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

Alterations of insular dynamic functional connectivity and psychological characteristics in unmedicated bipolar depression patients with a recent suicide attempt

BACKGROUND

Mounting evidence showed that insula contributed to the neurobiological mechanism of suicidal behaviors in bipolar disorder (BD). However, no studies have analyzed the dynamic functional connectivity (dFC) of insular Mubregions and its association with personality traits in BD with suicidal behaviors. Therefore, we investigated the alterations of dFC variability in insular subregions and personality characteristics in BD patients with a recent suicide attempt (SA).

METHODS

Thirty unmedicated BD patients with SA, 38 patients without SA (NSA) and 35 demographically matched healthy controls (HCs) were included. The sliding-window analysis was used to evaluate whole-brain dFC for each insular subregion seed. We assessed between-group differences of psychological characteristics on the Minnesota Multiphasic Personality Inventory-2. Finally, a multivariate regression model was adopted to predict the severity of suicidality.

RESULTS

Compared to NSA and HCs, the SA group exhibited decreased dFC variability values between the left dorsal anterior insula and the left anterior cerebellum. These dFC variability values could also be utilized to predict the severity of suicidality (r = 0.456, p = 0.031), while static functional connectivity values were not appropriate for this prediction. Besides, the SA group scored significantly higher on the schizophrenia clinical scales (p < 0.001) compared with the NSA group.

CONCLUSIONS

Our findings indicated that the dysfunction of insula-cerebellum connectivity may underlie the neural basis of SA in BD patients, and highlighted the dFC variability values could be considered a neuromarker for predictive models of the severity of suicidality. Moreover, the psychiatric features may increase the vulnerability of suicidal behavior.

Temperament traits mediate the relationship between CACNA1C polymorphisms and bipolar disorder in cisgender women

The influence of temperament traits on bipolar disorder (BD) has been investigated. Both temperament traits and BD are partially genetically determined and seem to be influenced by variations in the CACNA1C gene. These variations presented a significant interactive effect with biological sex, although studies that evaluate this relationship are scarce. Here, we assessed the mediation effect of temperament traits on the relationship between two polymorphisms in the CACNA1C gene (rs1006737 and rs4765913) and BD according to sex. This is a cross-sectional study consisting of 878 Caucasian individuals (508 women and 370 men), aged 18-35, enrolled in a population-based study in the city of Pelotas, Southern Brazil. BD diagnosis was evaluated using the clinical interview MINI 5.0, and temperament traits were assessed via the application of the Affective and Emotional Composite Temperament Scale (AFECTS). Mediation models were tested using the modeling tool PROCESS (version 3.3) for SPSS. Bootstrapping-enhanced mediation analyses in women indicated that traits anger (39%) and caution (27%) mediated the association between the rs4765913 SNP and BD, while traits volition (29%), anger (35%), and caution (29%) mediated the association between the AA haplotype (rs1006737-rs4765913) and the BD. No effect was encountered for cisgender men. Our model revealed that paths from CACNA1C SNPs to BD are mediated by specific temperament traits in women, reinforcing the definition of temperament traits as endophenotypes.

Personality subtypes in adults with social anxiety disorder - novelty seeking makes the difference

BACKGROUND

Up to now several subtypes of social anxiety disorder (SAD) have been proposed.

METHODS

In the present study, we used a cluster analytic approach to identify qualitatively different subgroups of SAD based on temperament characteristics, that is, harm avoidance (HA) and novelty seeking (NS) dimensions of Cloninger's Temperament and Character Inventory.

RESULTS

Based on a large, diverse clinical sample (n = 575), we found evidence for two distinct subgroups of SAD: a larger (59%) prototypic, inhibited cluster characterized by high HA and low NS, and a smaller atypic, and comparatively more impulsive cluster characterized by medium to high HA and increased NS. The subgroups differed regarding a variety of sociodemographic and clinical variables. While the prototypic SAD subtype suffered from more severe SAD and depressive symptoms, suicidal ideation, and reduced social functioning, the atypic NS subtype showcased higher reproductive behaviour, self-directedness and -transcendence, comparatively. Additional hierarchical logistic regression highlights the contribution of age and education.

CONCLUSIONS

Our results valuably extend previous evidence for the existence of at least two distinct subtypes of SAD. A better knowledge of the characteristic differences in prototypic behaviour, personality, coping strategies and comorbidities between the identified (and further) subtypes can contribute to the development of effective prevention interventions and promotes the conceptualization of tailored treatments.

Study of Risk Factors Associated with Suicide Attempt in Patients with Bipolar Disorder Type I

Background  Suicide is the leading contributor to mortality in bipolar disorder (BD). A history of suicidal attempt is a robust predictive marker for future suicide attempts. Personality profiles and coping strategies are the areas of contemporary research in bipolar suicides apart from clinical and demographic risk factors. However, similar research in developing countries is rarer.

Objectives  The present study aimed to identify the risk factors associated with suicidal attempts in BD type I (BD-I).

Materials and Methods  Patients with BD-I currently in clinical remission ( N = 102) were recruited. Sociodemographic details and the clinical data were collected using a semistructured pro forma. The psychiatric diagnoses were confirmed using the Mini-International Neuropsychiatric Interview 5.0. The National Institute of Mental Health–Life Chart Methodology Clinician Retrospective Chart was used to chart the illness course. Presumptive Stressful Life Events Scale, Coping Strategies Inventory Short Form, Buss–Perry aggression questionnaire, Past Feelings and Acts of Violence, and Barratt Impulsivity scale were used to assess the patient’s stress scores, coping skills, aggression, violence, and impulsivity, respectively.

Statistical Analysis  Descriptive statistics were used for demographic details and characteristics of the illness course. Binary logistic regression analyses were performed to identify the predictors for lifetime suicide attempt in BD-I.

Results  A total of 102 patients (males = 49 and females = 53) with BD-I were included. Thirty-seven subjects (36.3%) had a history of suicide attempt. The illness course in suicide attempters more frequently had an index episode of depression, was encumbered with frequent mood episodes, especially in depression, and had a higher propensity for psychiatric comorbidities. On binary logistic regression analysis, the odds ratios (ORs) for predicting a suicide attempt were highest for positive family history of suicide (OR: 13.65, 95% confidence interval [CI]: 1.28–145.38, p = 0.030), followed by the presence of an index depressive episode (OR: 6.88, 95% CI: 1.70–27.91, p = 0.007), and lower scores on problem-focused disengagement (OR: 0.72, 95% CI: 0.56–0.92, p = 0.009).

Conclusion  BD-I patients with lifetime suicide attempt differ from non-attempters on various course-related and temperamental factors. However, an index episode depression, family history of suicide, and lower problem-focused engagement can predict lifetime suicide attempt in patients with BD-I.

Eradicating Suicide at Its Roots: Preclinical Bases and Clinical Evidence of the Efficacy of Ketamine in the Treatment of Suicidal Behaviors

Despite the continuous advancement in neurosciences as well as in the knowledge of human behaviors pathophysiology, currently suicide represents a puzzling challenge. The World Health Organization (WHO) has established that one million people die by suicide every year, with the impressive daily rate of a suicide every 40 s. The weightiest concern about suicidal behavior is how difficult it is for healthcare professionals to predict. However, recent evidence in genomic studies has pointed out the essential role that genetics could play in influencing person's suicide risk. Combining genomic and clinical risk assessment approaches, some studies have identified a number of biomarkers for suicidal ideation, which are involved in neural connectivity, neural activity, mood, as well as in immune and inflammatory response, such as the mammalian target of rapamycin (mTOR) signaling. This interesting discovery provides the neurobiological bases for the use of drugs that impact these specific signaling pathways in the treatment of suicidality, such as ketamine. Ketamine, an N-methyl-d-aspartate glutamate (NMDA) antagonist agent, has recently hit the headlines because of its rapid antidepressant and concurrent anti-suicidal action. Here we review the preclinical and clinical evidence that lay the foundations of the efficacy of ketamine in the treatment of suicidal ideation in mood disorders, thereby also approaching the essential question of the understanding of neurobiological processes of suicide and the potential therapeutics.

Personality traits and suicide attempts with and without psychiatric disorders: analysis of impulsivity and neuroticism

BACKGROUND

There is a critical need for empirical data concerning the association of personality traits and attempted suicide with and without psychiatric disorders in mainland China. The objective of the present study is to provide such data by determining the prevalence of psychiatric disorders and analyzing the levels of impulsivity and neuroticism among people who have attempted suicide, and to examine the association between these personality traits and suicide attempt in people with or without psychiatric disorders.

METHODS

We administered self-reported tests and clinical interviews to 196 people who have attempted suicide who were admitted to a hospital emergency room or our psychiatric settings after a suicide attempt.

RESULTS

One hundred and fifty-six subjects (79.6%) met the criteria for Axis I disorders and eleven (6.6%) met the criteria Axis II personality disorders. Those who have attempted suicide who did not have psychiatric disorders exhibited a greater degree of background characteristics (e.g., high lethality, more interpersonal conflicts and more alcohol use), lower levels of suicidality (suicide risk, depressive symptoms) and differences of personality traits (e.g., more impulsive and less neuroticism) as compared to those who do have psychiatric disorders. Profile differences existed even after control for the stressful life event.

CONCLUSION

Our findings suggest that some personality traits differ between people who have attempted suicide depending on whether or not they have psychiatric disorders. Based on these findings, investigating the impact of personality traits on suicidal behavior in therapeutic settings would provide critical data to improve patient treatment and outcomes.