Neurocognition and inhibitory control in polysubstance use disorders: Comparison with alcohol use disorders and changes with abstinence

Identifying the role of (dis)inhibition in the vicious cycle of substance use through ecological momentary assessment and resting-state fMRI

Functional inhibition is known to improve treatment outcomes in substance use disorder (SUD), potentially through craving management enabled by underlying cerebral integrity. Whereas treatment is challenged by a multitude of substances that patients often use, no study has yet unraveled if inhibition and related cerebral integrity could prevent relapse from multiples substances, that is, one's primary drug of choice and secondary ones. Individuals with primary alcohol, cannabis, or tobacco use disorders completed intensive Ecological Momentary Assessment (EMA) coupled with resting-state functional MRI (rs-fMRI) to characterize the extent to which inhibition and cerebral substrates interact with craving and use of primary and any substances. Participants were 64 patients with SUD and 35 healthy controls who completed one week EMA using Smartphones to report 5 times daily their craving intensity and substance use and to complete Stroop inhibition testing twice daily. Subsamples of 40 patients with SUD and 34 control individuals underwent rs-fMRI. Mixed Model Analysis revealed that reported use of any substance by SUD individuals predicted later use of any and primary substance, whereas use of the primary substance only predicted higher use of that same substances. Craving and inhibition level independently predicted later use but did not significantly interact. Preserved inhibition performance additionally influenced use indirectly by mediating the link between subsequent uses and by being linked to rs-fMRI connectivity strength in fronto-frontal and cerebello-occipital connections. As hypothesized, preserved inhibition performance, reinforced by the integrity of inhibitory neurofunctional substrates, may partake in breaking an unhealthy substance use pattern for a primary substance but may not generalize to non-target substances or to craving management.

Cortical thickness of the inferior parietal lobule as a potential predictor of relapse in men with alcohol dependence

Alcohol dependence is a disorder with a high recurrence rate that leads to a considerable public health burden. The risk of relapse appears to be related to a complex interplay of multiple factors. Herein, we aimed to explore the potential neural predictors of relapse in Chinese male patients with alcohol dependence. This study enrolled 58 male patients with alcohol dependence who had undergone acute detoxification. General demographic information and clinical features were collected. Magnetic resonance imaging data were used to measure cortical thickness across 34 regions of the brain. Patients were followed up at six months, and 51 patients completed the follow-up visit. These patients were divided into a relapser and an abstainer group. A binary logistic regression analysis was performed to investigate the potential risk factors of relapse. Compared to abstainers, relapsers showed higher inattention and non-planning impulsivity on the 11th version of the Barratt Impulsive Scale. The cortical thicknesses of the inferior-parietal lobules were significantly higher in abstainers compared with those in relapsers. Furthermore, binary logistic regression analysis showed that the thickness of the inferior parietal lobule predicted relapse, and lower non-planning impulse was a protective factor against relapse. Relapsers show poorer impulse control than abstainers, and structural magnetic resonance imaging revealed a decreased thickness of the inferior parietal lobule in relapsers. Our results indicate the thickness of the inferior parietal lobule as a potential relapse predictor in male patients with alcohol dependence.

Gender disparities in neuropsychological assessment research in drug abuse populations: A systematic review

Objective: To systematically review the literature on the neurocognitive effects of drug use to determine if there are significant gender differences. Methods: In April 2023, we conducted a broad search in MEDLINE (via PubMed), PsycINFO, and Embase for original research studies that used objective neuropsychological assessment to evaluate neurocognition in persons with drug use. Data extraction was performed in a masked, duplicate fashion. Results: Our initial search returned 22,430 records, of which 273 articles were included in our analysis. We found significant underrepresentation of women as participants in the studies. Twenty-one percent of studies had exclusively male participants; when women were included, they averaged only 23% of the sample. Only 49 studies sufficiently documented an analysis of their results by gender; due to the heterogeneity in study characteristics, no conclusions about cognitive differences between women and men could be made. Conclusions: Women are significantly underrepresented in the research on cognition in drug use. Increased efforts to include more women participants and consistent analysis and reporting of data for potential gender differences will be required to close this gap in knowledge, which may lead to improved substance abuse treatment approaches for women.

Alcohol-related cognitive impairments in patients with and without cirrhosis

AIMS

up to 80% of patients with alcohol use disorder display cognitive impairments. Some studies have suggested that alcohol-related cognitive impairments could be worsened by hepatic damage. The primary objective of this study was to compare mean scores on the Brief Evaluation of Alcohol-Related Neurocognitive Impairments measure between alcohol use disorder patients with (CIR+) or without cirrhosis (CIR-).

METHODS

we conducted a prospective case-control study in a hepatology department of a university hospital. All patients were assessed using the Evaluation of Alcohol-Related Neuropsychological Impairments test.

RESULTS

a total of 82 patients (50 CIR+, 32 CIR-) were included in this study. CIR- patients were significantly younger than CIR+ patients (respectively, 45.5 ± 6.8 vs 60.1 ± 9.0; P < .0001). After adjusting for age and educational level, the mean Evaluation of Alcohol-Related Neuropsychological Impairments total scores in the CIR+ group were significantly lower than in the group of CIR- patients (14.1 ± 0.7 vs 7.8 ± 0.4, respectively, P < .0001). The mean subscores on delayed verbal memory, alphabetical ordination, alternating verbal fluency, visuospatial abilities, and ataxia subtests were also significantly lower in the CIR+ than in the CIR- group (respectively, 1.9 ± 0.2 vs 2.8 ± 0.2; 1.8 ± 0.2 vs 2.7 ± 0.2; 2.2 ± 0.2 vs 3.6 ± 0.2; 0.7 ± 0.2 vs 1.6 ± 0.2; 0.7 ± 0.2 vs 3.1 ± 0.2; P < .0001 for all comparisons).

CONCLUSIONS

in the present study, alcohol use disorder patients with cirrhosis presented more severe cognitive impairments than those without cirrhosis. Longitudinal studies are needed to investigate how cirrhosis can influence cognitive impairments.

Neurocognitive Recovery in Abstinent Patients with Alcohol Use Disorder: A Scoping Review for Associated Factors

Objective

Studies have reported inconsistent results regarding the extent to which neurocognitive recovery occurs in abstinent patients with alcohol use disorder (AUD). In addition to abstinence, other factors may have influenced this process and contributed to the inconsistencies. This review examines the factors investigated in this regard and describes the possible influence of each factor based on the evidence collected.

Methodology

PubMed was systematically searched for articles published between January 2000 and July 2023. Longitudinal humane studies investigating neurocognitive recovery in abstinent adult AUD patients were included. Studies with a cross-sectional design were excluded, as were studies that did not classify AUD according to the DSM-IV or 5 criteria, only examined binge use, did not report neuropsychological outcomes or duration of abstinence, or where neurological disorders were present.

Results

Sixteen categories of factors were distinguished from 31 full-text articles. Consistent patterns were found, indicating an association between neurocognitive recovery and the "smoking" and 'brain volume" factors. Consistent patterns were also found indicating that there is no relationship with "quantities of alcohol used" and "education level." A similar consistent pattern was also found for "polysubstance use", "gender" and "verbal reading", but the number of studies is considered limited. The association with "age" is studied frequently but with inconsistent findings. The remaining eight factors were regarded as understudied.

Conclusion

The clearest patterns emerging from the evidence are a predominantly negative influence of smoking on neurocognitive recovery, associations between changes in brain area volume and neurocognitive recovery, and no association between neurocognitive recovery and the amount of alcohol consumed, as measured by self-report, nor with educational attainment. Future research on the understudied factors and factors with inconsistent evidence is needed, preferably through longitudinal designs with multiple assessment periods starting after at least two weeks of abstinence.

Impact of Alcohol Use, Traumatic Stress, and Cigarette Smoking on Cognitive Functioning in Veterans With Co-occurring Alcohol Use Disorder and Posttraumatic Stress Disorder

INTRODUCTION

Alcohol use disorder (AUD) and PTSD have high rates of co-occurrence in U.S. Military Veterans resulting in incrementally worse functional outcomes relative to having either one of these disorders alone. Cognitive dysfunction can impede one's ability to benefit from standard behavioral AUD and PTSD treatments. Cigarette smoking is also highly prevalent among U.S. Military Veterans, and cognitive dysfunction is associated with chronic cigarette use among individuals with AUD and PTSD independently. However, much less is known about to what extent cigarette smoking further impairs cognitive functioning in individuals with both co-occurring AUD and PTSD.

MATERIALS AND METHODS

U.S. Veterans with co-occurring AUD and PTSD (n = 162) completed a comprehensive cognitive assessment covering various domains: working memory, processing speed, mental switching, cognitive inhibition, auditory-verbal learning, auditory-verbal memory, and verbal fluency. To examine the impact of alcohol use, traumatic stress, and cigarette smoking on cognitive function, we conducted a three-way interaction examining the moderated effects of smoking status on the association between alcohol use and PTSD symptoms on a composite domain of global cognition.

RESULTS

Smoking status in Veterans with co-occurring AUD and PTSD moderated the relationship between alcohol use and global cognition (P = .042), such that higher levels of alcohol use in the past week were related to worse global cognitive function among Veterans cigarette smokers (P = .015) but not among nonsmokers (P = .833). On follow-up analyses of individual cognitive domains, greater alcohol use in the past week was associated with lower cognitive inhibition in smokers but not nonsmokers, with traumatic stress symptoms moderating this effect (P = .039). Additionally, smoking status moderated the relationship between alcohol use and auditory-verbal learning, such that there was a differential relationship between alcohol use and auditory-verbal learning between smokers and nonsmokers.

CONCLUSIONS

Overall, results provide evidence for the compounding impact of alcohol use, traumatic stress, and cigarette smoking on cognitive functioning. Impaired cognitive performance on a global level as well as on individual domains of cognitive inhibition and auditory-verbal learning were evident. Cognitive dysfunction may impede a Veteran's ability to benefit from therapeutic treatment, and these cognitive domains may represent potential targets for cognitive training efforts. Further, study results support smoking cessation initiatives and smoke-free policies enacted at Veterans Affairs healthcare facilities and medical centers.

Intermittent theta burst stimulation to the left dorsolateral prefrontal cortex improves cognitive function in polydrug use disorder patients: a randomized controlled trial

Background

Polydrug abuse is common among opioid users. Individuals who use both heroin and methamphetamine (MA) have been shown to experience a wide range of cognitive deficits. Previous research shows that repetitive transcranial magnetic stimulation (rTMS) can change cerebral cortical excitability and regulate neurotransmitter concentration, which could improve cognitive function in drug addiction. However, the stimulation time, location, and possible mechanisms of rTMS are uncertain.

Methods

56 patients with polydrug use disorder were randomized to receive 20 sessions of 10 Hz rTMS (n = 19), iTBS (n = 19), or sham iTBS (n = 18) to the left DLPFC. All patients used MA and heroin concurrently. Cognitive function was assessed and several related proteins including EPI, GABA-Aα5, IL-10, etc. were quantified by ELISA before and after the treatment.

Results

Baseline RBANS scores were lower than normal for age (77.25; IQR 71.5-85.5). After 20 treatment sessions, in the iTBS group, the RBANS score increased by 11.95 (95% CI 0.02-13.90, p = 0.05). In particular, there were improvements in memory and attention as well as social cognition. Following treatment, serum EPI and GABA-Aα5 were reduced and IL-10 was elevated. The improvement of immediate memory was negatively correlated with GABA-Aα5 (r = -0.646, p = 0.017), and attention was positively correlated with IL-10 (r = 0.610, p = 0.027). In the 10 Hz rTMS group, the improvement of the RBANS total score (80.21 ± 14.08 before vs.84.32 ± 13.80 after) and immediate memory (74.53 ± 16.65 before vs.77.53 ± 17.78 after) was statistically significant compared with the baseline (p < 0.05). However, compared with the iTBS group, the improvement was small and the difference was statistically significant. There was no statistically significant change in the sham group (78.00 ± 12.91 before vs.79.89 ± 10.92 after; p > 0.05).

Conclusion

Intermittent theta burst stimulation to the left DLPFC may improve cognitive function in polydrug use disorder patients. Its efficacy appears to be better than that of 10 Hz rTMS. The improvement of cognitive function may be related to GABA-Aα5 and IL-10. Our findings preliminarily demonstrate the clinical value of iTBS to the DLPFC to augment neurocognitive recovery in polydrug use disorders.

Examining neurobehavioral differences that support success in recovery from alcohol and other substance use disorders

OBJECTIVE

Substance use disorders (SUDs) are brain disorders associated with impairments resulting from the recurrent use of alcohol, drugs, or both. Though recovery is possible, SUDs are chronic, relapsing-remitting disorders, with estimates of SUD relapse at 40-60%. Currently, we know little about the mechanisms underlying successful recovery processes and whether substance-specific mechanisms exist. The current study sought to examine delay discounting (a measure of future valuation), executive skills, abstinence duration, and health behaviors in a population of individuals in recovery from alcohol, stimulants, opioids, and other substances.

METHODS

In this observational study, we utilized a cohort of individuals (n = 238) from the International Quit and Recovery Registry, an online registry for those in recovery from SUDs around the world. We assessed delay discounting through a neurobehavioral task, and assessed abstinence duration, executive skills, and engagement in positive health behaviors through self-report measures.

RESULTS

We found that delay discounting, executive skills, and engagement in positive health behaviors were similar among individuals in recovery from different substances. Abstinence duration was associated with delay discounting and engagement in health behaviors. Additionally, executive skills and engagement in health behaviors were positively associated.

CONCLUSION

These findings suggest that common behavioral mechanisms support recovery from misuse of various substances. As both delay discounting and executive skills are dependent upon executive brain centers, such as the prefrontal cortex, strategies that target executive functioning, such as episodic future thinking, meditation, or exercise, may be efficient strategies for optimizing recovery from SUDs.

Cortical thickness of the inferior parietal lobule as a potential predictor of relapse in men with alcohol dependence

Background

Alcohol dependence (AD) is a disorder with a high recurrence rate that leads to a considerable public health burden. The risk of relapse appears to be related to a complex interplay of multiple factors. Herein, we aimed to explore the potential neural predictors of relapse in Chinese male patients with AD.

Methods

This study enrolled 58 male patients with AD who had undergone acute detoxification. General demographic information and clinical features were collected. Magnetic resonance imaging (MRI) data were used to measure cortical thickness across 34 regions of the brain. Patients were followed up at 6 months, and 51 patients completed the follow-up visit. These patients were divided into a relapser and an abstainer group. A binary logistic regression analysis was performed to investigate the potential risk factors of relapse.

Results

Compared to abstainers, relapsers showed higher inattention and non-planning impulsivity on the 11th version of the Barratt Impulsive Scale. The cortical thicknesses of the inferior-parietal lobule were significantly greater in abstainers compared with those in relapsers. Furthermore, binary logistic regression analysis showed that the thickness of the inferior parietal lobule predicted relapse.

Conclusions

Relapsers show poorer impulse control than abstainers, and MRI imaging shows a decreased thickness of the inferior parietal lobule in relapsers. Our results indicate the thickness of the inferior parietal lobule as a potential relapse predictor in male patients with AD.

Predictors of cognitive functioning in presentations to a community-based specialist addiction neuropsychology service

INTRODUCTION

Cognitive impairment is common in individuals presenting to alcohol and other drug (AOD) settings and the presence of biopsychosocial complexity and health inequities can complicate the experience of symptoms and access to treatment services. A challenge for neuropsychologists in these settings is to evaluate the likely individual contribution of these factors to cognition when providing an opinion regarding diagnoses such as acquired brain injury (ABI). This study therefore aimed to identify predictors of cognitive functioning in AOD clients attending for neuropsychological assessment.

METHODS

Clinical data from 200 clients with AOD histories who attended for assessment between 2014 and 2018 were analysed and a series of multiple regressions were conducted to explore predictors of cognitive impairment including demographic, diagnostic, substance use, medication, and mental health variables.

RESULTS

Regression modelling identified age, gender, years of education, age of first use, days of abstinence, sedative load, emotional distress and diagnoses of ABI and developmental disorders as contributing to aspects of neuropsychological functioning. Significant models were obtained for verbal intellectual functioning (Adj R2 = 0.19), nonverbal intellectual functioning (Adj R2 = 0.10), information processing speed (Adj R2 = 0.20), working memory (Adj R2 = 0.05), verbal recall (Adj R2 = 0.08), visual recall (Adj R2 = 0.22), divided attention (Adj R2 = 0.14), and cognitive inhibition (Adj R2 = 0.07).

CONCLUSIONS

These findings highlight the importance of careful provision of diagnoses in clients with AOD histories who have high levels of unmet clinical needs. They demonstrate the interaction of premorbid and potentially modifiable comorbid factors such as emotional distress and prescription medication on cognition. Ensuring that modifiable risk factors for cognitive impairment are managed may reduce experiences of cognitive impairment and improve diagnostic clarity.

Early Improvement of Neuropsychological Impairments During Detoxification in Patients with Alcohol Use Disorder

AIMS

To assess recovery of alcohol-related neuropsychological deficits in a group of patients with pure severe alcohol use disorder (AUD) during a detoxification program using the Brief Evaluation of Alcohol-Related Neuropsychological Impairment (BEARNI) test.

METHODS

Thirty-two patients with severe AUD using DSM-IV criteria (24 men, mean age = 45.5 ± 6.8 years old) were assessed using the BEARNI 8 ± 2 days after alcohol cessation (T1) and then were reassessed within 18 ± 2 days after alcohol cessation (T2). The primary study endpoint was the number of patients initially impaired at T1 who recovered cognitive functions at T2 assessment.

RESULTS

At T1, 59% (n = 19) patients with pure severe AUD had at least one impaired cognitive function assessed by the BEARNI. At T2, 63% of the patients with AUD with deficits at T1 had normal BEARNI cognitive scores (χ2 = 7.7, P = 0.005); specifically, the percentages of participants with normal subtest scores were 63% on memory (χ2 = 12.4, P = 0.0004), 100% on verbal fluency (χ2 = 16; P = <0.0001), 60% on alphabetical span (χ2 = 12.8; P = 0.0003) and 67% on visuospatial (χ2 = 15, P = 0.0001).

CONCLUSIONS

The cognitive impairments of two-thirds of patients with pure AUD included in the present study recovered within 18 days of abstinence, earlier than reported in previous studies.

A randomized wait-list controlled trial to investigate the role of cognitive mechanisms in parenting interventions on mothers with substance use disorder

Background

Maternal substance use disorder (SUD) represents a risk condition for quality of parenting and child development. The current literature highlights the need to identify interventions that effectively enhance the quality of parenting and to better understand which mechanisms are involved in the process of change. The present study protocol describes a randomized wait-list controlled trial that aims to examine (1) the efficacy of the Video-feedback Intervention to promote Positive Parenting and Sensitive Discipline (VIPP-SD) in improving the quality of parenting (i.e., sensitive parenting and sensitive discipline) in mothers with SUD, (2) whether the intervention affects parental cognitive mechanisms (i.e., attentional disengagement to infant negative emotions, inhibitory control confronted with children’s affective expression, and parental reflective functioning), and (3) whether changes in these processes act as mechanisms of change, mediating the effect of the VIPP-SD program on quality of parenting. Moreover, the study aims (4) to explore whether the VIPP-SD has an effect on parenting stress and (5) to compare mothers with SUD to low-risk mothers on the outcome measures.

Methods

The study will involve 40 mothers with SUD and 20 low-risk mothers of children aged between 14 months and 6 years old. Mothers in the SUD group will be randomly divided into two groups, one receiving the intervention (SUD experimental group) and one undergoing treatment as usual (SUD control group). All the mothers will be assessed pre-test and post-test. Quality of parenting will be assessed through observed parenting behaviors, whereas parental cognitive mechanisms will be assessed through neuropsychological tasks and self-report measures.

Discussion

The results of the study will reveal whether an intervention that has been proven effective in other at-risk samples is also effective in improving parenting behaviors in the context of SUD. The results will also provide insight into potential cognitive mechanisms involved in the process of change.

Trial registration

ISRCTN registry ISRCTN63070968. Registered on 25 June 2021. Retrospectively registered

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06420-8.

The effect of concurrent access to alcohol and oxycodone on self-administration and reinstatement in rats

RATIONALE

Although polysubstance use is highly prevalent, preclinical studies that assess voluntary consumption of multiple substances at the same time are rather uncommon. Overlooking drug taking patterns commonly observed in humans may limit the translational value of preclinical models.

OBJECTIVES

Here, we aimed to develop a model of polysubstance use that could be used to assess oral operant self-administration patterns under concurrent access to alcohol and the prescription opioid oxycodone.

METHODS

After a training period where animals associated specific cues and levers with each drug, rats self-administered alcohol and oxycodone solutions concurrently in daily sessions. Oxycodone was then removed to assess potential changes in alcohol consumption. The role of cues and stress on alcohol consumption and oxycodone seeking was also examined under reinstatement conditions.

RESULTS

We found that females consumed more alcohol and oxycodone than males when given access to both drugs, and this effect on alcohol intake persisted when oxycodone was removed. Additionally, re-exposure to oxycodone cues in combination with the administration of the pharmacological stressor yohimbine drove reinstatement of oxycodone seeking in females but did not have a strong effect in males, possibly due to low levels of oxycodone intake during active self-administration in male rats. Additionally, yohimbine drove increased alcohol consumption, in line with prior findings from our group and others.

CONCLUSIONS

Taken together, this study demonstrates that rats will concurrently self-administer both oxycodone and alcohol in operant chambers, and this procedure can serve as a platform for future investigations in polysubstance use and relapse-like behavior.

Morphometric similarity deviations in stimulant use disorder point towards abnormal brain ageing

Chronic drug use negatively impacts ageing, resulting in diminished health and quality of life. However, little is known about biomarkers of abnormal ageing in stimulant drug users. Using morphometric similarity network mapping, a novel approach to structural connectomics, we first mapped cross-sectional morphometric similarity trajectories of ageing in the publicly available Rockland Sample (20-80 years of age, n = 665). We then compared morphometric similarity and neuropsychological function between non-treatment-seeking, actively using patients with stimulant use disorder (n = 183, mean age 35.6 years) and healthy control participants (n = 148, mean age 36.0 years). Significantly altered mean regional morphometric similarity was found in 43 cortical regions including the inferior and orbital frontal gyri, pre/postcentral gyri and anterior temporal, superior parietal and occipital areas. Deviations from normative morphometric similarity trajectories in patients with stimulant use disorder suggested abnormal brain ageing. Furthermore, deficits in paired associates learning were consistent with neuropathology associated with both ageing and stimulant use disorder. Morphometric similarity mapping provides a promising biomarker for ageing in health and disease and may complement existing neuropsychological markers of age-related cognitive decline. Neuropathological ageing mechanisms in stimulant use disorder warrant further investigation to develop more age-appropriate treatments for older people addicted to stimulant drugs.

Protocol for Characterization of Addiction and Dual Disorders: Effectiveness of Coadjuvant Chronotherapy in Patients with Partial Response

This protocol aims to characterize patients with dual disorders (DD; comorbid major depression and schizophrenia) compared with patients with only a diagnosis of substance use disorder (SUD) and those with only a diagnosis of severe mental illness (SMI; major depression and schizophrenia), evaluating clinical and personality characteristics, circadian rhythmic functioning, genetic polymorphism and neuropsychological performance in order to obtain a clinical endophenotype of differential vulnerability for these diagnostic entities. Patients will be divided into three groups: DD (45 men with comorbid schizophrenia, 45 men and 30 women with major depression), SUD (n = 90, with a minimum of 30 women) and SMI males (45 with schizophrenia, 45 with major depression). All patients will be under treatment, with at least three months of SUD abstinence and/or with SMI in remission or with stabilized symptoms. Outpatients of both sexes with insufficient restoration of circadian rhythmicity with SUD (n = 30) and dual depression (n = 30) will be asked to participate in a second two-month study, being alternately assigned to the condition of the chronobiological adjuvant approach to the treatment of regular hour habits and exposure to light or to the usual treatment (control). The effect of the intervention and patient compliance will be monitored with a Kronowise KW6^® ambulatory device during the first two weeks of treatment and again at weeks 4 and 8 weeks. After completing the evaluation, follow-up of the clinical evolution will be carried out at 3, 6 and 12 months. This project will allow us to analyze the functional impact of DD comorbidity and to develop the first study of chronobiological therapy in the treatment of SUD and dual depression, with results transferable to the clinical setting with cost-effective recommendations for a personalized approach.

Association of impulsivity with quality of life and well-being after alcohol withdrawal treatment

OBJECTIVES

Impulsivity is related to a higher risk of relapse in alcohol use disorders. However, besides drinking behavior, other recovery outcomes like physical and mental health-related quality of life are at least as important. The present study aimed to fill a research gap regarding the association of different impulsivity facets with health-related quality of life and well-being in alcohol use disorder.

METHODS

Individuals with a primary alcohol use disorder diagnosis (n = 167) were interviewed with standardized self-report measures at the progressed stage of their withdrawal treatment and 6 weeks thereafter. Multiple regression models were calculated to examine the association of impulsivity, craving, and drinking patterns with health-related quality of life and well-being 6 weeks after withdrawal treatment, as well as the predictive role of impulsivity assessed during withdrawal for these two outcomes.

RESULTS

Craving was associated with health-related quality of life and well-being 6 weeks after withdrawal. Likewise, non-planning and attentional impulsivity were associated with well-being 6 weeks after withdrawal. Motor impulsivity during withdrawal treatment predicted health-related quality of life 6 weeks thereafter.

CONCLUSION

Impulsivity seems to be negatively related to health-related quality of life and well-being in the first weeks after alcohol withdrawal treatment, probably to a higher extent than drinking patterns, but differentiating between its facets seems to be important. These findings emphasize the importance of treatment approaches aiming at reduced impulsivity in the early recovery process.

Memory impairment in alcohol use disorder is associated with regional frontal brain volumes

BACKGROUND

Episodic memory deficits occur in alcohol use disorder (AUD), but their anatomical substrates remain in question. Although persistent memory impairment is classically associated with limbic circuitry disruption, learning and retrieval of new information also relies on frontal systems. Despite AUD vulnerability of frontal lobe integrity, relations between frontal regions and memory processes have been under-appreciated.

METHODS

Participants included 91 AUD (49 with a drug diagnosis history) and 36 controls. Verbal and visual episodic memory scores were age- and education-corrected. Structural magnetic resonance imaging (MRI) data yielded regional frontal lobe (precentral, superior, orbital, middle, inferior, supplemental motor, and medial) and total hippocampal volumes.

RESULTS

AUD were impaired on all memory scores and had smaller precentral frontal and hippocampal volumes than controls. Orbital, superior, and inferior frontal volumes and lifetime alcohol consumption were independent predictors of episodic memory in AUD. Selectivity was established with a double dissociation, where orbital frontal volume predicted verbal but not visual memory, whereas inferior frontal volumes predicted visual but not verbal memory. Further, superior frontal volumes predicted verbal memory in AUD alone, whereas orbital frontal volumes predicted verbal memory in AUD+drug abuse history.

CONCLUSIONS

Selective relations among frontal subregions and episodic memory processes highlight the relevance of extra-limbic regions in mnemonic processes in AUD. Memory deficits resulting from frontal dysfunction, unlike the episodic memory impairment associated with limbic dysfunction, may be more amenable to recovery with cessation or reduction of alcohol misuse and may partially explain the heterogeneity in episodic memory abilities in AUD.

A Systematic Review of the Balloon Analogue Risk Task (BART) in Alcohol Research

Risk-taking propensity has been crucial to the investigation of alcohol use and consequences. One measure, the balloon analogue risk task (BART), has been used consistently over the past two decades. However, it is unclear how this measure is related to alcohol outcomes. This paper systematically reviews the literature on the BART and alcohol outcomes. First, direct associations between the BART and alcohol use are reviewed including correlations, group comparisons, the BART's prediction of alcohol outcomes and BART performance after consuming alcohol. Then, potential moderators that explain when and for whom the BART is related to alcohol outcomes are reviewed. Finally, potential mechanisms that explain how the BART and alcohol outcomes are related are reviewed. This review reveals patterns in the BART suggesting risk-taking propensity may be related to changes in alcohol use over time; however, there is little evidence to suggest BART scores increase after consuming alcohol. Yet, additional research suggests adjusted average pump scores may be too simplistic for the amount of information the BART captures and understanding individual's patterns of responses on the BART is important for investigating its relation to alcohol outcomes. Finally, this review opens up several future directions for research to understand how risk-taking propensity is related to alcohol outcomes.

Stroop-related cerebellar and temporal activation is correlated with negative affect and alcohol use disorder severity

Impairment in cognitive control in alcohol use disorder (AUD) contributes to difficulty controlling alcohol use and, in many populations, difficulties with emotion regulation. However, the most reliable and robust marker of clinically-relevant deficits in cognitive control in AUD is unclear. Our aims were to measure relationships between BOLD signal during a Stroop task and AUD severity and change in BOLD signal and change in drinking over three weeks. We also aimed to explore the relationships between BOLD signal and subjective negative affect. Thirty-three individuals with AUD underwent a multisensory Stroop task during functional magnetic resonance imaging (fMRI), as well as a battery of neuropsychological tests and self-report assessments of negative affect and AUD severity. Greater activation in temporal gyrus and cerebellum during incongruent trials compared to congruent trials was observed, and percent signal change (incongruent minus congruent) in both clusters was positively correlated with AUD severity and self-reported negative affect. Neuropsychological task performance and self-reported impulsivity were not highly correlated with AUD severity. Hierarchical regression analyses indicated that percent signal change (incongruent minus congruent) in cerebellum was independently associated with negative affect after controlling for recent and chronic drinking. In a subset of individuals (n = 23) reduction in cerebellar percent signal change (incongruent minus congruent) was correlated with increases in percent days abstinent over 3 weeks. BOLD activation during this Stroop task may therefore be an important objective marker of AUD severity and negative affect. The potential importance of the cerebellum in emotion regulation and AUD severity is highlighted.

Substance-Specific and Shared Gray Matter Signatures in Alcohol, Opioid, and Polysubstance Use Disorder

Substance use disorders (SUD) have been shown to be associated with gray matter (GM) loss, particularly in the frontal cortex. However, unclear is to what degree these regional GM alterations are substance-specific or shared across different substances, and if these regional GM alterations are independent of each other or the result of system-level processes at the intrinsic connectivity network level. The T1 weighted MRI data of 65 treated patients with alcohol use disorder (AUD), 27 patients with opioid use disorder (OUD) on maintenance therapy, 21 treated patients with stimulant use disorder comorbid with alcohol use disorder (polysubstance use disorder patients, PSU), and 21 healthy controls were examined via data-driven vertex-wise and voxel-wise GM analyses. Then, structural covariance analyses and open-access fMRI database analyses were used to map the cortical thinning patterns found in the three SUD groups onto intrinsic functional systems. Among AUD and OUD, we identified both common cortical thinning in right anterior brain regions as well as SUD-specific regional GM alterations that were not present in the PSU group. Furthermore, AUD patients had not only the most extended regional thinning but also significantly smaller subcortical structures and cerebellum relative to controls, OUD and PSU individuals. The system-level analyses revealed that AUD and OUD showed cortical thinning in several functional systems. In the AUD group the default mode network was clearly most affected, followed by the salience and executive control networks, whereas the salience and somatomotor network were highlighted as critical for understanding OUD. Structural brain alterations in groups with different SUDs are largely unique in their spatial extent and functional network correlates.

Multiple Substance Use Disorders and Self-Reported Cognitive Function in U.S. Adults: Associations and Sex-Differences in a Nationally Representative Sample

Polysubstance use is a growing public health concern that has been associated with poor clinical outcomes. Compared to single-drug users, this population suffers greater deficits in cognitive function, which hinder treatment success and recovery. Despite its high prevalence and poor prognosis, epidemiological research on polysubstance use and accompanying cognitive profile is lacking. We investigated associations between numbers of past-year co-occurring substance use disorders (SUDs) and self-reported cognitive function using data from the National Epidemiologic Survey for Alcohol and Related Conditions III (NESARC-III). Regression analyses revealed a significant negative association between cognitive scores and numbers of past-year SUDs, which was moderated by sex. After adjusting for confounding variables, greater numbers of SUDs were associated with declining self-reported cognitive function, and this relationship was stronger among females. Our findings expand on current literature on cognitive impairments among polysubstance users and provide a novel, nuanced description of this relationship among the general population. We highlight the need for targeted and individualized treatment approaches in order to improve outcomes in this population.

E-cigarette use among young adults: A latent class analysis examining co-use and correlates of nicotine vaping

INTRODUCTION

Although a significant proportion of young adults report e-cigarette use (nicotine vaping), little is known about co-use with other substances, including correlates that predict co-use. The current study aimed to identify co-occurring substance use patterns and evaluate multiple correlates in a college student sample.

METHODS

435 participants (21.4 ± 2.9 years; 57% women; 41% Hispanic/Latina/o, 29% Asian-American/Pacific Islander, 17% Caucasian/White, 6% Multiracial, and 5% African-American/Black) from a large, urban university were recruited in-person and completed an online survey in the fall of 2018 and the spring of 2019.

RESULTS

Using latent class analysis (LCA), four substance use patterns were identified: Binge Drinkers (7%); e-cigarette Users (8%); Cannabis Users (14%); and Low Substance Users (71%). The e-cigarette Users class was characterized by moderate or greater use (>5 days of nicotine vaping in past 30-days) as well as past 30-day binge drinking and cannabis use. Higher levels of deviant peer affiliation (aOR = 1.28[1.11-1.47], p < .01), impulsivity-lack of premeditation (aOR = 1.36[1.05-1.78], p < .05), and lower levels of social anxiety (aOR = 0.94[0.88-0.99], p < .05), predicted membership in the e-cigarette Users class.

CONCLUSIONS

The most pervasive co-occurring substance use was observed among the e-cigarette Users class. Young adults reporting moderate or greater levels of nicotine vaping tended to engage in binge drinking and cannabis use, which may ultimately increase risk of deleterious health outcomes. Deviant peer affiliation and impulsivity-lack of premeditation (but not internalizing symptoms) predicted membership in the e-cigarette Users class; consequently, public health efforts may benefit from increased selectivity in targeting young adults for e-cigarette prevention and intervention services.

Risky decision-making in individuals with substance use disorder: A meta-analysis and meta-regression review

BACKGROUND

This review aims to identify whether risky decision-making is increased in substance users, and the impact of substance type, polysubstance use status, abstinence period, and treatment status on risky decision-making.

METHODS

A literature search with no date restrictions was conducted to identify case-control studies or cross-sectional studies that used behavioral tasks to measure risky decision-making in substance users. A random-effects model was performed. GRADE criteria was used to assess the quality of evidence.

RESULTS

52 studies were enrolled. The result showed that the difference in risky decision-making performance between user groups and control groups was significant (SMD = - 0.590; 95%CI = - 0.849 to - 0.330; p < 0.001; I² = 93.4%; P_{heterogeneity} < 0.001). Subgroup analysis showed that users in the subgroups of alcohol (p < 0.001), tobacco (p < 0.01), cocaine (p < 0.001), opioid (p < 0.001), mixed group (p < 0.01), adult users (p < 0.001), small sample size (p < 0.001), large sample size (p < 0.01), low education (p < 0.001), high education (p < 0.001), short-abstinence period (p < 0.001), long-abstinence period (p < 0.001), without current polysubstance dependence (p < 0.001), and with treatment (p < 0.001) had increased risky decision-making when compared to the controls. On the other hand, elderly substance users with short-abstinence period showed increased risky decision-making. Moreover, current treatment status and polysubstance use may not influence the level of decision-making in substance users.

CONCLUSIONS

The results show that substance use is associated with impaired risky decision-making, indicating that interventions targeting risky decision-making in substance users should be developed for relapse prevention and rehabilitation.

Evidence That Implementation Intentions Enhance Cognitive Training and Reduce Alcohol Consumption in Heavy Drinkers: A Randomized Trial

BACKGROUND

Current training tasks to improve the cognitive deficits thought to be involved in sustained heavy drinking need further investigation to optimize their effectiveness.

PURPOSE

The present study investigated whether combining implementation intention provision with a cognitive training task had a measurable effect on alcohol consumption in heavy drinkers and explored the neural mechanisms underpinning any reductions in subsequent alcohol consumption.

METHODS

Thirty-two heavy-drinking participants completed approach-avoidance and visual probe training tasks preintervention and postintervention during functional Magnetic Resonance Imaging. Participants in the intervention group were randomized to form implementation intentions and participants in the control condition read a goal intention. Alcohol consumption was recorded preintervention and at 1 month follow-up.

RESULTS

Compared to the control group, implementation intention provision significantly improved performance on alcohol-avoidance tasks postintervention, t(30) = -2.315, p = .028, d = .85, and reduced alcohol consumption by 6.9 units/week (1 unit = 10 mL or 8 g ethanol), F(1,30) = 4.263, p = .048 (d = .74), at follow-up. However, the analysis of functional Magnetic Resonance Imaging data revealed no significant differences between groups.

CONCLUSIONS

These findings show for the first time that implementation intentions targeting cognitive processes can significantly reduce alcohol consumption among heavy drinkers. However, there was no evidence that the effects were mediated by changes in neural activity. Further work is required to explore the neural mechanisms underpinning the operation of implementation intentions.

TRIAL REGISTRATION

This trial was registered (ISRCTN:35503634) and is available at https://www.isrctn.com/ISRCTN35503634.

Behavioral preference for viewing drug v. pleasant images predicts current and future opioid misuse among chronic pain patients

BACKGROUND

The USA is currently enduring an opioid crisis. Identifying cost-effective, easy-to-implement behavioral measures that predict treatment outcomes in opioid misusers is a crucial scientific, therapeutic, and epidemiological goal.

METHODS

The current study used a mixed cross-sectional and longitudinal design to test whether a behavioral choice task, previously validated in stimulant users, was associated with increased opioid misuse severity at baseline, and whether it predicted change in opioid misuse severity at follow-up. At baseline, data from 100 prescription opioid-treated chronic pain patients were analyzed; at follow-up, data were analyzed in 34 of these participants who were non-misusers at baseline. During the choice task, participants chose under probabilistic contingencies whether to view opioid-related images in comparison with affectively pleasant, unpleasant, and neutral images. Following previous procedures, we also assessed insight into choice behavior, operationalized as whether (yes/no) participants correctly self-reported the image category they chose most often.

RESULTS

At baseline, the higher choice for viewing opioid images in direct comparison with pleasant images was associated with opioid misuse and impaired insight into choice behavior; the combination of these produced especially elevated opioid-related choice behavior. In longitudinal analyses of individuals who were initially non-misusers, higher baseline opioid v. pleasant choice behavior predicted more opioid misuse behaviors at follow-up.

CONCLUSIONS

These results indicate that greater relative allocation of behavior toward opioid stimuli and away from stimuli depicting natural reinforcement is associated with concurrent opioid misuse and portends vulnerability toward future misuse. The choice task may provide important medical information to guide opioid-prescribing practices.

Brain-behavior relations and effects of aging and common comorbidities in alcohol use disorder: A review

OBJECTIVE

Alcohol use disorder (AUD) is a complex, dynamic condition that waxes and wanes with unhealthy drinking episodes and varies in drinking patterns and effects on brain structure and function with age. Its excessive use renders chronically heavy drinkers vulnerable to direct alcohol toxicity and a variety of comorbidities attributable to nonalcohol drug misuse, viral infections, and accelerated or premature aging. AUD affects widespread brain systems, commonly, frontolimbic, frontostriatal, and frontocerebellar networks.

METHOD AND RESULTS

Multimodal assessment using selective neuropsychological testing and whole-brain neuroimaging provides evidence for AUD-related specific brain structure-function relations established with double dissociations. Longitudinal study using noninvasive imaging provides evidence for brain structural and functional improvement with sustained sobriety and further decline with relapse. Functional imaging suggests the possibility that some alcoholics in recovery can compensate for impairment by invoking brain systems typically not used for a target task but that can enable normal-level performance.

CONCLUSIONS

Evidence for AUD-aging interactions, indicative of accelerated aging, together with increasing alcohol consumption in middle-age and older adults, put aging drinkers at special risk for developing cognitive decline and possibly dementia. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Distress tolerance trajectories following substance use treatment

OBJECTIVE

Distress tolerance (DT), the ability to withstand aversive internal states, represents an important risk factor for substance use relapse and a potential treatment target. Neurobiological research in substance using populations suggests that continued substance use could erode DT, whereas abstinence could bolster it. The current study characterized trajectories of behavioral and self-reported indices of DT and examined the prospective effect of substance use on DT trajectories among those seeking treatment for substance use.

METHOD

Individuals (N = 263, Mage = 42.68, SD = 11.8, 70.7% male, 94.7% African American) in residential substance use treatment completed subjective (Distress Tolerance Scale) and behavioral (Mirror Tracing Persistence Task-computerized version) DT measures, as well as report of daily substance use (timeline follow-back) over 5 assessment time-points from pretreatment to 12 months posttreatment. Latent curve modeling estimated DT trajectories and their associations with substance use behavior, including abstinence duration (days until first use) and substance use frequency (percentage of substance use days between assessments).

RESULTS

Self-reported and behavioral DT indicators both exhibited positive, nonlinear change over time (standardized slope parameter estimates: Distress Tolerance Scale β = 0.61, p < .01; Mirror Tracing Persistence Task β = 0.34, p < .01). Abstinence duration was associated with greater improvement in behavioral (β = .20, p = .03) DT specifically. Frequency of use was statistically significantly associated with attenuated behavioral DT at 6-month (β = -.12, p = .03) and 12-month follow-ups (β = -.08, p = .045).

CONCLUSIONS

DT appears to improve appreciably posttreatment, and return to substance use may shape the degree of this improvement. Collectively, these findings support the conceptualization of DT as a malleable treatment target and emphasize the benefit of abstinence on improvement in DT. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The importance of considering polysubstance use: lessons from cocaine research

BACKGROUND

Polysubstance use (PSU) is prevalent among individuals with substance use disorders, but the vast majority of preclinical substance use research has focused on individual substances in isolation. Cocaine has been prevalent in the repertoire of persons who use more than one illicit substance.

METHODS

We conducted a meta-analysis combining results from literature searches and secondary data analyses to estimate the prevalence of simultaneous and concurrent cocaine + alcohol and cocaine + cannabis use among cocaine users. We next summarized the small body of literature on behavioral, cognitive and neurobiological consequences of cocaine PSU across species, with a focus on alcohol and cannabis. Finally, we used systematic literature searches to assess the extent to which human and animal studies on the neurobiological consequences of cocaine include PSU subjects.

RESULTS

The estimated prevalence of simultaneous and concurrent alcohol use among human cocaine users was 74% and 77%, respectively. The estimated prevalence of simultaneous and concurrent cannabis use among cocaine users was 38% and 64%, respectively. Consumption of alcohol or cannabis with cocaine enhances subjective responses to cocaine, concomitant with changes in cocaine metabolism that increase blood cocaine levels, and, in the case of alcohol, produce the psychoactive metabolite cocaethylene. There is also consistent evidence for neurobiological effects of cocaine + alcohol combinations. However, animal PSU research with cocaine lags behind human research.

CONCLUSION

Based on the prevalence and known consequences of PSU, consideration of PSU in both human and animal research is vital for understanding patterns of substance use.

Socio-cognitive functioning in stimulant polysubstance users

BACKGROUND

Using more than one psychotropic substance is accompanied by increased risks for psychiatric and physical disorders. Accordingly, deficits in basal cognitive functions have been consistently associated with polysubstance use (PSU), whereas little is known about potential impairments in more complex socio-cognitive skills, which are relevant for daily-life functioning. Therefore, we investigated the effects of toxicological validated stimulant PSU on social cognition under consideration of potential cumulative effects.

METHODS

We compared socio-cognitive performances of 47 individuals with stimulant PSU with 59 matched stimulant-naïve controls using the Multifaceted Empathy Test (MET) and the Movie for the Assessment of Social Cognition (MASC). Additionally, social network size was assessed by the Social Network Questionnaire (SNQ). Hair and urine testing was employed to categorize three PSU subgroups (3, 4, and ≥5 substances used) and to ensure drug abstinence in controls.

RESULTS

Individuals with stimulant PSU showed lower emotional empathy (MET) and a smaller social network (SNQ) compared to controls (both with linear trends for increasing number of used substances: p < .05). In contrast, cognitive empathy (MET and MASC) was largely unaffected by PSU. Additional linear regression analyses within PSU individuals revealed number of used substances as the best predictor for inferior performance in emotional empathy (p < .01), while severity of the use of single substances or substance-classes did not show a significant impact.

CONCLUSION

These findings demonstrate cumulative adverse effects of stimulant PSU on an important facet of socio-cognitive functioning. Therefore, emotional empathy deficits should be targeted in future interventions and rehabilitations for individuals with PSU.

Emotional Availability, Neuropsychological Functioning, and Psychopathology: The Context of Parental Substance Use Disorder

Parental Substance Use Disorder (SUD) constitutes a high-risk condition for parent-child interactions and child development. Empirical evidence indicates high rates of psychopathology and neuropsychological impairments in individuals with SUD. Despite research indicating that parenting skills are related to psychological well-being and cognitive/neuropsychological functioning, prior studies have not examined the associations between these areas of parental functioning and the quality of parent-child interactions in the context of SUD. Aim(s). The present study adopts an integrated perspective to investigate the way in which maternal neuropsychological functioning and psychopathology are associated with mother-child emotional availability (EA), in the context of parental Substance Use Disorder. Methods. Twenty-nine mothers with SUD were assessed in interaction with their children, as well as with respect to their neuropsychological functioning and psychopathology. Results. In this group, high rates of maternal neuropsychological impairments and psychopathology, as well as generally low levels of EA, were uncovered. Regression analyses showed that maternal neuropsychological functioning was significantly associated with mother-child EA, specifically sensitivity; the role of maternal psychopathology, however, was only marginally significant. Conclusion. In the context of SUD, maternal neuropsychological impairments are significantly associated with mother-child EA. Clinical implications of the findings are discussed.

Parental reflective functioning and executive functioning in mothers with substance use disorder

Having a substance use disorder (SUD) may adversely affect caregiving capacities. Reflective functioning (RF) and executive functioning (EF) are both important capacities for sensitive parenting, and are often impaired in a SUD. Only a few studies have explored the possible association between the two phenomena. In this study, we used a neuropsychological test battery to assess EF, and the Parent Development Interview to assess RF in a sample of mothers with a SUD (N = 43). Although parental RF (PRF) was associated with EF, when controlled for intelligence (IQ) and mental health, there was no significant association between EF and PRF. Mental health, however, showed a significant negative association with PRF. Splitting the group in two based on PRF level, mothers with a negative to low PRF exhibited more severe difficulties in SUD-related aspects, as well as in several EF components, compared to mothers with an adequate to high PRF, highlighting the association between EF and PRF. The results from this study contribute to enhance our understanding of the dynamics underlying vulnerability in PRF that mothers with small children may experience. We suggest EF to be a prerequisite for adequate PRF, and for interventions to be customized accordingly regarding parents with a SUD.

Prone to feel guilty: Self-evaluative emotions in alcohol-dependence

BACKGROUND

Prior research has repeatedly shown that alcohol-dependence is associated with interpersonal difficulties. However, guilt and shame, two crucial self-evaluative emotions triggered by the transgression of social norms, have not been explored among alcohol-dependent individuals despite their important role in psychiatric disorders. The present study thus aimed to investigate whether alcohol-dependence is associated with greater proneness to negatively evaluate one's own behaviors (guilt) or the entire self (shame).

METHODS

25 alcohol-dependent individuals (ADI) and 25 matched healthy individuals completed a scenario-based inventory (TOSCA-3), requiring from participants to rate the extent they will react to each scenario in terms of (contextualized) guilt and shame. Participants also completed a list of adjectives related to the frequency at which they generally experience (uncontextualized) guilt and shame (PFQ-2).

RESULTS

When controlling for possible confounds (i.e., depression and anxiety), ADI reported greater proneness to experience guilt at the TOSCA-3 (η²=.22) compared to healthy individuals.

CONCLUSIONS

This study is the first to show that alcohol-dependence is associated with greater contextualized guilt-proneness, i.e., negative evaluation of one's own behaviors that transgress social norms. Therefore, these results reinforce the relevance of social disorders in alcohol-dependence and indicate that ADI may benefit of therapeutic programs to avoid a generalization of guilt towards shame.

Using the research domain criteria (RDoC) to conceptualize impulsivity and compulsivity in relation to addiction

Nomenclature for mental disorder was updated in 2013 with the publication of the fifth edition of the Diagnostic and Statistical Manual (DSM-5). In DSM-5, substance use disorders are framed as more dimensional. First, the distinction between abuse and dependence is replaced by substance use. Second, the addictions section now covers both substances and behavioral addictions. This contemporary move toward dimensionality and transdiagnosis in the addictions and other disorders embrace accumulating cognitive-affective neurobiological evidence that is reflected in the United States' National Institutes of Health Research Domain Criteria (NIH RDoC). The RDoC calls for the further development of transdiagnostic approaches to psychopathy and includes five domains to improve research. Additionally, the RDoC suggests that these domains can be measured in terms of specific units of analysis. In line with these suggestions, recent publications have stimulated updated neurobiological conceptualizations of two transdiagnostic concepts, namely impulsivity and compulsivity and their interactions that are applicable to addictive disorders. However, there has not yet been a review to examine the constructs of impulsivity and compulsivity in relation to addiction in light of the research-oriented RDoC. By doing so it may become clearer as to whether impulsivity and compulsivity function antagonistically, complementarily or in some other way at the behavioral, cognitive, and neural level and how this relationship underpins addiction. Thus, here we consider research into impulsivity and compulsivity in light of the transdiagnostic RDoC to help better understand these concepts and their application to evidence-based clinical intervention for addiction.

Structural Neuroimaging in Polysubstance Users

The simultaneous and/or concurrent use of licit and illicit substances (polysubstance use, PSU) is most common today. Structural magnetic resonance imaging (MRI) has been applied extensively to study individuals ostensibly using a single substance. These studies have produced a picture of regional gray matter and white matter alterations with each substance or class of substances. Very few studies measured regional brain morphometry in today's polysubstance users. This limited data suggest morphometric alterations with PSU that are not simply additive but often different from those of monosubstance users. Specifically, subcortical volume enlargements are observed that may be tied to mechanisms that also oppose volume reductions in cortical brain regions, thereby underestimating actual cortical atrophy. The complex actions of polysubstance use on brain structure and function need greater scrutiny with strong methodological approaches to inform more efficient treatment of polysubstance users.