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

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.

Suicide behavior as a quantitative trait and its genetic background

INTRODUCTION

Studies have not given yet a clear answer what is the genetic background of suicidal predisposition. The associations between polymorphisms of the TPH1 and 5-HTTLPR genes and violent suicidal behavior was revealed with the least inconsistencies.

METHOD

We selected 10 "strong candidate genes" and 35 SNPs, SLC6A4 and ACP1 for replication study. We searched associations between precisely described suicidal phenotype in 825 affective patients and polymorphisms of selected neurobiological pathways genes as well as their interactions that constitute suicidal risk.

RESULTS

The results confirm the role of TPH1, TPH2, 5HT2A, CRHR1 and ACP1 variants in the risk of suicidal behavior.

LIMITATIONS

In our study we analyzed limited number of candidate genes and only one of them is linked to lithium mechanism of action. We had no data on pharmacological treatment of investigated patients and its relation to the time of suicide attempt.

CONCLUSION

Our results indicate that polymorphisms of various signaling pathways are involved in the pathogenesis of suicidal behavior. Non-genetic factors are also involved in the risk of suicidal attempts.

Early Childhood Environment and Genetic Interactions: the Diathesis for Suicidal Behavior

Adverse childhood experiences are associated with higher risk for suicide and suicidal behavior later in life. There are known associations between childhood trauma, particularly sexual abuse, and higher rates of suicide, non-lethal suicide attempts, and non-suicidal self-injurious behaviors in adolescence and adulthood. Emotional abuse/neglect, disrupted parental attachment, and cumulative effect of multiple forms of maltreatment, also increase risk. Yet, the causal relationship remains unclear. The diathesis-stress model provides a framework for understanding how early life adverse experiences contribute to suicide vulnerability. Current findings from the fields of biology, neurology, and genetics shed new light on mediating variables and possible causal links between early childhood trauma and suicide. In this paper, we review recent advances, particularly regarding the interaction of early life environmental adverse events with genetics factors, that increase the diathesis for psychological traits are associated with subsequent deliberate self-harm behaviors.

Fluorine-18 Radiolabeled PET Tracers for Imaging Monoamine Transporters: Dopamine, Serotonin, and Norepinephrine

This review focuses on the development of fluorine-18 radiolabeled PET tracers for imaging the dopamine transporter (DAT), serotonin transporter (SERT), and norepinephrine transporter (NET). All successful DAT PET tracers reported to date are members of the 3β-phenyl tropane class and are synthesized from cocaine. Currently available carbon-11 SERT PET tracers come from both the diphenylsulfide and 3β-phenyl nortropane class, but so far only the nortropanes have found success with fluorine-18 derivatives. NET imaging has so far employed carbon-11 and fluorine-18 derivatives of reboxetine but due to defluorination of the fluorine-18 derivatives further research is still necessary.

Resting respiratory sinus arrhythmia is related to longer hospitalization in mood-disordered repetitive suicide attempters

OBJECTIVES

Our aims were (1) to measure respiratory sinus arrhythmia (RSA), a high-frequency spectrum component of heart rate variability (HRV) in mood-disordered suicide attempters and (2) to investigate the relationship of RSA to symptoms and length of hospitalization.

METHODS

Forty-nine female repetitive-suicide attempters with depressive disorder or bipolar disorder were recruited in a general hospital setting. Manic or psychotic patients were excluded. Resting RSA values were calculated from electrocardiogram data, and severity of clinical presentation shortly after admission and length of hospital stay were assessed.

RESULTS

RSA was positively associated with a higher Beck Scale for Suicidal Ideation score (r = 0.33 P = 0.019). Stepwise multiple regression analysis showed a significant correlation between RSA and hospitalization length after adjusting other variables (beta coefficient = 3.00; P = 0.030). Patients with a higher resting RSA had more prolonged hospitalizations (hospitalization beyond 30 days) after controlling for other variables (odds ratio = 5.08, P = 0.017).

CONCLUSIONS

Interaction between the environment and the autonomic nervous system is complex. Further and more comprehensive research is needed.

[Modelling the dynamics of suicides in the population of the Russian Federation for the period 1992-2012]

OBJECTIVE

Evaluation of the dynamics of suicides depending on the changes in medical-demographic and socio-economic factors in the Russian population in the period 1992--2012.

MATERIAL AND METHODS

The research material was the data of the official medical statistics on the groups of people with mental disorders, as well as the data on the socio-economic situation of the Russian population during this period. To assess the significance of the association between suicide and these factors, correlation and regression analysis was used.

RESULTS

The regression model explained 95.9% of the variance in the suicide index by two indicators: 1) life expectancy and 2) morbidity of psychotic disorders for the population of Russia during this period. The interpretation of the integral indicators used in the model, and the dynamics of suicides in the Russian population according to socio-economic changes in the country in 1992--2012 are presented.

CONCLUSION

The model can be used as a tool for operational forecasting and monitoring of suicidal patients by government agencies and medical and social services.

The investigation of factors related to suicide attempts in Southeastern Turkey

BACKGROUND

Suicide is an important health problem in Turkey as it is in all regions of the world. Suicidal behavior has multiple causes, which are broadly divided into those related to proximal stressors and those due to predisposition. Suicide statistics may be associated with mental health disorders, which are among the foremost predictors of suicide attempts. More than 90% of patients who commit suicide have a diagnosable psychiatric disorder, usually a major depressive disorder. Other major risk factors for suicide attempts are history of suicide attempts in the family, stressful life events, sleep disturbances, poor income, unemployment, severity of symptoms of depression, and anxiety. Sleep is a complex phenomenon. Sleep disturbances can therefore be contributed to the emergence of suicidal behavior allowing for the possibility of predicting future suicides.

METHODS

We evaluated 106 patients who were admitted after suicide attempts to the Department of Psychiatry at Dicle University Faculty of Medicine. The recruited subjects were assessed by Structured Clinical Interview for DSM-IV Axis I disorders, and the intensity of symptoms was evaluated using the Beck Anxiety Inventory, Hamilton Depression Rating Scale, and Pittsburgh Sleep Quality Index. The mean values of the subjects attempting multiple and single suicides were compared using appropriate inferential statistical tests.

RESULTS

Most suicide attempts are believed to be preventable. Our results revealed that a great variety of risk factors are associated with an increased risk for multiple suicide attempts. Most of these attempts appeared to be spontaneous and impulsive rather than planned. In particular, this study highlights the importance of previous suicide attempts, history of suicide in the family, history of stressful life events in the previous 6 months, poor income, unemployment, sleep disturbances, severe hopelessness with depression, and coexisting symptoms of anxiety as risk factors.

CONCLUSION

The first step in prevention of suicides is doubtlessly strong and reliable communication, due to the fact that the majority of subjects who commit suicide have had contact with a health professional during the month before the suicide.

Suicide Risk Associated with Experience of Violence and Impulsivity in Alcohol Dependent Patients

Alcohol dependence (AD) and aggression-impulsivity are both associated with increased suicide risk. There is a need to evaluate clinical tools in order to improve suicide risk assessment of AD patients. The present study consisted of 95 individuals with a diagnosis of AD, consecutively admitted for addiction treatment, compared with 95 healthy controls. Suicidal risk was assessed together with exposure of violence and impulsivity. AD patients reported significantly higher rates of exposure to violence in childhood, as measured by the Karolinska Interpersonal Violence Scale (KIVS), compared to HC. Within the AD group, individuals with history of suicidal ideation and suicidal behavior reported higher levels of violence experience compared to AD individuals without such history. AD patients with previous suicidal ideation scored higher on self-reported impulsivity as assessed by the Barratt Impulsivity Scale (BIS). Our main finding was that experience of trauma and expression of violent behavior, coupled with increased impulsivity are associated with an elevated suicide risk in AD patients. Future longitudinal studies assessing these traits are needed to evaluate their potential role in identifying AD patients at risk of future suicide.

Genetic Association Studies of Suicidal Behavior: A Review of the Past 10 Years, Progress, Limitations, and Future Directions

Suicidal behaviors (SBs), which range from suicidal ideation to suicide attempts and completed suicide, represent a fatal dimension of mental ill-health. The involvement of genetic risk factors in SB is supported by family, twin, and adoption studies. The aim of this paper is to review recent genetic association studies in SBs including (i) case-control studies, (ii) family-based association studies, and (iii) genome-wide association studies (GWAS). Various studies on genetic associations have tended to suggest that a number of genes [e.g., tryptophan hydroxylase, serotonin receptors and transporters, or brain-derived neurotrophic factors (BDNFs)] are linked to SBs, but these findings are not consistently supported by the results obtained. Although the candidate-gene approach is useful, it is hampered by the present state of knowledge concerning the pathophysiology of diseases. Interpretations of GWAS results are mostly hindered by a lack of annotation describing the functions of most variation throughout the genome. Association studies have addressed a wide range of single-nucleotide polymorphisms in numerous genes. We have included 104 such studies, of which 10 are family-based association studies and 11 are GWAS. Numerous meta-analyses of case-control studies have shown significant associations of SB with variants in the serotonin transporter gene (5-HTT or SLC6A4) and the tryptophan hydroxylase 1 gene (TPH1), but others report contradictory results. The gene encoding BDNF and its receptor (NTRK2) are also promising candidates. Only two of the GWAS showed any significant associations. Several pathways are mentioned in an attempt to understand the lack of reproducibility and the disappointing results. Consequently, we review and discuss here the following aspects: (i) sample characteristics and confounding factors; (ii) statistical limits; (iii) gene-gene interactions; (iv) gene, environment, and by time interactions; and (v) technological and theoretical limits.

Melanin-Concentrating Hormone (MCH): Role in REM Sleep and Depression

The melanin-concentrating hormone (MCH) is a peptidergic neuromodulator synthesized by neurons of the lateral sector of the posterior hypothalamus and zona incerta. MCHergic neurons project throughout the central nervous system, including areas such as the dorsal (DR) and median (MR) raphe nuclei, which are involved in the control of sleep and mood. Major Depression (MD) is a prevalent psychiatric disease diagnosed on the basis of symptomatic criteria such as sadness or melancholia, guilt, irritability, and anhedonia. A short REM sleep latency (i.e., the interval between sleep onset and the first REM sleep period), as well as an increase in the duration of REM sleep and the density of rapid-eye movements during this state, are considered important biological markers of depression. The fact that the greatest firing rate of MCHergic neurons occurs during REM sleep and that optogenetic stimulation of these neurons induces sleep, tends to indicate that MCH plays a critical role in the generation and maintenance of sleep, especially REM sleep. In addition, the acute microinjection of MCH into the DR promotes REM sleep, while immunoneutralization of this peptide within the DR decreases the time spent in this state. Moreover, microinjections of MCH into either the DR or MR promote a depressive-like behavior. In the DR, this effect is prevented by the systemic administration of antidepressant drugs (either fluoxetine or nortriptyline) and blocked by the intra-DR microinjection of a specific MCH receptor antagonist. Using electrophysiological and microdialysis techniques we demonstrated also that MCH decreases the activity of serotonergic DR neurons. Therefore, there are substantive experimental data suggesting that the MCHergic system plays a role in the control of REM sleep and, in addition, in the pathophysiology of depression. Consequently, in the present report, we summarize and evaluate the current data and hypotheses related to the role of MCH in REM sleep and MD.

Psychological strains and suicide intent: Results from a psychological autopsy study with Chinese rural young suicides

BACKGROUND

Previous studies have examined the prevalence of psychological strains among various suicide populations. However, it is still unexamined whether psychological strains can predict suicide intent directly.

AIMS

We planned to explore the prevalence of psychological strains and analyze the relationship between psychological strains and suicide intent among Chinese rural young suicides.

METHODS

Psychological autopsy method was used to investigate the environmental and other factors of rural young suicides. Psychological strains were identified from in-depth interviews by the proxy informants of each suicide. The first 8 items of Beck's Suicidal Intention Scale (SIS) were used to estimate the suicide intent.

RESULTS

Results showed that 96.6% of the suicides had at least one type of strain, and those suicides who had more strains tended to score higher on the suicide intent scale.

CONCLUSION

The study further supports that suicide intent can be predicted by psychological strains in Chinese rural young suicides. The scanning of psychological strains can be used for suicide prevention in Chinese rural young suicides.

Loudness dependence of auditory evoked potentials (LDAEP) in clinical monitoring of suicidal patients with major depression in comparison with non-suicidal depressed patients and healthy volunteers: A follow-up-study

Differences in central serotonergic function due to affective disorders and due to extraordinary situations like suicidality may be visualized using the loudness dependence of auditory evoked potentials (LDAEP). Twenty patients (mean age 43.25 ± 10.85, age range 20-61, 11 male) suffering from a major depressive episode who had either acutely attempted suicide or who had suicidal plans and behavior, which are reflected by item 3 of Hamilton Depression Rating Scale ≥ 3 (suicidality), were included in the study. Furthermore, we intended to compare their LDAEP to those of non-suicidal depressed patients as well as to healthy volunteers, each matched according to age and gender. LDAEP measurement and psychometric tests took place about 2, 5, 9, 16 and 30 days after acute suicidal action or suicide attempts. In contrast to previous results, significant differences in LDAEP could not have been shown in between the suicidal group, or by comparing results of suicidal patients to non-suicidal depressed patients or to healthy volunteers. However, when the LDAEP of non-suicidal depressed patients were compared to healthy volunteers, there was a trend for a higher LDAEP in the healthy volunteers. Further studies are necessary to detect and describe further influences on serotonergic function and confounding factors like medication, smoking, age, gender, comorbidities and methods of suicidal attempts.

Violent suicidal behaviour in bipolar disorder is associated with nitric oxide synthase 3 gene polymorphism

OBJECTIVE

Given the importance of nitric oxide system in oxidative stress, inflammation, neurotransmission and cerebrovascular tone regulation, we postulated its potential dysfunction in bipolar disorder (BD) and suicide. By simultaneously analysing variants of three isoforms of nitric oxide synthase (NOS) genes, we explored interindividual genetic liability to suicidal behaviour in BD.

METHOD

A total of 536 patients with BD (DSM-IV) and 160 healthy controls were genotyped for functionally relevant NOS1, NOS2 and NOS3 polymorphisms. History of suicidal behaviour and violent suicide attempt was documented for 511 patients with BD. Chi-squared test was used to perform genetic association analyses and logistic regression to test for gene-gene interactions.

RESULTS

NOS3 rs1799983 T homozygous state was associated with violent suicide attempts (26.4% vs. 10.8%, in patients and controls, P = 0.002, corrected P (Pc) = 0.004, OR: 2.96, 95% CI = 1.33-6.34), and this association was restricted to the early-onset BD subgroup (37.9% vs. 10.8%, in early-onset BD and controls, P = 0.0003, Pc = 0.0006 OR: 5.05, 95% CI: 1.95-12.45), while we found no association with BD per se and no gene-gene interactions.

CONCLUSION

Our results bring further evidence for the potential involvement of endothelial NOS gene variants in susceptibility to suicidal behaviour. Future exploration of this pathway on larger cohort of suicidal behaviour is warranted.

Searching human brain for mechanisms of psychiatric disorders. Implications for studies on schizophrenia

In the past 25years, research on the human brain has been providing a clear path toward understanding the pathophysiology of psychiatric illnesses. The successes that have been accrued are matched by significant difficulties identifying and controlling a large number of potential confounding variables. By systematically and effectively accounting for unwanted variance in data from imaging and postmortem human brain studies, meaningful and reliable information regarding the pathophysiology of human brain disorders can be obtained. This perspective paper focuses on postmortem investigations to discuss some of the most challenging sources of variance, including diagnosis, comorbidity, substance abuse and pharmacological treatment, which confound investigations of the human brain.

Genetic Vulnerability as a Distal Risk Factor for Suicidal Behaviour: Historical Perspective and Current Knowledge

INTRODUCTION

Suicide is a multidimensional problem. Observations of family history of suicide suggest the existence of a genetic vulnerability to suicidal behaviour.

AIM

Starting with a historical perspective, the article reviews current knowledge of a genetic vulnerability to suicidal behaviour, distinct from the genetic vulnerability to psychiatric disorders, focused on clinical and population-based studies, and findings from recent molecular genetics association studies.

METHOD

The review includes peer-reviewed research articles and review papers from the professional literature in English language, retrieved from PubMed/Medline and PsycINFO.

RESULTS

The research literature confirms a existence of a genetic vulnerability to suicidal behaviour. Even though the results of individual studies are difficult to compare, genetic influences could explain up to half of the variance of the occurrence of suicide.

CONCLUSION

Genetic vulnerability could be a distal risk factor for suicide, which helps us to understand the occurrence of suicide among vulnerable people. Ethical implications of such vulnerability are highlighted.

Epigenetic Dysregulation in the Prefrontal Cortex of Suicide Completers

The epigenome is thought to mediate between genes and the environment, particularly in response to adverse life experiences. Similar to other psychiatric diseases, the suicide liability of an individual appears to be influenced by many genetic factors of small effect size as well as by environmental stressors. To identify epigenetic marks associated with suicide, which is considered the endpoint of complex gene-environment interactions, we compared the cortex DNA methylation patterns of 6 suicide completers versus 6 non-psychiatric sudden-death controls, using Illumina 450K methylation arrays. Consistent with a multifactorial disease model, we found DNA methylation changes in a large number of genes, but no changes with large effects reaching genome-wide significance. Global methylation of all analyzed CpG sites was significantly (0.25 percentage point) lower in suicide than in control brains, whereas the vast majority (97%) of the top 1,000 differentially methylated regions (DMRs) were higher methylated (0.6 percentage point) in suicide brains. Annotation analysis of the top 1,000 DMRs revealed an enrichment of differentially methylated promoters in functional categories associated with transcription and expression in the brain. In addition, we performed a comprehensive literature research to identify suicide genes that have been replicated in independent genetic association, brain methylation and/or expression studies. Although, in general, there was no significant overlap between different published data sets or between our top 1,000 DMRs and published data sets, our methylation screen strengthens a number of candidate genes (APLP2, BDNF, HTR1A, NUAK1, PHACTR3, MSMP, SLC6A4, SYN2, and SYNE2) and supports a role for epigenetics in the pathophysiology of suicide.

5-HTTLPR × interpersonal stress interaction and nonsuicidal self-injury in general community sample of youth

No research with youth has investigated whether measured genetic risk interacts with stressful environment (G⁎E) to explain engagement in non-suicidal self-injury (NSSI). Two independent samples of youth were used to test the a priori hypothesis that the Transporter-Linked Polymorphic Region (5-HTTLPR) would interact with chronic interpersonal stress to predict NSSI. We tested this hypothesis with children and adolescents from United States public schools in two independent samples (N׳s=300 and 271) using identical procedures and methods. They were interviewed in person with the Self-Injurious Thoughts and Behaviors Interview to assess NSSI engagement and with the UCLA Chronic Stress Interview to assess interpersonal stress. Buccal cells were collected for genotyping of 5-HTTLPR. For both samples, ANOVAs revealed the hypothesized G*E. Specifically, short carriers who experienced severe interpersonal stress exhibited the highest level of NSSI engagement. Replicated across two independent samples, results provide the first demonstration that youth at high genetic susceptibility (5-HTTLPR) and high environmental exposure (chronic interpersonal stress) are at heightened risk for NSSI.

Insomnia Symptom, Mental Disorder and Suicide: A Case-Control Study in Chinese Rural Youths

Insomnia has been reported as a risk factor of suicidal behaviors, but few studies have examined the association among insomnia, mental disorder and suicide, especially among Chinese populations. In this study, we examined the effect of insomnia symptoms on completed suicide in a large sample of suicides and their controls in Chinese rural youths. Subjects were 388 consecutively recruited suicides and 416 community living controls aged 15-34 years in the rural areas of three provinces in China. Established psychological autopsy method was used for the data collection. Insomnia symptoms were assessed with sleep questions in the Hamilton Depression Rating Scale (HAMD) about insomnia, including difficulty initiating sleep (DIS), difficulty maintaining sleep (DMS) and early morning awakening (EMA). The results showed that DIS (OR=12.01, p<0.001), DMS (OR=12.82, p<0.001) or EMA (OR=12.08, p<0.001) was significantly associated with increased risk of suicide even after mental disorder was controlled for. Our study showed that insomnia can be an independent risk factor for suicide. Mental disorders mediated the association between insomnia and suicide. Insomnia should be assessed and treated for individuals at risk of suicide.

A Cross-National Tool for Assessing and Studying Suicidal Behaviors

Current methodologies employed in collecting data for suicide research present several limitations. In this article, we describe a novel method and tool to prospectively study suicidal behavior and its related risk and protective factors in different countries. This tool is a web-based database, which will initially be developed and piloted by suicide research groups from Austria, Brazil, Chile, France, Italy, Mexico, Spain, Sweden, and the US. The database will develop and integrate research tools key to collaboration, permit exploration of ethical considerations, and provide a universal interface in English, Spanish, French, Portuguese, Italian, and German that will make it possible to incorporate new groups from different countries to the network. The common database resulting of this cross-national effort will allow researchers to share and compare data across countries in a large sample of patients. Using anonymous electronic records of patients, we will: 1) determine the impact of risk and protective factors (viz. aggression and religious affiliation) in different socio-cultural environments; 2) develop a clinical model of suicidal behavior that integrates the multiple dimensions implicated; 3) try differentiating the effects of biological, environmental, and cultural factors on suicidal behavior, and 4) offer the global psychiatric research community a tool that will standardize assessment across nations, allowing for better generalization.

Association of poor subjective sleep quality with risk for death by suicide during a 10-year period: a longitudinal, population-based study of late life

IMPORTANCE

Older adults have high rates of sleep disturbance, die by suicide at disproportionately higher rates compared with other age groups, and tend to visit their physician in the weeks preceding suicide death. To our knowledge, to date, no study has examined disturbed sleep as an independent risk factor for late-life suicide.

OBJECTIVE

To examine the relative independent risk for suicide associated with poor subjective sleep quality in a population-based study of older adults during a 10-year observation period.

DESIGN, SETTING, AND PARTICIPANTS

A longitudinal case-control cohort study of late-life suicide among a multisite, population-based community sample of older adults participating in the Established Populations for Epidemiologic Studies of the Elderly. Of 14 456 community older adults sampled, 400 control subjects were matched (on age, sex, and study site) to 20 suicide decedents.

MAIN OUTCOMES AND MEASURES

Primary measures included the Sleep Quality Index, the Center for Epidemiologic Studies-Depression Scale, and vital statistics.

RESULTS

Hierarchical logistic regressions revealed that poor sleep quality at baseline was significantly associated with increased risk for suicide (odds ratio [OR], 1.39; 95% CI, 1.14-1.69; P < .001) by 10 follow-up years. In addition, 2 sleep items were individually associated with elevated risk for suicide at 10-year follow-up: difficulty falling asleep (OR, 2.24; 95% CI, 1.27-3.93; P < .01) and nonrestorative sleep (OR, 2.17; 95% CI, 1.28-3.67; P < .01). Controlling for depressive symptoms, baseline self-reported sleep quality was associated with increased risk for death by suicide (OR, 1.30; 95% CI, 1.04-1.63; P < .05).

CONCLUSIONS AND RELEVANCE

Our results indicate that poor subjective sleep quality is associated with increased risk for death by suicide 10 years later, even after adjustment for depressive symptoms. Disturbed sleep appears to confer considerable risk, independent of depressed mood, for the most severe suicidal behaviors and may warrant inclusion in suicide risk assessment frameworks to enhance detection of risk and intervention opportunity in late life.

Risk factors for suicide in epilepsy patients

ABSTRACT: 

Suicidal behavior is not uncommon in epilepsy patients. Risk factors for suicidal ideation are associated with social and vocational disturbances, such as low economic status, lack of social support and unemployment and psychiatric comorbidity. In epilepsy patients, interictal dysphoric disorder presents a depressive mood that may be associated with episodic suicidal ideation. Suicide may occur among patients with very severe epilepsy, but also in patients that recently achieved a complete seizure freedom. Recent research suggests that almost a third of epilepsy patients that endorsed suicidal ideation were euthymic or had only very mild depressive symptoms. People with epilepsy should be specifically asked about their psychiatric problems and potential suicidal ideation. Neurobiology of suicidal behavior in epilepsy patients is still unclear.

Transitions in the transcriptome of the serotonergic and dopaminergic systems in the human brain during adolescence

Adolescence is a period of profound neurophysiological, behavioral, cognitive and psychological changes, but not much is known about the underlying molecular neural mechanisms. The aim of this study was to systematically analyze expression levels of the genes forming serotonergic and dopaminergic synapses during adolescence. We analyzed the mRNA expression profiles of genes that code for all components of serotonergic and dopaminergic synapses, in 16 brain areas from human and non-human primates from public domain databases, to detect genes whose expression changes during adolescence. Two serotonin receptors, HTR1E and HTR1B had expression levels that exhibit a sharp transition in the prefrontal cortex in adolescence, but we found no similar transition in the dopaminergic system. A similar but smoother rise in expression levels is observed in HTR4 and HTR5A, and in HTR1E and HTR1B in three other expression datasets published. An earlier rise is observed in HTR1A, and a smooth and significant rise with age is observed in the expression of HTR1E in microarray measurements in macaque monkeys. The expression of HTR1E and HTR1B is correlated across subjects within each age group, suggesting that they are controlled by common mechanisms. These results point to HTR1E and HTR1B as major candidate genes involved in adolescence maturation processes, and to their operation through common control mechanisms. The maturation profiles may also involve several other 5-HT receptors, including the genes HTR5A, HTR4 and HTR1A.

Association of functional DBH genetic variants with alcohol dependence risk and related depression and suicide attempt phenotypes: results from a large multicenter association study

OBJECTIVE

Dopamine-beta-hydroxylase (DBH) metabolizes the conversion of dopamine to noradrenaline. DBH, located on chromosome 9q34.2 has variants with potential functional consequences which may be related to alterations of neurotransmitter function and several psychiatric phenotypes, including alcohol dependence (AD), depression (MD) and suicidal behavior (SA). The aim of this association study in a large multicenter sample of alcohol-dependent individuals and controls is to investigate the role of DBH SNPs and haplotypes in AD risk and associated phenotypes (AD with MD or SA).

METHOD

1606 inpatient subjects with DSM-IV AD from four addiction treatment centers and 1866 control subjects were included. Characteristics of AD, MD and SA were obtained using standardized structured interviews. After subjects were genotyped for 4 DBH polymorphisms, single SNP case-control and haplotype analyses were conducted.

RESULTS

rs1611115 (near 5') C-allele and related haplotypes were significantly associated with alcohol dependence in females. This association with female alcohol dependence also accounts for the significant relationship between this variant and comorbid conditions and traits.

CONCLUSIONS

This study presents evidence for a potentially functional DBH variant influencing the risk for alcohol dependence while other comorbid conditions are not independently influenced by this SNP. However, the study also supports the possible role of the dopamine system in the etiology of female alcohol dependence.

Field procedures in the Army Study to Assess Risk and Resilience in Servicemembers (Army STARRS)

The Army Study to Assess Risk and Resilience in Servicemembers (Army STARRS) is a multi-component epidemiological and neurobiological study of unprecedented size and complexity designed to generate actionable evidence-based recommendations to reduce US Army suicides and increase basic knowledge about determinants of suicidality by carrying out coordinated component studies. A number of major logistical challenges were faced in implementing these studies. The current report presents an overview of the approaches taken to meet these challenges, with a special focus on the field procedures used to implement the component studies. As detailed in the paper, these challenges were addressed at the onset of the initiative by establishing an Executive Committee, a Data Coordination Center (the Survey Research Center [SRC] at the University of Michigan), and study-specific design and analysis teams that worked with staff on instrumentation and field procedures. SRC staff, in turn, worked with the Office of the Deputy Under Secretary of the Army (ODUSA) and local Army Points of Contact (POCs) to address logistical issues and facilitate data collection. These structures, coupled with careful fieldworker training, supervision, and piloting, contributed to the major Army STARRS data collection efforts having higher response rates than previous large-scale studies of comparable military samples.

High rate of suicide attempt and associated psychological traits in an isolated tribal population of North-East India

BACKGROUND

Cases of suicide documented earlier all over the world reflect the presence of suicide behavior in primitive world at a higher rate compared to general urban population. The cause of such behavior is thought to be different among tribes and mental health was rarely presumed to be associated. In India, several ethnographic narratives described instances of suicides among several tribes, but evaluation of psychological traits were lacking. The present study on Idu Mishmi is an attempt to further validate earlier report of high rate of suicides among them and to evaluate psychological traits.

METHODS

Interview and administration of Patient Health Questionnaire (PHQ) on 218 individuals comprised the data. Bi-variate analyses and linear multiple regression were done to evaluate psychological traits in suicide behavior.

RESULTS

In the Idu Mishmi Population suicide attempt (14.22%) was higher than urban population in general (0.4-4.2%) and females were at higher risk. Depression (8.26%) was comparable with earlier reports, whereas anxiety syndrome (6.42%), alcohol abuse (36.24%) and eating disorder like Binge eating (6.42%), Bulimia nervosa (1.38%) were also recorded in the population.

LIMITATIONS

Absence of psychiatry clinic and mechanism of recording suicide occurrences in remote tribal area is the basic limitation of the study.

CONCLUSION

Depression and gender turned out to be significant determinants of suicide attempt in the studied population, whereas alcohol abuse was not a significant factor.

Differential effect of lithium on spermidine/spermine N1-acetyltransferase expression in suicidal behaviour

An altered polyamine system has been suggested to play a key role in mood disorders and suicide, a hypothesis corroborated by the evidence that lithium inhibits the polyamine mediated stress response in the rat brain. Recent post-mortem studies have shown that spermidine/spermine N1-acetyltransferase (SAT1), the key regulator of cellular polyamine content, is under-expressed in brains from suicide victims compared to controls. In our study we tested the effect of in vitro lithium treatment on SAT1 gene and protein expression in B lymphoblastoid cell lines (BLCLs) from bipolar disorder (BD) patients who committed suicide (and for which BLCLs were collected prior to their death), BD patients with high and low risk of suicide and a sample of non-psychiatric controls. Baseline mRNA levels were similar in the four groups of subjects (p > 0.05). Lithium had no effect in suicide completers (p > 0.05) while it significantly increased SAT1 expression in the high risk (p < 0.001) and low risk (p < 0.01) groups as well as in controls (p < 0.001). Protein and mRNA levels were not correlated; lithium significantly reduced protein levels only in the control sample (p < 0.05). Our findings suggest that SAT1 transcription is influenced by lithium and that this effect is altered in BD patients who completed suicide, further supporting a role for polyamines in suicide.

Traumatic brain injury - modeling neuropsychiatric symptoms in rodents

Each year in the US, ∼1.5 million people sustain a traumatic brain injury (TBI). Victims of TBI can suffer from chronic post-TBI symptoms, such as sensory and motor deficits, cognitive impairments including problems with memory, learning, and attention, and neuropsychiatric symptoms such as depression, anxiety, irritability, aggression, and suicidal rumination. Although partially associated with the site and severity of injury, the biological mechanisms associated with many of these symptoms - and why some patients experience differing assortments of persistent maladies - are largely unknown. The use of animal models is a promising strategy for elucidation of the mechanisms of impairment and treatment, and learning, memory, sensory, and motor tests have widespread utility in rodent models of TBI and psychopharmacology. Comparatively, behavioral tests for the evaluation of neuropsychiatric symptomatology are rarely employed in animal models of TBI and, as determined in this review, the results have been inconsistent. Animal behavioral studies contribute to the understanding of the biological mechanisms by which TBI is associated with neurobehavioral symptoms and offer a powerful means for pre-clinical treatment validation. Therefore, further exploration of the utility of animal behavioral tests for the study of injury mechanisms and therapeutic strategies for the alleviation of emotional symptoms are relevant and essential.

Serotonin transporter (5-HTT) gene polymorphisms and susceptibility to epilepsy: a meta-analysis and meta-regression

AIMS

Serotonin transporter (5-HTT) plays a central role in the regulation of serotonin (5-hydroxytryptamine [5-HT]) synaptic function. Disturbances in 5-HT transmission are the most frequently reported neurobiological substrates of suicidal behavior. Emerging evidence has shown that the common polymorphisms in the 5-HTT gene may contribute to the risk of epilepsy, but individually published studies showed inconclusive results. This meta-analysis aimed to derive a more precise estimation of the associations between 5-HTT gene polymorphisms and susceptibility to epilepsy.

METHODS

A literature search of PubMed, Embase, Web of Science, and China BioMedicine (CBM) databases was conducted on articles published before June 1st, 2013. Crude odds ratios with 95% confidence intervals were calculated.

RESULTS

Seven studies were assessed with a total 1303 epilepsy patients and 1288 healthy controls. The meta-analysis results indicated that there was no significant relationship between 5-HTT gene polymorphisms and an increased risk of epilepsy. Further subgroup analysis based on ethnicity also found no significant association between 5-HTT gene polymorphisms and epilepsy risk among both Caucasian and Asian populations. In addition, there was also no significant association between 5-HTT gene polymorphisms and the risk of psychiatric comorbidity in patients with epilepsy.

CONCLUSION

In conclusion, the current meta-analysis indicates that 5-HTT gene polymorphisms might not be the primary determinants of epilepsy susceptibility. 5-HTT genes might be expected to interact with other genes in different signaling pathways to initiate and promote the epileptogenic process.

Association between total sleep duration and suicidal ideation among the Korean general adult population

STUDY OBJECTIVES

Examine the association between sleep duration and suicidal ideation in Korean adults.

DESIGN

Cross-sectional survey.

SETTING

Data obtained by the Korea National Health and Nutrition Examination Survey IV (2007-2009) using a rolling sampling design involving a complex, stratified, multistage, and probability-cluster survey of civilian non-institutionalized Korean residents.

PARTICIPANTS

A total of 15,236 subjects (6,638 males and 8,598 females) ≥ 19 years old.

MEASUREMENTS AND RESULTS

The weighted prevalence of self-reported short sleep duration (≤ 5 h/day) was 11.7% in males and 15% in females, and of long sleep duration (≥ 9 h/day) was 6.7% in males and 8.9% in females. A U-shaped relationship existed, with both short and long sleep durations associated with a higher suicidal ideation risk. Multiple logistic regression analysis was used to analyze the relationship between sleep duration and suicidal ideation, adjusting for sociodemographic factors, health behavior, and health status. After controlling for covariates, people with short sleep were 38.1% more likely to have suicidal ideation (OR = 1.381, 95% CI 1.156-1.650) than people with sleep duration of 7 h/day. Suicidal ideation was 1.196 times higher (95% CI: 0.950-1.507) in long-sleeping people than people sleeping 7 h/day, although statistically not significant. Inclusion of depressive mood (a potential confounder) in multiple logistic regression models attenuated but did not eliminate the sleep duration/suicidal ideation association.

LIMITATIONS

Sleep duration and suicidal ideation were assessed only by self-report.

CONCLUSIONS

The sleep duration/suicidal ideation relationship is U-shaped in the Korean adult population. Self-reported habitual sleep duration may be a useful behavioral indicator for both individual and societal suicidal ideation risk.

National study of suicide method in violent criminal offenders

BACKGROUND

Gaining a greater knowledge of the mechanisms and means by which violent offenders die by suicide can inform tailored preventive strategies.

METHODS

Using interlinked national Danish registry data we constructed a nested case-control study dataset of all adult suicides during 1994-2006: N=9708 cases and N=188,134 age and gender matched living controls. Completely ascertained International Classification of Diseases 10th revision cause-specific mortality codes were examined, with all criminal charges since 1980, and covariate information on psychiatric treatment and socio-demographics. Self-poisonings were classified as 'nonviolent' suicide and all other methods as being 'violent' ones.

RESULTS

Compared with the general population, risk among male and female violent offenders was strongly and significantly elevated for suicide by either a violent or a nonviolent method, although the relative risk was greater for nonviolent suicide. These patterns were also observed among nonviolent offenders, albeit with smaller effect sizes. Risk was especially raised for self-poisoning with narcotics & hallucinogens. We could only examine the full range of suicide methods in male violent offenders. In these men, hanging was the most frequently used method, although risk was markedly and significantly elevated virtually across the entire range of regularly used suicide methods.

LIMITATIONS

We lacked sufficient statistical power for undertaking a detailed profiling of specific suicide methods among female violent offenders.

CONCLUSIONS

Our findings indicate that comprehensive and broadly-based preventive approaches are needed for tackling the markedly raised risk of suicide by both violent and nonviolent means in this population. Their high relative risk for self-poisoning by illicit or illegal drugs underlines the importance of access to means and of prevailing subculture.

Depression and suicide are natural kinds: implications for physician-assisted suicide

In this article, I argue that depression and suicide are natural kinds insofar as they are classes of abnormal behavior underwritten by sets of stable biological mechanisms. In particular, depression and suicide are neurobiological kinds characterized by disturbances in serotonin functioning that affect various brain areas (i.e., the amygdala, anterior cingulate, prefrontal cortex, and hippocampus). The significance of this argument is that the natural (biological) basis of depression and suicide allows for reliable projectable inferences (i.e., predictions) to be made about individual members of a kind. In the context of assisted suicide, inferences about the decision-making capacity of depressed individuals seeking physician-assisted suicide are of special interest. I examine evidence that depression can hamper the decision-making capacity of individuals seeking assisted suicide and discuss some implications.

Role of NAD(+), Oxidative Stress, and Tryptophan Metabolism in Autism Spectrum Disorders

Autism spectrum disorder (ASD) is a pervasive neuro-developmental disorder characterized by impaired social interaction, reduced/absent verbal and non-verbal communication, and repetitive behavior during early childhood. The etiology of this developmental disorder is poorly understood, and no biomarkers have been identified. Identification of novel biochemical markers related to autism would be advantageous for earlier clinical diagnosis and intervention. Studies suggest that oxidative stress-induced mechanisms and reduced antioxidant defense, mitochondrial dysfunction, and impaired energy metabolism (NAD(+), NADH, ATP, pyruvate, and lactate), are major causes of ASD. This review provides renewed insight regarding current autism research related to oxidative stress, mitochondrial dysfunction, and altered tryptophan metabolism in ASD.

Human biomarkers of rapid antidepressant effects

Mood disorders such as major depressive disorder and bipolar disorder--and their consequent effects on the individual and society--are among the most disabling and costly of all medical illnesses. Although a number of antidepressant treatments are available in clinical practice, many patients still undergo multiple and lengthy medication trials before experiencing relief of symptoms. Therefore a tremendous need exists to improve current treatment options and to facilitate more rapid, successful treatment in patients suffering from the deleterious neurobiological effects of ongoing depression. Toward that end, ongoing research is exploring the identification of biomarkers that might be involved in prevention, diagnosis, treatment response, severity, or prognosis of depression. Biomarkers evaluating treatment response will be the focus of this review, given the importance of providing relief to patients in a more expedient and systematic manner. A novel approach to developing such biomarkers of response would incorporate interventions with a rapid onset of action--such as sleep deprivation or intravenous drugs (e.g., ketamine or scopolamine). This alternative translational model for new treatments in psychiatry would facilitate shorter studies, improve feasibility, and increase higher compound throughput testing for these devastating disorders.

Modulation of firing and synaptic transmission of serotonergic neurons by intrinsic G protein-coupled receptors and ion channels

Serotonergic neurons project to virtually all regions of the central nervous system and are consequently involved in many critical physiological functions such as mood, sexual behavior, feeding, sleep/wake cycle, memory, cognition, blood pressure regulation, breathing, and reproductive success. Therefore, serotonin release and serotonergic neuronal activity have to be precisely controlled and modulated by interacting brain circuits to adapt to specific emotional and environmental states. We will review the current knowledge about G protein-coupled receptors and ion channels involved in the regulation of serotonergic system, how their regulation is modulating the intrinsic activity of serotonergic neurons and its transmitter release and will discuss the latest methods for controlling the modulation of serotonin release and intracellular signaling in serotonergic neurons in vitro and in vivo.

Risk factors for suicidal ideation of the general population

The aim of this study was to investigate risk factors of suicide ideation in general population. A total of 1,116 adults were sampled with randomization in an urban area. After excluding 116 participants due to incomplete answer, 1,000 participants (500 males; mean age 39.6 ± 11.6) completed self-report questionnaire including the Center for Epidemiologic Study Depression Scale (CES-D), the Beck Scale for Suicide Ideation (BSI), the Spielberger State-Trait Anger Expression Inventory (STAXI), the Barratt Impulsiveness Scale (BIS), and questions on weekday sleep duration. Results showed higher scores on the BSI were related with higher scores on the STAXI, CES-D, a family history of psychiatric illness, and short or long sleep duration (≤ 5 or ≥ 10 hr) (adjusted R (2) = 0.151, P < 0.001, P < 0.001, P = 0.001, and P = 0.008, respectively). The predictive power of the STAXI scores, the presence of psychiatric family history and short or long sleep duration was stronger in the high CES-D group with scores of 16 or higher (adjusted R (2) = 0.275, P < 0.001, P < 0.001, and P < 0.001, respectively). These findings suggest that suicide idea in general population may be related with the presence of family history for psychiatric illness, depressive mood, high anger and short or long sleep duration.

Personality and the acute subjective effects of d-amphetamine in humans

There is evidence that subjective responses to psychoactive drugs are related to personality traits. Here, we extend previous findings by examining personality measures in relation to acute responses to d-amphetamine (AMPH) in a large sample of healthy volunteers. Healthy adults (n=286) completed the Multidimensional Personality Questionnaire Brief Form (MPQ-BF) and participated in four sessions during which they received oral AMPH (0, 5, 10, 20 mg), under double-blind conditions. Subjective responses to the drug were measured using the Profile of Mood States, Addiction Research Center Inventory, and Drug Effects Questionnaire. Drug responses were reduced via principal components analysis to three higher-order factors ('Euphoria', 'Arousal', 'Dysphoria'). Participants were rank ordered on selected MPQ-BF scales; the top and bottom third on each trait were compared on the drug response factors. High trait physical fearlessness was significantly associated with greater amphetamine-related Arousal, and high trait reward sensitivity was significantly associated with greater Euphoria. In addition, high trait impulsivity was significantly associated with greater Arousal and Euphoria. These results provide further evidence that individual differences in the subjective effects of AMPH are partially explained by differences in personality, and are consistent with the idea that both personality and responses to stimulants depend upon shared neurochemical systems.

Investigating the roles of different monoamine transmitters and impulse control using the 5-choice serial reaction time task

Previous studies have shown that drugs which block the reuptake of catecholamine neurotransmitters improve impulse control in diseases such as attention deficit hyperactivity disorder (ADHD). Serotonin-specific reuptake inhibitors (SSRI) lack efficacy in ADHD and have been linked to increased suicide risk. The present study investigated drugs with affinity for one or more of the monoamine reuptake transporters using the 5-choice serial reaction time task, a model of attention and impulsivity in rodents. We also tested the effects of the alpha(2)-adreoceptor antagonist, idazoxan and novel antidepressant, agomelatine, which both increase cortical noradrenaline concentrations through non-reuptake mechanisms. Improvements in impulse control were observed with venlafaxine, a serotonin and noradrenaline re-uptake inhibitor (SNRI) but not bupropion (dopamine and noradrenaline re-uptake inhibitor). Sibutramine (SNRI) reduced premature responses by ~50% at the highest dose tested but this was not significant. All three of the SSRIs tested reduced premature responding in a dose-dependent manner, although also slowed response and collection latencies. Neither idazoxan nor agomelatine significantly reduced premature responding, suggesting a lack of efficacy at the doses tested. None of the drugs tested improved attention in this task but sibutramine (SNRI), fluoxetine (SSRI) and paroxetine (SSRI) all increased omissions at the highest dose tested. These data suggest that the SNRIs and SSRIs reduce premature responding but tend to be less specific than noradrenaline specific reuptake inhibitors in this model. SSRIs did not induce any specific impairment in impulse control in this model.

The role of the serotonergic system at the interface of aggression and suicide

Alterations in serotonin (5-HT) neurochemistry have been implicated in the aetiology of all major neuropsychiatric disorders, ranging from schizophrenia to mood and anxiety-spectrum disorders. This review will focus on the multifaceted implications of 5-HT-ergic dysfunctions in the pathophysiology of aggressive and suicidal behaviours. After a brief overview of the anatomical distribution of the 5-HT-ergic system in the key brain areas that govern aggression and suicidal behaviours, the implication of 5-HT markers (5-HT receptors, transporter as well as synthetic and metabolic enzymes) in these conditions is discussed. In this regard, particular emphasis is placed on the integration of pharmacological and genetic evidence from animal studies with the findings of human experimental and genetic association studies. Traditional views postulated an inverse relationship between 5-HT and aggression and suicidal behaviours; however, ample evidence has shown that this perspective may be overly simplistic, and that such pathological manifestations may reflect alterations in 5-HT homoeostasis due to the interaction of genetic, environmental and gender-related factors, particularly during early critical developmental stages. The development of animal models that may capture the complexity of such interactions promises to afford a powerful tool to elucidate the pathophysiology of impulsive aggression and suicidability, and identify new effective therapies for these conditions.

The role of the serotonergic system in suicidal behavior

Serotonin is a widely investigated neurotransmitter in several psychopathologies, including suicidal behavior (SB); however, its role extends to several physiological functions involving the nervous system, as well as the gastrointestinal and cardiovascular systems. This review summarizes recent research into ten serotonergic genes related to SB. These genes - TPH1, TPH2, SLC6A4, SLC18A2, HTR1A, HTR1B, HTR2A, DDC, MAOA, and MAOB - encode proteins that are vital to serotonergic function: tryptophan hydroxylase; the serotonin transporter 5-HTT; the vesicular transporter VMAT2; the HTR1A, HTR1B, and HTR2A receptors; the L-amino acid decarboxylase; and the monoamine oxidases. This review employed a systematic search strategy and a narrative research methodology to disseminate the current literature investigating the link between SB and serotonin.

Altered functional protein networks in the prefrontal cortex and amygdala of victims of suicide

Probing molecular brain mechanisms related to increased suicide risk is an important issue in biological psychiatry research. Gene expression studies on post mortem brains indicate extensive changes prior to a successful suicide attempt; however, proteomic studies are scarce. Thus, we performed a DIGE proteomic analysis of post mortem tissue samples from the prefrontal cortex and amygdala of suicide victims to identify protein changes and biomarker candidates of suicide. Among our matched spots we found 46 and 16 significant differences in the prefrontal cortex and amygdala, respectively; by using the industry standard t test and 1.3 fold change as cut off for significance. Because of the risk of false discoveries (FDR) in these data, we also made FDR adjustment by calculating the q-values for all the t tests performed and by using 0.06 and 0.4 as alpha thresholds we reduced the number of significant spots to 27 and 9 respectively. From these we identified 59 proteins in the cortex and 11 proteins in the amygdala. These proteins are related to biological functions and structures such as metabolism, the redox system, the cytoskeleton, synaptic function, and proteolysis. Thirteen of these proteins (CBR1, DPYSL2, EFHD2, FKBP4, GFAP, GLUL, HSPA8, NEFL, NEFM, PGAM1, PRDX6, SELENBP1 and VIM,) have already been suggested to be biomarkers of psychiatric disorders at protein or genome level. We also pointed out 9 proteins that changed in both the amygdala and the cortex, and from these, GFAP, INA, NEFL, NEFM and TUBA1 are interacting cytoskeletal proteins that have a functional connection to glutamate, GABA, and serotonin receptors. Moreover, ACTB, CTSD and GFAP displayed opposite changes in the two examined brain structures that might be a suitable characteristic for brain imaging studies. The opposite changes of ACTB, CTSD and GFAP in the two brain structures were validated by western blot analysis.

Loudness dependence of auditory evoked potentials (LDAEP) in clinical monitoring of suicidal patients with major depression: a pilot study

Loudness dependence of auditory evoked potentials (LDAEP) is a validated in vivo marker of central serotonergic function. We aimed at measuring serotonergic activity in a follow-up study of suicidal patients. It should be investigated whether suicide attempts or suicidal states cause changes in the LDAEP. Thirteen patients (mean age, 40.9 ± 11.3 years; age range, 20-61, 6 male) with a major depressive episode who had attempted suicide or had suicidal plans (Hamilton Depression Rating Scale item 3 [suicidality] ≥3) were included in the study. LDAEP and psychometric measurements took place about 2, 5, 9 and 16 days after attempted suicide or suicidal action. On day 9, LDAEP was significantly higher compared to day 2 and day 16; there was a similar tendency compared to day 5. Instability of central serotonergic function is suggested resulting in reduced serotonergic activity about 1 week after suicide attempt. Further studies are necessary that include larger samples in order to distinguish between different psychiatric diseases and to consider confounding factors like gender, smoking, medication, impulsivity or lethality of suicidal action.

Effects of sunshine on suicide rates

OBJECTIVES

Seasonal spring peaks of suicide are well described in epidemiological studies, but their origin is poorly understood. More recent evidence suggests that this peak may be associated with the increase in the duration of sunshine in spring. We investigated the effect of number of sunshine hours per month on suicide rates in Austria between 1996 and 2006.

METHODS

Suicide data, differentiated by month of suicide, sex, and method of suicide (violent vs nonviolent methods), were provided by Statistics Austria. Data on the average number of sunshine hours per month were calculated from 39 representative meteorological stations (provided by the Austrian Central Institute for Meteorology and Geodynamics). For statistical analysis, analysis of variance tests, Kruskal-Wallis tests, and Pearson correlation tests were used.

RESULTS

A total of 16,673 suicides with a median of 126 ± 19.8 suicides per month occurred in the examined period. A clear seasonal pattern was observed, with suicide frequencies being highest between March and May and lowest between November and January (df = 11, F = 5.2, P < .0001) for men (df = 11, F = 4.9, P < .0001) and women (df = 11, F = 2.4, P = .008). The average number of sunshine hours per month was significantly correlated with the number of suicides among both sexes (r = .43, P < .0001), violent methods (r = .48, P < .0001) but not with nonviolent methods (r = .03, P = .707).

CONCLUSIONS

This study shows that seasonal changes in sunshine account for variations in the number of suicides and especially violent suicides. We propose that sunshine, via interactions with serotonin neurotransmission, may trigger increased impulsivity and promote suicidal acts. However, because of the hypothesis-generating design of this study, more research is needed to further clarify the role of sunshine in triggering neurobiologic changes, which might contribute to suicidal behavior.

Age of first suicide attempt in men and women: an admixture analysis

OBJECTIVES

To define different subgroups of suicide attempters according to age at onset of suicide attempts.

METHODS

Participants were 229 suicide attempters (147 females; 82 males) admitted to a general hospital in Madrid, Spain. We used admixture analysis to determine the best-fitting model for the age at onset of suicide attempts separated by sex.

RESULTS

The best fitted model for the age at onset of suicide attempts was a mixture of two gaussian distributions. Females showed an earlier age at onset of suicide attempts in both Gaussian distributions (mean ± S.D.) (26.98 ± 5.69 and 47.98 ± 14.13) than males (32.77 ± 8.11 and 61.31 ± 14.61). Early-onset female attempters were more likely to show borderline personality disorder than late-onset female attempters (OR = 11.11; 95% CI = 2.43-50.0).

CONCLUSIONS

Age at onset of suicide attempts characterizes different subpopulations of suicide attempters.

Dopamine, serotonin and impulsivity

Impulsive people have a strong urge to act without thinking. It is sometimes regarded as a positive trait but rash impulsiveness is also widely present in clinical disorders such as attention deficit hyperactivity disorder (ADHD), drug dependence, mania, and antisocial behaviour. Contemporary research has begun to make major inroads into unravelling the brain mechanisms underlying impulsive behaviour with a prominent focus on the limbic cortico-striatal systems. With this progress has come the understanding that impulsivity is a multi-faceted behavioural trait involving neurally and psychologically diverse elements. We discuss the significance of this heterogeneity for clinical disorders expressing impulsive behaviour and the pivotal contribution made by the brain dopamine and serotonin systems in the aetiology and treatment of behavioural syndromes expressing impulsive symptoms.

Substance abuse and suicide risk among adolescents

The aim of this paper was to review the literature concerning the relationship between suicide and substance abuse behaviours among adolescents, focusing on epidemiology, comorbidity and preventive programmes. We performed a Pubmed/Medline, Scopus, PsycLit and PsycInfo search to identify all papers and book chapters during the period between 1980 and 2011. Adolescents with substance abuse disorder who attempt or complete suicide can be characterized as having mood disorders, stressful life events, interpersonal problems, poor social support, lonely lives and feelings of hopelessness. The research supports the existence of a strong relationship between suicide and substance abuse. Preventive programmes should be based on the detection of risk factors associated with both suicide and substance abuse disorder. Management programmes should combine different therapeutic strategies such as peer-to-peer education, school-based programmes, psychotherapy and pharmacological treatment. Evidence suggests that targeted suicide prevention programmes can be delivered which reduce the burden associated with substance abuse and suicide in youths.

Developmental perspectives on vulnerability to nonsuicidal self-injury in youth

Nonsuicidal self-injury (NSSI) is defined as intentionally causing bodily harm to oneself without the intent to kill oneself. Recently, there has been an increase in research aimed at understanding why individuals, especially youth and young adults, engage in NSSI. This chapter explores the emergence and maintenance of NSSI from a developmental perspective. Epidemiological research suggests that rates of NSSI increase dramatically from early adolescence to young adulthood. No study has investigated NSSI in youth younger than age 10. Current understanding of how emotion and cognitions as well as interpersonal processes play a role in the emergence and maintenance of NSSI is explored. Further, the role of biology (e.g., neurological underpinnings, genetic associations, HPA-axis functioning) on NSSI is explored. Throughout the chapter, particular limitations (e.g., sample selection, measurement issues) in the extant corpus of knowledge are highlighted. Finally, we consider future research directions that may inform developmentally sensitive understanding of the proximal and distal risk factors that may affect the emergence and maintenance of NSSI across the life span.