Leptin predicts cortical and subcortical gray matter volume recovery in alcohol dependent patients: A longitudinal structural magnetic resonance imaging study

Regional cortical thickness recovery with extended abstinence after treatment in those with alcohol use disorder

Several cross-sectional investigations reported widespread cortical thinning in those with alcohol use disorder (AUD). The few longitudinal studies investigating cortical thickness changes during abstinence are limited to the first month of sobriety. Consequently, cortical thickness changes during extended abstinence in those with AUD is unclear. In this study, AUD participants were studied at approximately 1 week (n = 68), 1 month (n = 88), and 7.3 months (n = 40) of abstinence. Forty-five never-smoking controls (CON) completed a baseline study, and 15 were reassessed after approximately 9.6 months. Participants completed magnetic resonance imaging studies at 1.5T, and cortical thickness for 34 bilateral regions of interest (ROI) was quantitated with FreeSurfer. AUD participants demonstrated significant linear thickness increases in 25/34 ROI over 7.3 months of abstinence. The rate of change from 1 week to 1 month was greater than 1 month to 7.3 months in 19/34 ROIs. Proatherogenic conditions were associated with lower thickness recovery in anterior frontal, inferior parietal, and lateral/mesial temporal regions. After 7.3 months of abstinence, AUD participants were statistically equivalent to CON on cortical thickness in 24/34 ROIs; the cortical thickness differences between AUD and CON in the banks superior temporal gyrus, post central, posterior cingulate, superior parietal, supramarginal, and superior frontal cortices were driven by thinner cortices in AUD with proatherogenic conditions relative to CON. In actively smoking AUD, increasing pack-years was associated with decreasing thickness recovery primarily in the anterior frontal ROIs. Widespread bilateral cortical thickness recovery over 7.3 months of abstinence was the central finding for this AUD cohort. The longitudinal and cross-sectional findings for AUD with proatherogenic suggests alterations in perfusion or vascular integrity may relate to structural recovery in those with AUD. These results support the adaptive and beneficial effects of sustained sobriety on brain structural recovery in people with AUD.

The role of the orbitofrontal cortex in exercise addiction and exercise motivation: A brain imaging study based on multimodal magnetic resonance imaging

BACKGROUND

Excessive exercise may also lead to exercise addiction (EXA), which is harmful to people's physical and mental health. Behavioral and neuroimaging studies have demonstrated that addictive disorders are essentially motivational problems. However, little is known about the neuropsychological mechanism of EXA and the effects of motivation on EXA.

METHODS

We investigated 130 regularly exercised participants with EXA symptoms to explore the neurobiological basis of EXA and its association with motivation. The correlation between EXA and gray matter volume (GMV) was evaluated by whole-brain regression analysis based on voxel-based morphometry. Then, regional brain function was extracted and the relationship between brain structure-function-EXA was analyzed. Finally, mediation analysis was performed to further detect the relationship between the brain, motivation, and EXA.

RESULTS

Whole-brain correlation analyses showed that the GMV of the right orbitofrontal cortex (OFC) was negatively correlated with EXA. The function of the right OFC played an indirect role in EXA and affected EXA via the GMV of the OFC. Importantly, the GMV of the right OFC played a mediating role in the relationship between ability motivation and EXA. These results remain significant even when adjusting for sex, age, body mass index, family socioeconomic status, general intelligence, total intracranial volume, and head motion.

LIMITATION

The results should be interpreted carefully because only the people with EXA symptoms were included.

CONCLUSION

This study provided evidence for the underlying neuropsychological mechanism of the important role of the right OFC in EXA and revealed that there may be a decrease in executive control function in EXA.

Body mass index interacts with sex to predict readmission in in-patients with alcohol use disorder

A previous highly controlled pilot study revealed that body mass index (BMI) predicts outcome of in-patients with alcohol use disorder (AUD) in a sex-specific manner. We here provide translational evidence from a daily clinical routine setting and investigated whether BMI and sex interact to predict 24-month readmission risk in four naturalistic cohorts of a specialized addiction clinic (i.e., all patients admitted to the clinic from 2016 to 2020): (i) in-patients (443 males and 197 females) and (ii) day clinic patients (241 males and 103 females) with a primary diagnosis of AUD; (iii) in-patients (175 males and 98 females) and (iv) day clinic patients (174 males and 64 females) with a primary substance use disorder (SUD) other than alcohol. In the in-patients with AUD, BMI interacted with sex to predict the 24-month readmission risks (p = 0.008; after adjustment for age and liver enzyme activities: p = 0.012); with higher BMI, the risk increases significantly in males, whereas for females, the risk tends to decrease. In the group of overweight in-patients, we found higher readmission rates in males relative to females with an odds ratio of 1.8 (p = 0.038). No such significant effects were found in the other cohorts. This study's findings support previous results, suggesting that the easily accessible BMI may serve as a predictive and sex-sensitive biomarker for outcome in in-patients with AUD. Future studies are necessary to elucidate the underlying aetiopathological mechanisms.

Structural and functional brain recovery in individuals with substance use disorders during abstinence: A review of longitudinal neuroimaging studies

BACKGROUND

Neuroimaging studies reveal structural and functional including neurochemical brain abnormalities in individuals with substance use disorders compared to healthy controls. However, whether and to what extent such dysfunction is reversible with abstinence remains unclear, and a review of studies with longitudinal within-subject designs is lacking. We performed a systematic review of longitudinal neuroimaging studies to explore putative brain changes associated with abstinence in treatment-seeking individuals with substance use disorders.

METHODS

Following PRISMA guidelines, we examined articles published up to May 2021 that employed a neuroimaging technique and assessed neurobiological recovery in treatment-seeking participants at a minimum of two time-points separated by a period of abstinence (longer than 24 h apart) or significant reduction in drug use.

RESULTS

Forty-five studies met inclusion criteria. Encouragingly, in this limited but growing literature, the majority of studies demonstrated at least partial neurobiological recovery with abstinence. Structural recovery appeared to occur predominantly in frontal cortical regions, the insula, hippocampus, and cerebellum. Functional and neurochemical recovery was similarly observed in prefrontal cortical regions but also in subcortical structures. The onset of structural recovery appears to precede neurochemical recovery, which begins soon after cessation (particularly for alcohol); functional recovery may require longer periods of abstinence.

CONCLUSIONS

The literature is still growing and more studies are warranted to better understand abstinence-mediated neural recovery in individuals with substance use disorders. Elucidating the temporal dynamics between neuronal recovery and abstinence will enable evidence-based planning for more effective and targeted treatment of substance use disorders, potentially pre-empting relapse.

Frontocerebellar gray matter plasticity in alcohol use disorder linked to abstinence

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GM loss in frontocerebellar circuit predicts relapse.

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GM recovery in AUD involves distinct neural processes.

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Recovery is not a reversal of any AUD-related GM damage.

Alcohol use disorder (AUD) is associated with brain-wide gray matter (GM) reduction, but the frontocerebellar circuit seems specifically affected by chronic alcohol consumption. T1 weighted MRI data from 38 AUD patients at one month of sobriety and three months later and from 25 controls were analyzed using voxel-based morphometry (VBM) and a graph theory approach (GTA). We investigated the degree to which the frontocerebellar circuit’s integration within the brain’s GM network architecture was altered by AUD-related GM volume loss. The VBM analyses did not reveal significant GM volume differences between relapsers and abstainers at either timepoint, but future relapsers at both timepoints had significantly less GM than controls in the frontocerebellar circuit. Abstainers, who at baseline also showed the most pronounced GM loss in the thalamus, showed a significant circuit-wide GM increase with inter-scan abstinence. The post-hoc GTAs revealed a persistent diffuse global atrophy in both AUD groups at follow-up relative to controls and different recovery patterns in the two AUD groups. Our findings suggest that future relapsers do not just present with a more severe expression of the same AUD consequences than abstainers, but that AUD affects the frontocerebellar circuit differently in relapsers and abstainers.

Meta-analysis of grey matter changes and their behavioral characterization in patients with alcohol use disorder

Alcohol Use Disorder (AUD) is associated with reductions in grey matter (GM) volume which can lead to changes in numerous brain functions. The results of previous studies on altered GM in AUD differ considerably in the regions identified. Three meta-analyses carried out between 2014 and 2017 yielded different results. The present study includes the considerable amount of newer research and delivers a state-of-the art meta-analysis in line with recently published guidelines. Additionally, we behaviorally characterized affected regions using fMRI metadata and identified related brain networks by determining their meta-analytic connectivity patterns. Twenty-seven studies with 1,045 AUD patients and 1,054 healthy controls were included in the analysis and analyzed by means of Anatomical Likelihood Estimation (ALE). GM alterations were identified in eight clusters covering different parts of the cingulate and medial frontal gyri, paracentral lobes, left post- and precentral gyri, left anterior and right posterior insulae and left superior frontal gyrus. The behavioral characterization associated these regions with specific cognitive, emotional, somatosensory and motor functions. Moreover, the clusters represent nodes within behaviorally relevant brain networks. Our results suggest that GM reduction in AUD could disrupt network communication responsible for the neurocognitive impairments associated with high chronic alcohol consumption.