Subcortical volumes in long-term abstinent alcoholics: associations with psychiatric comorbidity

Links between psychopathological symptoms and cortical thickness in men with severe alcohol use disorder: A Magnetic Resonance Imaging study

BACKGROUND

Anxiety and depression are psychopathological states frequently co-occurring with severe alcohol use disorder (SAUD). These symptoms generally disappear with abstinence but may persist in some patients, increasing the relapse risk.

METHODS

The cerebral cortex thickness of 94 male patients with SAUD was correlated with symptoms of depression and anxiety, both measured at the end (2-3 weeks) of the detoxification treatment. Cortical measures were obtained using surface-based morphometry implemented with Freesurfer.

RESULTS

Depressive symptoms were associated with reduced cortical thickness in the superior temporal gyrus of the right hemisphere. Anxiety level was correlated with lower cortical thickness in the rostral middle frontal region, inferior temporal region, and supramarginal, postcentral, superior temporal, and transverse temporal regions of the left hemisphere, as well as with a large cluster in the middle temporal region of the right hemisphere.

CONCLUSIONS

At the end of the detoxification stage, the intensity of depressive and anxiety symptoms is inversely associated with the cortical thickness of regions involved in emotions-related processes, and the persistence of the symptoms could be explained by these brain deficits.

Caudate gray matter volumes and risk of relapse in Type A alcohol-dependent patients: A 7-year MRI follow-up study

BACKGROUND

Whether alteration in regional brain volumes can be detected in Type A alcoholics both at baseline and after a long follow-up remains to be confirmed. Therefore, we examined volume alterations at baseline, and longitudinal changes in a small follow-up subsample.

METHODS

In total of 26 patients and 24 healthy controls were assessed at baseline using magnetic resonance imaging and voxel-based morphometry, among which 17 patients and 6 controls were re-evaluated 7 years later. At baseline, regional cerebral volumes of patients were compared to controls. At follow-up, three groups were compared: abstainers (n = 11, more than 2 years of abstinence), relapsers (n = 6, <2 years of abstinence), and controls (n = 6).

RESULTS

The cross-sectional analyses detected, at both times, higher caudate nuclei volumes bilaterally in relapsers compared to abstainers. In abstainers, the longitudinal analysis indicated recovery of normal gray matter volumes in the middle and inferior frontal gyrus, and in the middle cingulate, while white matter volumes recovery was detected in the corpus callosum and in anterior and superior white matter specific regions.

CONCLUSIONS

Overall, the present investigation revealed larger caudate nuclei in the relapser AUD patient group both at baseline and at follow-up in the cross-sectional analyses. This finding suggest that a higher caudate volume could be a candidate risk factor of relapse. In patients with specific type A alcohol-dependence, we showed that long-term recovery in fronto-striato-limbic GM and WM volumes occurs during long-term abstinence. These results support the crucial role of frontal circuitry in AUD.

Hippocampal subfield volumes in abstinent men and women with a history of alcohol use disorder

Alcohol Use Disorder (AUD) has been associated with abnormalities in hippocampal volumes, but these relationships have not been fully explored with respect to sub-regional volumes, nor in association with individual characteristics such as age, gender differences, drinking history, and memory. The present study examined the impact of those variables in relation to hippocampal subfield volumes in abstinent men and women with a history of AUD. Using Magnetic Resonance Imaging at 3 Tesla, we obtained brain images from 67 participants with AUD (31 women) and 64 nonalcoholic control (NC) participants (31 women). The average duration of the most recent period of sobriety for AUD participants was 7.1 years. We used Freesurfer 6.0 to segment the hippocampus into 12 regions. These were imputed into statistical models to examine the relationships of brain volume with AUD group, age, gender, memory, and drinking history. Interactions with gender and age were of particular interest. Compared to the NC group, the AUD group had approximately 5% smaller subiculum, CA1, molecular layer, and hippocampal tail regions. Age was negatively associated with volumes for the AUD group in the subiculum and the hippocampal tail, but no significant interactions with gender were identified. The relationships for delayed and immediate memory with hippocampal tail volume differed for AUD and NC groups: Higher scores on tests of immediate and delayed memory were associated with smaller volumes in the AUD group, but larger volumes in the NC group. Length of sobriety was associated with decreasing CA1 volume in women (0.19% per year) and increasing volume size in men (0.38% per year). The course of abstinence on CA1 volume differed for men and women, and the differential relationships of subfield volumes to age and memory could indicate a distinction in the impact of AUD on functions of the hippocampal tail. These findings confirm and extend evidence that AUD, age, gender, memory, and abstinence differentially impact volumes of component parts of the hippocampus.

The Long-Term Effects of Ethanol and Corticosterone on the Mood-Related Behaviours and the Balance Between Mature BDNF and proBDNF in Mice

In this study, we aimed to establish the effects of chronic corticosterone (CORT) and ethanol administration on mood-related behaviour and the levels of mature brain-derived neurotrophic factor (mBDNF) and its precursor protein proBDNF in mice. C57BL6 male and female mice received drinking water (n = 22), 1% ethanol in drinking water (n = 16) or 100 μg/ml corticosterone in drinking water (containing 1% ethanol, n = 18) for 4.5 weeks. At the end of experimental protocol, the open field test (OFT) and elevated plus maze test were performed. Brain and adrenal tissues were collected and mBDNF and proBDNF were measured by ELISA assays. We found that the mice fed with corticosterone and ethanol developed anxiety-like behaviours as evidenced by reduced time in the central zone in the OFT compared with the control group. Both proBDNF and mBDNF were significantly decreased in the corticosterone and ethanol groups compared with the control group in the prefrontal cortex, hippocampus, hypothalamus and adrenal. The ratio of proBDNF/mBDNF in prefrontal cortex in the corticosterone group was increased compared with the ethanol group. Our data suggest that the ratio of proBDNF/mBDNF is differentially regulated in different tissues. Ethanol and corticosterone downregulate both mBDNF and proBDNF and alter the balance of proBDNF/mBDNF in some tissues. In conclusion, the ethanol and corticosterone may cause abnormal regulation of mBDNF and proBDNF which may lead to mood disorders.

Grey matter structural differences in alcohol-dependent individuals with and without comorbid depression/anxiety-an MRI study

Although depression and anxiety disorders are common comorbid conditions in alcohol dependence, few structural brain imaging studies have compared alcohol-dependent subjects with and without such comorbidity. In the current study, brain scans of 35 alcohol-dependent with and 40 individuals without diagnosis of a comorbid ICD-10 depressive or anxiety disorder receiving detoxification inpatient treatment were evaluated. Thickness and volumes of automatically segmented neuroanatomical structures were measured in FreeSurfer. Furthermore, associations of brain structure with biological markers and clinical severity markers of alcohol dependence were assessed. Despite comparable addiction severity, the non-comorbid group had evidence of higher cytotoxic effects of alcohol use on hepatic and haematological markers, and showed significantly smaller volumes of total cerebral, and cerebellar grey matter. Similarly, they showed unexpected smaller hippocampal and nucleus accumbens volumes, and thinner frontal, temporal and occipital cortices. Smaller brain volumes correlated with increased markers of hepatic and haematological dysfunction, and with longer duration of alcohol dependence in the non-comorbid group. Evidence of higher biomarkers of alcohol use may be indicative of more severe alcohol dependence or higher vulnerability to ethanol toxicity in this group. Furthermore, psychopathology-related drug treatment, which occurred in 53% of the comorbid group over the recent years, or tissue inflammation may have a moderate effect on the grade of cerebral atrophy in alcohol-dependent patients. Longitudinal studies are needed to investigate this issue more fully.

Brain Volume Correlates with Duration of Abstinence from Substance Abuse in a Region-Specific and Substance-Specific Manner

Background

Human neuroimaging studies indicate that the loss of brain volume associated with substance abuse may be recovered during abstinence. Subcortical and prefrontal cortical regions involved in reward and decision-making are among the regions most consistently implicated in damage and recovery from substance abuse, but the relative capacities of these different brain regions to recover volume during abstinence remains unclear, and it is unknown whether recovery capacities depend on the substance that was abused.

Methods

Voxel-based morphometry in a prison inmate sample (n=107) of long-term abstinent former regular users (FRUs) and former light users (FLUs) of alcohol, cocaine, and/or cannabis. Cross-sectional indicators of volume recovery were operationalized as 1) positive correlation between abstinence duration and volume in FRUs and 2) absence of lower volume in FRUs compared to FLUs.

Results

In FRUs of alcohol, abstinence duration positively correlated with volume in subcortical regions (particularly the putamen and amygdala) but not prefrontal regions; lower prefrontal but not subcortical volume was observed in FRUs compared to FLUs. In FRUs of cocaine, abstinence duration positively correlated with volume in both subcortical regions (particularly the nucleus accumbens) and prefrontal regions; lower volume was not observed in either subcortical or prefrontal regions in FRUs. In FRUs of cannabis, abstinence duration positively correlated with subcortical but not prefrontal volume; lower prefrontal but not subcortical volume was observed in FRUs.

Conclusions

Subcortical structures displayed indicators of volume recovery across FRUs of all three substances, whereas prefrontal regions displayed indicators of volume recovery only in FRUs of cocaine.

Volumetric Reductions of Subcortical Structures and Their Localizations in Alcohol-Dependent Patients

Changes in brain morphometry have been extensively reported in various studies examining the effects of chronic alcohol use in alcohol-dependent patients. Such studies were able to confirm the association between chronic alcohol use and volumetric reductions in subcortical structures using FSL (FMRIB software library). However, each study that utilized FSL had different sets of subcortical structures that showed significant volumetric reduction. First, we aimed to investigate the reproducibility of using FSL to assess volumetric differences of subcortical structures between alcohol-dependent patients and control subjects. Second, we aimed to use Vertex analysis, a less utilized program, to visually inspect 3D meshes of subcortical structures and observe significant shape abnormalities that occurred in each subcortical structure. Vertex analysis results from the hippocampus and thalamus were overlaid on top of their respective subregional atlases to further pinpoint the subregional locations where shape abnormalities occurred. We analyzed the volumes of 14 subcortical structures (bilateral thalamus, caudate, putamen, globus pallidus, hippocampus, amygdala, nucleus accumbens) in 21 alcohol-dependent subjects and 21 healthy controls using images acquired with 3T MRI. The images were run through various programs found in FSL, such as SIENAX, FIRST, and Vertex analysis. We found that in alcohol-dependent patients, the bilateral thalamus (left: p < 0.01, right: p = 0.01), bilateral putamen (left: p = 0.02, right: p < 0.01), right globus pallidus (p < 0.01), bilateral hippocampus (left: p = 0.05, right: p = 0.03) and bilateral nucleus accumbens (left: p = 0.05, right: p = 0.03) were significantly reduced compared to the corresponding subcortical structures of healthy controls. With vertex analysis, we observed surface reductions of the following hippocampal subfields: Presubiculum, hippocampal tail, hippocampal molecular layer, hippocampal fissure, fimbria, and CA3. We reproduced the assessment made in previous studies that reductions in subcortical volume were negatively associated with alcohol dependence by using the FMRIB Software Library. In addition, we identified the subfields of the thalamus and hippocampus that showed volumetric reduction.

Subcortical Volume Changes in Migraine with Aura

Background and Purpose

Various features of the cerebral cortex and white matter have been extensively investigated in migraine with aura (MwA), but the morphological characteristics of subcortical structures have been largely neglected. The aim of this study was to identify possible differences in subcortical structures between MwA patients and healthy subjects (HS), and also to determine the correlations between the characteristics of migraine aura and the volumes of subcortical structures.

Methods

Thirty-two MwA patients and 32 HS matched by sex and age were analyzed in this study. Regional subcortical brain volumes were automatically calculated using the FSL/FMRIB Image Registration and Segmentation Tool software (https://fsl.fmrib.ox.ac.uk/fsl/fslwiki/Glossary). A general linear model analysis was used to investigate differences in the volume of subcortical structures between the MwA patients and HS. A partial correlation test was used to assess correlations between the volume of subcortical structures and characteristics of MwA.

Results

The volumes of the right globus pallidus, left globus pallidus, and left putamen were significantly smaller in MwA patients than in HS (mean±SD): 1,427±135 mm³ vs. 1,557±136 mm³ (p<0.001), 1,436±126 mm³ vs. 1,550±139 mm³ (p=0.001), and 4,235±437 mm³ vs. 4,522±412 mm³ (p=0.006), respectively. There were no significant relationships between subcortical structures and clinical parameters.

Conclusions

These findings suggest that both the globus pallidi and left putamen play significant roles in the pathophysiology of the MwA. Future studies should determine the cause-and-effect relationships, since these could not be discriminated in this study due to its cross-sectional design.

Neuroimaging Studies in Patients With Mental Disorder and Co-occurring Substance Use Disorder: Summary of Findings

Introduction: More than half of psychiatric patients have comorbid substance use disorder (dual diagnosis) and this rate, confirmed by many epidemiological studies, is substantially higher compared to general population. Combined operation of self-medication mechanisms, common etiological factors, and mutually causative influences most likely accounts for comorbidity, which, despite its clinical prevalence, remains underrepresented in psychiatric research, especially in terms of neuroimaging. The current paper attempts to review and discuss all existing methodologically sustainable structural and functional neuroimaging studies in comorbid subjects published in the last 20 years. Methods: Performing a systematic PubMed/MEDLINE, Web of Science, and Cochrane databases search with predefined key-words and selection criteria, 43 structural and functional neuroimaging studies were analyzed. Results: Although markedly inconsistent and confounded by a variety of sources, available data suggest that structural brain changes are slightly more pronounced, yet not qualitatively different in comorbid patients compared to non-comorbid ones. In schizophrenia (SZ) patients, somewhat greater gray matter reduction is seen in cingulate cortex, dorsolateral prefrontal and frontotemporal cortex, limbic structures (hippocampus), and basal ganglia (striatum). The magnitude of structural changes is positively correlated to duration and severity of substance use, but it is important to note that at least in the beginning of the disease, dual diagnosis subjects tend to show less brain abnormalities and better cognitive functioning than pure SZ ones suggesting lower preexisting neuropathological burden. When analysing neuroimaging findings in SZ and bipolar disorder subjects, dorsolateral prefrontal, cingular, and insular cortex emerge as common affected areas in both groups which might indicate a shared endophenotypic (i.e., transdiagnostic) disruption of brain networks involved in executive functioning, emotional processing, and social cognition, rendering affected individuals susceptible to both mental disorder and substance misuse. In patients with anxiety disorders and substance misuse, a common neuroimaging finding is reduced volume of limbic structures (n. accumbens, hippocampus and amygdala). Whether this is a neuropathological marker of common predisposition to specific behavioral symptoms and drug addiction or a result from neuroadaptation changes secondary to substance misuse is unknown. Future neuroimaging studies with larger samples, longitudinal design, and genetic subtyping are warranted to enhance current knowledge on comorbidity.

Imaging resilience and recovery in alcohol dependence

BACKGROUND AND AIMS

Resilience and recovery are of increasing importance in the field of alcohol dependence (AD). This paper describes how imaging studies in man can be used to assess the neurobiological correlates of resilience and, if longitudinal, of disease trajectories, progression rates and markers for recovery to inform treatment and prevention options.

METHODS

Original papers on recovery and resilience in alcohol addiction and its neurobiological correlates were identified from PubMed and have been analyzed and condensed within a systematic literature review.

RESULTS

Findings deriving from functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) studies have identified links between increased resilience and less task-elicited neural activation within the basal ganglia, and benefits of heightened neural pre-frontal cortex (PFC) engagement regarding resilience in a broader sense; namely, resilience against relapse in early abstinence of AD. Furthermore, findings consistently propose at least partial recovery of brain glucose metabolism and executive and general cognitive functioning, as well as structural plasticity effects throughout the brain of alcohol-dependent patients during the course of short-, medium- and long-term abstinence, even when patients only lowered their alcohol consumption to a moderate level. Additionally, specific factors were found that appear to influence these observed brain recovery processes in AD, e.g. genotype-dependent neuronal (re)growth, gender-specific neural recovery effects, critical interfering effects of psychiatric comorbidities, additional smoking or marijuana influences or adolescent alcohol abuse.

CONCLUSIONS

Neuroimaging research has uncovered neurobiological markers that appear to be linked to resilience and improved recovery capacities that are furthermore influenced by various factors such as gender or genetics. Consequently, future system-oriented approaches may help to establish a broad neuroscience-based research framework for alcohol dependence.

Gender dimorphism of brain reward system volumes in alcoholism

The brain's reward network has been reported to be smaller in alcoholic men compared to nonalcoholic men, but little is known about the volumes of reward regions in alcoholic women. Morphometric analyses were performed on magnetic resonance brain scans of 60 long-term chronic alcoholics (ALC; 30 men) and 60 nonalcoholic controls (NC; 29 men). We derived volumes of total brain, and cortical and subcortical reward-related structures including the dorsolateral prefrontal (DLPFC), orbitofrontal, and cingulate cortices, and the temporal pole, insula, amygdala, hippocampus, nucleus accumbens septi (NAc), and ventral diencephalon (VDC). We examined the relationships of the volumetric findings to drinking history. Analyses revealed a significant gender interaction for the association between alcoholism and total reward network volumes, with ALC men having smaller reward volumes than NC men and ALC women having larger reward volumes than NC women. Analyses of a priori subregions revealed a similar pattern of reward volume differences with significant gender interactions for DLPFC and VDC. Overall, the volume of the cerebral ventricles in ALC participants was negatively associated with duration of abstinence, suggesting decline in atrophy with greater length of sobriety.

Volume of hippocampal subfields in patients with alcohol dependence

Alcohol-induced hippocampal atrophy has been well documented in many studies and is known to affect various subfields. Given the functional heterogeneity of these subfields, we investigated the precise effects of alcohol-induced damage in these areas. Twenty-six male patients with alcohol dependence (alcohol group) and twenty-six age-matched male healthy social drinkers were recruited from a mental health hospital and the community respectively, with the aim of comparing the hippocampal subfields between groups. Each participant underwent a 3T MRI scan. Hippocampal subfield volumes were estimated using an automated procedure and drinking history recorded using Lifetime Drinking History, Alcohol Use Disorder Identification Test, and the Brief Michigan Alcoholism Screening Test. The alcohol group showed a lower total hippocampus volume, specifically in the left presubiculum, fimbria, and bilateral subiculum. Regression analysis assessing the influence of age and group showed that group was a more significant factor than age in most subfields. Our findings suggest that alcohol dependence alters hippocampal subfield volumes. Further longitudinal studies on the interaction of structural and neurocognitive changes would improve our understanding of brain structural changes resulting from long-term alcohol consumption.

Surface-Based Parameters of Brain Imaging in Male Patients with Alcohol Use Disorder

OBJECTIVE

The structural alteration of brain shown in patients with alcohol use disorder (AUD) can originate from both alcohol effects and genetic or developmental processes. We compared surface-based parameters of patients with AUD with healthy controls to prove the applicability of surface-based morphometry with head size correction and to determine the areas that were sensitive to brain alteration related to AUD.

METHODS

Twenty-six abstinent male patients with AUD (alcohol group, mean abstinence=13.2 months) and twenty-eight age-matched healthy participants (control group) were recruited from an inpatient mental hospital and community. All participants underwent a 3T MRI scan. Surface-based parameters were determined by using FreeSurfer.

RESULTS

Every surface-based parameter of the alcohol group was lower than the corresponding control group parameter. There were large group differences in the whole brain, grey and white matter volume, and the differences were more prominent after head size correction. Significant group differences were shown in cortical thicknesses in entire brain regions, especially in parietal, temporal and frontal areas. There were no significant group differences in surface areas, but group difference trends in surface areas of the frontal and parietal cortices were shown after head size correction.

CONCLUSION

Most of the surface-based parameters in alcohol group were altered because of incomplete recovery from chronic alcohol exposure and possibly genetic or developmental factors underlying the risk of AUD. Surface-based morphometry with controlling for head size is useful in comparing the volumetric parameters and the surface area to a lesser extent in alcohol-related brain alteration.

Family history density of alcoholism relates to left nucleus accumbens volume in adolescent girls

OBJECTIVE

A family history of alcoholism is a significant risk factor for the development of alcohol use disorders (AUDs). Because common structural abnormalities are present in reward and affective brain regions in alcoholics and those with familial alcoholism, the current study examined the relationship between familial loading of AUDs and volumes of the amygdala and nucleus accumbens (NAcc) in largely alcohol-naive adolescents, ages 12-16 years (N = 140).

METHOD

The amygdala and NAcc were delineated on each participant's T1-weighted anatomical scan, using FMRIB Software Library's FMRIB Integrated Registration & Segmentation Tool, and visually inspected for accuracy and volume outliers. In the 140 participants with accurate segmentation (75 male/65 female), subcortical volumes were represented as a ratio to intracranial volume (ICV). A family history density (FHD) score was calculated for each adolescent based on the presence of AUDs in first- and second-degree relatives (range: 0.03-1.50; higher scores represent a greater prevalence of familial AUDs). Multiple regressions, with age and sex controlled for, examined the association between FHD and left and right amygdala and NAcc volume/ICV.

RESULTS

There was a significant positive relationship between FHD and left NAcc volume/ICV (ΔR² = .04, p = .02). Post hoc regressions indicated that this effect was only significant in females (ΔR² = .11, p = .006).

CONCLUSIONS

This finding suggests that the degree of familial alcoholism, genetic or otherwise, is associated with alterations in reward-related brain structure. Further work will be necessary to examine whether FHD is related to future alcohol-related problems and reward-related behaviors.

Transcranial Magnetic Stimulation and Deep Brain Stimulation in the treatment of alcohol dependence

Alcohol dependence is a major social, economic, and public health problem. Alcoholism can lead to damage of the gastrointestinal, nervous, cardiovascular, and respiratory systems and it can be lethal, costing hundreds of billions to the health care system. Despite the existence of cognitive-behavioral therapy, psychosocial interventions, and spiritually integrated treatment to treat it, alcohol dependence has a high relapse rate and poor prognosis, albeit with high interindividual variability. In this review, we discuss the use of two neuromodulation techniques, namely repetitive transcranial magnetic stimulation (rTMS) and deep brain stimulation (DBS), and their advantages and disadvantages compared to first-line pharmacological treatment for alcohol dependence. We also discuss rTMS and DBS targets for alcohol dependence treatment, considering experimental animal and human evidence, with careful consideration of methodological issues preventing the identification of feasible targets for neuromodulation treatments, as well as inter-individual variability factors influencing alcoholism prognosis. Lastly, we anticipate future research aiming to tailor the treatment to each individual patient by combining neurofunctional, neuroanatomical and neurodisruptive techniques optimizing the outcome.

Thalamic abnormalities are a cardinal feature of alcohol-related brain dysfunction

Two brain networks are particularly affected by the harmful effect of chronic and excessive alcohol consumption: the circuit of Papez and the frontocerebellar circuit, in both of which the thalamus plays a key role. Shrinkage of the thalamus is more severe in alcoholics with Korsakoff's syndrome (KS) than in those without neurological complication (AL). In accordance with the gradient effect of thalamic abnormalities between AL and KS, the pattern of brain dysfunction in the Papez's circuit results in anterograde amnesia in KS and only mild-to-moderate episodic memory disorders in AL. On the opposite, dysfunction of the frontocerebellar circuit results in a similar pattern of working memory and executive deficits in the AL and KS. Several hypotheses, mutually compatible, can be drawn to explain that the severe thalamic shrinkage observed in KS has different consequences in the neuropsychological profile associated with the two brain networks.

Profiles of impaired, spared, and recovered neuropsychologic processes in alcoholism

Long-term chronic alcoholism is associated with disparate and widespread residual consequences for brain functioning and behavior, and alcoholics suffer a variety of cognitive deficiencies and emotional abnormalities. Alcoholism has heterogeneous origins and outcomes, depending upon factors such as family history, age, gender, and mental or physical health. Consequently, the neuropsychologic profiles associated with alcoholism are not uniform among individuals. Moreover, within and across research studies, variability among subjects is substantial and contributes to characteristics associated with differential treatment outcomes after detoxification. In order to refine our understanding of alcoholism-related impaired, spared, and recovered abilities, we focus on five specific functional domains: (1) memory; (2) executive functions; (3) emotion and psychosocial skills; (4) visuospatial cognition; and (5) psychomotor abilities. Although the entire brain might be vulnerable in uncomplicated alcoholism, the brain systems that are considered to be most at risk are the frontocerebellar and mesocorticolimbic circuitries. Over time, with abstinence from alcohol, the brain appears to become reorganized to provide compensation for structural and behavioral deficits. By relying on a combination of clinical and scientific approaches, future research will help to refine the compensatory roles of healthy brain systems, the degree to which abstinence and treatment facilitate the reversal of brain atrophy and dysfunction, and the importance of individual differences to outcome.

Perspectives on the neuroscience of alcohol from the National Institute on Alcohol Abuse and Alcoholism

Mounting evidence over the last 40 years clearly indicates that alcoholism (alcohol dependence) is a disorder of the brain. The National Institute on Alcohol Abuse and Alcoholism (NIAAA) has taken significant steps to advance research into the neuroscience of alcohol. The Division of Neuroscience and Behavior (DNB) was formed within NIAAA in 2002 to oversee, fund, and direct all research areas that examine the effects of alcohol on the brain, the genetic underpinnings of alcohol dependence, the neuroadaptations resulting from excessive alcohol consumption, advanced behavioral models of the various stages of the addiction cycle, and preclinical medications development. This research portfolio has produced important discoveries in the etiology, treatment, and prevention of alcohol abuse and dependence. Several of these salient discoveries are highlighted and future areas of neuroscience research on alcohol are presented.

Consensus paper of the WFSBP task force on biological markers: biological markers for alcoholism

OBJECTIVES

This article presents an overview of the current literature on biological markers for alcoholism, including markers associated with the pharmacological effects of alcohol and markers related to the clinical course and treatment of alcohol-related problems. Many of these studies are well known, while other studies cited are new and still being evaluated.

METHODS

In this paper we first describe known biomarkers of alcohol-related disorders, review their features and the problems involved in their use. We then consider future developments on biomarkers and their possible impact on the field.

RESULTS

More recent findings cited include the work on type 7 adenylcyclase (AC) polymorphism and its lower expression levels in female alcoholics. Neuroimaging studies involving biomarkers have also reported brain volume reductions of gray and white matter, including amygdala and subcortical regions in alcoholic patients, while a high association between the copy number variations (CNVs) in 6q14.1/5q13.2 and alcohol dependence has more recently been identified in genetic studies.

CONCLUSIONS

In addition to their possible importance for diagnosis, biomarkers may have utility for predicting prognosis, progression of the disorder, the development of new treatments, and monitoring treatment effects. Although such findings should be verified in independent studies, the search for new biomarkers is continuing. Several potential candidate biomarkers have been found recently in blood, imaging, and genetic studies with encouraging results.

Cortical and subcortical volumes in adolescents with alcohol dependence but without substance or psychiatric comorbidities

Most prior studies of the effects of excessive alcohol intake on the adolescent brain examined alcohol-use-dependent samples with comorbid psychiatric and substance use disorders. In the Cape Town region, we identified a sizeable cohort of adolescents with alcohol use disorders (AUD) without externalizing or other psychiatric disorders. We examined brain morphology in 64 such adolescents compared to age- and gender-matched healthy controls. Magnetic resonance imaging data were analyzed using FSL's FIRST software for subcortical volumes, and cortical gray matter (GM) was analyzed using voxel-based morphometry (VBM) and regions of interest (ROI) analysis. AUD boys had smaller thalamic and putamen volumes compared to non-drinking boys, while AUD girls had larger thalamic and putamen volumes compared to non-drinking girls. VBM revealed a large region of decreased GM density in AUDs compared to controls located in the left lateral frontal, temporal, and parietal lobes, extending medially deep into the parietal lobe. Smaller GM volume in this region was also present when examined using ROI analysis. Our lack of findings in other brain regions, particularly the hippocampus, suggests that reports of smaller brain volumes in adolescent AUDs in the literature are a consequence of psychiatric and substance abuse comorbidities.

Structural alterations in brainstem of fibromyalgia syndrome patients correlate with sensitivity to mechanical pressure

Fibromyalgia syndrome is a chronic pain disorder characterised by widespread pain and tenderness in muscles and deep tissues. Current theories regarding the pathophysiological origins of fibromyalgia syndrome point towards central sensitisation and a decreased capacity of descending nociceptive controls. Morphological alterations to subcortical brain regions may contribute to such pathophysiological mechanisms, and to pain and other symptoms seen in fibromyalgia. Therefore, we evaluated geometric differences in subcortical structures in fibromyalgia patients relative to healthy people using a novel method of shape analysis. Sixteen female fibromyalgia patients and 15 age and sex matched, healthy control subjects underwent high-resolution T1-weighted magnetic resonance image scanning. Data was analysed using shape analysis of 15 subcortical regions and standard voxel-based morphometry analysis.

Fibromyalgia syndrome patients, relative to healthy control participants, exhibited alterations to the shape of the left lateral aspect of the lower brainstem (medulla). The mean total volume of the brainstem was also found to be significantly reduced in the patient group compared to healthy control subjects, and this brainstem volume reduction in patient group significantly correlated with clinical manual tender point scale scores. Voxel-based morphometry analysis revealed that patients also demonstrated decreased local grey matter volumes in the brainstem (pons) and left precuneus, and increased grey matter volumes in bilateral primary somatosensory cortices.

Results suggest that the volume reduction and associated geometric shape alterations seen in the brainstem of the patient group may contribute to sensitivity to pressure pain in fibromyalgia syndrome. This finding may be due to structure-related deficiencies in regions subserving descending nociceptive control.

•

Fibromyalgia syndrome patients exhibited shape alterations in the brainstem.

•

The mean brainstem volume was also significantly reduced in FMS patients.

•

This volume reduction correlated with clinical manual tender point scores.

•

Structural alterations in the brainstem may contribute to clinical symptoms of FMS.

Subcortical volumes are reduced in short-term and long-term abstinent alcoholics but not those with a comorbid stimulant disorder

Chronic alcohol abuse affects brain structure and function. We examined subcortical structure volumes in 77 short (6–15 week) and 90 long (multi-year) term abstinent alcoholics, along with 74 controls. We used a 3T Siemens MPRAGE sequence for image acquisition and FSL FIRST software for measuring subcortical volumes. When examining alcoholics without a comorbid stimulant disorder we found reduced hippocampal, pallidum and thalamus volumes in short term abstinence compared to a non-substance abusing control sample with numerically smaller yet still significant reductions compared to controls in long term abstinence. When examining alcoholics with a comorbid stimulant disorder, no difference from controls was found for any subcortical volume. Alcoholics with a stimulant disorder had significantly larger subcortical volumes than alcoholics without a stimulant disorder.

This study replicates past research showing that chronic alcohol abuse is associated with lower subcortical volumes in short-term abstinent chronic alcoholics and extends this finding, although with smaller effects to long-term abstinent samples. The absence of this effect in the presence of a comorbid stimulant disorder suggests either a protective effect of stimulant abuse/dependence or that the measurements reflect the aggregate of alcohol dependence associated atrophy and stimulant abuse associated inflammation. Associations with function suggest the second of these two alternatives.

•

Subcortical atrophy

•

Chronic alcohol dependence

•

Comorbid stimulant disorder

Reduced limbic metabolism and fronto-cortical volume in rats vulnerable to alcohol addiction

Alcohol abuse is associated with long-term reductions in fronto-cortical volume and limbic metabolism. However, an unanswered question in alcohol research is whether these alterations are the sole consequence of chronic alcohol use, or contain heritable contributions reflecting biological propensity toward ethanol addiction. Animal models of genetic predisposition to alcohol dependence can be used to investigate the role of inborn brain abnormalities in the aetiology of alcoholism. Here we used magnetic resonance imaging (MRI) in the Marchigian-Sardinian (msP) alcohol-preferring rats to assess the presence of inherited structural or functional brain alterations. Alcohol-naïve msP (N=22) and control rats (N=26) were subjected to basal cerebral blood volume (bCBV) mapping followed by voxel-based morphometry (VBM) of grey matter and tract-based spatial statistics mapping of white matter fractional anisotropy. msP rats exhibited significantly reduced bCBV, an established marker of resting brain function, in focal cortico-limbic and thalamic areas, together with reduced grey matter volume in the thalamus, ventral tegmental area, insular and cingulate cortex. No statistically significant differences in fractional anisotropy were observed between groups. These findings highlight the presence of inborn grey matter and metabolic abnormalities in alcohol-naïve msP rats, the localization and sign of which are remarkably similar to those mapped in abstinent alcoholics and subjects at high risk for alcohol dependence. Collectively, these results point for a significant role of heritable neurofunctional brain alterations in biological propensity toward ethanol addiction, and support the translational use of advanced imaging methods to describe the circuital determinants of vulnerability to drug addiction.

Age effect on subcortical structures in healthy adults

Cross-sectional age effects in normal control volunteers were investigated using magnetic resonance imaging in the following eight subcortical structures: lateral ventricles, thalamus, caudate, putamen, pallidum, hippocampus, amygdala and nucleus accumbens. Two hundred and twenty-six control subjects, ranging in age from 19 to 85 years, were scanned on a 1.5 T GE system (n=184) or a 3.0 T Siemens system (n=42). Volumes of subcortical structures, adjusted for cranium size, were estimated using FSL's FIRST software, which is fully automated. Significant age effects were found for all volumes when the entire age range was analyzed; however, the older subjects (60-85 years of age) showed a stronger correlation between age and structural volume for the ventricles, hippocampus, amygdala and accumbens than middle-aged (35-60 years of age) subjects. Middle-aged subjects were studied at both sites, and age effects in these groups were comparable, despite differences in magnet strength and acquisition systems. This agreement lends support to the validity of the image-analysis tools and procedures used in the present study.