PTSD, alcohol dependence, and conduct problems: Distinct pathways via lability and disinhibition

Adverse childhood experience and depression: the role of gut microbiota

Depression is the most common psychiatric disorder that burdens modern society heavily. Numerous studies have shown that adverse childhood experiences can increase susceptibility to depression, and depression with adverse childhood experiences has specific clinical-biological features. However, the specific neurobiological mechanisms are not yet precise. Recent studies suggest that the gut microbiota can influence brain function and behavior associated with depression through the "microbe-gut-brain axis" and that the composition and function of the gut microbiota are influenced by early stress. These studies offer a possibility that gut microbiota mediates the relationship between adverse childhood experiences and depression. However, few studies directly link adverse childhood experiences, gut microbiota, and depression. This article reviews recent studies on the relationship among adverse childhood experiences, gut microbiota, and depression, intending to provide insights for new research.

Molecular Toxicology and Pathophysiology of Comorbid Alcohol Use Disorder and Post-Traumatic Stress Disorder Associated with Traumatic Brain Injury

The increasing comorbidity of alcohol use disorder (AUD) and post-traumatic stress disorder (PTSD) associated with traumatic brain injury (TBI) is a serious medical, economic, and social issue. However, the molecular toxicology and pathophysiological mechanisms of comorbid AUD and PTSD are not well understood and the identification of the comorbidity state markers is significantly challenging. This review summarizes the main characteristics of comorbidity between AUD and PTSD (AUD/PTSD) and highlights the significance of a comprehensive understanding of the molecular toxicology and pathophysiological mechanisms of AUD/PTSD, particularly following TBI, with a focus on the role of metabolomics, inflammation, neuroendocrine, signal transduction pathways, and genetic regulation. Instead of a separate disease state, a comprehensive examination of comorbid AUD and PTSD is emphasized by considering additive and synergistic interactions between the two diseases. Finally, we propose several hypotheses of molecular mechanisms for AUD/PTSD and discuss potential future research directions that may provide new insights and translational application opportunities.

The BDNF Val68Met polymorphism causes a sex specific alcohol preference over social interaction and also acute tolerance to the anxiolytic effects of alcohol, a phenotype driven by malfunction of BDNF in the ventral hippocampus of male mice

BACKGROUND

The brain-derived neurotrophic factor (BDNF) Valine 66 to Methionine human polymorphism results in impaired activity-dependent BDNF release and has been linked to psychiatric disorders including depression and anxiety. We previously showed that male knock-in mice carrying the mouse Methionine homolog (Met68BDNF) exhibit excessive and compulsive alcohol drinking behaviors as compared to the wild-type Val68BDNF mice.

OBJECTIVE

Here, we set out to determine the potential mechanism for the heightened and compulsive alcohol drinking phenotypes detected in Met68BDNF mice.

RESULTS

We found that male, but not female Met68BDNF mice exhibit social anxiety-like behaviors. We further show that male Met68BDNF mice exhibit a preference for alcohol over social interaction. In contrast, alcohol place preference without an alternative social reward, is similar in male Met68BDNF and Val68BDNF mice. Since the Met68BDNF mice show social anxiety phenotypes, we tested whether alcohol reliefs anxiety similarly in Met68BDNF and Val68BDNF mice and found that male, but not female Met68BDNF mice are insensitive to the acute anxiolytic action of alcohol. Finally, we show that this acute tolerance to alcohol-dependent anxiolysis can be restored by overexpressing wild-type Val68BDNF in the ventral hippocampus (vHC) of Met68BDNF mice.

CONCLUSIONS

Together, our results suggest that excessive alcohol drinking in the Met68BDNF may be attributed, in part, to heighted social anxiety and a lack of alcohol-dependent anxiolysis, a phenotype that is associated with malfunction of BDNF signaling in the vHC of male Met68BDNF mice.

Validation of a shortened version of the Eating Attitude Test (EAT-7) in the Arabic language

BACKGROUND

Eating disorders are quite common around the world, disabling, and potentially lethal; but they remain so far under-captured and subject to substantial delays in treatment. We propose through this study to develop and validate a shortened version of the Eating Attitude Test (EAT) in the Arabic language among non-clinical Arabic-speaking Lebanese participants from the general population.

METHODS

1175 participants enrolled in this cross-sectional study, based on an online survey. The Eating Attitude Test-26 items, Drunkorexia Motives and Behaviors Scales and Lebanese Anxiety Scale were used to answer our objectives.

RESULTS

Our results confirmed validity and reliability of the questionnaire. Exploratory Factor Analyses showed that all items converged over a one-factor solution, with an excellent Cronbach's alpha (> 0.9). Confirmatory Factor Analyses found that the 7-item-version yielded excellent model fit. The instrument also revealed strong evidence of divergent validity, being highly correlated with measures of anxiety and drunkorexia motives and behaviors.

DISCUSSION

Findings provided evidence supporting that the Arabic seven-item one-factor structure of the scale (EAT-7) is valid, reliable, and can be used in clinical practice, preventive interventions and future eating disorders research in Arab settings.

Drunkorexia behaviors and motives, eating attitudes and mental health in Lebanese alcohol drinkers: a path analysis model

BACKGROUND

Drunkorexia refers to limited intake of high-calorie food to avert gaining weight and the need to increase in alcohol excessive consumption. The present study aimed to check for an association between depression, anxiety, and stress with drunkorexia behaviors/motives among Lebanese adults, while evaluating the mediating role of inappropriate eating attitude in those associations.

METHODS

Two hundred and fifty-eight participants enrolled in this cross-sectional study, who filled an online survey (September-December 2020).

RESULTS

Drunkorexia behaviors were considered as the dependent variable; the path coefficients from stress to anxiety, from anxiety to eating attitudes, from eating attitudes to drunkorexia behaviors and from anxiety to drunkorexia behaviors were all significant. The indirect relationships showed that eating attitudes mediated the association between anxiety and drunkorexia behaviors. When taking the drunkorexia motives as the dependent variable, the path coefficients from stress to anxiety, from anxiety to eating attitudes, from eating attitudes to drunkorexia motives, and from anxiety to drunkorexia motives were all significant. The indirect relationships showed that eating attitudes mediated the association between anxiety and drunkorexia motives.

CONCLUSION

This study highlighted that individuals with more psychological problems (depression, anxiety, and stress) and inappropriate eating habits exhibit more drunkorexic motivations and behaviors.

LEVEL OF EVIDENCE

Level V, Cross-sectional study.

Adverse childhood experiences, the serotonergic system, and depressive and anxiety disorders in adulthood: A systematic literature review

BACKGROUND

Recent studies have examined the role that the serotonergic system plays in moderating the association between adverse childhood experiences (ACEs) and depressive and anxiety disorders in adulthood. The aim of this literature review is to synthesize studies that examined serotonin's impact in relation to ACEs, and depressive and anxiety disorders in this population.

METHODS

Published studies from 2008 to 2018 were retrieved from PubMed, CINAHL, and PsychINFO databases, and were included if ACEs, the serotonergic system, and depressive and or anxiety disorders were assessed in those with a mean age between nineteen and forty.

RESULTS

Twenty-eight studies were included. Various genetic polymorphisms in the serotonergic signaling system moderated the association between ACEs and depression. Additionally, selective serotonin reuptake inhibitors with a high affinity for the serotonin transporter, resulted in poor treatment outcomes for those with history of ACEs.

CONCLUSION

Additional research is needed in order to further define the role that the serotonergic genes play in the association between ACEs and depressive and anxiety disorders in adulthood.

Posttraumatic Stress Disorder and Conduct Problems: The Role of Self-Control Demands

We tested within- and between-person effects of posttraumatic stress disorder (PTSD) symptoms on conduct problems and alcohol intoxication via self-control demands using multilevel structural equation modeling in a longitudinal burst-design study of 251 U.S. veterans who participated in the recent wars in Iraq and Afghanistan. We theorized that experiencing PTSD symptoms engenders efforts to regulate mood, control thoughts, and inhibit or control behavior that is taxing to the individual (i.e., it places demands on self-control) and hypothesized that this process results in subsequent deficits in regulatory control that manifest in heightened intoxication and conduct problems associated with PTSD. At the within-person level, daytime PTSD symptoms, IRR = 1.09, and self-control demands, IRR = 1.12, exhibited within-person associations with nighttime conduct problems over and above nighttime intoxication. Consistent with our hypothesis, daytime increases in self-control demands mediated the associations between daytime PTSD symptoms and subsequent nighttime conduct problems. The indirect effect between daytime PTSD symptoms and nighttime intoxication via self-control demands was nonsignificant. At the between-person level, self-control demands mediated the associations between PTSD symptoms and conduct problems; however, the expected between-person associations with intoxication were nonsignificant. Drinking behavior is related to but cannot fully account for various difficulties in psychosocial functioning associated with PTSD. The present results suggest that dysregulated behavior may, ironically, stem from individuals' concerted efforts to control and manage overwhelming symptoms. Self-control demands may be a common factor that accounts for a broad range of functional impairments associated with PTSD.

A Critical Review of Behavioral and Emotional Disinhibition

The theory of "disinhibition" has been very influential in psychiatry and neurology for over a century. Disinhibition has been used to explain clinical findings in many neurological and psychiatric disorders including dementia, traumatic brain injury, attention deficit hyperactive disorder, substance abuse, impulsivity in personality disorders, and neurodevelopmental disorders. In addition, disinhibition has been used as a unifying theory to link clinical observations with cognitive findings, and even cellular findings. This review discusses the origins and history of the theory of disinhibition and its strengths and weaknesses in four domains: face validity, consistency with other brain mechanisms, consistency with evolutionary mechanisms, and empiric support. I assert that the vagueness of the theory, inconsistency with other brain mechanisms, and lack of empiric support limit the usefulness of this theory. Alternative approaches, based on findings in other motor, language, and cognitive functions, are discussed.

Affective dynamics among veterans: Associations with distress tolerance and posttraumatic stress symptoms

We tested a dynamic structural equation model (DSEM; Asparouhov, Hamaker, & Muthén, 2018) of positive and negative affect in 254 veterans with approximately 1.5 years of experience sampling data. The analysis provided estimates of several aspects of veteran's emotional experience including "trait" positive and negative affect (i.e., mean levels), inertia (i.e., tendency for emotions to self-perpetuate), innovation variance (conceptualized as lability, reactivity, or exposure to stressors), and cross-lagged associations between positive and negative affect. Veterans with higher trait negative affect had more negative affect inertia and innovation variance. This suggests a pattern whereby the veteran has more negative reactions, and negative emotions, in turn, tend to maintain themselves, contributing to higher trait negative affect. In contrast, veterans with higher trait positive affect exhibited more positive affect innovation variance (e.g., positive reactivity). Although veterans showed some consistency in dynamics across emotions (e.g., positive and negative reactivity were positively correlated), trait positive and negative affect were not significantly associated. Veterans with higher posttraumatic stress symptoms (PTSS) at baseline exhibited higher reactivity to negative events, less positive affect, and more negative affect during the follow-up. Veterans with higher distress tolerance reported not only lower PTSS but also a more adaptive pattern of affective experience characterized by lower inertia and reactivity in negative affect and more positive lagged associations between negative affect and subsequent positive affect. The results demonstrated that distress tolerance and PTSS in veterans were associated with dynamics of positive and negative emotion over time, suggesting specific differences in affect regulation processes. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Animal models of liability to post-traumatic stress disorder: going beyond fear memory

In this review, we advocate a dimensional approach on the basis of candidate endophenotypes to the development of animal models of post-traumatic stress disorder (PTSD) capable of including genetic liability factors, variations in symptoms profile and underlying neurobiological mechanisms, and specific comorbidities. Results from the clinical literature pointed to two candidate endophenotypes of PTSD: low sensory gating and high waiting impulsivity. Findings of comparative studies in mice of two inbred strains characterized by different expressions of the two candidate endophenotypes showed different strain-specific neural and behavioral effects of stress experiences. Thus, mice of the standard C57BL/6J strain show stress-induced helplessness, stress-learned helplessness, and stress-extinction-resistant conditioned freezing. Instead, mice of the genetically unrelated DBA/2J strain, expressing both candidate endophenotypes, show stress-induced extinction-resistant avoidance and neural and behavioral phenotypes promoted by prolonged exposure to addictive drugs. These strain differences are in line with evidence of associations between genetic variants and specific stress-promoted pathological profiles in PTSD, support a role of genotype in determining different PTSD comorbidities, and offer the means to investigate specific pathogenic processes.

Nexus of despair: A network analysis of suicidal ideation among veterans

The objective of this study was to estimate a network model of risk and resilience factors of suicidal ideation among veterans. Two network models of suicidal ideation among Operation Iraqi Freedom/Operation Enduring Freedom/Operation New Dawn veterans (N = 276) incorporated key disorders, traumatic stress, and resilience constructs to contextualize suicidal ideation. Childhood trauma was positively connected with suicidal ideation and harassment and inversely connected with social support and distress tolerance. This exemplifies long-lasting associations between childhood trauma and re-victimization, emotion regulation, and ability to form supportive social relationships. A subsequent model including lower-order facets indicated that combat trauma was predominantly associated with posttraumatic stress disorder-intrusion symptoms. This study highlights the importance of addressing both risk and resilience to reduce suicide risk among veterans and increases understanding of factors that contribute to suicidal ideation.

Interaction effects may actually be nonlinear effects in disguise: A review of the problem and potential solutions

It is common in addictions research for statistical analyses to include interaction effects to test moderation hypotheses. Far less commonly do researchers consider the possibility that a given predictor may exert a nonlinear effect on the outcome. This lack of attention to the possible nonlinear effects of individual predictors is problematic because it may result in identification of entirely spurious interactions with other, correlated predictors. Given the commonplace practice of testing interactions, and the rarity of testing nonlinear effects, we speculate that some of the significant interactions reported in the literature may actually be spurious, reflecting only the misspecification of nonlinear effects. We outline the mathematical reasons for this problem using the relatively simple case of a quadratic regression model. Within this context, prior research by Busemeyer and Jones (1983) clearly demonstrated that quadratic effects of individual predictors can masquerade as interaction effects between correlated predictors. Furthermore, the explosive growth of mediation, moderation, and moderated mediation analyses in behavioral research makes this issue especially relevant for researchers of addiction. In this article, we (1) call further attention to the potential problems of omitting nonlinear effects in linear regression, (2) extend these findings to the more complex moderated mediation model, and (3) provide practical recommendations for applied researchers for differentiating nonlinear from interactive effects.

PTSD symptoms and alcohol-related problems among veterans: Temporal associations and vulnerability

Posttraumatic stress disorder (PTSD) is associated with elevated risk of both alcohol use disorder (AUD) and related conduct problems, which are associated with behavioral and emotional dysregulation. We conducted an intensive longitudinal burst design study with 10 weeks of experience sampling over the course of 1.5 years with 250 veterans of recent conflicts. We tested time-series models of daily associations between posttraumatic stress symptoms (PTSS), alcohol dependence syndrome, and conduct problems. Exacerbations of PTSS predicted higher dependence syndrome and conduct problems the next day. This effect was significant after controlling for both concurrent (i.e., same-day) associations between drinking and the outcomes as well as the strength of associations between the outcomes from one day to the next (i.e., autoregression). Affect lability and disinhibition were hypothesized vulnerability factors increasing the strength of within-person predictors of dependence syndrome and conduct problems. Lability and disinhibition were associated with greater dependence syndrome symptoms and conduct problems over the follow-up period. Consistent with expectation, lability rather than disinhibition increased the association between drinking and dependence syndrome as well as the strength of association between dependence syndrome symptoms from one day to the next. Moderating effects of disinhibition in the conduct problems model were not significant. Importantly, results indicated reciprocal associations over time. Lability potentiated the association between dependence syndrome symptoms and next day PTSS, whereas disinhibition potentiated the association between conduct problems and next day PTSS. Results demonstrate complex dynamic associations between PTSS, AUD symptoms, and conduct problems over time indicative of broad regulatory impairments. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Associations of serotonin transporter gene promoter polymorphisms and monoamine oxidase A gene polymorphisms with oppositional defiant disorder in a Chinese Han population

BACKGROUND

Oppositional defiant disorder (ODD) is a behavioral disorder that mainly refers to a recurrent pattern of disobedient, defiant, negativistic and hostile behaviors toward authority figures. Previous studies have showed associations of serotonin transporter (5-HTT) and monoamine oxidase A (MAOA) with behavioral and psychiatric disorders. The purposes of this study were to investigate the potential association of 5-HTT gene promoter polymorphism (5-HTTLPR) and MAOA gene polymorphism with susceptibility to ODD in a Han Chinese school population.

METHODS

The 5-HTTLPR gene polymorphism and the MAOA gene polymorphism were genotyped in a case-control study of 257 Han Chinese children (123 ODD and 134 healthy controls).

RESULTS

There was significant difference in the allele distribution of 5-HTTLPR (χ² = 7.849, P = 0.005) between the ODD and control groups. Further, there were significant differences in genotype (χ² = 5.168, P = 0.023) and allele distributions (χ² = 10.336, P = 0.001) of the MAOA gene polymorphism that is variable-number tandem repeat (MAOA-uVNTR) between two groups. Moreover, there were significant differences in genotype (χ² = 4.624, P = 0.032) and allele distributions (χ² = 9.248, P = 0.002) of MAOA-uVNTR only in the male ODD and healthy groups.

CONCLUSIONS

Our results suggest that 5-HTTLPR and MAOA-uVNTR gene variants may contribute to susceptibility to ODD. Further, MAOA-uVNTR gene polymorphism may play a role in susceptibility to ODD only in male children.

Insomnia severity as a mediator of the association between mental health symptoms and alcohol use in young adult veterans

PURPOSE

Prior research has documented associations between mental health and alcohol use, mental health and insomnia, and insomnia and alcohol use. This study examined insomnia severity as a mediator of the association between mental health and alcohol-related outcomes in young adult veterans.

PROCEDURES

Veterans aged 18-34 years (N=622, 83% male) who reported drinking in the past year completed assessments at baseline and one-month follow-up as part of a larger intervention trial. Participants reported symptoms of depression and posttraumatic stress disorder (PTSD) at baseline, insomnia severity at one month, and alcohol use and related consequences at baseline and one month. Mediation analyses using bootstrapped confidence intervals were used to examine the indirect effects of baseline mental health symptoms on alcohol-related outcomes at one month via insomnia severity.

MAIN FINDINGS

Insomnia severity was associated with both drinking quantity and alcohol-related consequences. Greater depressive (but not PTSD) symptoms were associated directly with more alcohol-related consequences. Neither depressive nor PTSD symptoms had direct effects on drinking quantity when controlling for the other mental health symptoms (e.g., depressive symptoms did not predict drinking quantity when controlling for symptoms of PTSD). However, symptoms of depression and PTSD predicted drinks per week and alcohol-related consequences indirectly through insomnia severity.

CONCLUSIONS

Symptoms of depression and PTSD increase risk for alcohol use and related consequences in part by increasing symptoms of insomnia. Findings suggest that insomnia may be an appropriate target for prevention and intervention efforts among heavy-drinking Veterans reporting symptoms of depression or PTSD.