Sex differences in suicidal behaviors and aggression in US Veterans

Female Veterans are the fastest growing demographic group in the Department of Veterans Affairs. Moreover, suicide rates in female Veterans are increasing, making suicide in female Veterans a topic of vital clinical and research significance. The current study examined the association between suicide, aggression, and mood symptoms by sex. Participants consisted of 264 Veterans (female=54, male=210) ages 18-55. Veterans completed well-validated measures of suicidal behaviors, aggression, anxiety, and depression. Male Veterans reported higher physical aggression, verbal aggression, anger, hostility, and total aggression compared to female Veterans. In male Veterans, lifetime suicidal behavior including ideation and attempts was correlated with total aggression and subscales of physical aggression, verbal aggression, anger, and hostility. However, in female Veterans lifetime suicidal behavior was significantly associated with hostility and anger. There were no between-group differences in measures of suicidal behaviors, anxious or depressive symptoms. These results suggest important differences in the association between aggression and suicidal behavior by sex. These data have significant clinical implications, as males with aggressive traits and females who endorse hostility and anger may be more likely to engage in suicidal behaviors.

Neurobiological evidence of sexual dimorphism in limbic circuitry of US Veterans

BACKGROUND

Female Veterans are an increasing patient population in the Department of Veterans Affairs and may have distinct clinical and neurobiological features compared to males.

METHODS

Nineteen female and 19 male Veterans who met diagnostic criteria for depression/posttraumatic stress disorder (MDD/PTSD) completed diagnostic interviews, symptom measures, and resting-state neuroimaging. Participants completed clinical measures of mood and aggression in addition to magnetic resonance imaging on a 3.0 Tesla Siemens scanner.

RESULTS

Females showed increased functional connectivity between the left and right basolateral amygdala (BLA) and the left and right cerebellar and occipital lobes. Sex differences also were evident in the relationship between affective and clinical symptoms with BLA connectivity. Females showed a correlation between revenge planning and decreased connectivity between the left BLA and left occipital lobe and also a correlation between aggression and decreased connectivity between the right BLA and right mid cingulate, right and left medial frontal lobe, and right frontal lobe. Males evidenced a relationship between increased depressive symptoms and increased connectivity between the left BLA and right and left occipital lobe, left calcarine, and other areas associated with visual memory and processing, and interpretation of sensory information. Additionally, males reported higher levels of physical aggression and revenge planning compared to females.

LIMITATIONS

This study included neuroimaging and self-report clinical measures. Further studies will benefit from multimodal measures, including behavioral measures of aggression.

CONCLUSIONS

Results suggest that male Veterans report more aggression than females and symptoms of aggression and mood are differentially related to BLA connectivity by sex.

Interaction of Cannabis Use and Aging: From Molecule to Mind

Given the aging Baby Boomer generation, changes in cannabis legislation, and the growing acknowledgment of cannabis for its therapeutic potential, it is predicted that cannabis use in the older population will escalate. It is, therefore, important to determine the interaction between the effects of cannabis and aging. The aim of this report is to describe the link between cannabis use and the aging brain. Our review of the literature found few and inconsistent empirical studies that directly address the impact of cannabis use on the aging brain. However, research focused on long-term cannabis use points toward cumulative effects on multimodal systems in the brain that are similarly affected during aging. Specifically, the effects of cannabis and aging converge on overlapping networks in the endocannabinoid, opioid, and dopamine systems that may affect functional decline particularly in the hippocampus and prefrontal cortex, which are critical areas for memory and executive functioning. To conclude, despite the limited current knowledge on the potential interactive effects between cannabis and aging, evidence from the literature suggests that cannabis and aging effects are concurrently present across several neurotransmitter systems. There is a great need for future research to directly test the interactions between cannabis and aging.

The Effect of Citicoline Supplementation on Motor Speed and Attention in Adolescent Males

OBJECTIVE

This study assessed the effects of citicoline, a nutraceutical, on attention, psychomotor function, and impulsivity in healthy adolescent males.

METHOD

Seventy-five healthy adolescent males were randomly assigned to either the citicoline group ( n = 51 with 250 or 500 mg citicoline) or placebo ( n = 24). Participants completed the Ruff 2&7 Selective Attention Test, Finger Tap Test, and the Computerized Performance Test, Second Edition (CPT-II) at baseline and after 28 days of supplementation.

RESULTS

Individuals receiving citicoline exhibited improved attention ( p = 0.02) and increased psychomotor speed ( p = 0.03) compared with those receiving placebo. Higher weight-adjusted dose significantly predicted increased accuracy on an attention task ( p = 0.01), improved signal detectability on a computerized attention task ( p = 0.03), and decreased impulsivity ( p = 0.01).

DISCUSSION

Adolescent males receiving 28 days of Cognizin® citicoline showed improved attention and psychomotor speed and reduced impulsivity compared to adolescent males who received placebo.

Orbitofrontal connectivity is associated with depression and anxiety in marijuana-using adolescents

BACKGROUND

Prevalence of marijuana (MJ) use among adolescents has been on the rise. MJ use has been reported to impact several brain regions, including frontal regions such as the orbitofrontal cortex (OFC). The OFC is involved in emotion regulation and processing and has been associated with symptoms of depression and anxiety. Therefore, we hypothesized that adolescent MJ users would show disruptions in OFC connectivity compared with healthy adolescents (HC) which would be associated with symptoms of mood and anxiety.

METHODS

43 MJ-using and 31 HC adolescents completed clinical measures including the Hamilton Anxiety Scale (HAM-A) and Hamilton Depression Rating Scale (HAM-D). Resting-state functional magnetic resonance imaging data was also acquired for all participants.

RESULTS

In MJ users, increased depressive symptoms were associated with increased connectivity between the left OFC and left parietal regions. In contrast, lower ratings of anxiety were associated with increased connectivity between right and left OFC and right occipital and temporal regions. These findings indicate significant differences in OFC connectivity in MJ-using adolescents, which correlated with mood/anxiety.

LIMITATIONS

Future studies with an increased number of female participants is required to address potential sex differences in connectivity patterns related to symptoms of depression and anxiety.

CONCLUSIONS

This study highlights the association between OFC connectivity, MJ use, and symptoms of depression and anxiety in adolescents. These findings provide further insight into understanding the neural correlates that modulate the relationship between comorbid MJ use and mood disorders and could potentially help us better develop preventive and treatment measures.

Alterations in anterior cingulate cortex myoinositol and aggression in veterans with suicidal behavior: A proton magnetic resonance spectroscopy study

Studies investigating the neurochemical changes that correspond with suicidal behavior (SB) have not yielded conclusive results. Suicide correlates such as aggression have been used to explore risk factors for SB. Yet the neurobiological basis for the association between aggression and SB is unclear. Aggression and SB are both prevalent in veterans relative to civilian populations. The current study evaluated the relationship between brain chemistry in the anterior (ACC) and the posterior cingulate cortex (POC), as well as the relationship between aggression and SB in a veteran population using proton magnetic resonance spectroscopy (¹H-MRS). Single-voxel MRS data at 3 Tesla (T) were acquired from the ACC and POC voxels using a 2-dimensional J-resolved point spectroscopy sequence and quantified using the ProFit algorithm. Participants also completed a structured diagnostic interview and a clinical battery. Our results showed that the myoinositol (mI)/H2O ratio in the ACC and POC was significantly higher in veterans who reported SB when compared to veterans who did not. The two groups did not differ significantly with regard to other metabolites. Second, verbal aggression and SB measures positively correlated with mI/H2O in the ACC. Finally, verbal aggression mediated the relationship between mI/H2O in the ACC and SB.

Increased efficiency of brain connectivity networks in veterans with suicide attempts

Background

Suicide is a public health concern for United States veterans and civilians. Prior research has shown neurobiological factors in suicide. However, studies of neuroimaging correlates of suicide risk have been limited. This study applied complex weighted network analyses to characterize the neural connectivity in white matter in veterans with suicide behavior.

Methods

Twenty-eight veterans without suicide behavior (NS), 29 with a history of suicidal ideation only (SI), and 23 with prior suicide attempt (SA) completed diffusion tensor brain imaging, the Columbia Suicide Severity Rating Scale and Barratt Impulsiveness Scale (BIS). Structural connectivity networks among 82 parcellated brain regions were produced using whole-brain tractography. Global and nodal metrics of network topology have been calculated.

Results

SA had shorter characteristic path length and greater global efficiency and mean weighted degree of global network metrics (p < 0.024). SA had more hub nodes than NS and SI. The left posterior cingulate cortex (PCC) showed significantly greater weighted degree in SA relative to others (p < 0.0003). Nonplanning subscale of BIS correlated with the weighted degrees of the left PCC within SA. In rich club connectivity, SA had higher local connections than others (p = 0.001).

Conclusion

Veterans with prior suicide attempt had altered connectivity networks characteristics in the white matter. These findings may be distinctive neurobiological markers for individuals with suicide attempt. Strong connectivity in the left PCC may be implicated in impulsivity in veterans with suicide attempt.

Mast cell mediators prostaglandin-D2 and histamine activate human eosinophils

Airway damage secondary to eosinophil activation is thought to contribute to the development of asthma. Using the fluorescent dye FURA-2 to measure the concentration of cytosolic calcium, we found that supernatants from anti-IgE-stimulated human lung mast cells increased cytosolic calcium in human eosinophils. We then examined the major mast cell mediators (histamine, PGD2, platelet-activating factor (PAF), eosinophil chemotactic factor of anaphylaxis (ECF-A), leukotriene (LT)C4 and LTB4) for their ability to increase cytosolic calcium in eosinophils. We found that both PAF (5 x 10(-9) to 5 x 10(-6) M) and PGD2 (two of five donors responsive at 1 x 10(-9) M) were potent stimuli for calcium mobilization. LTB4 (10(-8), 10(-7) M) and histamine were also active, although higher concentrations of histamine were required to see a response (3 x 10(-7) to 10(-5) M). LTC4, val-ECF-A, and ala-ECF-A were inactive. The effects of PGD2 and histamine were specific for eosinophils, although LTB4 and PAF increased calcium in both neutrophils and eosinophils. The histamine-induced increase in intracellular calcium was not blocked by the H1 or H2 antagonists pyrilamine or cimetidine (10(-4) M), respectively; however, the response to 10(-6) M histamine was completely blocked by the specific H3 antagonist thioperamide (10(-6) M). To evaluate the relative contribution of these stimulatory mast cell mediators on the calcium mobilizing activity in supernatants from anti-IgE-stimulated human lung mast cell (HLMC), we examined the effect of supernatants from HLMC pretreated with indomethacin and/or the 5-lipoxygenase pathway inhibitor MK886. These supernatants were added to FURA-2-loaded eosinophils that had been preincubated with thioperamide and/or the PAF antagonist WEB-2086. We found that the increase in eosinophil calcium in response to supernatants from anti-IgE-stimulated-HLMC was totally inhibited only when the mast cells were challenged in the presence of indomethacin and MK886, and the eosinophils were preincubated with thioperamide. WEB-2086 had little effect. When we examined the effect of these mediators on eosinophil secretory function, we found that PGD2 (not histamine) primed eosinophils for enhanced release of LTC4 in response to the calcium ionophore A23187. We conclude that the activation of eosinophils by PGD2 and other mast cell products may contribute to airways inflammation that is characteristic of asthma.

Mast cell mediators prostaglandin-D2 and histamine activate human eosinophils

Airway damage secondary to eosinophil activation is thought to contribute to the development of asthma. Using the fluorescent dye FURA-2 to measure the concentration of cytosolic calcium, we found that supernatants from anti-IgE-stimulated human lung mast cells increased cytosolic calcium in human eosinophils. We then examined the major mast cell mediators (histamine, PGD2, platelet-activating factor (PAF), eosinophil chemotactic factor of anaphylaxis (ECF-A), leukotriene (LT)C4 and LTB4) for their ability to increase cytosolic calcium in eosinophils. We found that both PAF (5 x 10(-9) to 5 x 10(-6) M) and PGD2 (two of five donors responsive at 1 x 10(-9) M) were potent stimuli for calcium mobilization. LTB4 (10(-8), 10(-7) M) and histamine were also active, although higher concentrations of histamine were required to see a response (3 x 10(-7) to 10(-5) M). LTC4, val-ECF-A, and ala-ECF-A were inactive. The effects of PGD2 and histamine were specific for eosinophils, although LTB4 and PAF increased calcium in both neutrophils and eosinophils. The histamine-induced increase in intracellular calcium was not blocked by the H1 or H2 antagonists pyrilamine or cimetidine (10(-4) M), respectively; however, the response to 10(-6) M histamine was completely blocked by the specific H3 antagonist thioperamide (10(-6) M). To evaluate the relative contribution of these stimulatory mast cell mediators on the calcium mobilizing activity in supernatants from anti-IgE-stimulated human lung mast cell (HLMC), we examined the effect of supernatants from HLMC pretreated with indomethacin and/or the 5-lipoxygenase pathway inhibitor MK886. These supernatants were added to FURA-2-loaded eosinophils that had been preincubated with thioperamide and/or the PAF antagonist WEB-2086. We found that the increase in eosinophil calcium in response to supernatants from anti-IgE-stimulated-HLMC was totally inhibited only when the mast cells were challenged in the presence of indomethacin and MK886, and the eosinophils were preincubated with thioperamide. WEB-2086 had little effect. When we examined the effect of these mediators on eosinophil secretory function, we found that PGD2 (not histamine) primed eosinophils for enhanced release of LTC4 in response to the calcium ionophore A23187. We conclude that the activation of eosinophils by PGD2 and other mast cell products may contribute to airways inflammation that is characteristic of asthma.