Volumetric brain abnormalities in polysubstance use disorder patients

Functional and structural brain abnormalities in substance use disorder: A multimodal meta-analysis of neuroimaging studies

INTRODUCTION

Numerous neuroimaging studies of resting-state functional imaging and voxel-based morphometry (VBM) have revealed that patients with substance use disorder (SUD) may present brain abnormalities, but their results were inconsistent. This multimodal neuroimaging meta-analysis aimed to estimate common and specific alterations in SUD patients by combining information from all available studies of spontaneous functional activity and gray matter volume (GMV).

METHODS

A whole-brain meta-analysis on resting-state functional imaging and VBM studies was conducted using the Seed-based d Mapping with Permutation of Subject Images (SDM-PSI) software, followed by multimodal overlapping to comprehensively investigate function and structure of the brain in SUD.

RESULTS

In this meta-analysis, 39 independent studies with 47 datasets related to resting-state functional brain activity (1444 SUD patients; 1446 healthy controls [HCs]) were included, as well as 77 studies with 89 datasets for GMV (3457 SUD patients; 3774 HCs). Patients with SUD showed the decreased resting-state functional brain activity in the bilateral anterior cingulate cortex/medial prefrontal cortex (ACC/mPFC). For the VBM meta-analysis, patients with SUD showed the reduced GMV in the bilateral ACC/mPFC, insula, thalamus extending to striatum, and left sensorimotor cortex.

CONCLUSIONS

This multimodal meta-analysis exhibited that SUD shows common impairment in both function and structure in the ACC/mPFC, suggesting that the deficits in functional and structural domains could be correlated together. In addition, a few regions exhibited only structural impairment in SUD, including the insula, thalamus, striatum, and sensorimotor areas.

A retrospective analysis of substance use among female psychiatric patients in Saudi Arabia

Objective

This study investigated the prevalence of substance use (SU), and its risk factors, among women attending psychiatric outpatients center in Saudi Arabia.

Design

A retrospective cross-sectional design.

Materials and methods

We reviewed outpatients' records of 200 female patients with a history of SU from a psychiatric unit in Jeddah, Saudi Arabia from December 2018 to February 2019. The researchers developed the pro forma, and 2 psychiatrists and a family medicine physician validated the form.

Results

The most common and widely used were psychoactive substances (58%), followed by central nervous system (CNS) depressants (22%), and finally cannabinols (9.5%). Overall, the highest substance use was the amphetamine-cannabis-nicotine (ACN) representing nearly half of the illicit items (46.6%), followed by heroine-alcohol-benzodiazepine (16.4%), and with the lowest being benzodiazepine-nicotine (1.7%). There was a significant difference between the single substance and multiple substance use in terms of age (p = 0.001), smoking behavior (p = 0.001), patients past history (p = 0.005), and age of the patient at the start of drug use (p = 0.005).

Conclusion

Although the prevalence of substance use among women is low in Saudi Arabia, screening of substance use disorders risks and building a rehabilitation program to control drug dependence are needed.

Correlates of methamphetamine use severity among patients receiving methadone maintenance treatment for opioid use disorder in Vietnam

OBJECTIVES

To assess the severity of methamphetamine use among methadone maintenance treatment (MMT) patients in Vietnam with opioid use disorder and concurrent methamphetamine use, and to identify risk factors associated with higher severity of methamphetamine use.

METHODS

We used survey data and medical record abstractions from 428 people with opioid use disorder who also use methamphetamine while partaking in methadone treatment in five clinics in Hanoi, Vietnam. We used multinomial logistic regression to assess other risk factors and problems associated with high methamphetamine use severity.

RESULTS

Those who reported injecting heroin in the past 3 months (AOR = 4.05, 95% CI [1.30, 12.55], p = 0.02), having a longer history of lifetime heroin use (AOR = 1.13, 95% CI [1.03, 1.24], p < 0.01), and having higher cravings (AOR = 1.97, 95% CI [1.31, 2.98], p < 0.01) and fatigue (AOR = 1.25, 95% CI [0.96, 1.61], p = 0.09) related to methamphetamine withdrawal had greater odds of high methamphetamine use severity. One of five clinics had a significantly higher percentage of methamphetamine use severity than others.

CONCLUSION

Successful MMT in patients with opioid use disorder in Vietnam may additionally require methamphetamine-focused screening and intervention.

A Virtual Reality Meditative Intervention Modulates Pain and the Pain Neuromatrix in Patients with Opioid Use Disorder

OBJECTIVE

Standard of care for opioid use disorder (OUD) includes medication and counseling. However, there is an unmet need for complementary approaches to treat OUD patients coping with pain; furthermore, few studies have probed neurobiological features of pain or its management during OUD treatment. This preliminary study examines neurobiological and behavioral effects of a virtual reality-based meditative intervention in patients undergoing methadone maintenance treatment (MMT).

DESIGN

Prospective, non-blinded, single-arm, 12-week intervention with standardized assessments.

SETTING

Academic research laboratory affiliated with an on-site MMT clinic.

METHODS

Fifteen (11 female) MMT patients completed a virtual reality, therapist-guided meditative intervention that included breathing and relaxation exercisessessions were scheduled twice weekly. Assessments included functional magnetic resonance imaging (fMRI) of pain neuromatrix activation and connectivity (pre- and post-intervention), saliva cortisol and C-reactive protein (CRP) at baseline and weeks 4, 8 and 12; and self-reported pain and affective symptoms before and after each intervention session.

RESULTS

After each intervention session (relative to pre-session), ratings of pain, opioid craving, anxiety and depression (but not anger) decreased. Saliva cortisol (but not CRP) levels decreased from pre- to post-session. From pre- to post-intervention fMRI assessments, pain task-related left postcentral gyrus (PCG) activation decreased. At baseline, PCG showed positive connectivity with other regions of the pain neuromatrix, but this pattern changed post-intervention.

CONCLUSIONS

These preliminary findings demonstrate feasibility, therapeutic promise, and brain basis of a meditative intervention for OUD patients undergoing MMT.

The associations of comorbid substance use disorders and psychiatric conditions with adolescent brain structure and function: A review

Adolescence is a period of rapid neural and behavioral development that often precipitates substance use, substance use disorders (SUDs), and other psychopathology. While externalizing disorders have been closely linked to SUD epidemiologically, the comorbidity of internalizing disorders and SUD is less well understood. Neuroimaging studies can be used to measure structural and functional developments in the brain that mediate the relationship between psychopathology and SUD in adolescence. Externalizing disorders and SUD are both associated with structural and functional changes in the basal ganglia and prefrontal cortex in adolescence. The neural mechanisms underlying internalizing disorders and SUD are less clear, but evidence points to involvement of the amygdala and prefrontal cortex. We also highlight independent contributions of SUD, which may vary in certain ways by the substances assessed. A deeper understanding of the neural basis of the relationship between psychopathology and SUD will allow for more informed interventions in this critical developmental stage.

The thalamus in drug addiction: from rodents to humans

Impairments in response inhibition and salience attribution (iRISA) have been proposed to underlie the clinical symptoms of drug addiction as mediated by cortico-striatal-thalamo-cortical networks. The bulk of evidence supporting the iRISA model comes from neuroimaging research that has focused on cortical and striatal influences with less emphasis on the role of the thalamus. Here, we highlight the importance of the thalamus in drug addiction, focusing on animal literature findings on thalamic nuclei in the context of drug-seeking, structural and functional changes of the thalamus as measured by imaging studies in human drug addiction, particularly during drug cue and non-drug reward processing, and response inhibition tasks. Findings from the animal literature suggest that the paraventricular nucleus of the thalamus, the lateral habenula and the mediodorsal nucleus may be involved in the reinstatement, extinction and expression of drug-seeking behaviours. In support of the iRISA model, the human addiction imaging literature demonstrates enhanced thalamus activation when reacting to drug cues and reduced thalamus activation during response inhibition. This pattern of response was further associated with the severity of, and relapse in, drug addiction. Future animal studies could widen their field of focus by investigating the specific role(s) of different thalamic nuclei in different phases of the addiction cycle. Similarly, future human imaging studies should aim to specifically delineate the structure and function of different thalamic nuclei, for example, through the application of advanced imaging protocols at higher magnetic fields (7 Tesla).This article is part of a discussion meeting issue 'Of mice and mental health: facilitating dialogue between basic and clinical neuroscientists'.

Testing associations between cannabis use and subcortical volumes in two large population-based samples

BACKGROUND AND AIMS

Disentangling the putative impact of cannabis on brain morphology from other comorbid substance use is critical. After controlling for the effects of nicotine, alcohol and multi-substance use, this study aimed to determine whether frequent cannabis use is associated with significantly smaller subcortical grey matter volumes.

DESIGN

Exploratory analyses using mixed linear models, one per region of interest (ROI), were performed whereby individual differences in volume (outcome) at seven subcortical ROIs were regressed onto cannabis and comorbid substance use (predictors).

SETTING

Two large population-based twin samples from the United States and Australia.

PARTICIPANTS

A total of 622 young Australian adults [66% female; μage  = 25.9, standard deviation SD) = 3.6] and 474 middle-aged US males (μage  = 56.1SD = 2.6 ) of predominately Anglo-Saxon ancestry with complete substance use and imaging data. Subjects with a history of stroke or traumatic brain injury were excluded.

MEASUREMENTS

Magnetic resonance imaging (MRI) and volumetric segmentation methods were used to estimate volume in seven subcortical ROIs: thalamus, caudate nucleus, putamen, pallidum, hippocampus, amygdala and nucleus accumbens. Substance use measurements included maximum nicotine and alcohol use, total life-time multi-substance use, maximum cannabis use in the young adults and regular cannabis use in the middle-aged males.

FINDINGS

After correcting for multiple testing (P = 0.007), cannabis use was unrelated to any subcortical ROI. However, maximum nicotine use was associated with significantly smaller thalamus volumes in middle-aged males.

CONCLUSIONS

In exploratory analyses based on young adult and middle-aged samples, normal variation in cannabis use is unrelated statistically to individual differences in brain morphology as measured by subcortical volume.