An insula-driven network computes decision uncertainty and promotes abstinence in chronic cocaine users.

The anterior insular cortex (AIC) and its interconnected brain regions have been associated with both addiction and decision-making under uncertainty. However, the causal interactions in this uncertainty-encoding neurocircuitry and how these neural dynamics impact relapse remain elusive. Here, we used model-based fMRI to measure choice uncertainty in a motor decision task in 61 individuals with cocaine use disorder (CUD) and 25 healthy controls. CUD participants were assessed before discharge from a residential treatment program and followed for up to 24 weeks. We found that choice uncertainty was tracked by the AIC, dorsal anterior cingulate cortex (dACC) and ventral striatum (VS), across participants. Stronger activations in these regions measured pre-discharge predicted longer abstinence after discharge in individuals with CUD. Dynamic causal modeling revealed an AIC-to-dACC-directed connectivity modulated by uncertainty in controls, but a dACC-to-AIC connectivity in CUD participants. This reversal was mostly driven by early relapsers (<30 days). Furthermore, CUD individuals who displayed a stronger AIC-to-dACC excitatory connection during uncertainty encoding remained abstinent for longer periods. These findings reveal a critical role of an AIC-driven, uncertainty-encoding neurocircuitry in protecting against relapse and promoting abstinence.

Alcohol Use Disorder Masks the Effects of Childhood Adversity, Lifetime Trauma, and Chronic Stress on Hypothalamic-Pituitary-Adrenal Axis Reactivity.

BACKGROUND: Individuals with alcohol use disorder (AUD) and those who have experienced traumas or chronic stress exhibit dysregulated hypothalamic-pituitary-adrenal (HPA) axis reactivity. Whether and how trauma and stress histories interact with AUD to affect HPA axis reactivity has not been assessed. METHODS: In the present study, 26 healthy male controls and 70 abstinent men with AUD were administered a pharmacologic probe [ovine corticotropin-releasing hormone (oCRH)] and psychosocial stressor to assess HPA axis reactivity. Plasma adrenocorticotropin hormone (ACTH) and cortisol were assessed every 10-20 minutes. Hierarchical clustering of multiple measures of trauma and stress identified 3 distinct clusters: childhood adversity, lifetime trauma, and chronic stress. General linear model procedures were used to examine main effects of group (AUD/control) and interaction effects of the 3 clusters upon net-integrated ACTH and cortisol response. RESULTS: We found that higher levels of childhood adversity, lifetime trauma, and chronic stress were each associated with blunted oCRH-induced ACTH reactivity in controls, but not in the AUD group. Recent chronic stress within the prior 6 months had the strongest influence upon ACTH reactivity in the control group, and lifetime trauma, the least. CONCLUSIONS: Childhood adversity, lifetime trauma, and chronic stress likely exert persistent, measurable effects upon HPA axis functioning in healthy controls. This association appears to be masked in individuals with AUD, potentially confounding studies examining the effects of stress, adversity, and/or trauma upon the HPA axis in this population during the protracted withdrawal phase of recovery. Future work targeting stress exposure and reactivity should consider the heightened effect of previous alcohol use relative to past adversity and trauma.

Classification of cocaine-dependent participants with dynamic functional connectivity from functional magnetic resonance imaging data.

Static functional connectivity (FC) analyses based on functional magnetic resonance imaging (fMRI) data have been extensively explored for studying various psychiatric conditions in the brain, including cocaine addiction. A recently emerging, more powerful technique, dynamic functional connectivity (DFC), studies how the FC dynamics change during the course of the fMRI experiments. The aim in this paper was to develop a computational approach, using a machine learning framework, to determine if DFC features were more successful than FC features in the classification of cocaine-dependent patients and healthy controls. fMRI data were obtained from of 25 healthy and 58 cocaine-dependent participants while performing a motor response inhibition task, stop signal task. Group independent component analysis was carried out on all participant data to compute spatially independent components (ICs). Eight ICs were selected manually as relevant brain networks, which were used to classify healthy versus cocaine-dependent participants. FC and DFC measures of the chosen IC pairs were used as features for the classification algorithm. Support Vector Machines were used for both feature selection/reduction and participant classification. Based on DFC with only seven IC pairs, participants were successfully classified with 95% accuracy (and with 90% accuracy with three IC pairs), whereas static FC yielded only 81% accuracy. Visual, sensorimotor, default mode, and executive control networks, amygdala, and insula played the most significant role in the DFC-based classification. These findings support the use of DFC-based classification of fMRI data as a potential biomarker for the identification of cocaine dependence.

Effect of Selective Serotonin Reuptake Inhibitors on Healthcare Utilization in Patients with Post-Traumatic Stress Disorder and Alcohol Use Disorder.

AIMS: The objective of this study is to address equivocation in estimates of selective serotonin reuptake inhibitor initiation (SSRI) effect on all-cause and alcohol-related ER visits, and medical or psychiatric admissions within 2 years of initial Post-Traumatic Stress Disorder (PTSD) diagnosis in patients with PTSD and Alcohol Use Disorder (AUD). METHODS: This study is a quasi-experimental, new-user-design cohort study of 3235 patients seen at the VA North Texas Healthcare System between January 1, 2000 and December 31, 2016. High dimensional propensity score (HDPS) techniques were used to estimate likelihood of SSRI initiation within 30 days of first PTSD diagnosis. Propensity scores were used to calculate weights for likelihood of SSRI initiation which were used to control for baseline covariates in estimations of SSRI medication effect on odds of each outcome occurring. RESULTS: Compared to those who did not receive SSRIs, patients prescribed an SSRI within 30 days showed significantly lower odds of alcohol-related ER visits (OR=0.668, 95%CI = 0.476 to 0.938, P = 0.02) and alcohol-related medical admissions (OR=0.583, 95%CI = 0.399 to 0.851, P = 0.005). LIMITATIONS: Inconsistent assessment of PTSD severity necessitated the use of HDPS models to control for baseline confounding. Our study design mimicked intent-to-treat trial design and therefore could not control for SSRI initiations after the 30-day grace period following initial PTSD diagnosis. CONCLUSIONS: SSRI initiation in patients with AUD and PTSD is associated with significantly reduced odds of alcohol-related medical hospitalization and alcohol-related ER visits within 2 years of first PTSD diagnosis. Additional studies are needed to verify these results.

Implementing social justice in the transition from illicit to legal cannabis.

Background: The legalization of cannabis for adult use is being increasingly embraced in several countries and local entities. A driving force for these changes has been the individual, family, community, societal, and economic costs of cannabis prohibition, which have fallen most heavily upon disadvantaged minority populations.Objectives: In this review, we explore whether the legalization of cannabis has begun to correct the injustices of cannabis prohibition. Progress is assessed in five areas of social justice related to cannabis prohibition: expungement of previous arrests and convictions for cannabis-related crimes that are no longer illegal; consequences of cannabis-related offenses in a cannabis-legal environment; diversity of the cannabis-legal industry; funding of equity and/or restorative justice programs for those communities most affected by cannabis prohibition; and risks of cannabis legalization negatively impacting the populations that most suffered under the legacy of cannabis prohibition.Methods: Iterative and focused review.Results: There has been some progress in expunging previous cannabis-related convictions, particularly misdemeanors, and decreasing cannabis-related arrests. Encouraging diversity in the cannabis industry and the funding of equity programs has been very limited. There is no evidence to-date that populations that have suffered most as a result of cannabis prohibition are at increased risk from its legalization.Conclusions: Focused regulatory efforts and financial resources (from both cannabis revenue and savings from the abolition of cannabis prohibition) as well as more attentive data collection and analysis should be utilized to assure that all individuals experience the benefits, and avoid the consequences, of cannabis legalization.

Systematic review of preclinical, clinical, and post-marketing evidence of bupropion misuse potential.

Background: Bupropion is a substituted cathinone compound widely used as a first line or add-on treatment for depression, smoking cessation, and more recently in combination with naltrexone for weight loss. As abuse of synthetic cathinone compounds has received more attention in recent years, concern about the misuse potential of bupropion has grown as well. Objectives: We review bupropion pharmacology and assessments of misuse potential including preclinical evidence, human studies, and post-marketing surveillance of bupropion misuse. Methods: This review reports the results of a systematic review of publications evaluating the potential for bupropion to be misused. Publications were identified using PubMed and Medline through Ovid® as well as iterative bibliographic searches. A summary of data from informal sources of information including substance-user experience from online forum entries is included. Results: Preclinical evidence demonstrates some potential for misuse based on psychomotor, discrimination, self-administration, and conditioned place preference tasks. However, this potential is less than that of commonly misused stimulants. Studies in human populations similarly indicate that bupropion shares interoceptive effects with other stimulants, but lacks some key reinforcing effects of other stimulants. In the real-world setting, misuse of bupropion occurs, but is uncommon. Adverse effects of bupropion misuse are frequently cited as significant barriers to obtaining any desired interoceptive effect. Conclusions: While bupropion demonstrates some potential for misuse, pharmacological differences from other structurally-related stimulants limit bupropion's reinforcing effects. Without additional data indicating susceptibility of specific populations to bupropion misuse, there is no empirical data suggesting a need to modify bupropion prescribing patterns.

Salience and default mode network dysregulation in chronic cocaine users predict treatment outcome.

While chronic cocaine use is associated with abnormalities in both brain structure and function within and interactions between regions, previous studies have been limited to interrogating structure and function independently, and the detected neural differences have not been applied to independent samples to assess the clinical relevance of results. We investigated consequences of structural differences on resting-state functional connectivity in cocaine addiction and tested whether resting-state functional connectivity of the identified circuits predict relapse in an independent cohort. Subjects included 64 non-treatment-seeking cocaine users (NTSCUs) and 67 healthy control subjects and an independent treatment-completed cohort (n = 45) of cocaine-dependent individuals scanned at the end of a 30-day residential treatment programme. Differences in cortical thickness and related resting-state functional connectivity between NTSCUs and healthy control subjects were identified. Survival analysis, applying cortical thickness of the identified regions, resting-state functional connectivity of the identified circuits and clinical characteristics to the treatment cohort, was used to predict relapse. Lower cortical thickness in bilateral insula and higher thickness in bilateral temporal pole were found in NTSCUs versus healthy control subjects. Whole brain resting-state functional connectivity analyses with these four different anatomical regions as seeds revealed eight weaker circuits including within the salience network (insula seeds) and between temporal pole and elements of the default mode network in NTSCUs. Applying these circuits and clinical characteristics to the independent cocaine-dependent treatment cohort, functional connectivity between right temporal pole and medial prefrontal cortex, combined with years of education, predicted relapse status at 150 days with 88% accuracy. Deficits in the salience network suggest an impaired ability to process physiologically salient events, while abnormalities in a temporal pole-medial prefrontal cortex circuit might speak to the social-emotional functional alterations in cocaine addiction. The involvement of the temporal pole-medial prefrontal cortex circuit in a model highly predictive of relapse highlights the importance of social-emotional functions in cocaine dependence, and provides a potential underlying neural target for therapeutic interventions, and for identifying those at high risk of relapse.

Association of Biological Markers of Alcohol Consumption and Self-Reported Drinking with Hippocampal Volume in a Population-Based Sample of Adults.

AIMS: The current study examined a large community cohort to understand relationships between indicators of alcohol consumption and hippocampal volume. SHORT SUMMARY: Alcohol use measures were not associated with hippocampal volume in a population-based sample. However, alcohol consumption was associated with hippocampal volume reduction in subsets of the sample including subjects aged ≥50 years old, and those with none to moderate levels of depressive symptoms. METHODS: A total of 1848 adults with magnetic resonance imaging (MRI) and alcohol consumption data were included. Multiple linear regressions were performed with left or right hippocampal volume as dependent variables, and age, gender, race, education, body mass index, Quick Inventory of Depressive Symptomatology (QIDS-SR) scores, drinks per week (DPW), aspartate aminotransferase (AST), alanine aminotransferase (ALT), AST/ALT, γ-glutamyl transferase and mean corpuscular volume (MCV) as independent variables. Post hoc analyses were conducted to assess interactions of demographic factors and variables of interest (DPW, AST, ALT, AST/ALT, GGT and MCV). For statistically significant interactions, analyses were conducted in groups split by gender, depression (QIDS-SR scores ≥11 and <11) and age (≥50 and <50 years). RESULTS: Average alcohol consumption in the population was low (µ = 2.95 ± 6.7 DPW). Alcohol consumption measures were not significantly associated with hippocampal volume in the primary analysis. Exploratory analyses revealed significant associations between DPW and right hippocampal volume in participants with QIDS-SR scores <11 (B = -3.75, P = 0.02, CI = -6.97, -0.52) and in those aged ≥50 years (B = -4.844, P = 0.023 CI = -9.023 to -0.664). AST/ALT was significantly associated with right (B = -93.66, P = 0.022, CI = -173.64 to -13.68) and left hippocampal volume (B = -109.79 P = 0.008, CI = -190.97 to -28.61) in participants aged ≥50 but not <50 years. Gender differences were not observed. CONCLUSIONS: The findings suggest a relationship between alcohol use indicators and right hippocampal volume in non-depressed and older adults.

The mixed message behind "Medication-Assisted Treatment" for substance use disorder.

The gap between treatment utilization and treatment need for substance use disorders (SUDs) remains a significant concern in our field. While the growing call to bridge this gap often takes the form of more treatment services and/or better integration of existing services, this perspective proposes that more effective labels for and transparent descriptions of existing services would also have a meaningful impact. Adopting the perspective of a consumer-based health-care model (wherein treatments and services are products and patients are consumers) allows us to consider how labels like Addiction-focused Medical Management, Medication-Assisted Treatment, Medication-Assisted Therapy, and others may actually be contributing to the underutilization problem rather than alleviating it. In this perspective, "Medication-Assisted Therapy" for opioid-use disorder (OUD) is singled out and discussed as inherently confusing, providing the message that pharmacotherapy for this disorder is a secondary treatment to other services which are generally regarded, in practice, as ancillary. That this mixed message is occurring amidst a nationwide "opioid epidemic" is a potential cause for concern and may actually serve to reinforce the longstanding, documented stigma against OUD pharmacotherapy. We recommend that referring to pharmacotherapy for SUD as simply "medication," as we do for other chronic medical disorders, will bring both clarity and precision to this effective treatment approach.

Brain intrinsic network connectivity in individuals with frequent tanning behavior.

BACKGROUND: Emergent studies suggest a bidirectional relationship between brain functioning and the skin. This neurocutaneous connection may be responsible for the reward response to tanning and, thus, may contribute to excessive tanning behavior. To date, however, this association has not yet been examined. OBJECTIVES: To explore whether intrinsic brain functional connectivity within the default mode network (DMN) is related to indoor tanning behavior. METHODS: Resting state functional connectivity (rsFC) was obtained in twenty adults (16 females) with a history of indoor tanning. Using a seed-based [(posterior cingulate cortex (PCC)] approach, the relationship between tanning severity and FC strength was assessed. Tanning severity was measured with symptom count from the Structured Clinical Interview for Tanning Abuse and Dependence (SITAD) and tanning intensity (lifetime indoor tanning episodes/years tanning). RESULTS: rsFC strength between the PCC and other DMN regions (left globus pallidus, left medial frontal gyrus, left superior frontal gyrus) is positively correlated with tanning symptom count. rsFC strength between the PCC and salience network regions (right anterior cingulate cortex, left inferior parietal lobe, left inferior temporal gyrus) is correlated with tanning intensity. CONCLUSION: Greater connectivity between tanning severity and DMN and salience network connectivity suggests that heightened self-awareness of salient stimuli may be a mechanism that underlies frequent tanning behavior. These findings add to the growing evidence of brain-skin connection and reflect dysregulation in the reward processing networks in those with frequent tanning.

Posterior hippocampal regional cerebral blood flow predicts abstinence: a replication study.

The posterior hippocampus (pHp) plays a major role in the processing and storage of drug-related cues and is linked to striatal-limbic brain circuits involved with craving and drug salience. We have recently reported that increased basal regional cerebral blood flow (rCBF) in a pHp loci, as measured by pseudo-continuous arterial spin labeling magnetic resonance imaging, predicted days to cocaine relapse following residential treatment. In this secondary analysis, we explored whether rCBF in this same pHp region would successfully predict 30-day point prevalence abstinence 60 days following residential treatment in an independent group of previously studied participants with cocaine dependence. rCBF was assessed with single photon emission computerized tomography during a saline infusion in 21 cocaine dependence and 22 healthy control participants. pHp rCBF was significantly higher in those endorsing substance use (n = 10) relative to both abstinent (n = 11) (p < 0.001) and control (p < 0.05) participants. There were no significant differences in measured demographic or clinical variables between the actively using and non-using participants. This replicative finding suggests that heightened pHp activation is a significant predictor of substance use in cocaine-dependent individuals, possibly reflecting a neural susceptibility to continued drug cues.

Executive control network connectivity strength protects against relapse to cocaine use.

Cocaine addiction is characterized by notoriously high relapse rates following treatment. Recent efforts to address poor treatment outcomes have turned to potential neural markers of relapse risk. Accordingly, the present study examined resting state functional connectivity (rsFC) within and between three large-scale cortical networks: the default mode network (DMN), salience network (SN) and executive control network (ECN). All three have been implicated in relapse-related phenomena including craving, withdrawal and executive control deficits. Forty-five cocaine-dependent individuals and 22 healthy controls completed 6-min resting fMRI scans, The Wisconsin Card Sorting Task, Continuous Performance Test and Cocaine Craving Questionnaire. Cocaine-dependent individuals completed all measures in the final week of a residential treatment episode. Ten control and 9 abstinent cocaine-dependent individuals returned for 3-6 month follow-up scan visits. A group-level independent component analysis was employed to generate ECN, DMN and SN components. For individuals abstinent up to day 30 post-treatment (n = 21), we found enhanced pre-discharge rsFC between the left ECN and both the right ECN and SN as well as between the right ECN and left ECN. Left ECN rsFC effects remained elevated 3-6 months later among abstinent cocaine-dependent individuals. Relapse was related to fewer years of education and more years smoking but no other demographic, clinical, treatment and neurocognitive characteristics. Findings suggest that interhemispheric ECN and ECN-SN connectivity strength may protect against relapse to cocaine use following treatment. These patterns of enhanced interhemispheric network connectivity may reflect a greater capacity to engage executive control processes when faced with opportunities to use cocaine post-treatment.

Family Discord After Completion of an Outpatient Community Treatment Program Predicts Greater Substance Use During Follow-up.

BACKGROUND: It is reasonable to consider family discord after treatment as a potential target for a next-step intervention, since family discord is often comorbid with substance use disorders. OBJECTIVE: This study evaluated family discord after completing an initial course of treatment as a predictor of substance use and retention in the community treatment program during follow-up. METHOD: Patients were from two multisite randomized clinical trials implemented through the Clinical Trials Network of the National Institute on Drug Abuse. There were 315 participants from Study 1 (12-week posttreatment follow-up) and 295 participants from Study 2 (8-week posttreatment follow-up). Negative binomial and logistic regression were used to estimate days of substance use and odds of retention in the community treatment program at follow-up, respectively, from family discord status. RESULTS: Family discord was significantly associated with more days of substance use during the posttreatment follow-up period than those without family discord in both Study 1 (9.12 vs. 2.89 days, p =.0001) and Study 2 (5.58 vs. 2.83 days, p =.0062). Family discord was significantly associated with lower retention in the community treatment program at follow-up than those not reporting family discord in Study 1 (47.6% vs. 60.6%; p =.03), but not in Study 2 (55.3% vs. 64.9%; p =.11). CONCLUSION: Family discord after an initial course of treatment might be a clinically relevant predictor of substance use. There is mixed support for a conclusion that family discord is associated with lower retention in the community treatment program at follow-up.

Successful classification of cocaine dependence using brain imaging: a generalizable machine learning approach.

BACKGROUND: Neuroimaging studies have yielded significant advances in the understanding of neural processes relevant to the development and persistence of addiction. However, these advances have not explored extensively for diagnostic accuracy in human subjects. The aim of this study was to develop a statistical approach, using a machine learning framework, to correctly classify brain images of cocaine-dependent participants and healthy controls. In this study, a framework suitable for educing potential brain regions that differed between the two groups was developed and implemented. Single Photon Emission Computerized Tomography (SPECT) images obtained during rest or a saline infusion in three cohorts of 2-4 week abstinent cocaine-dependent participants (n = 93) and healthy controls (n = 69) were used to develop a classification model. An information theoretic-based feature selection algorithm was first conducted to reduce the number of voxels. A density-based clustering algorithm was then used to form spatially connected voxel clouds in three-dimensional space. A statistical classifier, Support Vectors Machine (SVM), was then used for participant classification. Statistically insignificant voxels of spatially connected brain regions were removed iteratively and classification accuracy was reported through the iterations. RESULTS: The voxel-based analysis identified 1,500 spatially connected voxels in 30 distinct clusters after a grid search in SVM parameters. Participants were successfully classified with 0.88 and 0.89 F-measure accuracies in 10-fold cross validation (10xCV) and leave-one-out (LOO) approaches, respectively. Sensitivity and specificity were 0.90 and 0.89 for LOO; 0.83 and 0.83 for 10xCV. Many of the 30 selected clusters are highly relevant to the addictive process, including regions relevant to cognitive control, default mode network related self-referential thought, behavioral inhibition, and contextual memories. Relative hyperactivity and hypoactivity of regional cerebral blood flow in brain regions in cocaine-dependent participants are presented with corresponding level of significance. CONCLUSIONS: The SVM-based approach successfully classified cocaine-dependent and healthy control participants using voxels selected with information theoretic-based and statistical methods from participants' SPECT data. The regions found in this study align with brain regions reported in the literature. These findings support the future use of brain imaging and SVM-based classifier in the diagnosis of substance use disorders and furthering an understanding of their underlying pathology.

Legal regimes surrounding naloxone access: considerations for prescribers.

BACKGROUND: Since the late 1980s, opioid-related morbidity and mortality in the United States has dramatically increased. This serious epidemic requires a coordinated medical, public policy, and social response. It is becoming readily apparent that widespread provision of naloxone may help to address this problem. However, because naloxone access laws vary between states, the extent of antidote dissemination may be limited by a given provider's geographic location. OBJECTIVE: This review targets a physician or prescriber audience, in hopes of providing evidence for the safety and utility of naloxone, education on the baseline legal liability of naloxone provision and protections afforded by access laws, and resources for the proposal of statewide legislation to promote antidote distribution. CONCLUSION: Evidence suggests that naloxone administration by laypersons, pursuant to physician prescription or standing order, is safe and effective for reversal of opioid overdose. As of July 2015, 44 states and the District of Columbia have passed naloxone access laws, offering varying degrees of protections for prescribers. Although the likelihood of naloxone-related legal action may parallel that inherent to the usual practice of medicine, providers should be mindful of potential scenarios, exercise methods to mitigate risk, and appreciate the utility of comprehensive naloxone access legislation in orchestrating a coordinated response to the opioid overdose epidemic.

Decision-making processes as predictors of relapse and subsequent use in stimulant-dependent patients.

BACKGROUND: Decision-making processes have been posited to affect treatment outcome in addicted patients. OBJECTIVE: The present multi-site study assessed whether two measures of decision-making predicted relapse and subsequent use in stimulant-dependent patients. METHODS: A total of 160 methamphetamine- or cocaine-dependent patients participating in a multi-site clinical trial evaluating a modified 12-step facilitation intervention for stimulant-dependent patients (STAGE-12) were assessed. Decision-making processes of risk and delay (Iowa Gambling Task [IGT]) and response reversal (Wisconsin Card Sorting Task [WCST]) were obtained shortly after treatment admission followed by assessment of stimulant use over the next six months. The relationships of the IGT and WCST (Perseverative Errors) with relapse (yes/no) and days of stimulant use during the 6-month period following post-randomization were evaluated. RESULTS: Performance on the IGT and WCST did not significantly predict relapse status or time to relapse. Unexpectedly, worse performance on the IGT was associated with a fewer number of stimulant use days (p = 0.001). In contrast, worse performance on the WCST (more perseverative errors) was associated with a greater number of stimulant use days (p = 0.0003). The predictive effects of perseverative errors on subsequent use were confined to methamphetamine-dependent and Minority participants. CONCLUSIONS: Decision-making processes, as measured in the current study, do not uniformly predict relapse or subsequent use. A decrease in the salience attribution of non-drug reinforcers may explain the positive relationship between IGT performance and post-relapse use. More comprehensive and global measures of impulsiveness may better assess relapse risk and use.

Interaction between early life stress and alcohol dependence on neural stress reactivity.

Stress response biologic systems are altered in alcohol-dependent individuals. Early life stress (ELS) is associated with a heightened risk of alcohol dependence, presumably because of stress-induced neuroplastic changes. This study was designed to assess the contribution of ELS to a stress-induced neural response in alcohol-dependent participants. Fifteen alcohol-dependent men abstinent for 3-5 weeks and 15 age- and race-matched healthy controls were studied. Anticipatory anxiety was induced by a conditioned stimulus paired with an uncertain physically painful unconditioned stressor. Neural response was assessed with functional magnetic resonance imaging. ELS was assessed with the Childhood Adversity Interview. There was a significant interaction between ELS and group on blood-oxygen-level-dependent (BOLD) amplitude during anticipatory anxiety in the right amygdala and bilateral orbitofrontal cortex, posterior putamen and insula. Higher ELS scores were associated with decreased BOLD amplitude during anticipatory anxiety in alcohol-dependent, but not control, participants. These findings suggest that ELS interacts with alcohol dependence to induce a muted cortico-striatal response to high threat stimuli. Allostatic changes due to both ELS and excessive alcohol use may jointly induce persistent changes in the neural response to acute stressors.

A systematic approach to subgroup analyses in a smoking cessation trial.

BACKGROUND: Traditional approaches to subgroup analyses that test each moderating factor as a separate hypothesis can lead to erroneous conclusions due to the problems of multiple comparisons, model misspecification, and multicollinearity. OBJECTIVE: To demonstrate a novel, systematic approach to subgroup analyses that avoids these pitfalls. METHODS: A Best Approximating Model (BAM) approach that identifies multiple moderators and estimates their simultaneous impact on treatment effect sizes was applied to a randomized, controlled, 11-week, double-blind efficacy trial on smoking cessation of adult smokers with attention-deficit/hyperactivity disorder (ADHD), randomized to either OROS-methylphenidate (n = 127) or placebo (n = 128), and treated with nicotine patch. Binary outcomes measures were prolonged smoking abstinence and point prevalence smoking abstinence. RESULTS: Although the original clinical trial data analysis showed no treatment effect on smoking cessation, the BAM analysis showed significant subgroup effects for the primary outcome of prolonged smoking abstinence: (1) lifetime history of substance use disorders (adjusted odds ratio [AOR] 0.27; 95% confidence interval [CI] 0.10-0.74), and (2) more severe ADHD symptoms (baseline score >36; AOR 2.64; 95% CI 1.17-5.96). A significant subgroup effect was also shown for the secondary outcome of point prevalence smoking abstinence--age 18 to 29 years (AOR 0.23; 95% CI 0.07-0.76). CONCLUSIONS: The BAM analysis resulted in different conclusions about subgroup effects compared to a hypothesis-driven approach. By examining moderator independence and avoiding multiple testing, BAMs have the potential to better identify and explain how treatment effects vary across subgroups in heterogeneous patient populations, thus providing better guidance to more effectively match individual patients with specific treatments.

Age-related increase of resting metabolic rate in the human brain.

With age, many aspects of the brain structure undergo a pronounced decline, yet individuals generally function well until advanced old age. There appear to be several compensatory mechanisms in brain aging, but their precise nature is not well characterized. Here we provide evidence that the brain of older adults expends more energy when compared to younger adults, as manifested by an age-related increase (P=0.03) in cerebral metabolic rate of oxygen (CMRO2) (N=118, men=56, ages 18 to 74). We further showed that, before the mean menopausal age of 51years old, female and male groups have similar rates of CMRO2 increase (P=0.015) and there was no interaction between age and sex effects (P=0.85). However, when using data from the entire age range, women have a slower rate of CMRO2 change when compared to men (P<0.001 for age×sex interaction term). Thus, menopause and estrogen level may have played a role in this sex difference. Our data also revealed a possible circadian rhythm of CMRO2 in that brain metabolic rate is greater at noon than in the morning (P=0.02). This study reveals a potential neurobiological mechanism for age-related compensation in brain function and also suggests a sex-difference in its temporal pattern.

MRI assessment of cerebral oxygen metabolism in cocaine-addicted individuals: hypoactivity and dose dependence.

Long-term cocaine use is known to negatively impact neural and cerebrovascular systems. However, the use of imaging markers to separately assess these parameters remains challenging. The primary reason is that most functional imaging markers, such as cerebral blood flow, functional connectivity, and task-evoked functional MRI, are known to reflect a complex interplay between neural and vascular components, thus the interpretation of the results is not straightforward. The goal of the present study is to examine neural-activity-specific changes in cocaine addiction, using cerebral metabolic rate of oxygen (CMRO2) as a surrogate marker of aggregated neural activity. We applied a recently developed CMRO2 technique in 13 cocaine-addicted subjects and 13 age- and gender-matched control subjects, and examined the impact of long-term cocaine use on CMRO2. Our results showed that CMRO2 in cocaine-addicted subjects (152 ± 16 µmol/100 g/min) is significantly lower (p = 0.031) than that in controls (169 ± 20 µmol/100 g/min). Furthermore, the severity of this decreased metabolism is associated with lifetime cocaine use (p = 0.05). Additionally, the CMRO2 reduction was accompanied by a trend of decrease in cerebral blood flow (p = 0.058), but venous oxygenation was unaffected (p = 0.96), which suggested that the CMRO2 change may be attributed to a vascular deficiency in chronic cocaine users. To our knowledge, this is the first study to measure CMRO2 in cocaine-addicted individuals. Our findings suggest that CMRO2 may be a promising approach for assessing the long-term effects of cocaine use on the brain.