Biologic alterations in the brainstem of suicides

In Search for a Pathogenesis of Major Depression and Suicide-A Joint Investigation of Dopamine and Fiber Tract Anatomy Focusing on the Human Ventral Mesencephalic Tegmentum: Description of a Workflow

Major depressive disorder (MDD) is prevalent with a high subjective and socio-economic burden. Despite the effectiveness of classical treatment methods, 20-30% of patients stay treatment-resistant. Deep Brain Stimulation of the superolateral branch of the medial forebrain bundle is emerging as a clinical treatment. The stimulation region (ventral tegmental area, VTA), supported by experimental data, points to the role of dopaminergic (DA) transmission in disease pathology. This work sets out to develop a workflow that will allow the performance of analyses on midbrain DA-ergic neurons and projections in subjects who have committed suicide. Human midbrains were retrieved during autopsy, formalin-fixed, and scanned in a Bruker MRI scanner (7T). Sections were sliced, stained for tyrosine hydroxylase (TH), digitized, and integrated into the Montreal Neurological Institute (MNI) brain space together with a high-resolution fiber tract atlas. Subnuclei of the VTA region were identified. TH-positive neurons and fibers were semi-quantitatively evaluated. The study established a rigorous protocol allowing for parallel histological assessments and fiber tractographic analysis in a common space. Semi-quantitative readings are feasible and allow the detection of cell loss in VTA subnuclei. This work describes the intricate workflow and first results of an investigation of DA anatomy in VTA subnuclei in a growing naturalistic database.

Association Between Chronic Exposure to Pesticide and Suicide

OBJECTIVE

We investigated the association between suicide and pesticide exposure in a community-based cohort study.

METHODS

We performed a longitudinal analysis of 6333 who participated in the initial survey of the Korean Genome and Epidemiology Study. Data were collected using a questionnaire to assess the prevalence of suicide. We calculated the hazard ratios (HRs) for suicide by pesticide exposure using the Cox proportional hazard model.

RESULTS

After adjusting for variables, participants exposed to pesticides had a 1.88-fold increased risk of suicide (HR, 1.88; 95% confidence interval [CI], 1.11 to 3.16) than those who were not exposed. Study populations with greater pesticide use (HR, 2.42; 95% CI, 1.27 to 4.60) and pesticide addiction had the highest suicide rates (HR, 1.91; 95% CI, 1.03 to 3.56).

CONCLUSIONS

Pesticide exposure for suicide should be considered during the development and implementation of suicide prevention in rural area.

[Experiences of Individuals With Suicidal Ideation and Attempts]

INTRODUCTION

Suicide is a major public health problem. It covers about half of violent deaths and results in approximately one million deaths annually. Although completed suicide rates in Colombia are relatively low when compared with other countries, suicidal behavior, represented not only by completed suicide, is a significant mental health problem.

OBJECTIVE

To understand life experiences of a group of subjects related to the phenomenon of ideation and suicide attempt.

METHODOLOGY

A qualitative study with a psychodynamic approach. In-depth interviews were conducted in order to explore thought processes, emotions, motivations and experiences that underlie and accompany the suicide attempt.

RESULTS

Five women and 3 men were interviewed. The average age was 29 years. The exploration of subjective experiences in the present study showed that loneliness and psychic pain were linked to hopelessness, pessimism and discouragement. Also, the illusion of death represents an invitation to suicide attempt.

CONCLUSIONS

It is important to consider the subjective assessment that patients with suicidal risk make of their depression and stressful life situations. Additionally, the concepts of loneliness and psychic pain have a leading role in the interaction between discourse and the experiences of the participants interviewed.

Is pain associated with suicidality in stroke?

OBJECTIVE

To evaluate the relation between poststroke pain and suicidality (SI) in Chinese patients with first or recurrent stroke.

DESIGN

Cross-sectional survey.

SETTING

Acute stroke unit of a university-affiliated general hospital.

PARTICIPANTS

Patients (N=496) with acute ischemic stroke admitted to the Acute Stroke Unit.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Patients were interviewed 3 months after the index stroke. SI was assessed with the Geriatric Mental State Examination. Pain was evaluated with the Faces Pain Rating Scale-Revised (FPS-R). The association between FPS-R scores and SI was examined and adjusted for potential confounders, including marital status, depression, neurologic deficits assessed by the National Institute of Health Stroke Scale, and functioning measured by the Barthel Index.

RESULTS

Thirty-seven (7.5%) of the patients had SI (the SI group). Compared with the non-SI group, patients in the SI group were more likely to experience pain (59.5% vs 37.7%), had a higher mean FPS-R score (6.0±2.5 vs 4.5±2.3), and had an FPS-R score of >4 (43.2% vs 15.9%). After adjustment for possible confounders, the FPS-R score of >4 (odds ratio=2.9) remained a significant predictor of SI in the subsequent forward logistic regression models.

CONCLUSIONS

These findings should alert clinicians that the early identification and treatment of pain may reduce suicide risk in patients with stroke.

Is fatigue associated with suicidality in stroke?

OBJECTIVE

To evaluate the relationship between poststroke fatigue and suicidality (SI) in Chinese patients with first or recurrent stroke.

DESIGN

Cross-sectional survey.

SETTING

Acute stroke unit of a general hospital.

PARTICIPANTS

Patients with acute ischemic stroke (N=595) admitted to the acute stroke unit of a university-affiliated regional hospital in Hong Kong.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

SI was assessed with the Geriatric Mental State Examination at 3 months after the subjects' index stroke. Fatigue was evaluated using the Fatigue Severity Scale (FSS). The association between the mean FSS score and SI was examined and adjusted for potential confounders, including age, sex, marital status, previous stroke, depression, Mini-Mental State Examination score, and neurologic deficits in terms of the National Institutes of Health Stroke Scale score.

RESULTS

Seventy-six (12.8%) of the patients had SI (the SI group). The FSS score was significantly higher in the SI group (4.0±1.4 vs 2.8±1.2). The FSS score remained a significant predictor of SI in the subsequent forward logistic regression (odds ratio=1.5), adjusting for the possible confounders.

CONCLUSIONS

These findings should alert clinicians that early identification and treatment of fatigue may reduce the suicidal risk in stroke patients.

The possible contributory role of the S allele of 5-HTTLPR in the emergence of suicidality

Suicide is a complex and challenging human phenomenon, and, although knowledge is expanding concerning its risk factors, its background is still not fully understood. There is currently an increasing interest in genetic factors associated with suicide, since these may lead to the emergence of personality traits and temperaments that may be long-term predictors of suicidal behaviour. One of the most likely genetic candidates in the background of suicide is the 5-HTTLPR polymorphism of the serotonin transporter gene. This review focused on papers published on the association of the 5-HTTLPR polymorphism of the serotonin transporter gene and suicidal behaviour as well as research on possible endophenotypes related to suicide. Although there are contradictory results, several studies and meta-analyses support the idea that the S allele plays a role in the background of violent suicide. However, in order to be able to delineate the genetic background of suicide, different types of suicidal behaviour should be distinguished, since studies indicate that these may have different genetic factors. Also, personality traits and temperaments should be identified that may play a modulating role between genetic factors and suicidal behaviour. So far, neuroticism, affective temperaments, and impulsive aggression have been found to be associated with both the S allele and suicidal behaviour. This study aimed to integrate findings concerning possible endophenotypes modulating between genetic factors and manifested suicidal behaviour.

Tyrosine hydroxylase immunoreactivity in the locus coeruleus is elevated in violent suicidal depressive patients

Our postmortem study aimed to determine the impact of suicide on the number of noradrenergic neurons of the locus coeruleus (LC) in suicidal depressive patients. Noradrenergic neurons were shown by immunostaining tyrosine hydroxylase in the LC of 22 non-elderly patients with mood disorders compared to 21 age- and sex-matched normal controls. Eleven patients were suicide victims and the other eleven died of natural causes. Seven violent suicide victims revealed an increased number of tyrosine hydroxylase immunoreactive (TH-ir) neurons compared with non-violent suicide victims and controls. No difference was found between the number of TH-ir neurons in all suicidal patients and controls and between non-suicidal patients and controls. The differences of TH-immunoreactivity could neither be attributed to medication nor to the polarity of depressive disorder (unipolar/bipolar). The numbers of TH-ir neurons in suicidal patients correlated negatively with the mean doses of antidepressants. The study suggested a presynaptic noradrenergic dysregulation in the LC related to the level of self-aggression. Traditional antidepressants may, therefore, regulate noradrenergic activity of the LC in suicide patients, however, without demonstrating the suicide-preventing effect.

Impulsivity and chronic stress are associated with amphetamine-induced striatal dopamine release

A challenging question that continues to plague the field of addiction is why some individuals are more vulnerable for substance use disorders than others. Several important risk factors for substance abuse have been identified in clinical studies, including trait impulsivity and environmental stress. However, the neurobiological mechanisms that underlie the relationships remain poorly understood. The purpose of this study was to examine associations among impulsivity, stress, and striatal dopamine (DA) responses to amphetamine (AMPH) in humans. Forty healthy M, F adults, ages 18-29 years, completed self-report measures of trait impulsivity, life events stress, and perceived stress. Subjects subsequently underwent two consecutive 90-min positron emission tomography (PET) studies with high specific activity [11C]raclopride. The first scan was preceded by an intravenous injection of saline; the second was preceded by 0.3 mg/kg AMPH. Findings showed that high impulsivity was associated with blunted right ventral striatal DA release. However, effects were modified by a significant interaction with life events stress. Dopamine release was greater in low vs. high impulsivity subjects under conditions of low or moderate stress. Under conditions of high stress, both groups had low DA release. Subjects with high impulsivity reported more pleasant effects with AMPH than subjects with low impulsivity. In contrast, stress was negatively associated with pleasant drug effects. No associations were observed between impulsivity or stress and cortisol responses to AMPH. The findings are consistent with notions that blunted DA responses represent an endophenotype for substance use disorders.

Corticotropin-releasing hormone, arginine vasopressin, gastrin-releasing peptide, and neuromedin B alterations in stress-relevant brain regions of suicides and control subjects

BACKGROUND

Postmortem levels of several stress- and depression-relevant neuropeptides were assessed in brain regions of depressed suicides relative to control subjects that had died of other causes.

METHODS

Brains of suicides and those that died from other causes were collected soon after death (typically <6 hours). Immunoreactivity levels (ir) of corticotropin-releasing hormone (CRH-ir) and arginine vasopressin (AVP-ir), and the bombesin analogs, gastrin-releasing peptide (GRP-ir), and neuromedin B (NMB-ir), were assessed.

RESULTS

Levels of CRH-ir among suicides were elevated in the locus coeruleus (LC), frontopolar, dorsolateral prefrontal (DMPFC) and ventromedial prefrontal cortices, but were reduced at the dorsovagal complex (DVC). The concentration of AVP-ir was elevated at the paraventricluar hypothalamic nucleus, LC, and DMPFC, and reduced at the DVC. Finally, GRP and NMB variations, which might influence anxiety states, were limited, although GRP-ir within the LC of suicides was higher than in control subjects, while NMB-ir was reduced at the DVC of suicides.

CONCLUSIONS

The data show several neuropeptide changes in relation to suicide, although it is premature to ascribe these outcomes specifically to the suicide act versus depression. Likewise, it is uncertain whether the neuropeptide alterations were etiologically related to suicide/depression or secondary to the depressive state.

Noradrenaline storage function of species-specific protein bodies, markers of monoamine neurons in human locus coeruleus demonstrated by dopamine-beta-hydroxylase immunogold localization

Our histochemical and ultrastructural studies have identified, in human catecholamine locus coeruleus (LC) neurons, abundant and large spherical protein bodies (PB), containing histone-like, arginine-rich proteins, which originate as dense bodies in mitochondria. This species-specific phenotype in the neurons of man is highly intriguing. In the electron microscope PB are disrupted in LC neurons in depressed individuals, where noradrenaline is known to be reduced. This coincidence of ultrastructure and neurochemistry raises the question whether these bodies could qualify as noradrenaline-storing organelles in the human LC. Our rationale was to examine, in known model tissues that contain catecholamines--sympathetic ganglia and tumors of the autonomic nervous system--if vesicles show the same fine structure and histochemistry as the PB of the human LC. Hence, we selected biopsy tissues of five ganglioneuromas and postmortem tissues of LC from 25 control subjects. Since dopamine-beta-hydroxylase (DBH) is a hallmark of noradrenaline identity and present in dense core vesicles, the investigation of DBH localization with the immunogold method constituted the experiment of choice for this study. Histochemical determinations of arginine with Carmoisine L, and of lipids with Rhodamine B complemented the study of similarities between the PB of the human LC and ganglioneuromas. Our results showed, with the colloidal gold method, that DBH immunogold labeling was localized in the core and in the double membranes of the PB, and also in the adjacent mitochondria. These results indicate that protein bodies (a) are unequivocal storage vesicles of noradrenaline, and (b) derive from regular mitochondria and represent a new phenotype in man, which is probably an evolutionary adaptation of amine-storing organelles.

Normal levels of tryptophan hydroxylase immunoreactivity in the dorsal raphe of depressed suicide victims

A variety of evidence suggests that serotonin neurotransmission is altered in the brain of suicide victims and depressed patients. While numerous post-mortem studies have investigated serotonin transporters and receptors, few studies have examined the biosynthetic integrity of the rate-limiting enzyme, tryptophan hydroxylase (TPH), in post-mortem specimens of depressed suicide subjects. Therefore, the aim of the present study was to test the hypothesis that the levels of TPH immunoreactivity (IR) are altered in specific subnuclei of the dorsal raphe (DR) in depressed suicide victims. Suicide victims with a confirmed diagnosis of major depression were matched with non-psychiatric controls based on age, gender and post-mortem interval. Frozen tissue sections containing the DR were selected from two anatomical levels and processed for TPH radioimmunocytochemistry. The optical density corresponding to the regional levels of TPH-IR was quantified in specific subnuclei of the DR from the film autoradiographic images. No significant differences in the levels of TPH-IR were found in any DR subnuclei between depressed suicide victims and control subjects. The lack of change in TPH-IR levels does not necessarily imply that serotonin synthesis or neurotransmission is not altered in the brain of depressed subjects. Many factors influence and regulate serotonin synthesis, and it is conceivable that alterations exist at other levels of regulation of serotonin biosynthesis in depression. Our findings indicate that TPH biosynthesis, at least at the protein level, is not significantly altered in the DR of depressed suicide victims.

5HTTLPR polymorphism in schizophrenic patients: further support for association with violent suicide attempts

Previous studies testing the functional polymorphism in the promoter of the serotonin-transporter gene (5HTTLPR) in various psychiatric conditions have suggested that the association could be with an intermediate phenotype, impulsivity and/or violence rather than with a diagnosis. Schizophrenia is associated with a high risk of suicide, especially in patients with high impulsivity. We examined whether this polymorphism could be associated with violent suicide and/or impulsivity in schizophrenic patients. We genotyped the 5HTTLPR polymorphism in 185 unrelated schizophrenic patients from a French Caucasian population. The genotype frequencies significantly differed between patients who made violent suicide attempts and both, those who attempted suicide with a non-violent method (P = 0.013) and those who never attempted suicide (P = 0.026). The genotypes containing the low activity "short" allele was significantly more frequent in violent suicide attempters (P = 0.007) than in non-violent suicide attempters. No evidence was found for an association either with schizophrenia itself, when compared to gender and ethnically matched controls (n = 159) or with impulsivity, assessed using Barratt's Impulsivity Scale. Although replication studies are warranted, these results in schizophrenia further support the hypothesis that 5HTTLPR polymorphism is a risk factor for violent suicidal behavior.

Early experience as a determinant of adult behavioural responses to reward: the effects of repeated maternal separation in the rat

Depression is a major public health concern, representing one of the most significant causes of disability and morbidity. Despite significant advances in the definition of specific cognitive, emotional and neural dysfunctions that are associated with depression, there has been frustratingly little progress in the elucidation of plausible aetiological and pathophysiological mechanisms. The complex, multi-system dysfunctions of depressive illness do not lend themselves to hypothesis-driven, systematic manipulation in patients. For this reason, there is a need to develop valid and reliable models of affective psychopathology in laboratory animals. In this paper, we review briefly some of our previous work demonstrating that a specific periodic neonatal maternal separation procedure leads to a robust constellation of behavioural changes in the adult rat that resemble core aspects of human depressive psychopathology. We also present data from a study of the adult effects of the same manipulation on electrical intracranial self-stimulation behaviour. These data further support the hypothesis that it is possible to model vulnerability to anhedonia in the adult rat by manipulation of early experience.

PERSONALITY FACTOR CORRELATES OF GROWTH HORMONE AND HYPOTHERMIC RESPONSE TO BUSPIRONE CHALLENGE IN SUICIDAL SOLDIERS

The biological underpinnings of suicidal behaviour and possible rational pharmacotherapy of persons exhibiting such behaviour is the focus of this study. The study was conducted on 25 male Armed Forces personnel who attempted suicide and 25 matched healthy controls. Hypothermic and Growth Hormone response to Buspirone challenge was measured serially. 11 cases of attempted suicide had subsensitive postsynaptic 5 HT-1A receptors as indicated by blunted Growth Hormone response, while in other suicidal soldiers hypothermic response was markedly blunted indicating subsensitive presynaptic 5HT-IA receptors in the latter. Personality factor assessment carried out by 16 personality factor test, indicated overt extraversion marks for subsensitive postsynaptic 5 HT-IA receptors, while overt intraversion marks for subsensitive presynaptic 5 HT-IA receptors, in suicidal soldiers. In the light of the above, therapeutic options of Serotonin reuptake inhibition, agonist load at presynaptic 5 HT-IA and reciprocal stimulation of postsynatpic 5 HT-IA receptors for prevention of future attempts and completed suicides is discussed.

Practice parameter for the assessment and treatment of children and adolescents with suicidal behavior. American Academy of Child and Adolescent Psychiatry

These guidelines review what is known about the epidemiology, causes, management, and prevention of suicide and attempted suicide in young people. Detailed guidelines are provided concerning the assessment and emergency management of the children and adolescents who present with suicidal behavior. The guidelines also present suggestions on how the clinician may interface with the community. Crisis hotlines, method restriction, educational programs, and screening/ case-finding suicide prevention strategies are examined, and the clinician is advised on media counseling. Intervention in the community after a suicide, minimization of suicide contagion or imitation, and the training of primary care physicians and other gatekeepers to recognize and refer the potentially suicidal child and adolescent are discussed.

Association between violent suicidal behavior and the low activity allele of the serotonin transporter gene

There is compelling evidence that serotonin system dysfunction is associated with certain behavioral disorders, such as suicidal behavior and impulsive aggression. A functional polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) was recently identified and the presence of the short allele found to be associated with a lower level of expression of the gene, lower levels of 5-HT uptake, suicidal behavior and anxiety-related traits. We genotyped 51 West European Caucasians who had made violent suicide attempts and 139 controls of the same ethnic origin, with no history of suicidal behavior. The frequencies of the S allele and the SS genotype were significantly higher in the violent suicide attempters than in the controls. The odds ratio for the SS genotype vs the LL genotype was 3.63 (95% CI (1.27--10.40)). This suggests that a change in expression of the gene encoding the 5-HT transporter may be involved in violent suicidal behavior.

The depressed suicidal patient. Assessment and treatment

Depressive disorders are associated with significant psychosocial impairment and disability. Depression should be thoroughly evaluated, as should current and past suicidality and potential risk factors for suicide. Mortality by suicide characterizes the course of major affective disorders in approximately 15% of those suffering from these illnesses. Several neurobiological correlates of suicidality have been discovered. Treatment of depression with suicidality may involve hospitalization, pharmacotherapy, electroconvulsive therapy, and psychotherapy. Special populations include children and adolescents, the elderly, medically ill patients, patients with comorbid personality disorders, and patients with comorbid substance abuse disorders. Clinicians encountering patients with depressive disorders should be proficient in the assessment and treatment of depression with suicidality.

Corticotropic-releasing hormone and serotonin interact in the human brainstem: behavioral implications

The objective of this human post mortem study was to determine whether neurons which synthesize corticotropic-releasing hormone and serotonin form circuits implicated in the pathophysiology of major depression and suicide. For the first time, a sensitive, dual immunocytochemical procedure was used to identify circuits formed by corticotropic-releasing hormone-synthesizing and serotonergic cell groups. Corticotropic-releasing hormone-immunoreactive varicose fibers and puncta with morphological characteristics of terminals were labeled in the midline raphe, periventricular gray and pontine parabrachial complex, on single-labeled tissues processed immunocytochemically with a rabbit antibody to rat/human corticotropic-releasing hormone. Presumptive synaptic interactions with monoaminergic neurons were demonstrated with dual labeling techniques. Corticotropic-releasing hormone-immunoreactive terminals apposed neuronal somata and primary dendrites of serotonergic neurons in the pontine raphe. Serotonergic neurons were immunolabeled with a mouse antibody to phenylalanine hydroxylase, an enzyme with substantial sequence homology to tryptophan hydroxylase. Interactions in the lateral parabrachial nucleus were suggested by precise overlap of corticotropic-releasing hormone and serotonergic terminal fields. Corticotropic-releasing hormone projections were confirmed to noradrenergic neurons containing neuromelanin in the locus ceruleus. Maps of corticotropic-releasing hormone fiber trajectories suggest that these pathways may derive from the forebrain and, locally, from the human homologue of Barrington's nucleus--a neurochemically specialized division of the laterodorsal tegmental complex. Chemosensory functions were predicted by novel evidence for corticotropic-releasing hormone- and monoaminergic neurovascular and subependymal fiber plexuses. In conclusion, corticotropic-releasing hormone may influence the activity of two major monoaminergic cell systems implicated in the stress-diathesis model of mental illness, through neural and humoral mechanisms.