The Association between Default-mode Network Functional Connectivity and Childhood Trauma on the Symptom Load in Male Adults with Methamphetamine Use Disorder

Objective

: The relationship between adverse childhood experiences and methamphetamine use disorder (MUD) has been shown in previous studies; nevertheless, the underlying neural mechanisms remain elusive. Childhood trauma is associated with aberrant functional connectivity (FC) within the default-mode network (DMN). Furthermore, within the DMN, FC may contribute to impaired self-awareness in addiction, while cross-network FC is critical for relapse. We aimed to investigate whether childhood trauma was associated with DMN-related resting-state FC among healthy controls and patients with MUD and to examine whether DMN-related FC affected the effect of childhood trauma on the symptom load of MUD diagnosis.

Methods

: Twenty-seven male patients with MUD and 27 male healthy controls were enrolled and completed the Childhood Trauma Questionnaire. DMN-related resting-state FC was examined using functional magnetic resonance imaging.

Results

: There were 47.1% healthy controls and 66.7% MUD patients in this study with adverse childhood experiences. Negative correlations between adverse childhood experiences and within-DMN FC were observed in both healthy controls and MUD patients, while within-DMN FC was significantly altered in MUD patients. The detrimental effects of adverse childhood experiences on MUD patients may be attenuated through DMN-executive control networks (ECN) FC.

Conclusion

: Adverse childhood experiences were negatively associated with within-DMN FC in MUD patients and healthy controls. However, DMN-ECN FC may attenuate the effects of childhood trauma on symptoms load of MUD.

The association between proportion of night shifts and musculoskeletal pain and headaches in nurses: a cross-sectional study

BACKGROUND AND PURPOSE

Shift work is associated with musculoskeletal pain and headaches, but little is known about how the intensity of shift work exposure is related to musculoskeletal pain and headaches. This study aimed to investigate whether a higher proportion of night shifts is associated with a higher occurrence of musculoskeletal pain and headaches. Furthermore, to investigate whether sleep duration can mediate this potential association.

METHOD

The study included 684 nurses in rotating shift work who responded to a daily questionnaire about working hours, sleep, and pain for 28 consecutive days. The data were treated cross-sectionally.

RESULTS

A negative binomial regression analysis adjusted for age and BMI revealed that working a higher proportion of night shifts is not associated with a higher occurrence of musculoskeletal pain and headaches. On the contrary, those working ≥ 50% night shifts had a significantly lower occurrence of pain in the lower extremities than those who worked < 25% night shifts (IRR 0.69 95% CI 0.51, 0.94). There was no indication of a mediation effect with total sleep time (TST).

CONCLUSION

The results of this study indicate that working a higher proportion of night shifts is not associated with a higher occurrence of musculoskeletal pain and headaches.

A Causal Approach to Functional Mediation Analysis with Application to a Smoking Cessation Intervention

The increase in the use of mobile and wearable devices now allows dense assessment of mediating processes over time. For example, a pharmacological intervention may have an effect on smoking cessation via reductions in momentary withdrawal symptoms. We define and identify the causal direct and indirect effects in terms of potential outcomes on the mean difference and odds ratio scales, and present a method for estimating and testing the indirect effect of a randomized treatment on a distal binary variable as mediated by the nonparametric trajectory of an intensively measured longitudinal variable (e.g., from ecological momentary assessment). Coverage of a bootstrap test for the indirect effect is demonstrated via simulation. An empirical example is presented based on estimating later smoking abstinence from patterns of craving during smoking cessation treatment. We provide an R package, funmediation, available on CRAN at https://cran.r-project.org/web/packages/funmediation/index.html, to conveniently apply this technique. We conclude by discussing possible extensions to multiple mediators and directions for future research.

Shame-and-guilt-proneness, interpersonal sensitivity, and alcohol: Results from a moderated mediation

BACKGROUND

Shame-proneness has been consistently associated with more problematic alcohol outcomes, and guilt-proneness has been associated with fewer. The aim of this study was to determine if the associations of shame-and-guilt-proneness with alcohol outcomes vary as a function of interpersonal sensitivity.

METHOD

A longitudinal study examined shame-proneness and guilt-proneness as predictors of alcohol consumption and related problems one month later. This research was conducted at a large public university in the United States.

RESULTS

Participants (N=414) were heavy-drinking college students (51% female) with a mean age of 21.76 (SD=2.02) who consumed an average of 12.13 (SD=8.81) standard drinks per week. Shame-proneness, but not guilt-proneness, was directly associated with increased drinking and indirectly associated with increased problems. The indirect effects of shame on problems through drinking were stronger at higher levels of interpersonal sensitivity.

CONCLUSIONS

Results suggest that shame-proneness may increase alcohol consumption and subsequent problems among those high in interpersonal sensitivity. Alcohol may be used as a means to withdraw from social threats that are amplified by interpersonal sensitivity.

Friendship Conflict, Drinking to Cope, and Alcohol-Related Problems: A Longitudinal Actor-Partner Interdependence Model

Drinking to cope with negative affect is a strong predictor of alcohol-related problems. We hypothesized that the association between friendship conflict and alcohol-related problems would be mediated by coping-with-depression motives in emerging adults' close friendships. We used a 4-wave, 4-month longitudinal self-report survey design measuring friendship conflict, coping motives, and alcohol-related problems from 174 same-sex friendship dyads. Participants were recruited from Nova Scotia, Canada between September 2016 and February 2019. Participants had a mean age of 18.66 (SD = 1.17) and were 66.1% female. Data were analyzed using multilevel structural equation modeling. Coping-with-depression motives mediated the link between conflict and alcohol-related problems at the between- and within-subject levels. Unexpectedly, coping-with-anxiety motives was an additional mediator at the within-subjects level. Interventions for emerging adults' problem drinking should consider the influence of friendship conflict and its impact on emerging adults' tendencies to drink to cope with both depression and anxiety. Materials/Syntax: https://osf.io/krs3v/.

Networks as mediating variables: a Bayesian latent space approach

The use of network analysis to investigate social structures has recently seen a rise due to the high availability of data and the numerous insights it can provide into different fields. Most analyses focus on the topological characteristics of networks and the estimation of relationships between the nodes. We adopt a different perspective by considering the whole network as a random variable conveying the effect of an exposure on a response. This point of view represents a classical mediation setting, where the interest lies in estimating the indirect effect, that is, the effect propagated through the mediating variable. We introduce a latent space model mapping the network into a space of smaller dimension by considering the hidden positions of the units in the network. The coordinates of each node are used as mediators in the relationship between the exposure and the response. We further extend mediation analysis in the latent space framework by using Generalised Linear Models instead of linear ones, as previously done in the literature, adopting an approach based on derivatives to obtain the effects of interest. A Bayesian approach allows us to get the entire distribution of the indirect effect, generally unknown, and compute the corresponding highest density interval, which gives accurate and interpretable bounds for the mediated effect. Finally, an application to social interactions among a group of adolescents and their attitude toward substance use is presented.

Alcohol and marijuana protective behavioral strategies mediate the relationship between substance use identity and use-related outcomes: A multi-sample examination

Substance use identity has been consistently associated with problematic substance use. Limited attention has considered mechanisms of this association. This research examined whether greater identification as a drinker or marijuana user would be associated with the use of fewer alcohol/marijuana protective behavioral strategies (PBS; e.g., avoiding drinking games/avoiding using marijuana in public places). Further, PBS have been associated with lower levels of negative alcohol/marijuana-related outcomes (i.e., frequency, quantity, consequences). In the current multi-sample study, PBS were examined as a mediator of the relationship between drinking/marijuana identity and alcohol/marijuana-related outcomes across three studies. Study 1 was an intervention study with heavy drinking college students (N = 605), Study 2 was a multisite study of marijuana outcomes among college students (N = 2,077), and Study 3 was a study of substance use in a community sample (n = 369_alcohol; n = 146_marijuana). Cross-sectional and/or longitudinal data were collected across studies. Substance use identity, PBS, and use-related outcomes were measured across the three studies. Indirect effects were evaluated by Monte Carlo confidence intervals. Manner of Drinking PBS were found to be the only statistically significant mediator of the relationship between drinking identity and alcohol-related outcomes (i.e., quantity and consequences) cross-sectionally. These significant cross-sectional mediation effects for alcohol were replicated in one of three longitudinal models. Marijuana PBS were also found to mediate the relationship between marijuana identity and all marijuana-related outcomes examined in the current study. Study findings may help to inform the development of identity-based and PBS-based interventions that aim to reduce negative alcohol/marijuana-related outcomes.

Childhood Socioeconomic Status and Physical Activity in Later Life: The Role of Perceived Neighborhood Cohesion and Wealth in Adulthood

The literature indicates that perceived neighborhood social cohesion is related to later life physical activity. However, there is no research that examines the role of childhood socioeconomic status (SES) in shaping this relationship. We use data from the Health and Retirement Study (2006-2016; N = 8,754) and a structural equation modeling approach to examine whether perceived neighborhood social cohesion and adulthood wealth mediate the relationship between childhood SES and physical activity. Perceived neighborhood social cohesion and adulthood wealth have small but statistically significant mediational effects in the relationship between childhood SES and physical activity. Research on the relationship between health and place should consider the potential impact of childhood circumstances on the neighborhood one lives in during adulthood.

Assessing Relationships Among Impulsive Sensation Seeking, Reward Circuitry Activity, and Risk for Psychopathology: A Functional Magnetic Resonance Imaging Replication and Extension Study

BACKGROUND

High trait impulsive sensation seeking (ISS), the tendency to engage in behavior without forethought and to seek out new or extreme experiences, is a transdiagnostic risk factor for externalizing and mood disorders, particularly bipolar disorder. We published a positive association between trait ISS and reward expectancy-related activity in the left ventrolateral prefrontal cortex (L vlPFC) and the ventral striatum. We aimed to replicate this finding and extend it by testing for mediation effects of ISS on relationships between reward expectancy-related activity and measures denoting hypomania.

METHODS

A transdiagnostic sample of 127 adults, 18 to 25 years of age, completed a card-guessing functional magnetic resonance imaging task as well as measures of ISS (inattention, motor impulsivity, fun seeking, positive and negative urgency) and the Moods Spectrum as a measure of hypomania. An original sample of 98 was included for confirmatory and mediation analyses.

RESULTS

We replicated a positive relationship between reward expectancy-related L vlPFC activity and negative urgency, an ISS component (β = .28, t = 2.44, p = .0169). We combined these data with the original sample, confirming this finding (β = .27, t = 2.41, p = .0184). Negative urgency statistically mediated the relationship between reward expectancy-related L vlPFC activity and Moods Spectrum factors associated with hypomania. No other associations between ISS measures and reward expectancy-related activity were replicated.

CONCLUSIONS

We replicated findings showing that reward expectancy-related L vlPFC activity is a biomarker for negative urgency, the tendency to react with frustration during distressing conditions. Negative urgency also statistically mediated the relationship between L vlPFC activity and measures indicative of hypomanic symptoms.

Intimate Partner Violence and Coerced Unprotected Sex Among Young Women Attending Community College

The present study examined the mediating role of sexual assertiveness in the relationship between psychological, physical, and sexual intimate partner violence (IPV) victimization and unprotected sex as a result of condom use resistance among sexually active young women attending community college. Women reported engagement in unprotected sex as a result of a partner's use of one of 32 forms of condom use resistance (e.g., physical force, deception, or other forms of coercion to avoid using a condom during intercourse). Women ages 18-24 years (N = 212) attending community college were recruited through paper advertisements to complete assessments of social and dating behavior in the campus computer laboratory. Only the women with a history of sexual intercourse (N = 178; 84% of the sample) were included in analyses. More frequent engagement in unprotected sex as a result of a partner's condom use resistance was associated with physical, psychological, and sexual IPV victimization. Sexual assertiveness mediated the relationship between physical IPV victimization and the frequency of unprotected sex as a result of condom use resistance. Efforts to prevent dating violence and enhance the sexual health of community college women may benefit from focusing on targeting sexual assertiveness as a protective factor.

Mediation analysis with zero-inflated substance use outcomes: Challenges and recommendations

Mediating mechanisms are important components of substance use research, as many substance use interventions work by targeting mediating variables. One issue that is common in substance use research is the presence of many responses of zero in a count variable that is the primary outcome of interest, such as number of drinks per week or number of substances used in the past month. The goal of this paper is to highlight the unique challenges that substance use researchers face when conducting mediation analysis with a zero-inflated count outcome. In this paper, we first describe the models that are commonly used for zero-inflated count data, and when it is appropriate to use them. We then describe general mediation analysis and summarize the small body of work that has focused on mediation for count and zero-inflated count outcomes. We identify the main issue of computing the mediated effect when outcomes are zero-inflated, namely, that the path leading to the zero-inflated count outcome (or mediator) is modeled in two parts. We then provide two examples of mediation models with different conclusions that have zero-inflated count outcomes using adolescent substance use data and define the issues that arise when assessing mediation for each. Finally, we describe the directions in which we must target future methodological research to create accessible solutions for handling mediation with zero-inflated count data in substance use research.