP and suicide in patients with major depressive disorder, and suggests future research directions. Serotonergic dysfunction in suicidality seems to be more complicated than was originally thought. Studies of suicide based on the LDAEP have produced controversial results, but it is possible that these are due to differences in study designs and the smallness of samples. For example, some studies have evaluated suicide ideation and the LDAEP, while others have evaluated suicide attempts and the LDAEP. Furthermore, some of the latter studies enrolled acute suicide attempters, while others enrolled those with the history of previous suicide attempts, irrespective of whether these were acute or chronic. Thus, a more robust study design is needed in future studies, for example by evaluating the LDAEP immediately after a suicide attempt rather than in those with a history of suicide attempts and suicide ideation in order to reduce bias. Moreover, genuine suicide attempt, self-injurious behaviors, and faked suicide attempt need to be discriminated in the future.

Gender and brain regions specific differences in brain derived neurotrophic factor protein levels of depressed individuals who died through suicide

Considerable evidence supports the view that depressive illness and suicidal behaviour stem from perturbations of neuroplasticity. Presently, we assessed whether depressed individuals who died by suicide displayed brain region-specific changes in brain derived neurotrophic factor (BDNF) and whether such effects varied by gender. Using postmortem samples from non-psychiatric controls and depressed individuals who died by suicide, BDNF protein levels were assessed within the hippocampus and frontopolar prefrontal cortex using Western blot. As expected, BDNF levels were reduced within the frontopolar prefrontal cortex among female depressed suicides; however, males showed no such effect. Contrastingly, within the hippocampus, depressed male but not female suicides displayed significant reductions of BDNF protein levels. Although the mechanisms driving the gender and brain region specific BDNF changes are unclear, our data do support the notion that complex alterations of neuroplasticity may be fundamentally involved in the illness.

Blood BDNF level is gender specific in severe depression

Though the role of brain derived neurotrophic factor (BDNF) as a marker for major depressive disorder (MDD) and antidepressant efficacy has been widely studied, the role of BDNF in distinct groups of patients remains unclear. We evaluated the diagnostic value of BDNF as a marker of disease severity measured by HAM-D scores and antidepressants efficacy among MDD patients. Fifty-one patients who met DSM-IV criteria for MDD and were prescribed antidepressants and 38 controls participated in this study. BDNF in serum was measured at baseline, 1st, 2nd and 8th treatment weeks. Depression severity was evaluated using the Hamilton Rating Scale for Depression (HAM-D). BDNF polymorphism rs6265 (val66met) was genotyped. We found a positive correlation between blood BDNF levels and severity of depression only among untreated women with severe MDD (HAM-D>24). Serum BDNF levels were lower in untreated MDD patients compared to control group. Antidepressants increased serum BDNF levels and reduced between-group differences after two weeks of treatment. No correlations were observed between BDNF polymorphism, depression severity, duration of illness, age and BDNF serum levels. Further supporting the role of BDNF in the pathology and treatment of MDD, we suggest that it should not be used as a universal biomarker for diagnosis of MDD in the general population. However, it has diagnostic value for the assessment of disease progression and treatment efficacy in individual patients.

Exploring the Determinants of Suicidal Behavior: Conventional and Emergent Risk (DISCOVER): a feasibility study

BACKGROUND

Suicidal behavior is a growing public health concern resulting in morbidity and premature death. Although certain factors such as age, sex, and psychiatric disorders have been consistently reported to be associated with suicidal behavior, other factors including biological markers, diet, and physical activity may also influence suicidal behavior. The purpose of this pilot study was to evaluate the feasibility of conducting a full-scale study to identify the conventional and novel risk factors of suicidal behavior in individuals who made a recent suicide attempt.

METHODS

This pilot study was a case-control study of participants with recent (within 1 month of admission) suicide attempts admitted to hospital and compared to two control groups: 1) psychiatric inpatient participants without a history of suicide attempts and 2) community-based controls. We collected information on demographic variables, circumstances of suicide attempts (for cases), medical and psychiatric diagnoses, behavioral patterns, physical measurements, and social factors. Blood and urine samples were also collected for biological markers. Feasibility outcomes are as follows: 1) 50 % of all eligible cases will consent to participate, 2) 50 cases and 100 controls per year can be recruited, and 3) at least 80 % of the participants will provide blood samples for DNA and biological markers.

RESULTS

We recruited 179 participants in total; 51 cases, 57 psychiatric controls without suicide attempt, and 71 non-psychiatric controls in Hamilton, Ontario. Recruitment rate was 70 % (213/304), and we obtained urine and blood specimens from 90 % (191/213) of participants. Questionnaire completion rates were high, and data quality was very good with few data-related queries to resolve. We learned that cases tended to be hospitalized for long periods of time and the suicide attempt occurred more than a month ago in many of the cases; therefore, we expanded our inclusion criterion related to timing of suicide attempt to 3 months instead of 1 month.

CONCLUSIONS

The study procedures needed certain modifications including extending the time between suicide attempt and date of recruitment, and more detailed questionnaires related to diet were necessary while other questionnaires such as social support needed to be shortened. Overall, this study showed that it is feasible to conduct a larger-scale study.

Serum brain-derived neurotropic factor level predicts adverse clinical outcomes in patients with heart failure

BACKGROUND

Brain-derived neurotropic factor (BDNF) is involved in cardiovascular diseases as well as skeletal muscle energy metabolism and depression. We investigated whether serum BDNF level was associated with prognosis in patients with heart failure (HF).

METHODS AND RESULTS

We measured the serum BDNF level in 58 patients with HF (59.2 ± 13.7 years old, New York Heart Association functional class I-III) at baseline, and adverse events, including all cardiac deaths and HF rehospitalizations, were recorded during the median follow-up of 20.3 months. In a univariate analysis, serum BDNF levels were significantly associated with peak oxygen capacity (β = 0.547; P = .003), anaerobic threshold (β = 0.929; P = .004), and log minute ventilation/carbon dioxide production slope (β = -10.15; P = .005), but not Patient Health Questionnaire scores (β = -0.099; P = .586). A multivariate analysis demonstrated that serum BDNF level was an independent prognostic factor of adverse events (hazard ratio 0.41, 95% confidence interval 0.20-0.84; P = .003). The receiver operating characteristic curve demonstrated that low levels of BDNF (<17.4 ng/mL) were associated with higher rates of adverse events compared with high levels of BDNF (≥17.4 ng/mL; log rank test: P < .001).

CONCLUSIONS

Decreased serum BDNF levels were significantly associated with adverse outcomes in HF patients, suggesting that these levels can be a useful prognostic biomarker.

Relationships between brain-derived neurotrophic factor, clinical symptoms, and decision-making in chronic schizophrenia: data from the Iowa Gambling Task

The levels of brain-derived neurotrophic factor (BDNF) are significantly decreased in patients with schizophrenia and correlate with impairments in cognitive function. However, no study has investigated the relationship between the serum BDNF levels and decision-making. We compared patients with schizophrenia to healthy controls with respect to their decision-making ability and serum BDNF levels. Eighty-six chronic schizophrenia patients and 51 healthy controls participated in this study. We controlled for gender, age, and estimated intelligence quotient (IQ), and we investigated the differences in decision-making performance on the Iowa Gambling Task (IGT) between the schizophrenia patient and control groups. We also compared the IGT scores, the serum BDNF levels, and the clinical symptoms between the groups. The IGT scores of the schizophrenia patients were lower than those of the controls. A negative correlation was detected between the mean net scores on the trials in the final two blocks and the serum BDNF levels (p < 0.05). Multiple regression analysis revealed that depressive symptoms and the serum BDNF levels were significantly associated with the mean net scores on the trials in the final two blocks. Based on these results, impaired sensitivity to both reward and punishment is associated with depressive symptoms and reduced serum BDNF levels in chronic schizophrenia patients and may be related to their poor performance on the IGT.