[Thirty years of research in suicidology in France: A bibliometric study]. / Trente ans de recherche en suicidologie en France : une étude bibliométrique.

OBJECTIVES: To study the quantitative evolution of research in suicidology in France for 30 years. METHODS: Analysis of the Web of Science database; identification of publications between 1989 and 2018 with at least one author with an affiliation in France and focusing on suicidal behavior and self-inflicted acts. RESULTS: In total, 1188 publications were identified. Over 30 years, the number of publications has been multiplied by 8.8 (particularly since 2005), a growth higher than those published in psychiatry and science in France, and in suicidology worldwide. France has contributed 3.3% of global publications since 2014 (ranks 8th in the world, recently outnumbered by South Korea and China) and 10.6% of European publications (ranks 3rd after the United Kingdom and Germany). The number of international co-publications has risen sharply over the last 30 years (44.9% between 2014 and 2018), notably with the USA, Canada and Spain. Use of English has increased from 37 to 78% of publications. Inserm, and the Universities and Academic hospitals of Paris and Montpellier are among the first institutions in terms of number of publications. Twenty-one of the 30 most published authors are men. The mention of the origin of the financing of the publications is increasing but remains limited. CONCLUSION: Suicidology has been a dynamic field of research in France for the last fifteen years, with a growing international visibility, but there is also room for improvement. An effort remains to be made to improve women's place in these publications.

Altered brain processing of decision-making in healthy first-degree biological relatives of suicide completers.

Suicidal behavior is heritable, with the transmission of risk being related to the transmission of vulnerability traits. Previous studies suggest that risky decision-making may be an endophenotype of suicide. Here, we aimed at investigating brain processing of decision-making in relatives of suicide completers in order to shed light on heritable mechanisms of suicidal vulnerability. Seventeen healthy first-degree biological relatives of suicide completers with no personal history of suicidal behavior, 16 relatives of depressed patients without any personal or family history of suicidal behavior, and 19 healthy controls were recruited. Functional 3 T magnetic resonance imaging scans were acquired while participants underwent the Iowa Gambling Task, an economic decision-making test. Whole-brain analyses contrasting activations during risky vs safe choices were conducted with AFNI and FSL. Individuals with a family history of suicide in comparison to control groups showed altered contrasts in left medial orbitofrontal cortex, and right dorsomedial prefrontal cortex. This pattern was different from the neural basis of familial depression. Moreover, controls in comparison to relatives showed increased contrast in several regions including the post-central gyrus, posterior cingulate and parietal cortices, and cerebellum (culmen) in familial suicide; and inferior parietal, temporal, occipital, anteromedial and dorsolateral prefrontal cortices, and cerebellum (vermis) in familial depression. These findings most likely represent a complex combination of vulnerability and protective mechanisms in relatives. They also support a significant role for deficient risk processing, and ventral and dorsal prefrontal cortex functioning in the suicidal diathesis.

Cognitive inhibition in depression and suicidal behavior: a neuroimaging study.

BACKGROUND: Cognitive inhibition deficits have previously been found in suicide attempters. This study examined the neural basis for these deficits in depressed patients with and without a history of suicidal behavior. METHOD: Functional magnetic resonance imaging was used to measure brain activation during the Go/No-Go response inhibition task in 25 unmedicated and depressed middle-aged suicide attempters, 22 unmedicated depressed patient controls with no personal or family history of suicidal behavior, and 27 healthy controls. Whole-brain analyses were conducted with SPM12. RESULTS: Suicide attempters exhibited an elevated number of commission errors relative to both control groups. However, suicide attempters did not differ from patient controls in terms of brain activation for any contrast. Analyses showed a significant association between depression and brain activation in the left inferior frontal gyrus and medial thalamus during Go v. No-Go, and in the bilateral parietal cortex and left orbitofrontal cortex during No-Go v. baseline. These regions were correlated with psychological pain, suicidal ideation and global functioning. There was no association between brain activation and personal histories of suicidal act. CONCLUSIONS: Our study suggests that deficits in cognitive inhibition, in relation to the inferior frontal gyrus, thalamus, orbitofrontal cortex and parietal cortex, are related to the depressive state and not specifically to suicide vulnerability. We hypothesize that state-related deficits may add to trait-like cognitive impairments to facilitate suicidal acts. These different types of cognitive impairments may necessitate different therapeutic strategies for the prevention of suicide.

Impaired decision-making in symptomatic anorexia and bulimia nervosa patients: a meta-analysis.

BACKGROUND: Impaired decision-making is a potential neurocognitive phenotype of eating disorders. It is therefore important to disentangle the decision-making deficits associated with the eating disorder subtypes and determine whether this putative impairment is a state or trait marker of the disease or more related to starvation. We systematically reviewed the literature on decision-making in eating disorders and conducted a meta-analysis to explore its role in anorexia nervosa (AN), bulimia nervosa (BN) and binge-eating disorder (BED). METHOD: A search of the Medline and EMBASE databases and article references was performed. A total of 23 studies (2044 participants) met the selection criteria. When the Iowa gambling task (IGT) was used in at least three of the studies, a meta-analysis was run. RESULTS: IGT performance was significantly worse in patients with an eating disorder diagnosis (AN, BN or BED) compared with healthy controls, indicating that eating disorders have a negative effect on decision-making. Hedges' g effect sizes were moderate to large (-0.72 in AN, -0.62 in BN, and -1.26 in BED). Recovered AN patients had IGT scores similar to those of healthy controls. Restrictive AN patients had significantly lower IGT net scores than purging AN patients, and both AN subtypes had worse performances than healthy controls. Age and body mass index did not explain results. CONCLUSIONS: Decision-making was significantly altered in patients with eating disorders. Poor decision-making was more pronounced during the acute phase than in the recovered state of AN. Nutritional status during the acute phase of the disease did not seem to influence decision-making skills.

A meta-analysis of neuropsychological markers of vulnerability to suicidal behavior in mood disorders.

BACKGROUND: Suicidal behavior results from a complex interplay between stressful events and vulnerability factors, including cognitive deficits. However, it is not clear which cognitive tests may best reveal this vulnerability. The objective was to identify neuropsychological tests of vulnerability to suicidal acts in patients with mood disorders. METHOD: A search was made of Medline, EMBASE and PsycINFO databases, and article references. A total of 25 studies (2323 participants) met the selection criteria. A total of seven neuropsychological tests [Iowa gambling task (IGT), Stroop test, trail making test part B, Wisconsin card sorting test, category and semantic verbal fluencies, and continuous performance test] were used in at least three studies to be analysed. RESULTS: IGT and category verbal fluency performances were lower in suicide attempters than in patient controls [respectively, g = -0.47, 95% confidence interval (CI) -0.65 to -0.29 and g = -0.32, 95% CI -0.60 to -0.04] and healthy controls, with no difference between the last two groups. Stroop performance was lower in suicide attempters than in patient controls (g = 0.37, 95% CI 0.10-0.63) and healthy controls, with patient controls scoring lower than healthy controls. The four other tests were altered in both patient groups versus healthy controls but did not differ between patient groups. CONCLUSIONS: Deficits in decision-making, category verbal fluency and the Stroop interference test were associated with histories of suicidal behavior in patients with mood disorders. Altered value-based and cognitive control processes may be important factors of suicidal vulnerability. These tests may also have the potential of guiding therapeutic interventions and becoming part of future systematic assessment of suicide risk.

A pocket of very high suicide rates in a non-violent, egalitarian and cooperative population of South-East Asia.

BACKGROUND: Extremely high rates of suicide localized within subgroups of populations where suicide is rare have been reported. We investigated this intriguing observation in a population of South-East Asia, where local culture should theoretically be preventative of suicide. METHOD: A team including an anthropologist and a psychiatrist surveyed all cases of suicide that had occurred over 10 years in four isolated regions. A psychological autopsy was carried out comparing each suicide case with two matched control cases. RESULTS: In a region of 1192 inhabitants, 16 suicides occurred, leading to an annual suicide rate of 134/1,000,00 which is 10 times the rate in the USA or Canada. By contrast, three ethnically similar distant communities showed low to null rates. The gender ratio was three males to one female and two-thirds of cases were aged below 35 years. Methods of suicide were poisoning and hanging and motives mainly included interpersonal discord. The pattern of developmental and clinical risk factors was somewhat different from Western countries, showing no childhood maltreatment, only one case of alcohol/substance abuse and impulsive-aggressive personality but elevated rates of social anxiety. Suicide cases had very high frequencies of second-degree biological relatives who committed suicide. CONCLUSIONS: Our study confirms a persistent phenomenon of high suicide rates restricted to a subgroup of a pre-industrialized population. We hypothesized this might be explained by isolation and endogamy, which may have promoted the selection/amplification of genetic vulnerability factors, or a contagion effect. These findings shed light on suicide from both a singular and a universal perspective, suggesting that particular local conditions may significantly modulate the rate of this complex behavior.

[Homicide, schizophrenia and substance abuse: a complex interaction]. / Homicide, schizophrénie et abus de substances : des liaisons dangereuses ?

BACKGROUND AND AIM: The prevalence of homicide perpetrators with a diagnosis of schizophrenia is 6% in Western countries populations. The relationship between schizophrenia and homicide is complex and cannot be reduced to a simple causal link. The aim of this systematic review was to clarify the role of substance abuse in the commission of murder in people suffering from schizophrenia. METHODS: A systematic English-French Medline and EMBASE literature search of cohort studies, case-control studies and transversal studies published between January 2001 and December 2011 was performed, combining the MeSH terms "schizophrenia", "psychotic disorders", "homicide", "violence", "substance use disorder", and the TIAB term "alcohol". Abstract selection was based on the STROBE and PRISMA checklist for observational studies and systematic and meta-analysis studies, respectively. RESULTS: Of the 471 selected studies, eight prospective studies and six systematic reviews and meta-analysis studies met the selection criteria and were included in the final analysis. Homicide committed by a schizophrenic person is associated with socio-demographic (young age, male gender, low socioeconomic status), historical (history of violence against others), contextual (a stressful event in the year prior to the homicide), and clinical risk factors (severe psychotic symptoms, long duration of untreated psychosis, poor adherence to medication). In comparison to the general population, the risk of homicide is increased 8-fold in schizophrenics with a substance abuse disorder (mainly alcohol abuse) and 2-fold in schizophrenics without any comorbidities. A co-diagnosis of substance abuse allows us to divide the violent schizophrenics into "early-starters" and "late-starters" according to the age of onset of their antisocial and violent behavior. The violence of the "early-starters" is unplanned, usually affects an acquaintance and is not necessarily associated with the schizophrenic symptoms. Substance abuse is frequent and plays an important role in the homicide commission. In addition, the risk of reoffending is high. In the "late-starters", the violence is linked to the psychotic symptoms and is directed to a member of the family. The reoffence risk is low and it depends on the pursuit of care or not. CONCLUSION: Defining subgroups of violent schizophrenic patients would avoid stigmatization and would help to prevent the risk of homicide by offering a multidisciplinary care which would take into account any substance abuse.

Self-harm hospitalization following bariatric surgery in adolescents and young adults.

BACKGROUND: While bariatric surgery has demonstrated physical and psychological benefits, a risk of suicide and non-fatal self-harm has also been shown. The aim of this study was to compared the rate of hospitalization for self-harm during a three-year observational follow-up period between adolescents/young adults who underwent bariatric surgery in France in 2013-2014 and two control groups. METHODS: All individuals aged 12-25 years old who underwent bariatric surgery in France between January 1st, 2013, and December 31st, 2014, were identified with a validated algorithm from the French national hospital database, and compared to a healthy sample of the general population matched for age and gender. Information relative to hospitalizations, including for self-harm (ICD-10 codes X60-84), were extracted i) between 2008 and the surgery, and ii) for a three-year follow-up period. A second unmatched control group with obesity but no bariatric surgery was also identified. Survival analyses with adjustments for confounding variables were used. RESULTS: In 2013-2014, 1984 youths had bariatric surgery in France. During follow-up, 1.5% were hospitalized for self-harm vs. 0.3% for controls (p < 0.0001). After adjustment, subsequent hospitalization for self-harm was associated with bariatric surgery (HR 3.64, 95% CI 1.70-7.81), prior psychiatric disorders (HR 7.76, 95% CI 3.76-16.01), and prior self-harm (HR 4.43, 95% CI 1.75-11.24). When compared to non-operated youths with obesity, bariatric surgery was not associated with self-harm while prior mental disorders and self-harm were. Mortality reached 0.3% after surgery. CONCLUSIONS: Bariatric surgery is associated with an increased risk of self-harm, mainly in relation to preexisting psychological conditions. Vigilance and appropriate care are thus warranted in vulnerable individuals.

Prolonged impact of the COVID-19 pandemic on self-harm hospitalizations in France: A nationwide retrospective observational study.

BACKGROUND: The first wave of the COVID-19 pandemic in France was associated with a reduced number of hospitalizations for self-harm, with the exception of older people. The on-going pandemic may have both sustained and delayed effects. METHODS: Data were extracted from the French national hospital database (PMSI), a nationwide exhaustive database. The number of self-harm hospitalizations (ICD-10 codes X60-84) between September 1, 2020 and August 31, 2021 (N = 85,679) was compared to 2019 (N = 88,782) using Poisson regression models. RESULTS: There was a decrease in the total number of self-harm hospitalizations during the studied period versus 2019 (-3.5%; Relative Risk [RR] [95% Confidence Intervals] = 0.97 [0.96-0.97]; p < 0.0001). However, sex and age effects were identified. While adults aged 30-59-years-old showed a decrease (monthly decreases: -12.6 to -15.0%), we found an increase in adolescent girls (+27.7%, RR = 1.28 [1.25-1.31]; p < 0.0001), notably since January 2021. Moreover, the numbers were similar to 2019 in adolescent boys, in youths aged 20-29 years, and in people aged 70 and more. Hospitalizations in intensive care units decreased (-6.7%, RR = 0.93 [0.91-0.96]; p < 0.0001) and deaths at hospital following self-harm remained stable (+0.6%, Hazard Ratio = 0.99 [0.91-1.08], p = 0.79). CONCLUSIONS: During this second stage, the number of self-harm hospitalizations remained at a lower level than in the prepandemic period. However, significant variations over time, age, and sex were observed. Young people (notably adolescent girls) appear to have particularly suffered from the persistence of the pandemic, while older people did not show any decrease since the beginning. Vigilance and continuing prevention are warranted.

The need to consider mood disorders, and especially chronic mania, in cases of Diogenes syndrome (squalor syndrome).

We report the case of a 69 year-old female patient who was hospitalized for Diogenes syndrome, defined by marked self-neglect, social withdrawal and excessive hoarding, leading to squalor. Somatic causes were eliminated. Her personal history showed an eight-year depressive episode followed by a 20-year hypomanic episode without remission, followed by a persistent manic episode associated with Diogenes syndrome for four years. The Diogenes syndrome was successfully treated with mood stabilizers. Mood disorders - in particular chronic mania (i.e. a manic episode lasting more than two years) - should be considered in cases of Diogenes syndrome and in current classifications.

Childhood trauma as a correlative factor of suicidal behavior - via aggression traits. Similar results in an Italian and in a French sample.

BACKGROUND AND OBJECTIVE: Childhood trauma and aggressive traits are considered risk factors for suicidal behavior. The hypothesis we aimed to test in this study was the existence of an association between childhood trauma and aggression in two distinct samples of Italian and French suicide attempters. METHOD: Study participants comprise 587 subjects with different psychiatric diagnoses according to DSM-IV-TR criteria. Three different samples were analyzed and compared: a group of French suicide attempters (N=396; mean age 40.47 SD=13.52; M/F: 110/286); a group of Italian suicide attempters (N=103; mean age 38.60 SD=12.04; M/F 27/76) and an Italian psychiatric comparison group (N=88; mean age: 41.49 SD=12.05; M/F; 37/51). Patients were interviewed with the Brown-Goodwin Assessment for Lifetime History of Aggression (BGLHA) and the Childhood Trauma Questionnaire (CTQ) 34-items for Italian data and 28-items for French data. RESULTS: When compared with the comparison group, Italian suicide attempters had significantly higher scores on the BGLHA scale and reported higher scores on the CTQ scores for physical abuse, sexual abuse and emotional abuse. Significant correlations between childhood trauma and aggression were found in both groups, Italian and French, of suicide attempters. CONCLUSION: The hypothesis tested was supported as psychiatric patients who had attempted suicide reported significantly more childhood trauma and aggression. Significant correlations were found between aggressive behavior, and childhood trauma in suicidal patients. This finding was replicated in two independently recruited samples in two countries with different prevalence of suicidal behavior.

[Severe depression : functional neuroanatomy]. / Dépressions sévères : neuro-anatomie fonctionnelle.

Depression is a severe disorder to which some individuals are more vulnerable than others. The study of the neurocognitive basis of the vulnerability to depression is, therefore, of major importance. Several neuroimaging studies have shown the persistence of brain dysfunctions in remitted patients. At the neuroanatomic level, alterations of the amygdala, ventral, medial and dorsolateral prefrontal cortices, cingulate gyrus, hippocampus and basal nuclei, and their connections, have been reported. These impairments have been linked to altered cognitive and emotional processes including a higher sensitivity to specific environmental stimuli, impairment in emotional regulation and diminished working memory or inhibition. Moreover, other studies suggest that these dysfunctions should be distinguished from those related to the vulnerability to suicidal behavior, which should be considered as a specific pathological entity. Finally, preliminary studies have underlined the genetic modulation and the influence of early traumatic events on brain activations, which underscore the developmental features of these alterations. These findings open the door to new treatments.

[Clinical features of suicide occurring in schizophrenia (I). Risk-factors identification]. / Approche clinique du suicide au cours de la schizophrénie (I). Identification des facteurs de risque.

INTRODUCTION: Suicide is the leading cause of premature death in schizophrenia. Approximately 10 to 13% of deaths in schizophrenia are explained by suicide, despite widespread availability of generally effective antipsychotic treatments and suicide attempts have been reported among 20 to 50% of patients. This relatively low ratio of attempts/suicide is consistent with greater lethality of means - more violent - and intents - less ambivalence - in this population. LITERATURE FINDINGS: Many studies have focused on risk factors and clinical characteristics for completed and/or attempted suicide. Commonly, sociodemographic risk factors for suicide are male sex, younger age and, among women, being unmarried, divorced or widowed. Previous suicidal behaviour is a strong risk factor for suicide and contrary to the common view, schizophrenic patients often communicate their suicidal intents shortly before death. Moreover, family history of suicide is associated with a heightened risk of suicide and is independent of the diagnosis, according to the growing literature that shows that vulnerability to suicidal behaviour is independent of psychiatric diagnosis. Suicide can occur throughout the entire course of schizophrenia. This is particularly true in those high-risk periods: early phase of the disease, active illness phase, period of relapse or during a depressive episode. The role of insight and positive symptoms remains unclear and probably needs further studies. Although not specifically for people with schizophrenia, hopelessness is a major risk factor and tragic loss is often presented as a trigger for suicide. It has been suggested that treatment side-effects, such as akathisia are associated with suicidal behaviour. CONCLUSION: A better knowledge of risk and protective factors is necessary to prevent suicide and suicidality.

Recurrence and mortality 1 year after hospital admission for non-fatal self-harm: a nationwide population-based study.

AIMS: A large number of people present each day at hospitals for non-fatal deliberate self-harm (DSH). Examination of the short-term risk of non-fatal recurrence and mortality at the national level is of major importance for both individual medical decision-making and global organisation of care. METHODS: Following the almost exhaustive linkage (96%) of two national registries in France covering 45 million inhabitants (i.e. 70% of the whole population), information about hospitalisation for DSH in 2008-2009 and vital status at 1 year was obtained. Individuals who died during the index hospital stay were excluded from analyses. RESULTS: Over 2 years, 136,451 individuals were hospitalised in medicine or surgery for DSH. The sample comprised 62.8% women, median age 38 in both genders, with two peaks at 16 and 44 years in women, and one peak at 37 years in men. The method used for DSH was drug overdose in 82.1% of cases. Admission to an intensive care unit occurred in 12.9%. Following index hospitalisation, 71.3% returned home and 23.7% were transferred to a psychiatric inpatient care unit. DSH recurrence during the following year occurred in 12.4% of the sample, within the first 6 months in 75.2%, and only once in 74.6%. At 1 year, 2.6% of the sample had died. The overall standardised mortality ratio was 7.5 but reached more than 20 in young adults. The causes were natural causes (35.7%), suicide (34.4%), unspecified cause (17.5%) and accident (12.4%). Most (62.9%) deaths by suicide occurred within the first 6 months following index DSH. Violent means (i.e. not drug overdose) were used in 70% of suicide cases. Concordance between means used for index DSH and for suicide was low (30% overall), except for drug overdose. Main suicide risk factors were older age, being male, use of a violent means at index DSH, index admission to an intensive care unit, a transfer to another medical department or to a psychiatric inpatient unit, and recurrence of DSH. However, these factors had low positive predictive values individually (below 2%). CONCLUSIONS: Non-fatal DSH represent frequent events with a significant risk of short-term recurrence and death from various causes. The first 6 months following hospital discharge appear to be a critical period. Specific short-term aftercare programs targeting all people with a DSH episode have to be developed, along other suicide prevention strategies.

Association between hypovitaminosis D and cognitive inhibition impairment during major depression episode.

BACKGROUND: Major depressive episode (MDE) has been associated with cognitive functioning alteration and hypovitaminosis D (hypoVD), but the relationship between hypoVD, depression, and cognition is not well understood. We aimed to compare patient with MDE with or without hypoVD in regard of cognitive functioning. METHODS: 91 patients (38.5 years old, 65.9% female) with MDE were included in a cross-sectional study and were evaluated with a complete cognitive battery. None of the participants were medicated at the time of the inclusion. Serum 25-hydroxyvitamin D was measured using LC-MS/MS method, and hypovitaminosis was defined as 25OHD < 50nmol/L. Covariates were gender, season of dosage, first MDE onset, age, body mass index and depression severity RESULTS: Patients with hypoVD demonstrated a higher stroop intereference index time underscoring that means low cognitive inhibition ability. Mutiple logistic regression confirmed that hypoVD was significantly associated with high stroop interference time index after controlling by gender, season of dosage, first MDE onset, age, body mass index and depression severity. CONCLUSION: Our results suggest that patient with MDE having hypoVD may be more prone to cognitive impairment.

Psychiatric diagnoses and personality traits associated with disadvantageous decision-making.

OBJECTIVE: Decision-making impairment is an important feature of psychiatric disorders. In a large comorbid psychiatric population, we explored the link between decision-making deficit and clinical variables. METHOD: We used the Iowa Gambling Task to measure decision-making in 317 patients. Psychiatric diagnoses were made according to the DSM-IV criteria. Self-questionnaires were used to assess several personality traits. The last and most severe suicidal acts were characterized. RESULTS: (1) After controlling for age and medication intake, a past history of suicide attempt (OR=2.0 [1.1-3.8]) and normothymic bipolar disorders (OR=3.4 [1.1-10.5]) were significantly and independently associated with impaired decision-making. (2) Decision-making performance was significantly correlated with affective lability. (3) No association was found between decision-making skills and suicidal characteristics. DISCUSSION: A lack of statistical power may have masked associations with obsessive-compulsive disorder and anorexia nervosa. We did not control for other cognitive functions except attention. CONCLUSION: This study supports the independent association of decision-making impairment with vulnerability to suicidal behaviour but not with substance abuse. Normothymic bipolar disorders, but not unipolar disorders, were also linked to low performance. At the dimensional level, impulsivity and decision-making abilities may be distinct processes. Affective regulation skills appear to be a major influence on decision-making performance and following a relevant therapeutic target.

Neurobiology of Elderly Suicide.

Suicide in the elderly is an underestimated and complex issue that has mainly been explored in sociological, clinical and psychological perspectives. Suicide in non-elderly adults has been associated with diverse neurobiological alterations that may shed light on future predictive markers and more efficient preventative interventions. The aim of this paper was to review studies specifically investigating the neurobiology of elderly suicidal behaviour. We performed a systematic English and French Medline and EMBASE search until 2013. Contrary to literature about the non-elderly, we found a paucity of studies investigating the biomarkers of suicidal risk in elderly adults. Main findings were found in the neurocognitive domain. Studies generally supported the existence of cognitive deficits, notably decision-making impairment and reduced cognitive inhibition, in patients with a history of suicidal act compared to patients without such history. However, replications are needed to confirm findings. Due to several limitations including the small number of available studies, frequent lack of replication and small sample size, no firm conclusions can be drawn. The authors encourage further investigations in this field as insight in the neurobiology of these complex behaviors may limit clichés about end of life and aging, as well as improve future prevention of suicide in the elderly.

Endogamy and suicide: An observation-based hypothesis.

Suicide is a complex and multifactorial behavior, which is likely the result of distinct pathways in different individuals or groups. Endogamy has been associated with numerous diseases, including behavioral disorders. Here, we discuss the hypothesis of endogamy as one mechanism facilitating high rates of suicide in some small and isolated groups of people across the world. To support our hypothesis, we describe four geographically and culturally distinct populations (the Aguarunas of Peru, the Vaqueiros of Spain, the Baruyas of New Guinea, and the Palawans of the Philippines), which present the following characteristics: (1) a high level of isolation and endogamy; (2) very high rates of suicide restricted to one group with (3) adjacent groups of similar origin and culture displaying low rates of suicide. Within these four distinct populations, endogamy could act in one isolated group as the amplifier of both selected genetic risk alleles and microcultural values (e.g. suicide as an acceptable solution), beyond cultural and genetic traits shared by the whole population (and therefore found in all groups). Genetic and microcultural risk factors are transmitted through close kinship and imitation/modeling, and could interact to increase the frequency of vulnerable individuals leading, in turn, to heightened rates of suicide. Culture could sometimes additionally act by generating stressful conditions for some individuals (e.g. lower social status and maltreatment). In contrast to endogamy, suicide motives (notably interpersonal conflicts) and mental disorders appear to be universal risk factors. More investigation of this endogamy hypothesis is necessary, which could represent a singular case of gene-culture co-transmission and shed light on particular conditions of suicide genesis.

First-degree relatives of suicide completers may have impaired decision-making but functional cognitive control.

BACKGROUND: The heritability of suicide is well established. Transmission of risk appears to follow traits more than disorders like depression. In the present project, we aimed at investigating the potential for transmission of cognitive deficits previously observed in suicide attempters, specifically impaired decision-making and cognitive control. METHODS: Seventeen healthy first-degree relatives of suicide completers with no personal history of suicidal act were compared to 18 first-degree relatives of individuals with major depressive disorder but no family history of suicidal act, and 19 healthy controls. Decision-making was assessed with the Iowa Gambling Task, and cognitive control with the Stroop Task, the Hayling Sentence Completion Test, and the Trail-Making Test. RESULTS: Both suicide and depressed relatives showed lower gambling task net scores than healthy controls. However, there were trends toward lower learning abilities in suicide than depressed relatives (interaction: p = 0.07), with more risky choices at the end of the test. Suicide relatives also showed a higher number of self-corrected errors relative to the total number of errors in the Stroop colour test compared to both control groups, with no difference in interference scores. There was no group-difference for any other cognitive tests. CONCLUSION: Our findings suggest that decision-making impairment may be found in healthy relatives of suicides and represent a cognitive endophenotype of suicidal behaviour. Normal cognitive control (or self-corrected deficits) may protect relatives against suicidal acts. Impairments in value-based and control processes may, therefore, be part of the suicide vulnerability and represent potential targets of preventative interventions.