The neurobiology and genetics of suicide and attempted suicide: a focus on the serotonergic system

Trait Impulsivity as a Feature of Parkinson's Disease Treatment and Progression

Heightened trait impulsivity in both subclinical and pathological senses is becoming increasingly recognised in Parkinson's disease (PD). Impulsive behaviours and impulse control disorders (ICDs) are a consequence of perturbation to the rewards pathway leading individuals to conduct activities in a repetitive, excessive, and maladaptive fashion. Commonly linked to PD, heightened trait impulsivity has been found to primarily manifest in the forms of hypersexuality, pathological gambling, compulsive shopping, and binge eating, all of which may significantly impact social and financial standing. Subsequent burden to quality of life for both individuals with PD and caregivers are common. Although risk factors and indicators for ICDs in PD are currently lacking, it is recognised that the condition is often precipitated by dopamine replacement therapies, primarily dopamine agonist administration. While this nonmotor symptom is being increasingly diagnosed in PD populations, it remains relatively elusive in comparison to its motor counterparts. Through discussion of impulsivity characteristics, neuroanatomy, and neurochemistry, in addition to reviewing existing research on the potential contributing factors to impulsivity in PD, this review highlights impulsivity as a significant and detrimental PD symptom. Thus, emphasising the imperative need to establish efficacious diagnostic tools and treatments.

Impact of Serotonin Pathway Gene Polymorphisms and Serotonin Levels in Suicidal Behavior

OBJECTIVE

Suicide is a significant public health issue and a major cause of death in all ages worldwide. Previous studies have shown the involvement of genetics in suicidal behaviour. This study aimed to assess the role of the genetic variants of the serotonin transporter genes (5HTTLPR, SLC6A4 intron 2) and receptor gene (5HTR2AT102C) in individuals who died of suicide. The study compares the serum levels of serotonin between the cases and controls.

METHODS

We conducted a case control study with 120 cases and 126 controls. Socio-economic details of the subjects were collected using a semi-structured proforma and psychological autopsy was used to collect details of medical and other clinical conditions. Blood was drawn after taking informed consent and serum levels of serotonin were estimated by ELISA. Genotyping was performed using appropriate primers followed by polymerase chain reaction (PCR) and a restriction fragment length polymorphism (RFLP).

RESULTS

Mean age was 32.59 ± 12.58 for cases and 33.64 ± 9.78 for controls. The risk associated LL genotype of 5HTTLPR was higher among cases. The heterozygous 12/10 genotype of SLC6A4 intron 2 polymorphism was increased among controls. Serum levels of serotonin were lower among cases. Variant genotypes of all the 3 polymorphisms showed significant interaction (OR= 39.26) indicating that this model may increase suicidal tendency.

CONCLUSION

The findings of this study suggest that low serum levels of serotonin and two variants of the serotonin gene may influence suicide behaviour in a south Indian population.

Relationship between chronotypes and aggression in adolescents: a cross-sectional study

BACKGROUND

This study aimed to investigate the relationship between chronotypes and aggression in adolescents.

METHODS

A cross-sectional study was conducted on 755 primary and secondary school students aged 11-16 years in rural areas of Ningxia Province, China. The Chinese version of the Buss-Perry Aggression Questionnaire (AQ-CV) and the Chinese version Morningness-Eveningness Questionnaire (MEQ-CV) were used to assess the aggressive behavior and chronotypes of the study subjects. The Kruskal-Wallis test was then used to compare the differences in aggression among adolescents with different chronotypes, and Spearman correlation analysis to determine the relationship between chronotypes and aggression. Further linear regression analysis was used to investigate the effects of chronotype, personality traits, family environment, and class environment on adolescent aggression.

RESULTS

There were significant differences in chronotypes between different age groups and different sexes. Spearman correlation analysis showed that the MEQ-CV total score was negatively correlated with the AQ-CV total score (r = -0.263) and score of each AQ-CV subscale. In Model 1, chronotypes were negatively associated with aggression when controlling for age and sex, and evening-type adolescents might be more likely to exhibit aggressive behavior (b = -0.513, 95% CI: [-0.712, -0.315], P < 0.001); in Model 2, the negative association remained after controlling for family and class environment on the basis of Model 1 (b = -0.404, 95% CI: [-0.601, -0.208], P < 0.001); and in Model 3, the negative association still existed after controlling for personality traits on the basis of Model 2 (b = -0.383, 95% CI: [-0.577, -0.190], P < 0.001).

CONCLUSION

Compared to morning-type adolescents, evening-type adolescents were more likely to exhibit aggressive behavior. Given social expectations for MT adolescents, adolescents should be actively guided to develop a good circadian rhythm that may be more conducive to their physical and mental development.

Risk of suicide ideation in comorbid substance use disorder and major depression

BACKGROUND

Suicidal behaviour is commonly associated with major depression (MD) and substance use disorders (SUDs). However, there is a paucity of research on risk for suicide ideation among individuals with comorbid SUDs and MD in the general population.

OBJECTIVES

This study investigated the associated risk of suicide ideation in comorbid SUDs-cannabis use disorder (CUD), alcohol use disorder (AUD), drug use disorder (DUD) with major depressive episode (MDE) in a nationally representative sample.

METHODS

Multilevel logistic regression models were used to analyze the 2012 Canadian Community Health Survey- Mental Health (CCHS-MH) data. This is a cross-sectional survey of nationally representative samples of Canadians (n = 25,113) aged 15 years and older residing in the ten Canadian provinces between January and December 2012. Diagnoses of MDE, AUD, DUD, and CUD were based on a modified WHO-CIDI, derived from DSM-IV diagnostic criteria.

RESULTS

Comorbidity was found to be the strongest predictor of suicide ideation. Compared to those with no diagnosis of either a SUD or MDE, individuals with a comorbid diagnosis of AUD with MDE, CUD with MDE, or DUD with MDE were 9, 11 and 16 times more likely to have 12-month suicide ideation respectively. A diagnosis of MDE was a significant predictor of 12-month suicide ideation with about a 7-fold increased risk compared with individuals not diagnosed with either MDE or a SUD.

CONCLUSION

Suicide is a preventable public health issue. Our study found a significantly increased risk of suicide ideation among persons who have comorbid SUD with MD. Effective integration of mental health and addictions services could mitigate the risk of suicide and contribute to better outcomes.

Ventral prefrontal serotonin 1A receptor binding: a neural marker of vulnerability for mood disorder and suicidal behavior?

Mood disorders and suicidal behavior have moderate heritability and are associated with altered corticolimbic serotonin 1A receptor (5-HT1A) brain binding. However, it is unclear whether this reflects genetic effects or epigenetic effects of childhood adversity, compensatory mechanisms, or illness stress-related changes. We sought to separate such effects on 5-HT1A binding by examining high familial risk individuals (HR) who have passed through the age of greatest risk for psychopathology onset with and without developing mood disorder or suicidal behavior. PET imaging quantified 5-HT1A binding potential BPND using [11C]CUMI-101 in healthy volunteers (HV, N = 23) and three groups with one or more relatives manifesting early-onset mood disorder and suicide attempt: 1. unaffected HR (N = 23); 2. HR with lifetime mood disorder and no suicide attempt (HR-MOOD, N = 26); and 3. HR-MOOD with previous suicide attempt (HR-MOOD + SA, N = 20). Findings were tested in an independent cohort not selected for family history (HV, MOOD, and MOOD + SA, total N = 185). We tested for regional BPND differences and whether brain-wide patterns distinguished between groups. Low ventral prefrontal 5-HT1A BPND was associated with lifetime mood disorder diagnosis and suicide attempt, but only in subjects with a family history of mood disorder and suicide attempt. Brain-wide 5-HT1A BPND patterns including low ventral prefrontal and mesiotemporal cortical binding distinguished HR-MOOD + SA from HV. A biological endophenotype associated with resilience was not observed. Low ventral prefrontal 5-HT1A BPND may reflect familial mood disorder and suicide-related pathology. Further studies are needed to determine if higher ventral prefrontal 5-HT1A BPND confers resilience, reducing risk of suicidal behavior in the context of familial risk, and thereby offer a potential prevention target.

Effects of pharmacological treatments on neuroimaging findings in borderline personality disorder: A review of FDG-PET and fNIRS studies

BACKGROUND

Borderline personality disorder (BPD) is a serious mental condition characterized by instability in identity, interpersonal relationships, emotion regulation and impulsivity. These symptoms seem to be associated to specific brain alterations, which have been largely investigated. In particular, positron emission tomography (PET) and functional near-infrared spectroscopy (fNIRS) have demonstrated abnormalities in brain metabolism and hemodynamics in BPD, specifically in the fronto-limbic system. However, the role of medications on brain metabolism and hemodynamics in BPD is still largely unknown.

METHODS

We conducted a search on PubMed, Scopus and Web of Science of PET and fNIRS studies exploring the effect of medications on brain metabolism and hemodynamics in BPD. A total of 10 studies met the inclusion criteria.

RESULTS

Overall, PET studies showed an effect of psychotropic agents on brain metabolism, especially in frontal and temporal areas. Also, higher metabolic rates in frontal areas were found to correlate with clinical improvements. In contrast, fNIRS investigations reported an inconclusive or absent effects on brain hemodynamics in BPD patients.

LIMITATIONS

The small sample size, the elevated percentage of women, the heterogeneity in pharmacological agents and the presence of comorbidities limit the conclusions of the present review.

CONCLUSIONS

Serotoninergic agents and second-generation antipsychotics produce changes in frontal and temporal metabolism in BPD, which appear to correlate with clinical improvements. Differently, brain hemodynamics do not seem to be significantly affected by the most commonly prescribed drugs in BPD, suggesting that the therapeutic actions of medications are not mediated by changes in neural hemodynamics.

Short-term changes in meteorological conditions and suicide: A systematic review and meta-analysis

BACKGROUND

Suicide is a leading cause of death, particularly for young adults. Suicidal behaviours are influenced by a wide-range of personal, social, and cultural factors. Emerging evidence suggests that daily changes in meteorological conditions, including temperature, increases the risk of suicide.

METHODS

We conducted a systematic review and meta-analysis of studies that examined associations between either daily, or weekly, variations for eight meteorological variables and suicide outcomes (attempts, or deaths). Meta-analytic methods were applied to derive summary measures of association using random effect models. We assessed the heterogeneity in these associations by region and biological sex.

RESULTS

We identified 29 studies of suicide. Of these, 26 reported associations between temperature, while fewer studies reported on rain (n = 4), solar radiation (n = 4), humidity (n = 3), sunshine (n = 3), atmospheric pressure (n = 2), wind (n = 2) and cloud cover (n = 2). The overall relative risk for suicide deaths/attempts per 1 °C increase in ambient temperature was 1.016 (95% CI: 1.013-1.019). Subgroup analysis of temperature found stronger associations with suicide when using the maximum rather than the mean daily temperature, among men, and for completed suicides relative to attempts. Regionally, the strongest associations were found in the East Asia and Pacific region. While associations were found for solar radiation and cloud coverage and suicide, we did not undertake a meta-analysis for these exposures as it was not possible to standardize measures of association across studies. Statistically significant associations were not observed for other identified meteorological variables.

CONCLUSIONS

Our findings suggest that daily increases in temperature increase the risk of suicide, particularly, among men and in the East Asia and Pacific region.

The Impact of Probiotic Bacillus subtilis on Injurious Behavior in Laying Hens

Simple Summary

Injurious behavior prevention is a critical issue in the poultry industry due to increasing social stress, leading to negative effects on bird production and survivability, consequently enhancing gut microbiota dysbiosis and neuroinflammation via the microbiota–gut–brain axis. Probiotics have been used as potential therapeutic psychobiotics to treat or improve neuropsychiatric disorders or symptoms by boosting cognitive and behavioral processes and reducing stress reactions in humans and various experimental animals. The current data will first report that probiotic Bacillus subtilis reduces stress-induced injurious behavior in laying hens via regulating microbiota–gut–brain function with the potential to be an alternative to beak trimming during poultry egg production.

Abstract

Intestinal microbiota functions such as an endocrine organ to regulate host physiological homeostasis and behavioral exhibition in stress responses via regulating the gut–brain axis in humans and other mammals. In humans, stress-induced dysbiosis of the gut microbiota leads to intestinal permeability, subsequently affecting the clinical course of neuropsychiatric disorders, increasing the frequency of aggression and related violent behaviors. Probiotics, as direct-fed microorganism, have been used as dietary supplements or functional foods to target gut microbiota (microbiome) for the prevention or therapeutic treatment of mental diseases including social stress-induced psychiatric disorders such as depression, anxiety, impulsivity, and schizophrenia. Similar function of the probiotics may present in laying hens due to the intestinal microbiota having a similar function between avian and mammals. In laying hens, some management practices such as hens reared in conventional cages or at a high stocking density may cause stress, leading to injurious behaviors such as aggressive pecking, severe feather pecking, and cannibalism, which is a critical issue facing the poultry industry due to negative effects on hen health and welfare with devastating economic consequences. We discuss the current development of using probiotic Bacillus subtilis to prevent or reduce injurious behavior in laying hens.

Imperatorin Influences Depressive-like Behaviors: A Preclinical Study on Behavioral and Neurochemical Sex Differences

Imperatorin, a naturally derived furanocoumarin, exerts promising neuropharmacological properties. Therefore, it might be applicable in the treatment of brain diseases such as depression. In the present project, we aimed to investigate the sex-dependent effects of imperatorin (1, 5, and 10 mg/kg) on behavior and neurochemistry associated with antidepressant effects. The depressive-like behaviors of male and female Swiss mice were investigated in a forced swim test (FST). Subsequently, High-Performance Liquid Chromatography (HPLC) was used to evaluate the level of serotonin, its metabolite, 5-HIAA, and noradrenaline, in mouse brains. The study revealed that only males responded to imperatorin (1 and 5 mg/kg) treatment and caused an antidepressant effect, such as with respect to depressive-like behaviors, lowering immobility time and increasing immobility latency. The HPLC analysis demonstrated that serotonin levels in the prefrontal cortex of females decreased with the middle dose of imperatorin (5 mg/kg), while in the male prefrontal cortex, the lower dose (1 mg/kg) boosted serotonin levels. There were no evident changes observed with respect to noradrenaline and serotonin metabolite levels in the male hippocampus. To conclude, we propose that imperatorin has antidepressant potential, seemingly only in males, influencing brain serotonin level, but the direct mechanism of action requires further investigation.

Increased Levels of Cortisol in Individuals With Suicide Attempt and Its Relation With the Number of Suicide Attempts and Depression

BACKGROUND

Abnormalities in the hypothalamic-pituitary-adrenal axis (HPA) have been reported in individuals with suicide behavior. The aim of the study was to evaluate cortisol levels in peripheral plasma of individuals with more than one suicide attempt.

METHODS

Cortisol concentrations in peripheral plasma were measured using the ELISA technique. Suicide attempts were evaluated by the Columbia Suicide Severity Rating Scale, while depression was evaluated by the Hamilton Depression Rating Scale.

RESULTS

We found elevated cortisol levels in the suicide attempt group when compared with healthy controls (F = 7.26, p-value = 0.008), but no statistical differences with the psychiatric diseases group (F = 1.49, p-value = 0.22). Cortisol levels were higher in individuals with depression (F = 8.99, P = 0.004) and in individuals with two or more suicide attempts (F = 13.56, P < 0.001).

CONCLUSIONS

Cortisol levels are increased in individuals who attempt suicide and higher of cortisol concentrations in plasma regard to depression and more attempts of suicide.

Suicidal and violent ideation in acute psychiatric inpatients: prevalence, co-occurrence, and associated characteristics

OBJECTIVE

We studied the point prevalence of suicidal and violent ideation, as well as their co-occurrence and associated characteristics in inpatients with mental health disorders.

METHODS

Data on suicidal and violent ideation, and sociodemographic and clinical information, were gathered from 1,737 patients when admitted to the acute psychiatric ward.

RESULTS

The point prevalence was 51.9% for suicidal ideation and 19.8% for violent ideation. The point prevalence of co-occurring suicidal and violent ideation was 12.3%, which was significantly greater than expected by chance. Logistic regression analyses indicated that both suicidal and violent ideation were associated with young age and the absence of diagnoses of psychotic disorders; in addition, suicidal ideation was associated with female gender, violent ideation, and diagnoses of mood- neurotic and personality disorders, whereas violent ideation was associated with male gender, suicidal ideation, and diagnoses of mood and neurotic disorders.

CONCLUSIONS

Overall, the findings highlight the need for further research on suicidal and violent ideation in people with mental health problems including, but not limited to, their association with adverse behavioral outcomes, as well as the need to routinely assess both suicidal and violent ideation in clinical practice.

Sleep Duration Is Closely Associated with Suicidal Ideation and Suicide Attempt in Korean Adults: A Nationwide Cross-Sectional Study

Introduction: Suicidal ideation and suicide attempts are major risk factors for suicidal death, and sleep problems are associated with an increased risk for mental disorders. We investigated the relationship between sleep duration and suicidal ideation and suicide attempts in a representative sample of the Korean general population from a nationwide survey. Methods: We analyzed data collected from the Korea National Health and Nutrition Examination Survey VI and VII (2013–2018). Suicidal ideation was identified via self-report, and we accessed suicide attempt history. Sleep duration was divided into three categories: short sleep duration (SSD) (≤5 h), normal sleep duration (NSD) (>5 and <9 h), and long sleep duration (LSD) (≥9 h). Sampling weights were applied to obtain estimates for the general Korean population. Results: Overall, 4015 (12.0%), 25,609 (76.5%), and 3857 (11.5%) participants were in the SSD, NSD, and LSD groups, respectively. Among these groups, 7.2%, 2.8%, and 3.3% reported suicidal ideation; while 1.2%, 0.4%, and 0.7% reported a history of suicide attempts. Multiple regression analyses revealed that SSD was significantly more strongly associated with suicidal ideation (adjusted odds ratio (AOR) 1.46, p < 0.001) and attempts (AOR 2.05, p = 0.003) than NSD. No association was found between LSD and suicidal ideation/attempts. Conclusion: Sleep duration is significantly associated with suicidal behavior, and SSD was particularly closely related with an increased risk for suicidal ideation and suicide attempt. Clinicians should carefully consider sleep duration in suicidal patients.

Neural Correlates Associated With Suicide and Nonsuicidal Self-injury in Youth

There is no definitive neural marker of suicidal thoughts and behaviors (STBs) or nonsuicidal self-injury (NSSI), and relative to adults, research in youth is more limited. This comprehensive review focuses on magnetic resonance imaging studies reporting structural and functional neural correlates of STBs and NSSI in youth to 1) elucidate shared and independent neural alternations, 2) clarify how developmental processes may interact with neural alterations to confer risk, and 3) provide recommendations based on convergence across studies. Forty-seven articles were reviewed (STBs = 27; NSSI = 20), and notably, 63% of STB articles and 45% of NSSI articles were published in the previous 3 years. Structural magnetic resonance imaging research suggests reduced volume in the ventral prefrontal and orbitofrontal cortices among youth reporting STBs, and there is reduced anterior cingulate cortex volume related to STBs and NSSI. With regard to functional alterations, blunted striatal activation may characterize STB and NSSI youth, and there is reduced frontolimbic task-based connectivity in suicide ideators and attempters. Resting-state functional connectivity findings highlight reduced positive connectivity between the default mode network and salience network in attempters and show that self-injurers exhibit frontolimbic alterations. Together, suicidal and nonsuicidal behaviors are related to top-down and bottom-up neural alterations, which may compromise approach, avoidance, and regulatory systems. Future longitudinal research with larger and well-characterized samples, especially those integrating ambulatory stress assessments, will be well positioned to identify novel targets that may improve early identification and treatment for youth with STBs and NSSI.

Alcohol Intoxication and Suicide by Hanging in Poland

AIMS

An integral part of the World Health Organization (WHO) plan to reduce suicide by 10% by 2020 is to identify areas and demographic groups, which should be priority target groups for preventive activities. This study aimed to present the demographic differences between victims of suicide by hanging in the Warsaw metropolitan area, in Poland, by examining the sobriety of victims.

METHODS

Data for analysis were obtained from the documentation of the Department of Forensic Medicine (DFM) at the Medical University of Warsaw (MUW). The retrospective analysis included 358 out of 466 victims of suicides by hanging in the Warsaw metropolitan area, in Poland, recorded in the DFM documentation covering 2011-2013. The data gathered included age, gender, the cause of death, a post-mortem examination as well as the level of ethanol in the blood and muscles of victims.

RESULTS

In both groups, men accounted for a larger percentage of victims than women, P = 0.068. In the no-alcohol group, the victims were older than in the alcohol group (47.52 ± 19.21 vs. 40.88 ± 12.77) (P < 0.001). The majority of the studied population were victims aged 25-34 (22.90%), mainly men (20.95%). Young men were also the largest group among victims in the alcohol group (28.33%). The most numerous age group among no-alcohol group were older victims aged 55-64 (19.10%), especially men (16.29%).

CONCLUSION

Regardless of sobriety, men were the largest group of suicide victims in the study population, which means that men die suicide more often than women. Differences in gender proportions are related to age. In the studied population, it was primarily young victims, mainly men. These are the groups that should be priority target groups for preventive activities aimed at reducing the number of suicides. The presence of ethanol in more than half of the victims of suicide in the study population indicates that alcohol is an important suicidal risk factor.

Completed Suicide With Violent and Non-violent Methods by the Elderly in Rural China: A Psychological Autopsy Study

Background: Late-life suicide is a severe public health problem in rural China; however, knowledge regarding the specific characteristics and risk factors for completed suicide via violent and non-violent methods among elderly individuals in rural China is limited. Methods: Subjects aged 60 years or older were selected from rural areas in Shandong, Hunan, and Guangxi provinces in China. This study was a 1:1 matched case-control design conducted by using the psychological autopsy method. Results: According to the univariate analyses, the presence of mental disorder, higher degree of depression, loneliness, lack of social support, hopelessness, impulsivity, and increased quantity of life events were associated with suicide in both violent and non-violent methods. For violent suicide, another risk factor was the lack of pesticides at home. For non-violent suicide, other risk factors were not currently married, family suicide history, and alcohol use disorder (P < 0.05). Variables that remained in the logistic regression model were the severity of depressive symptoms for both violent and non-violent suicide. For non-violent suicide, the degree of hopelessness was another independent risk factor. In addition, violent suicides were more likely to lack pesticides at home, choose the spring season and have an increased quantity of life events than those who died by suicide via non-violent methods. Conclusion: The major risk factor for both violent and non-violent suicide was the severity of depressive symptoms. Suicide prevention measures that focus on depression among this vulnerable population are urgently needed. Moreover, the characteristics of suicides via violent methods differed from those via non-violent methods among elderly individuals. Suicide prevention efforts should be tailored to the specific characteristics of the different suicide methods utilized by older adults in rural areas.

Social and Biological Parameters Involved in Suicide Ideation During the COVID-19 Pandemic: A Narrative Review

Fear is an indispensable characteristic of any infectious disease, and the alarm will be further amplified when the infection spreads uncontrollable, unpredictable, and global. The novel corona virus (SARS CoV-2) lead Covid-19, has been declared as a global emergency by WHO as it has affected millions of people with a high mortality rate. The non-availability of medicine for Covid-19 and the various control measures such as social distancing, self-isolation, house quarantine, and the new normal implementation by different nations across the world to control the spread of Covid-19 made people vulnerable to fear and anxiety. As a result, considerable number of Covid-19-related suicidal deaths has been reported across the world during this pandemic. There have been several studies which describe the psychosocial aspects of suicidal ideation. However, the research on the biological aspects of suicidal ideation/suicidal risk factors that are related to pandemic are unreported. Hence this review article is intended to provide a comprehensive analysis of suicidal deaths during Covid-19 and also aimed to addresses the possible link between suicidal ideation and different factors, including psycho-social, behavioral, neurobiological factors (proximal, distal, and inflammatory) and immunity. The alterations in glutamatergic and GABAergic neurotransmitters had upregulated the GABARB3, GABARA4, GABARA3, GABARR1, GABARG2, and GAD2 gene expressions in suicidal victims. The changes in the Kynurenine (KYN) pathway, Hypothalamus-Pituitary-Adrenal axis (HPA axis) hyperactivation, and dysregulation of serotonin biosynthesis would significantly alter the brain chemistry in people with suicide ideation.

Explaining why childhood abuse is a risk factor for poorer clinical course in bipolar disorder: a path analysis of 923 people with bipolar I disorder

BACKGROUND

Childhood abuse is a risk factor for poorer illness course in bipolar disorder, but the reasons why are unclear. Trait-like features such as affective instability and impulsivity could be part of the explanation. We aimed to examine whether childhood abuse was associated with clinical features of bipolar disorder, and whether associations were mediated by affective instability or impulsivity.

METHODS

We analysed data from 923 people with bipolar I disorder recruited by the Bipolar Disorder Research Network. Adjusted associations between childhood abuse, affective instability and impulsivity and eight clinical variables were analysed. A path analysis examined the direct and indirect links between childhood abuse and clinical features with affective instability and impulsivity as mediators.

RESULTS

Affective instability significantly mediated the association between childhood abuse and earlier age of onset [effect estimate (θ)/standard error (SE): 2.49], number of depressive (θ/SE: 2.08) and manic episodes/illness year (θ/SE: 1.32), anxiety disorders (θ/SE: 1.98) and rapid cycling (θ/SE: 2.25). Impulsivity significantly mediated the association between childhood abuse and manic episodes/illness year (θ/SE: 1.79), anxiety disorders (θ/SE: 1.59), rapid cycling (θ/SE: 1.809), suicidal behaviour (θ/SE: 2.12) and substance misuse (θ/SE: 3.09). Measures of path analysis fit indicated an excellent fit to the data.

CONCLUSIONS

Affective instability and impulsivity are likely part of the mechanism of why childhood abuse increases risk of poorer clinical course in bipolar disorder, with each showing some selectivity in pathways. They are potential novel targets for intervention to improve outcome in bipolar disorder.

Why competitive productivity sometimes goes too far: a multilevel evolutionary model of “karoshi”

Purpose

The aim of this paper is to outline an innovative multilevel conceptual model capable of explaining “karoshi” (death from overwork) and its relationship to molecular-, micro-, meso- and macro-competitive productivity (CP).

Design/methodology/approach

A theoretical model, grounded in the evolutionary biological, psychological, organizational and sociological literatures, is provided.

Findings

Karoshi is a function of molecular (genetic), micro (individual), meso (organizational) and macro (cultural) evolutionary forces. It is also demonstrated to be a function of time, geography, agri-climate and cultural and ethnic homogeneity.

Research limitations/implications

The analysis is purely theoretical and its theoretically informed hypotheses are not tested empirically. As such, further data-driven research is indicated. Additional analyses are also needed to further unpack the recursive nature of the relationship between karoshi and CP and the subtle differences between genetic evolution and cultural and organizational evolution.

Practical implications

Karoshi-related deaths are a public health epidemic and increasingly a major obstacle to sustainable CP. As such, organizations can leverage these analyses to help them implement interventions aimed at reducing incidents of work-related deaths, not only in Japan, but across the world.

Originality/value

This multilevel conceptual framework makes a unique contribution to the cross-cultural and strategic management literatures. More specifically, it constitutes a new and innovative contribution to one’s current understanding of CP by uniquely integrating biology, psychology, organization studies and cultural studies into one overarching model.

Suicidal attempts, insomnia, and major depressive disorder among family members of suicide victims in South Korea

BACKGROUND

Suicide survivors are defined as victims who experienced suicide of siblings or parents, spouses, or lineal relatives within the fourth degree who had lived with them. We compared the effects of major depressive disorder (MDD), symptoms of posttraumatic stress disorder (PTSD), and impulsivity on lifetime suicide attempts among suicide survivors.

METHODS

Participants included 272 suicide survivors. We compared them to 5,200 members from the general population who were matched by age, sex, and years of education. We evaluated participants using the Patient Health Questionnaire-9 (PHQ-9), the EuroQuality of Life (EuroQol) scale, the Impact of Events Scale-Revised (IES-R), the Barratt Impulsiveness Scale-11 (BIS-11), and the Composite International Diagnostic Interview (K-CIDI).

RESULTS

Among the 272 suicide survivors, MDD was nine times higher (47.1% vs. 5.3%), and suicidal attempts were six times higher (20.5% vs. 3.3%) than reported among the general population. The suicide survivors showed more severe depression, greater impulsivity, and poorer quality of life than did the general population. In multivariate logistic regression analyses performed to evaluate each IES-R item, "trouble staying asleep" was the only PTSD symptom item that was significantly associated with suicide attempts among suicide survivors. Suicide survivors who had both MDD with insomnia and high impulsivity were at four times higher risk for suicide attempts than the general population with no MDD (AOR = 4.04, 95% CI: 1.25-13.09).

CONCLUSIONS

Surviving suicide by family members is an important risk factor for suicide attempts. In particular, MDD with insomnia and impulsivity are associated with suicide attempts among suicide survivors.

Contribution of genes and environment to the longitudinal association between childhood impulsive-aggression and suicidality in adolescence

BACKGROUND

Population-based and family studies showed that impulsive-aggression predicts suicidality; however, the underlying etiological nature of this association is poorly understood. The objective was to determine the contribution of genes and environment to the association between childhood impulsive-aggression and serious suicidal ideation/attempt in young adulthood.

METHODS

N = 862 twins (435 families) from the Quebec Newborn Twin Study were followed up from birth to 20 years. Repeated measures of teacher-assessed impulsive-aggression were modeled using a genetically informed latent growth model including intercept and slope parameters reflecting individual differences in the baseline level (age 6 years) and in the change (increase/decrease) of impulsive-aggression during childhood (6 to 12 years), respectively. Lifetime suicidality (serious suicidal ideation/attempt) was self-reported at 20 years. Associations of impulsive-aggression intercept and slope with suicidality were decomposed into additive genetic (A) and unique environmental (E) components.

RESULTS

Additive genetic factors accounted for an important part of individual differences in impulsive-aggression intercept (A = 90%, E = 10%) and slope (A = 65%, E = 35%). Genetic (50%) and unique environmental (50%) factors equally contributed to suicidality. We found that 38% of the genetic factors accounting for suicidality were shared with those underlying impulsive-aggression slope, whereas 40% of the environmental factors accounting for suicidality were shared with those associated with impulsive-aggression intercept. The genetic correlation between impulsive-aggression slope and suicidality was 0.60, p = .027.

CONCLUSIONS

Genetic and unique environmental factors underlying suicidality significantly overlap with those underlying childhood impulsive-aggression. Future studies should identify putative genetic and environmental factors to inform prevention.

Suicide Risk Assessment and Prevention: Challenges and Opportunities

Despite increased access to mental health care for the previously uninsured and expanding evidence-based treatments for mood, anxiety, psychotic, and substance use disorders, suicide is on the rise in the United States. Since 1999, the age-adjusted suicide rate in the United States has increased 33%, from 10.5 per 100,000 standard population to 14.0. As of yet, there are no clinically available biomarkers, laboratory tests, or imaging to assist in diagnosis or the identification of the suicidal individual. Suicide risk assessment remains a high-stakes component of the psychiatric evaluation and can lead to overly restrictive management in the name of prevention or to inadequate intervention because of poor appreciation of the severity of risk. This article focuses primarily on suicide risk assessment and management as a critical first step to prevention, given the fact that more research is needed to identify precision treatments and effective suicide prevention strategies. Suicide risk assessment provides the clinical psychiatrist with an opportunity for therapeutic engagement with the ultimate goals of relieving suffering and preventing suicide.

Risk Factors for Serious Suicide Attempts with High Medical Severity

OBJECTIVES

his study investigated the risk factors leading to serious suicide attempts with high medical severity.

METHODS

Nine hundred and eighty-two patients who visited the emergency room after attempting suicide were divided into two groups: suicide attempters with high medical severity (25.3%) and those with low medical severity (74.7%). Demographic variables, clinical characteristics, and factors related to each suicide attempt were compared between the two groups. Multivariate logistic regression analysis was conducted to investigate risk factors for high medical severity in patients' current suicide attempts.

RESULTS

The results show that suicide attempters with high medical severity had more severe depression and psychological disturbances such as agitation, intense emotions, and self-reproach. Suicide attempters with high medical severity also had more serious risk factors for suicide such as repetitive/intense/continuous thoughts of suicide, suicidal planning, and a stronger wish to die. School/work problems and physical illnesses were related to high medical severity with more lethal methods. Logistic regression demonstrated that school/work problems, total risk rating, severity of suicidal ideation, and agitation were risks for more serious suicide attempts, whereas more frequent lifetime suicide attempts were a protective factor.

CONCLUSION

This study demonstrates that suicide attempters with high medical severity had more severe psychopathologies and risk factors related to suicidal behavior than those with low medical severity.

Suicide: Genetics and Heritability

Nature vs nurture is, and has been, a never stopping debate since Lamarck and Darwin exposed their corresponding theories on evolution, and even before them, such discussion already existed. Is suicide a heritable conduct? Is it learnt? Maybe the answer is both and none, at the same time. From genetic twin studies to epigenetic and environmental influence on development, this chapter aims to take a look at different points of view and most relevant theories in one of the worlds leading causes of death, specially for young individuals. We explore different studies aiming to find biomarkers for suicide, as well as other traits frequently encountered in individuals who engage in suicidal behavior, such as impulsivity, aggressivity, and hopelessness. Finally, this chapter also looks at some of the most recent approaches in treatment and prevention of suicidal behavior, in order to highlight what they have in common and try to explain (at least partially) why they could be effective.

Reduced peripheral availability of tryptophan and increased activation of the kynurenine pathway and cortisol correlate with major depression and suicide

Objectives: Patients affected by major depression (MDD) are at high risk of suicide. The metabolism of tryptophan (Trp) along the serotonin (5-HT) and kynurenine (Kyn) pathways was found dysfunctional in MDD and in suicide. However, a clear biological framework linking dysfunctions in Trp metabolism via 5-HT and Kyn, cortisol, and the activities of tryptophan and indoleamino 2,3-dioxygenase (TDO, IDO) enzymes has not been yet clarified in MDD with or without suicidal behaviours.Methods: We analysed peripheral markers of Trp via 5-HT and Kyn pathways, Kyn/Trp ratio as a measure of TDO/IDO activities, cortisol, and psychopathology in 73 non-suicidal and 56 suicidal MDD patients, and in 40 healthy controls.Results: Plasma Trp levels were lower and the ratio Kyn/Trp higher in suicidal MDD than in non-suicidal MDD patients and controls. Trp levels and the ratio Kyn/Trp correlated with suicidal ideation, and cortisol with the Kyn/Trp ratio. Finally, Trp levels discriminated controls from non-suicidal and suicidal MDD patients, and also non-suicidal from suicidal MDD patients.Conclusions: Reduced availability of Trp for 5-HT synthesis and increased activation of the Kyn pathway and cortisol correlate with depression and suicide. Low plasma Trp levels may be a biomarker of MDD and suicide in MDD.

Association of Bedtime with both Suicidal Ideation and Suicide Planning among Korean Adolescents

STUDY OBJECTIVES

In comparison to other countries, the South Korean population has a short average sleep duration, and studies have suggested that insufficient sleep is a risk factor for suicidal behavior. This study aimed to examine the association of bedtime with suicidal ideation and with suicide planning, respectively, among Korean adolescents.

METHODS

This study included 48,218 participants from the 2017 Korea Youth Risk Behavior Web-based Survey. Participants were divided into three categories: pre-23:00 bedtime, 23:00-01:30 bedtime, and post-01:30 bedtime. Suicidal ideation and suicide planning were the main dependent variables, and multiple logistic regression analysis was performed to examine the target association.

RESULTS

For both male and female respondents, compared to those who had a pre-23:00 bedtime, those whose bedtime was after 01:30 were more likely to have suicidal ideation (post-01:30 bedtime for men: OR = 1.29, 95% CI = 1.16-1.45; for women: OR = 1.32, 95% CI = 1.20-1.44). For suicide planning, the results were also significant for both genders (post-01:30 bedtime for men: OR = 1.41, 95% CI = 1.16-1.70; for women: OR = 1.21, 95% CI = 1.03-1.43). Odds of suicidal ideation were higher for those who had a post-01:30 bedtime on weekdays but not weekends.

CONCLUSIONS

We found that, among adolescents, going to bed after 01:30 is significantly associated with suicidal ideation and suicide planning, after adjusting for demographic, socioeconomic, and health-related characteristics. Therefore, late bedtime should be the timepoint of a suicide intervention for adolescents, in order to prevent developing suicidal ideations and suicide planning.

Social isolation as a promising animal model of PTSD comorbid suicide: neurosteroids and cannabinoids as possible treatment options

Post-traumatic stress disorder (PTSD) is a psychiatric condition characterized by drastic alterations in mood, emotions, social abilities and cognition. Notably, one aspect of PTSD, particularly in veterans, is its comorbidity with suicide. Elevated aggressiveness predicts high-risk to suicide in humans and despite the difficulty in reproducing a complex human suicidal behavior in rodents, aggressive behavior is a well reproducible behavioral trait of suicide. PTSD animal models are based on a peculiar phenotype, including exaggerated fear memory and impaired fear extinction associated with neurochemical dysregulations in the brain circuitry regulating emotion. The endocannabinoid and the neurosteroid systems regulate emotions and stress responses, and recent evidence shows these two systems are interrelated and critically compromised in neuropsychiatric disorders. For instance, levels of the neurosteroid, allopregnanolone, as well as those of the endocannabinoids, anandamide and its congener, palmitoylethanolamide are decreased in PTSD. Similarly, the endocannabinoid system and neurosteroid biosynthesis are altered in suicidal individuals. Selective serotonin reuptake inhibitors (SSRIs), the only FDA-approved treatments for PTSD, fail to help half of the treatment-seeking patients. This highlights the need for developing biomarker-based efficient therapies. One promising alternative to SSRIs points to stimulation of allopregnanolone biosynthesis as a treatment and a valid end-point to predict treatment response in PTSD patients. This review highlights running findings on the role of the endocannabinoid and neurosteroid systems in PTSD and suicidal behavior both in a preclinical and clinical perspective. A specific focus is given to predictive PTSD/suicide animal models. Ultimately, we discuss the idea that disruption of neurosteroid and endocannabinoid biosynthesis may offer a novel promising biomarker axis to develop new treatments for PTSD and, perhaps, suicidal behavior.

The impact of attention deficit hyperactivity disorder in obsessive-compulsive disorder subjects

BACKGROUND

Recent findings suggest an association between attention deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). Thus, we evaluated the clinical associated features of ADHD in a large sample of adult OCD patients.

METHODS

A cross-sectional study including 955 adult patients with OCD from the Brazilian Research Consortium of Obsessive-Compulsive Spectrum Disorders (C-TOC). Clinical characteristics in adult OCD patients with and without comorbid ADHD were compared using Fisher's exact test, t-tests or Mann-Whitney tests. Bivariate analyses were followed by logistic regression analysis to identify clinical characteristics independently associated with ADHD comorbidity.

RESULTS

The lifetime prevalence of ADHD in adult OCD patients was 13.7%. The current results indicate that OCD + ADHD patients were more severe, had an earlier onset of the obsessive-compulsive symptoms, a higher history of rheumatic fever, with higher frequencies of sensory phenomena and comorbidity with Tourette syndrome. They also had an increased risk for academic impairment and suicide attempts.

CONCLUSION

Adult OCD patients with ADHD present some specific clinical features and may represent a special subgroup of adult OCD. Future studies should focus on the development of interventions more tailored to the phenotype of this subgroup of patients.

Association between completed suicide and bipolar disorder: A systematic review of the literature

BACKGROUND

Completed suicide is a major cause of death in bipolar disorder (BD) patients.

OBJECTIVE

The aim of this paper is to provide an overall review of the existing literature of completed suicide in BD patients, including clinical and genetic data DATA SOURCES: We performed a systematic review of English and non-English articles published on MEDLINE/PubMed, PsycInfo and Cochrane database (1970-2017). Additional studies were identified by contacting clinical experts, searching bibliographies, major textbooks and website of World Health Organization. Initially we did a broad search for the association of bipolar disorder and suicide and we were narrowing the search in terms included "bipolar disorder" and "completed suicide".

STUDY SELECTION

Inclusion criteria were articles about completed suicide in patients with BD. Articles exclusively focusing on suicide attempts and suicidal behaviour have been excluded. We used PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) consensus for drafting this systematic review.

RESULTS

The initial search generated 2806 articles and a total of 61 meeting our inclusion criteria. We reviewed epidemiological data, genetic factors, risk factors and treatment of completed suicide in BD. Suicide rates in BD vary between studies but our analyses show that they are approximately 20-30-fold greater than in general population. The highest risk of successful suicide was observed in BD-II subjects. The heritability of completed suicide is about 40% and some genes related to major neurotransmitter systems have been associated with suicide. Lithium is the only treatment that has shown anti-suicide potential.

LIMITATIONS

The most important limitation of the present review is the limited existing literature on completed suicide in BD.

CONCLUSIONS

BD patients are at high risk for suicide. It is possible to identify some factors related to completed suicide, such as early onset, family history of suicide among first-degree relatives, previous attempted suicides, comorbidities and treatment. However it is necessary to promote research on this serious health problem.

Understanding suicide: Focusing on its mechanisms through a lithium lens

BACKGROUND

Current intervention strategies have been slow in reducing suicide rates, particularly in mood disorders. Thus, for intervention and prevention, a new approach is necessary. Investigating the effects of a medication known for its anti-suicidal properties on neurobiological and neurocognitive substrates of suicidal thinking may provide a deeper and more meaningful understanding of suicide.

METHOD

A literature search of recognised databases was conducted to examine the intersection of suicide, mood disorders, and the mechanisms of lithium.

RESULTS

This review synthesises the extant evidence of putative suicide biomarkers and endophenotypes and melds these with known actions of lithium to provide a comprehensive picture of processes underlying suicide. Specifically, the central importance of glycogen synthase kinase-3β (GSK3β) is discussed in detail because it modulates multiple systems that have been repeatedly implicated in suicide, and which lithium also exerts effects on.

LIMITATIONS

Suicide also occurs outside of mood disorders but we limited our discussion to mood because of our focus on lithium and extending our existing model of suicidal thinking and behaviour that is contextualised within mood disorders.

CONCLUSIONS

Focusing on the neurobiological mechanisms underpinning suicidal thinking and behaviours through a lithium lens identifies important targets for assessment and intervention. The use of objective measures is critical and using these within a framework that integrates findings from different perspectives and domains of research is likely to yield replicable and validated markers that can be employed both clinically and for further investigation of this complex phenomenon.

Platelet serotonin and serotonin transporter as peripheral surrogates in depression and anxiety patients

Previous studies suggested that serotonergic neurons and platelets share similarities in serotonin (5-HT) uptake by serotonin transporter (SERT), storage, metabolism and release mechanisms, indicating that platelets may be used as a reliable peripheral surrogate to measure central SERT activity in neuropsychiatric research. In this study, platelet 5-HT content and 5-HT uptake capacity of SERT in depression and anxiety patients were measured by ELISA and flow cytometry with IDT307 at baseline and after serotonin reuptake inhibitors (SSRIs) treatment for 4 weeks. Healthy persons matched with age and gender were used as reference. The clinical presentations of the patients were assessed with Hamilton Depression (HAMD) and Anxiety Rating Scales (HAMA) at the same time points. Compared to healthy subjects, anxiety and depression patients showed higher levels of platelet 5-HT and IDT307 fluorescence intensity, but the values were comparable between the patient groups. SSRIs administration for 4 weeks significantly decreased scores of HAMD (29 vs 14) and HAMA (22 vs 14) in depression and anxiety patients, respectively; while it decreased platelet 5-HT content, but did not change the IDT307 fluorescence intensity of platelets. After incubation with fluoxetine in vitro, the IDT307 fluorescence intensity of isolated platelets from both healthy subjects and patients decreased in a dose-dependent manner. These results provide further evidence supporting the employment of platelet 5-HT content and SERT as peripheral surrogates in depression and anxiety patients, and are of help in understanding the several weeks' delay from the initiation of antidepressant medication to their full therapeutic effects in the patients.

Optical Coherence Tomography of Small Retinoblastoma

PURPOSE

To investigate hand-held optical coherence tomography (HH-OCT) characteristics of small (<1 mm thickness) retinoblastoma.

DESIGN

Retrospective observational case series.

METHODS

Patient and tumor data were extracted from the medical record and analyzed along with HH-OCT scans. Determination of tumor layer of origin was performed using a layer-by-layer analysis of HH-OCT data and specific HH-OCT-related features were described.

RESULTS

There were 20 sub-millimeter retinoblastomas from 16 eyes of 15 patients. Mean largest tumor basal diameter by HH-OCT was 2.2 mm (median, 1.9; range, 0.7-4.1 mm), and mean tumor thickness was 468 μm (median, 441; range, 151-998 μm). In all cases, the retinoblastoma caused discontinuity or disruption of the inner nuclear (INL), outer plexiform (OPL), outer nuclear (ONL), and external limiting membrane (ELM) layers (20/20, 100%). Tumor origin was in the INL in 19/20 (95%) and equivocal (INL vs ONL) in 1/20 (5%). Intratumoral microcalcification was present in 14/20 tumors (70%). There were 2 characteristic findings (signs) on HH-OCT including the INL "fish tail" sign with splaying of the INL at the tumor margin (19/20, 95%) and the ONL "shark fin" sign with folding of the ONL and OPL, conforming to the lateral tumor margins (15/20, 75%). Both signs were concurrently present in 15 tumors (15/20, 75%).

CONCLUSIONS

HH-OCT demonstrated that sub-millimeter retinoblastoma seems to originate from the INL, with tumor base and thickness growth progressing in a linear relationship. Characteristic HH-OCT findings included intratumoral microcalcification, INL "fish tail" sign, and ONL "shark fin" sign.

Serotonin transporter gene polymorphism as a predictor of short-term risk of suicide reattempts

Objective:

The serotonin-transporter-linked polymorphic region (5-HTTLPR) polymorphisms are associated with suicidal behavior; however, prospective studies are scarce. Herein we aim to determine if 5-HTTLPR polymorphisms predict risk of short-term suicide reattempt in a high-risk suicidal sample. We also explore possible mediators or moderators of this relationship.

Methods:

A multicenter prospective cohort study was designed to compare data obtained form 136 patients admitted to the emergency department for current suicidal ideation or a recent suicide attempt. Subjects were clinically evaluated, genotyped, and monitored for a new suicide attempt for 6 months.

Results:

At 6 months of follow up, 21% of the subjects had a new suicide attempt. The frequency of L-allele and L-carrier was higher in reattempters when compared with non-reattempters (55.8% vs. 35.4%, p = 0.01 and 76.9% vs. 54.2%, p = 0.04, respectively). Reattempters also differ from non-reattempters patients with respect to age, history of previous suicide attempts, and age of onset of suicidal behavior. The logistic regression model showed that L-carriers had an odds ratio of 2.8 (95% CI: 1.0–7.6) for reattempts when compared to SS genotype. The adjusted model indicates that this association is not mediated or moderated by impulsivity.

Conclusion:

The 5-HTTLPR polymorphisms predicted short-term risk of suicidal reattempt independently of age and sex. L-carriers have almost three times more risk of relapse when compared with SS carriers.

Resting-state functional connectivity of neurotransmitter producing sites in female patients with borderline personality disorder

Impulsive behavior, difficulties in controlling anger and suicidal behavior are typical patterns of affective/behavioral dysregulation in patients with borderline personality disorder (BPD). Previous functional MRI studies in the resting state condition demonstrated altered functional connectivity (FC) between the anterior cingulate cortex (ACC) and the frontoparietal executive control network (ECN), which was significantly associated with impulsivity in BPD. Impulsivity is often defined as a function of inhibitory control, strongly relying on the proper functioning of the fronto-cingulo-striatal network. Noradrenergic, dopaminergic and serotonergic neurotransmitter systems are assumed to be involved in different forms of impulsive behavior and inhibitory control. In our previous study, we investigated the FC of the main monoamine-producing nuclei within the midbrain and brainstem, which were functionally integrated in specific resting-state networks. In the present study we investigated the resting-state FC of midbrain/brainstem nuclei in 33 unmedicated female patients with BPD and 33 matched healthy controls. We further related altered functional connectivity of these nuclei to the patient's degree of impulsivity. The main finding was that BPD patients showed stronger FC from the noradrenergic locus coeruleus (LC) to the ACC. Functional connectivity between the LC and ACC was positively associated with the degree of motor impulsivity in the total group. Controlling for aggression, a stronger FC was also found between serotonergic nucleus centralis superior (NCS) and the frontopolar cortex (FPC) in patients compared to controls. Furthermore, patients showed a weaker "anti-correlation" from the substantia nigra (SNc) to the left dorsolateral prefrontal cortex (DLPFC). The observed enhanced LC-ACC FC in BPD and its association with the motor impulsivity might be indicative of a noradrenergic dysfunction in the neural inhibitory control network, whereas the significant relationship between NCS-FPC FC and aggression points toward serotonergic contribution to prefrontal control of aggressive reactions.

Kynurenine pathway and white matter microstructure in bipolar disorder

Decreased availability of serotonin in the central nervous system has been suggested to be a central factor in the pathogenesis of depression. Activation of indoleamine 2-3 dioxygenase following a pro-inflammatory state could reduce the amount of tryptophan converted to serotonin and increase the production of tryptophan catabolites such as kynurenic acid, an antagonist of ionotropic excitatory aminoacid receptors, whose levels are reduced in bipolar disorder. Abnormalities in white matter (WM) integrity have been widely reported in BD. We then hypothesized that metabolites involved in serotoninergic turnover in BD could influence DTI measures of WM microstructure. Peripheral levels of tryptophan, kynurenine, kynurenic acid, 3-hydroxy-kynurenine, and 5-HIAA were analysed in 22 patients affected by BD and 15 healthy controls. WM microstructure was evaluated using diffusion tensor imaging and tract-based spatial statistics with threshold-free cluster enhancement only in bipolar patients. We observed that kynurenic acid and 5-HIAA were reduced in BD and associated with DTI measures of WM integrity in several association fibres: inferior and superior longitudinal fasciculus, cingulum bundle, corpus callosum, uncus, anterior thalamic radiation and corona radiata. Our results seem to suggest that higher levels of 5-HIAA, a measure of serotonin levels, and higher levels of kynurenic acid, which protects from glutamate excitotoxicity, could exert a protective effect on WM microstructure. Reduced levels of these metabolites in BD thus seem to confirm a crucial role of serotonin turnover in BD pathophysiology.

Depressive Symptoms and Suicidal Ideation Among Symptomatic Patients With a History of Lyme Disease vs Two Comparison Groups

BACKGROUND

Depression has been reported in 8-45% of patients with posttreatment Lyme symptoms (PTLS), but little is known about suicidal ideation in these patients.

METHOD

Depression and suicidal ideation were assessed using the Beck Depression Inventory (BDI-II). Scores from the PTLS group (n = 81) were compared to those from 2 other groups: HIV+ patients being treated for fatigue (n = 70), and a nonpatient comparison group (NPCG; n = 44). ANOVA and t-tests were used to compare groups; logistic regression was used to identify the strongest correlates of suicidal ideation.

RESULTS

Mean BDI-II scores fell in the mildly depressed range for PTLS and HIV+ patients, with both groups having higher depression scores than the NPCG. Suicidal ideation was reported by 19.8% of the PTLS patients and 27.1% of the HIV+ patients, a nonsignificant difference. Among those with mild or no depression, suicidal ideation was uncommon (6.5% PTLS and 11.9% HIV+). Among the patients with moderate-to-severe depression, suicidal ideation was more common (63.2% of 19 PTLS and 50% of 28 HIV+); among these, 2 with PTLS and 1 with HIV+ expressed suicidal intent. Further, 4.5% (n = 2) of the NPCG had suicidal ideation, each had scores in the moderate-to-severe depression range. Higher scores on the cognitive symptoms subscale of the BDI-II predicted greater likelihood of suicidal ideation across patient groups.

CONCLUSION

As expected, suicidal ideation is increased among patients who are depressed. The fact that 1 in 5 patients with PTLS reported suicidal ideation highlights the importance of screening for depression and suicidality to optimize patient care.

Schizophrenia and depression, two poles of endocannabinoid system deregulation

The activity of certain G protein-coupled receptors (GPCRs) and of glutamate N-Methyl-D-aspartate receptors (NMDARs) is altered in both schizophrenia and depression. Using postmortem prefrontal cortex samples from subjects with schizophrenia or depression, we observed a series of opposite changes in the expression of signaling proteins that have been implicated in the cross-talk between GPCRs and NMDARs. Thus, the levels of HINT1 proteins and NMDAR NR1 subunits carrying the C1 cytosolic segment were increased in depressives and decreased in schizophrenics, respect to matched controls. The differences in NR1 C1 subunits were compensated for via altered expression of NR1 subunits lacking the C1 segment; thus, the total number of NR1 subunits was comparable among the three groups. GPCRs influence the function of NR1 C1-containing NMDARs via PKC/Src, and thus, the association of mu-opioid and dopamine 2 receptors with NR1 C1 subunits was augmented in depressives and decreased in schizophrenics. However, the association of cannabinoid 1 receptors (CB1Rs) with NR1 C1 remained nearly constant. Endocannabinoids, via CB1Rs, control the presence of NR1 C1 subunits in the neural membrane. Thus, an altered endocannabinoid system may contribute to the pathophysiology of schizophrenia and depression by modifying the HINT1-NR1 C1/GPCR ratio, thereby altering GPCR-NMDAR cross-regulation.

The role of stressful life events preceding death by suicide: Evidence from two samples of suicide decedents

Stressful life events (SLEs) are associated with increased risk for suicidal behavior. Less is known regarding the intensity of SLEs and how this may vary as a function of suicide attempt history. As a large percentage of suicide decedents do not have a history of suicidal behavior, SLEs precipitating suicide may help characterize suicidality in this understudied population. This paper examines the intensity, number, and accumulation of SLEs preceding death by suicide among decedents with varying suicide attempt histories. Suicide attempts, SLEs, and suicide methods were examined in two samples: 62 prison-based and 117 community-based suicide decedents. Regression was used to compare the level of stressor precipitating death by suicide in decedents who died on a first attempt versus multiple previous attempts. A non-significant trend was observed in the prison population which was supported by significant findings in the community-based sample. Decedents who died on a first attempt experienced a stressor of a lower magnitude when compared to decedents with multiple previous suicide attempts. We discuss the implications of these findings in relation to the stress-diathesis model for suicide.

Tryptophan status in autism spectrum disorder and the influence of supplementation on its level

Recent reports show that the worldwide incidence of autism spectrum disorder (ASD) is dramatically increasing, although ASD etiology and pathogenesis are still far to be fully elucidated. Some dietary-derived essential compounds, such as the amino acid tryptophan, appear to be impaired in patients with ASD. Tryptophan (Trp) plays a significant role in the human organism and serves as a precursor for a wide range of bioactive compounds, including major neurotransmitters. Research indicates that tryptophan might be deficient in subjects with ASD. Deficiency in the tryptophan level can be retrieved by investigating Trp levels or its major metabolite kynurenine in urines. The purpose of the present study is to quantify tryptophan content in urine samples (n = 236) of ASD patients, who underwent a supplemented dietary panel with B vitamins and magnesium, compared to controls (without this diet regimen). The samples were analyzed with gas chromatography-mass spectrometry. Additionally, the correlation between body mass index (BMI) and the level of this amino acid in urine was accomplished. Basic parameters of urine samples were also evaluated. Statistical evaluations in the concentration of tryptophan in ASD patients with different severity of symptoms were reported. A significant difference in tryptophan levels in all groups was observed. Supplementation with B vitamins and magnesium has an influence on the Trp concentration. Furthermore, no correlation between BMI and tryptophan levels was found. These results assess that the Trp level in ASD subjects is critical and that intake of B vitamins and magnesium with diet might influence its metabolic homeostasis.

Association between serotonin transporter gene polymorphisms and increased suicidal risk among HIV positive patients in Uganda

BACKGROUND

Persons living with HIV/AIDS (PLWHA) are at an increased risk of suicide. Increased suicidal risk is a predictor of future attempted and completed suicides and has been associated with poor quality of life and poor adherence with antiretroviral therapy. Clinical risk factors have low predictive value for suicide, hence the interest in potential neurobiological correlates and specific heritable markers of suicide vulnerability. The serotonin transporter gene has previously been implicated in the aetiology of increased suicidal risk in non-HIV infected study populations and its variations may provide a platform for identifying genetic risk for suicidality among PLWHA. The present cross-sectional study aimed at identifying two common genetic variants of the serotonin transporter gene and their association with increased suicidal risk among human immunodeficiency virus (HIV)-positive adults in Uganda.

RESULTS

The prevalence of increased suicidal risk (defined as moderate to high risk suicidality on the suicidality module of the Mini Neuropsychiatric Interview (M.I.N.I) was 3.3% (95% CI, 2.0-5.3). The 5-HTTLPR was found to be associated with increased suicidal risk before Bonferroni correction (p-value = 0.0174). A protective effect on increased suicidal risk was found for the 5-HTTLPR/rs25531 S A allele (p-value = 0.0046)- which directs reduced expression of the serotonin transporter gene (5-HTT).

CONCLUSION

The S A allele at the 5-HTTLPR/rs25531 locus is associated with increased suicidal risk among Ugandan PLWHA. Further studies are needed to validate this finding in Ugandan and other sub-Saharan samples.

ABCA1 Polymorphism, a Genetic Risk Factor of Harm Avoidance

Abstract. Even though cholesterol homeostasis and self-harm behaviors have shown to be associated, gene polymorphisms of the cholesterol system have not been studied yet in the context of self-harm related personality traits. Here we present an association study between six ABCA1 polymorphisms and temperament scales measured by Cloninger’s Temperament and Character Inventory on 253 young adults. An association between ABCA1 rs4149264 and harm avoidance has been observed. This association remained significant after Bonferroni correction. Haplotype analysis confirmed an independent association between rs4149264 and harm avoidance. ABCA1, a cholesterol homeostasis gene, is a candidate gene for harm related personality traits.

Objectively Assessed Sleep Variability as an Acute Warning Sign of Suicidal Ideation in a Longitudinal Evaluation of Young Adults at High Suicide Risk

OBJECTIVE

Young adults attempt suicide at disproportionately high rates relative to other groups and demonstrate high rates of sleep disturbance. No study has yet prospectively evaluated disturbed sleep as an acute indicator of risk using an objective index of sleep. We investigated objective and subjective parameters of disturbed sleep as a warning sign of suicidal ideation among young adults over an acute period.

METHODS

A longitudinal study across a 21-day observation period and 3 time points. Fifty of 4,847 participants (aged 18-23 years) were prescreened from a university undergraduate research pool (February 2007-June 2008) on the basis of suicide attempt history and recent suicidal ideation. Actigraphic and subjective sleep parameters were evaluated as acute predictors of suicidal ideation (Beck Scale for Suicide Ideation), with adjustment for baseline symptoms. Hierarchical regression analyses were employed to predict residual change scores.

RESULTS

Ninety-six percent of participants (n = 48) endorsed a suicide attempt history. Mean actigraphy values revealed objectively disturbed sleep parameters; 78% (n = 39) and 36% (n = 18) endorsed clinically significant insomnia and nightmares, respectively. When results were controlled for baseline suicidal and depressive symptoms, actigraphic and subjective sleep parameters predicted suicidal ideation residual change scores at 7- and 21-day follow-ups (P < .001). Specifically, actigraphy-defined variability in sleep timing, insomnia, and nightmares predicted increases in suicidal ideation (P < .05). In a test of competing risk factors, sleep variability outperformed depressive symptoms in the longitudinal prediction of suicidal ideation across time points (P < .05).

CONCLUSIONS

Objectively and subjectively measured sleep disturbances predicted acute suicidal ideation increases in this population, independent of depressed mood. Self-reported insomnia and nightmares and actigraphically assessed sleep variability emerged as acute warning signs of suicidal ideation. These findings highlight the potential utility of sleep as a proposed biomarker of suicide risk and a therapeutic target.

Serotonin Dysfunction, Aggressive Behavior, and Mental Illness: Exploring the Link Using a Dimensional Approach

Aggressive individuals have higher rates of mental illness compared to non-aggressive individuals. Multiple factors, including psychosocial, genetic, and neurobiological determinants modulate the liability to both aggressive behavior and mental illness. Concerning the latter factors, multiple lines of evidence have shown a dysfunction in the serotonin (5-HT) system occurring in aggressive and in mentally ill individuals. In particular, reduced 5-HT activity has been associated with depression as well as with aggressive behavior, especially with impulsive aggression. Consistently, psychopharmacological interventions aimed at boosting the 5-HT system (e.g., with selective serotonin reuptake inhibitors) have demonstrated therapeutic efficacy in a high percentage of patients with either or both pathological conditions. Current knowledge does not yet allow to clearly disentangle whether 5-HT dysfunction, most often a 5-HT deficiency, is the cause or the consequence of the aggressive/violent behavior, of the underlying mental disease/s, or the expression of the comorbidity. Future studies are thus needed to clarify the association between changes in 5-HT levels, altered activity of 5-HT receptors and their intracellular signaling cascades, and modifications of 5-HT genes, and in particular the neurobiological link between the altered 5-HT machinery and aggressive behavior in the context or in the absence of mental illness. In this Review, we employ a dimensional approach to discuss the trivariate relationship among the 5-HT system, aggressive behavior, and mental illness, focusing our attention on 5-HT levels, 5-HT receptors, metabolic enzymes, and their genes. Emphasis is given to controversial findings, still unanswered questions, and future perspectives.

Whole-transcriptome brain expression and exon-usage profiling in major depression and suicide: evidence for altered glial, endothelial and ATPase activity

Brain gene expression profiling studies of suicide and depression using oligonucleotide microarrays have often failed to distinguish these two phenotypes. Moreover, next generation sequencing approaches are more accurate in quantifying gene expression and can detect alternative splicing. Using RNA-seq, we examined whole-exome gene and exon expression in non-psychiatric controls (CON, N=29), DSM-IV major depressive disorder suicides (MDD-S, N=21) and MDD non-suicides (MDD, N=9) in the dorsal lateral prefrontal cortex (Brodmann Area 9) of sudden death medication-free individuals post mortem. Using small RNA-seq, we also examined miRNA expression (nine samples per group). DeSeq2 identified 35 genes differentially expressed between groups and surviving adjustment for false discovery rate (adjusted P<0.1). In depression, altered genes include humanin-like-8 (MTRNRL8), interleukin-8 (IL8), and serpin peptidase inhibitor, clade H (SERPINH1) and chemokine ligand 4 (CCL4), while exploratory gene ontology (GO) analyses revealed lower expression of immune-related pathways such as chemokine receptor activity, chemotaxis and cytokine biosynthesis, and angiogenesis and vascular development in (adjusted P<0.1). Hypothesis-driven GO analysis suggests lower expression of genes involved in oligodendrocyte differentiation, regulation of glutamatergic neurotransmission, and oxytocin receptor expression in both suicide and depression, and provisional evidence for altered DNA-dependent ATPase expression in suicide only. DEXSEq analysis identified differential exon usage in ATPase, class II, type 9B (adjusted P<0.1) in depression. Differences in miRNA expression or structural gene variants were not detected. Results lend further support for models in which deficits in microglial, endothelial (blood-brain barrier), ATPase activity and astrocytic cell functions contribute to MDD and suicide, and identify putative pathways and mechanisms for further study in these disorders.

Animal models to improve our understanding and treatment of suicidal behavior

Worldwide, suicide is a leading cause of death. Although a sizable proportion of deaths by suicide may be preventable, it is well documented that despite major governmental and international investments in research, education and clinical practice suicide rates have not diminished and are even increasing among several at-risk populations. Although nonhuman animals do not engage in suicidal behavior amenable to translational studies, we argue that animal model systems are necessary to investigate candidate endophenotypes of suicidal behavior and the neurobiology underlying these endophenotypes. Animal models are similarly a critical resource to help delineate treatment targets and pharmacological means to improve our ability to manage the risk of suicide. In particular, certain pathophysiological pathways to suicidal behavior, including stress and hypothalamic-pituitary-adrenal axis dysfunction, neurotransmitter system abnormalities, endocrine and neuroimmune changes, aggression, impulsivity and decision-making deficits, as well as the role of critical interactions between genetic and epigenetic factors, development and environmental risk factors can be modeled in laboratory animals. We broadly describe human biological findings, as well as protective effects of medications such as lithium, clozapine, and ketamine associated with modifying risk of engaging in suicidal behavior that are readily translatable to animal models. Endophenotypes of suicidal behavior, studied in animal models, are further useful for moving observed associations with harmful environmental factors (for example, childhood adversity, mechanical trauma aeroallergens, pathogens, inflammation triggers) from association to causation, and developing preventative strategies. Further study in animals will contribute to a more informed, comprehensive, accelerated and ultimately impactful suicide research portfolio.

Personality traits as an endophenotype in genetic studies on suicidality in bipolar disorder

Introduction The influence of personality traits on suicidal behaviour risk has been well documented. Personality traits and suicidal behaviour are partially genetically determined and personality has been described as an endophenotype of suicidal behaviour. The aim of this study was to investigate a possible association between personality traits with suicidal behaviour and selected serotonergic gene polymorphisms.

METHODS

In the study we included 156 patients meeting DSM-IV criteria for bipolar disorder (BP) and 93 healthy controls. The personality dimensions were assessed using the Temperament and Character Inventory (TCI). We genotyped two selected polymorphisms of the tryptophan hydroxylase 1 (TPH1) gene (rs1800532 218A>C and rs1799913 779A>C) and polymorphism in the promoter region of serotonin transporter gene (5-HTTLPR, rs25531) related to serotoninergic neurotransmission. Multiple poisson regression, logistic regression and Kruskal-Wallis tests were applied.

RESULTS

We found numerous differences between the BP patients and the control group in terms of their TCI dimensions/subdimensions. Significant differences were found between patients with, and without, suicidal attempts in fatigability and asthenia (Ha4), as well as in harm avoidance (Ha). We also found that the interactions between TCI subdimensions (the interaction of disordiness (Ns4) and spiritual acceptance (St3), disordiness (Ns4) and integrated conscience (C5), extravagance (Ns3) and resourcefulness (Sd3)) were significantly contributing for suicidal behaviour risk. We found association between all studied genetic polymorphisms and several TCI dimensions and subdimensions.

CONCLUSION

Our results confirm that personality traits are partially determined by genes. Both personality traits and the interactions between temperament and character traits, may be helpful in predicting suicidal behaviour.

Chromatographic determination of harmalans in the urine of autistic children

This paper presents a new approach to autism - a complex and still enigmatic condition. We present the results of our preliminary research which was based on the detection of the hallucinogenic substance 6- (or 10-)methoxyharmalan in the urine samples of autistic children with the use of chromatographic methods. Additionally, we aim to describe the relationship between the level of tryptophan and harmalan, and the influence of supplementation on the level of this compound. We applied HPLC-UV/vis, HPLC-DAD and LC-MS in order to determine McIsaac's compound in the urine samples obtained from autistic children (n = 132) and healthy individuals (n = 10). The level of tryptophan was quantified with the use of GC-MS. Our research shows the presence of the McIsaac's compound in 110 samples of ASD children contrary to healthy children, where it was not found. No relationship between the level of tryptophan and 6-methoxyharmalan was noticed. The study shows a strong influence of melatonin supplementation on the presence of the McIsaac's compound. We believe that the results of our research can contribute to a better understanding of autism spectrum disorders. Moreover, our findings can form the basis for other studies focused on autism, eventually making it possible to understand its etiology.