Substance use disorders and the orbitofrontal cortex: systematic review of behavioural decision-making and neuroimaging studies

Diet quality, nutritional status and taste recognition are impaired in men with substance use disorder

This study aimed to (1) evaluate the nutritional status, prevalence of malnutrition and dietary habits in individuals using substances and (2) examine the possible effects of substance use on the perception of five basic tastes. Ninety male individuals with substance use disorder (SUD) (heroin = 78, cocaine = 12) and 32 non-users participated in the study conducted at Manisa Alcohol and Substance Addiction Treatment Center (AMATEM), Turkey. To determine the quality of the diet, the mean nutrient adequacy ratio (MAR) was calculated based on 24-h recall food consumption records of the individuals. Subjective Global Assessment (SGA) was employed to determine nutritional status, and anthropometric measurements were also taken from the individuals. The taste detection and recognition thresholds were determined with solutions with different concentrations for bitter, sour, sweet, umami and salty tastes and scored, with higher scores indicating lower thresholds. Mild-moderate malnutrition was determined in 50% of the individuals with SUD based on SGA. The body mass index (BMI) of individuals with SUD was found to be 21.2 ± 1.88 kg/m2 , and 24.1 ± 1.64 kg/m2 for non-users (p < 0.001). Diet quality, evaluated by MAR, was lower in individuals with SUD (54.7 ± 18.9%) than in non-users (93.5 ± 9.0%) (p < 0.001). The taste detection and taste recognition thresholds of individuals with SUD were impaired, and the threshold scores for sour, salty, sweet and umami taste recognition were significantly lower compared with non-users, with the lowest substance user threshold scores observed for the sweet recognition threshold. Standardised nutritional and behavioural interventions designed by dietitians should be provided for drug users in treatment centres and integrated with medical treatment practices.

Computational modelling of reinforcement learning and functional neuroimaging of probabilistic reversal for dissociating compulsive behaviours in gambling and cocaine use disorders

BACKGROUND

Individuals with cocaine use disorder or gambling disorder demonstrate impairments in cognitive flexibility: the ability to adapt to changes in the environment. Flexibility is commonly assessed in a laboratory setting using probabilistic reversal learning, which involves reinforcement learning, the process by which feedback from the environment is used to adjust behavior.

AIMS

It is poorly understood whether impairments in flexibility differ between individuals with cocaine use and gambling disorders, and how this is instantiated by the brain. We applied computational modelling methods to gain a deeper mechanistic explanation of the latent processes underlying cognitive flexibility across two disorders of compulsivity.

METHOD

We present a re-analysis of probabilistic reversal data from individuals with either gambling disorder (n = 18) or cocaine use disorder (n = 20) and control participants (n = 18), using a hierarchical Bayesian approach. Furthermore, we relate behavioural findings to their underlying neural substrates through an analysis of task-based functional magnetic resonanceimaging (fMRI) data.

RESULTS

We observed lower 'stimulus stickiness' in gambling disorder, and report differences in tracking expected values in individuals with gambling disorder compared to controls, with greater activity during reward expected value tracking in the cingulate gyrus and amygdala. In cocaine use disorder, we observed lower responses to positive punishment prediction errors and greater activity following negative punishment prediction errors in the superior frontal gyrus compared to controls.

CONCLUSIONS

Using a computational approach, we show that individuals with gambling disorder and cocaine use disorder differed in their perseverative tendencies and in how they tracked value neurally, which has implications for psychiatric classification.

Brain Morphology Predictors of Alcohol, Tobacco, and Cannabis Use in Adolescence: A Systematic Review

In the last decade, extensive research has emerged on the predictive value of brain morphology for substance use initiation and related problems during adolescence. This systematic review provides an overview of longitudinal studies on pre-existing brain variations and later initiation of alcohol, tobacco, and cannabis use (N = 18). Adolescent structural neuroimaging studies that started before substance use initiation suggest that a smaller anterior cingulate cortex (ACC) volume, thicker or smaller superior frontal gyrus, and larger nucleus accumbens (NAcc) volume are associated with future alcohol use. Also, both smaller and larger orbitofrontal cortex (OFC) volumes were associated with future cannabis and combined alcohol/cannabis use. Smaller amygdala volumes were related to future daily tobacco smoking. These findings could point to specific vulnerabilities for adolescent substance use, as these brain areas are involved in cognitive control (ACC), reward (NAcc), motivation (OFC), and emotional memory (amygdala). However, the reported findings were inconsistent in directionality and laterality, and the largest study on alcohol use predictors reported null findings. Therefore, large population-based longitudinal studies should investigate the robustness and mechanisms of these associations. We suggested future research directions regarding sample selection, timing of baseline and follow-up measurements, and a harmonization approach of study methods.

Prefrontal cortical activation in Internet Gaming Disorder Scale high scorers during actual real-time internet gaming: A preliminary study using fNIRS

Background

Observation of real-time neural characteristics during gameplay would provide distinct evidence for discriminating the currently controversial diagnosis of internet gaming disorder (IGD), and elucidate neural mechanisms that may be involved in addiction. We aimed to provide preliminary findings on possible neural features of IGD during real-time internet gaming using functional near-infrared spectroscopy (fNIRS).

Methods

Prefrontal cortical activations accompanying positive and negative in-game events were investigated. Positive events: (1) participant's champion slays or assists in slaying an opponent without being slain. (2) the opposing team's nexus is destroyed. Negative events: (1) participant's champion is slain without slaying or assisting in slaying any opponent. (2) the team's nexus is destroyed. Collected data were compared between the IGD group and control group, each with 15 participants.

Results

The IGD group scored significantly higher than the CTRL group on the craving scale. Following positive events, the IGD group displayed significantly stronger activation in the DLPFC. Following negative events, the IGD group displayed significantly weaker activation in the lateral OFC.

Discussion and Conclusions

Individuals scoring high on the IGD scale may crave for more internet gaming after encountering desired events during the game. Such observations are supported by the correlation between the craving scale and DLPFC activation. The IGD group may also show diminished punishment sensitivity to negative in-game experiences rendering them to continue playing the game. The present study provides preliminary evidence that IGD may demonstrate neural characteristics observed in other addictive disorders and suggests the use of fNIRS in behavioral addiction studies.

Sinful pleasures and pious woes? Using fMRI to examine evaluative and hedonic emotion knowledge

Traditionally, lust and pride have been considered pleasurable, yet sinful in the West. Conversely, guilt is often considered aversive, yet valuable. These emotions illustrate how evaluations about specific emotions and beliefs about their hedonic properties may often diverge. Evaluations about specific emotions may shape important aspects of emotional life (e.g. in emotion regulation, emotion experience and acquisition of emotion concepts). Yet these evaluations are often understudied in affective neuroscience. Prior work in emotion regulation, affective experience, evaluation/attitudes and decision-making point to anterior prefrontal areas as candidates for supporting evaluative emotion knowledge. Thus, we examined the brain areas associated with evaluative and hedonic emotion knowledge, with a focus on the anterior prefrontal cortex. Participants (N = 25) made evaluative and hedonic ratings about emotion knowledge during functional magnetic resonance imaging (fMRI). We found that greater activity in the medial prefrontal cortex (mPFC), ventromedial PFC (vmPFC) and precuneus was associated with an evaluative (vs hedonic) focus on emotion knowledge. Our results suggest that the mPFC and vmPFC, in particular, may play a role in evaluating discrete emotions.

Associations of agression and use of caffeine, alcohol and nicotine in healthy and aggressive individuals

BACKGROUND

Caffeine, alcohol, and nicotine are the three most commonly used psychoactive substances in the world. Given the known propensity of these substances to influence behavior, the relationship between these substances and aggressive and impulsive behaviors, in particular is of interest.

METHODS

1062 adult individuals participated in this study including those with Intermittent Explosive Disorder (IED) and non-aggressive healthy (HC) and psychiatric (PC) controls. Data regarding current and life use of caffeine, alcohol, and nicotine were recorded as were responses on measures of aggression, anger, and impulsivity.

RESULTS

Dimensional measures of aggression, anger, and impulsiveness were variably but significantly related to the consumption of these commonly used psychoactive substances. These findings were generally mirrored when using the categorical construct of IED. Finally, these findings were not due to comorbidity with other psychiatric disorders.

CONCLUSIONS

These data confirm a link between these externalizing behaviors and these three legal and commonly consumed psychoactive substances in clinically relevant individuals.

Intimate Partner Violence and Illicit Substance Use Among Sexual and Gender Minority Youth: The Protective Role of Cognitive Reappraisal

Sexual and gender minority youth (SGMY) disproportionately experience intimate partner violence (IPV) and report illicit substance use compared with cisgender heterosexual youth. Cognitive reappraisal strategies have been shown to decrease trauma-exposed individuals' likelihood of engaging in substance use. However, virtually no research has examined the relationship between various forms of IPV, including identity abuse, and illicit substance use, as well as the protective role of cognitive reappraisal among IPV-exposed SGMY. The current study addressed these limitations and examined cognitive reappraisal as a moderator of the associations between various IPV forms and illicit substance use among 149 SGMY (ages 18-25; 28.9% bisexual, 42.3% transgender or gender nonbinary, 45.0% racial and ethnic minority) between 2016 and 2017. Results indicated that many SGMY used cocaine in the past 6 months (24.8%), followed by hallucinogens (24.8%), stimulants (22.8%), and heroin (20.8%). More than half (62.4%) of SGMY experienced psychological abuse, 44.3% physical abuse, and 43.6% identity abuse in the past year. Cognitive reappraisal buffered the associations between two forms of IPV, identity abuse and physical abuse, and illicit substance use among SGMY, underscoring its importance for clinical intervention. Specifically, past year identity abuse and physical abuse were associated with greater illicit substance use only for SGMY with lower cognitive reappraisal, not for youth with higher cognitive reappraisal. This study adds to the burgeoning literature on identity, physical, and psychological forms of IPV and illicit substance use among SGMY. Our findings provide evidence that cognitive reappraisal strategies buffer the effect of identity abuse and physical abuse on illicit drug use among SGMY. These findings shed light on new avenues for clinical intervention that may help to reduce the prevalence of illicit substance use among IPV-exposed SGMY.

Neurophysiological correlate of incubation of craving in individuals with methamphetamine use disorder

Previous studies both in laboratory animals and humans have reported that abstinence induces incubation of cue-induced drug craving for nicotine, alcohol, cocaine, and methamphetamine. However, current experimental procedures utilized to study incubation of methamphetamine craving do not incorporate the temporal dynamics of neuropsychological measures and electrophysiological activities associated with this incubation process. This study utilized the high-density electroencephalogram (EEG) signals as a rapid, inexpensive, and noninvasive measure of cue-induced craving potential. A total of 156 male individuals with methamphetamine use disorder (MUD) enrolled in this multisite, cross-sectional study. Structured clinical interview data, self-report questionnaires (cued craving, quality of sleep, impulsivity, anxiety, and depression) and resting-state, eye-closed 128 high-density channel EEG signals were collected at 5 abstinence duration time points (<1, 1-3, 3-6, 6-12, and 12-24 months) to track the neuropsychological and neurophysiological signatures. Cue-induced craving was higher after 1-3 months than after the other time points. This incubation effect was also observed for sleep quality but not for anxiety, depression, and impulsivity symptoms, along with exhibited decreased power spectrum for theta (5.5-8 Hz) and alpha (8-13 Hz), and increased in beta (16.5-26.5 Hz) frequency band. Source reconstructed resting-state EEG analysis showed increased synchronization of medial prefrontal cortex (MPFC) for the beta frequency band in 1-3 months abstinent MUD group, and associated with the incubation of craving. Remarkably, the robust incubation-related abnormalities may be driven by beta-band source space connectivity between MPFC and bilateral orbital gyrus (ORB). Our findings suggest the enhancement of beta activity in the incubation period most likely originates from a dysfunction involving frontal brain regions. This neurophysiological signature of incubation of craving can be used to identify individuals who might be most susceptible to relapse, providing a potential insight into future therapeutic interventions for MUD via neuromodulation of beta activity.

Atypical interoception as a common risk factor for psychopathology: A review

The inadequacy of a categorial approach to mental health diagnosis is now well-recognised, with many authors, diagnostic manuals and funding bodies advocating a dimensional, trans-diagnostic approach to mental health research. Variance in interoception, the ability to perceive one's internal bodily state, is reported across diagnostic boundaries, and is associated with atypical functioning across symptom categories. Drawing on behavioural and neuroscientific evidence, we outline current research on the contribution of interoception to numerous cognitive and affective abilities (in both typical and clinical populations), and describe the interoceptive atypicalities seen in a range of psychiatric conditions. We discuss the role that interoception may play in the development and maintenance of psychopathology, as well as the ways in which interoception may differ across clinical presentations. A number of important areas for further research on the role of interoception in psychopathology are highlighted.

Over-representation of fundamental decision variables in the prefrontal cortex underlies decision bias

The brain is organized into anatomically distinct structures consisting of a variety of projection neurons. While such evolutionarily conserved neural circuit organization underlies the innate ability of animals to swiftly adapt to environments, they can cause biased cognition and behavior. Although recent studies have begun to address the causal importance of projection-neuron types as distinct computational units, it remains unclear how projection types are functionally organized in encoding variables during cognitive tasks. This review focuses on the neural computation of decision making in the prefrontal cortex and discusses what decision variables are encoded by single neurons, neuronal populations, and projection type, alongside how specific projection types constrain decision making. We focus particularly on "over-representations" of distinct decision variables in the prefrontal cortex that reflect the biological and subjective significance of the variables for the decision makers. We suggest that task-specific over-representation in the prefrontal cortex involves the refinement of the given decision making, while generalized over-representation of fundamental decision variables is associated with suboptimal decision biases, including pathological ones such as those in patients with psychiatric disorders. Such over-representation of the fundamental decision variables in the prefrontal cortex appear to be tightly constrained by afferent and efferent connections that can be optogenetically intervened on. These ideas may provide critical insights into potential therapeutic targets for psychiatric disorders, including addiction and depression.

Transition to substance use disorders: impulsivity for reward and learning from reward

Substance dependence constitutes a profound societal burden. Although large numbers of individuals use licit or illicit substances, few transition to dependence. The specific factors influencing this transition are not well understood. Substance-dependent individuals tend to be swayed by the immediate rewards of drug taking, but are often insensitive to delayed negative consequences of their behavior. Dependence is consequently associated with impulsivity for reward and atypical learning from feedback. Behavioral impulsivity is indexed using tasks measuring spontaneous decision-making and capacity to control impulses. While evidence indicates drug taking exacerbates behavioral impulsivity for reward, animal and human studies of drug naïve populations demonstrate it might precede any drug-related problems. Research suggests dependent individuals are also more likely to learn from rewarding (relative to punishing) feedback. This may partly explain why substance-dependent individuals fail to modify their behavior in response to negative outcomes. This enhanced learning from reward may constitute a further pre-existing risk factor for substance dependence. Although impulsivity for reward and preferential learning from rewarding feedback are both underpinned by a compromised dopaminergic system, few studies have examined the relationship between these two mechanisms. The interplay of these processes may help enrich understanding of why some individuals transition to substance dependence.

Multimodal indicators of risk for and consequences of substance use disorders: Executive functions and trait disconstraint assessed from preadolescence into early adulthood

Risk for substance use disorders (SUDs) is hypothesized to include behavioral disinhibition, a genetically mediated inability to inhibit or regulate behavior given task demands or motivational drives. In the present study, we examined developmental trajectories of multiple indicators of behavioral disinhibition assessed from preadolescence into early adulthood among individuals with versus without alcohol, tobacco, and cannabis use disorders. Participants were a population-based sample of 1512 male and female twins from the Minnesota Twin Family Study, prospectively assessed at ages 11, 14, 17, 20, and 24. Multimodal indicators of behavioral disinhibition included measures of executive function (visuospatial working memory accuracy, antisaccade task performance) and mother- and self-reported trait disconstraint. Multilevel modeling analyses that accounted for the repeated measures and nested nature of the twin family data were used to examine premorbid (age 11) indicators of executive function and trait disconstraint prior to the onset of any SUD symptoms, as well as changes from preadolescence into early adulthood (ages 11 to 24). Premorbid deviations evident at age 11 among individuals who subsequently developed SUDs included poorer performance on the visuospatial working memory test and higher levels of trait disconstraint. In addition, individuals with SUDs did not demonstrate developmentally normative improvements in inhibitory control (i.e., antisaccade performance did not improve) or in their levels of trait disconstraint. We conclude that these deviations in both neurocognitive and dispositional correlates of behavioral disinhibition precede onset of SUDs and may confer risk for their development, and in addition, problematic substance use may exacerbate preexisting deviations and interfere with normative developmental trajectories of executive function and trait disconstraint, with deleterious consequences for functioning.

Sleep disturbance and the long-term impact of early adversity

Sleep disturbance may be a central, yet underappreciated mechanism by which early adversity has a long-term impact upon mental and physical health. The fundamental regulatory processes shaped by early adversity - neural, neuroendocrine, and immune - are also central to sleep. Sleep problems, in turn, lead to a similar constellation of chronic health problems that have been linked to early adversity. We bring together work from the fields of early adversity and sleep in order to suggest a model by which sleep disturbance plays a critical role in the far-reaching impacts of early adversity on health. Future research should employ more longitudinal designs and pay particular attention to the impact of developmental periods such as adolescence and midlife when maturational and environmental factors conspire to create a unique time of sleep disturbance. We also suggesting that intervening to minimize sleep disturbance may be a promising means by which to test the model, as well as potentially blunt the long-term impact of early adversity on health.

Interoception moderates the relation between alexithymia and risky-choices in a framing task: A proposal of two-stage model of decision-making

Decision-making depends on the context (frame) in which questions and alternatives are presented. Moreover, research has showed that the ability to detect bodily sensations (interoception) and being able to attribute these changes to emotions correctly (alexithymia) influence how we make decisions. The aim of the present research was to study how interoception and alexithymia might affect the Framing effect (FE), a cognitive bias closely related to emotional system. 42 healthy participants completed the Risky-choice Framing task and their interoception and alexithymia levels were measured. Results showed that the participants were more risk-taking under the negative frames in comparison to the positive ones. In addition, we found that alexithymia and interoception were negatively and positively correlated with the FE, respectively. Finally, the moderation analyses revealed that alexithymia predicted a lower FE only when the interoception was high. Based on previous literature and in our results, we propose a two-stage model of intuitive decision-making.

Appetitive Motivation and Regulatory Processes in Adolescent Ketamine Users

Ketamine has remained the most commonly used illicit drug among adolescents in Taiwan. A dual process model proposes that addictive behaviors develop in adolescents as a result of an imbalance between an appetitive, approach-oriented system (implicit and explicit attitudes) and a regulatory executive system (cool and hot executive functions). We aimed to examine the appetitive and regulatory processes in adolescent ketamine users in comparison to matched healthy adolescents. Method: The participants were 30 adolescent ketamine users and 32 nondrug controls, matched with gender, age, education years, and education systems. Both groups completed the affective priming task (APT), the stop-signal task (SST), an Iowa Gambling Task (IGT), and finally a Drug Use Disorders Identification Test: Extended (DUDIT-E). Results: The controls had higher positive and negative outcome expectancy with respect to using ketamine compared to the adolescent ketamine users. There was no significant between-group performance difference in APT. The adolescent ketamine users may have shown marginally poorer performance compared to the controls in hot executive functions (IGT), but their cold executive functions (SST) remained intact. Conclusion: The current study reported that the adolescent ketamine users may not have imbalanced dual processes (biased appetitive motivation and impaired regulatory executive process). A different therapeutic focus on adolescent ketamine users may be developed accordingly. More advocacies on ketamine's aversive outcomes are needed, particularly on campus in order to reduce substance misuse.

Review of Orbitofrontal Cortex in Alcohol Dependence: A Disrupted Cognitive Map?

Alcoholism is a persistent worldwide problem associated with long-lasting impairments to decision making processes. Some aspects of dysfunction are thought to reflect alcohol-induced changes to relevant brain areas such as the orbitofrontal cortex (OFC). In this review, we will examine how chronic alcohol exposure alters OFC function to potentially contribute to maladaptive decision making, and explore experimental behavioral approaches that may be better suited to test whether alcohol dependence disrupts OFC's function. We argue that although past works suggest impairments in aspects of OFC function, more information may be gained by specifically targeting tasks to the broader function of OFC as put forth by the recent hypothesis of OFC as a "cognitive map" of task space. Overall, we suggest that such a focus could provide a better understanding of how OFC function changes in alcohol dependence, and could inform better assessment tools and treatment options for clinicians working with this population.

BOLD activation during cue induced craving in adolescent inhalant users

Inhalants are legally available substances, most of them inexpensive, which are often abused by adolescents. Craving causes their continued use and repeated relapses. There is a need to understand the cue-induced craving and the associated neural mechanisms. In absence of any such prior study, the present study compared the hemodynamic changes in brain associated with craving effect in adolescent inhalant users and healthy controls using blood oxygen level dependent (BOLD) mechanism. This was an observational case control study with twelve adolescents, aged 12-18 years, with current use of inhalants as their primary drug, and twelve healthy, age and gender-matched adolescents, with no lifetime use of inhalants. Clinical assessments included Teen Addiction Severity Index and Visual Analogue Scale for craving. Participants abstained from all substances during 48 h prior to fMRI, confirmed by urinalysis. A validated visual cue block paradigm with neutral and craving cues was presented during the BOLD assessments in a 3 T MR system. The inhalant users exhibited BOLD activation in inferior frontal gyrus, inferior parietal lobule, superior occipital gyrus, cingulate gyrus, lentiform nucleus, thalamus, and culmen as compared to control group. The control group exhibited activation of insula as compared to cases. The results may be attributed to visuo-spatial attention, visual perception, working memory, and motivation associated with visual cue reactivity. This preliminary study provides important findings pertaining to activation patterns in response to cue-induced craving among adolescent inhalant users.

Chemogenetic Inactivation of Orbitofrontal Cortex Decreases Cue-induced Reinstatement of Ethanol and Sucrose Seeking in Male and Female Wistar Rats

BACKGROUND

The orbitofrontal cortex (OFC) encodes internal representations of outcomes and subjective value to facilitate flexible reward seeking. OFC activation is associated with drug seeking in both human subjects and animal models. OFC plays a role in alcohol use, but studies in animal models have produced conflicting results with some showing decreased seeking after OFC inactivation but others showing increased seeking or no changes. In part, this may be due to the different measures of alcohol seeking used (e.g., homecage drinking vs. operant seeking).

METHODS

We characterized the impact of transient inactivation of OFC (primarily lateral and, to a lesser extent, ventral subregions) using inhibitory hM4Di designer receptors exclusively activated by designer drugs (DREADDs). OFC neurons were transiently inhibited during 10% and 20% alcohol (ethanol, EtOH) and sucrose homecage consumption, fixed ratio (FR1) operant self-administration, and cue-induced reinstatement of either 10% EtOH or sucrose in male and female rats.

RESULTS

OFC inactivation did not affect sucrose or EtOH consumption in the homecage, nor did it influence seeking or consumption under FR1 operant conditions. In contrast, OFC inactivation suppressed cued-induced reinstatement for both EtOH and sucrose in both male and female rats.

CONCLUSIONS

Our results are aligned with previous work indicating a selective suppressive effect of OFC inactivation on reinstatement for alcohol and other drugs of abuse. They extend these findings to demonstrate no effect on homecage consumption or FR1 seeking as well as showing an impact of sucrose reinstatement. These data indicate that OFC plays a uniquely important role when reward seeking is driven by associations between external stimuli and internal representations of reward value, both for natural and drug rewards. They further implicate the OFC as a key structure driving relapse-associated seeking and potentially contributing to alcohol use disorder and other diseases of compulsive reward seeking.

Orbitofrontal Cortex Encodes Preference for Alcohol

Orbitofrontal cortex (OFC) plays a key role in representation and regulation of reward value, preference, and seeking. OFC function is disrupted in drug use and dependence, but its specific role in alcohol use disorders has not been thoroughly studied. In alcohol-dependent humans OFC activity is increased by alcohol cue presentation. Ethanol (EtOH) also alters OFC neuron excitability in vitro, and OFC manipulation influences EtOH seeking and drinking in rodents.

Orbitofrontal cortex (OFC) plays a key role in representation and regulation of reward value, preference, and seeking. OFC function is disrupted in drug use and dependence, but its specific role in alcohol use disorders has not been thoroughly studied. In alcohol-dependent humans OFC activity is increased by alcohol cue presentation. Ethanol (EtOH) also alters OFC neuron excitability in vitro, and OFC manipulation influences EtOH seeking and drinking in rodents. To understand the relationship between OFC function and individual alcohol use, we recorded OFC neuron activity in rats during EtOH self-administration, characterizing the neural correlates of individual preference for alcohol. After one month of intermittent access to 20% EtOH, male Long–Evans rats were trained to self-administer 20% EtOH, 10% EtOH, and 15% sucrose. OFC neuronal activity was recorded and associated with task performance and EtOH preference. Rats segregated into high and low EtOH drinkers based on homecage consumption and operant seeking of 20% EtOH. Motivation for 10% EtOH and sucrose was equally high in both groups. OFC neuronal activity was robustly increased or decreased during sucrose and EtOH seeking and consumption, and strength of changes in OFC activity was directly associated with individual preference for 20% EtOH. EtOH-associated OFC activity was more similar to sucrose-associated activity in high versus low EtOH drinkers. The results show that OFC neurons are activated during alcohol seeking based on individual preference, supporting this brain region as a potential substrate for alcohol motivation that may be dysregulated in alcohol misuse.

Selective impact of lateral orbitofrontal cortex inactivation on reinstatement of alcohol seeking in male Long-Evans rats

The orbitofrontal cortex (OFC) plays a fundamental role in motivated behavior and decision-making. In humans, OFC structure and function is significantly disrupted in drug using and dependent individuals, including those exhibiting chronic alcohol use and alcoholism. In animal models, the OFC has been shown to significantly influence the seeking of non-alcohol drugs of abuse. However direct investigations of the OFC during alcohol seeking and use have been more limited. In the studies reported here, we inactivated lateral (lOFC) or medial OFC (mOFC) subregions in rats during multiple stages of alcohol seeking. After one month of intermittent access to homecage 20% ethanol (EtOH), rats were trained to self-administer EtOH under an FR3 schedule and implanted with cannulae directed to lOFC or mOFC. We inactivated OFC subregions with baclofen/muscimol during EtOH self-administration, extinction, cue-induced reinstatement, and progressive ratio testing to broadly characterize the influence of these subregions on alcohol seeking. There were no significant effects of mOFC or lOFC inactivation during FR3 self-administration, extinction, or progressive ratio self-administration. However, lOFC, and not mOFC, inactivation significantly decreased cue-induced reinstatement of EtOH seeking. These findings contribute new information to the specific impact of OFC manipulation on operant alcohol seeking, support previous studies investigating the role of OFC in seeking and consumption of alcohol and other drugs of abuse, and indicate a specific role for lOFC vs. mOFC in reinstatement.

Differential cortical and subcortical projection targets of subfields in the core region of mouse auditory cortex

The core region of the rodent auditory cortex has two areas: the primary auditory area (A1) and the anterior auditory field (AAF). However, the functional difference between these areas is unclear. To elucidate this issue, here we studied the projections from A1 and AAF in mice using adeno-associated virus (AAV) vectors expressing either a green fluorescent protein or a red fluorescent protein. After mapping A1 and AAF using optical imaging, we injected a distinct AAV vector into each of the two fields at a frequency-matched high-frequency location. We found that A1 and AAF projected commonly to virtually all target areas examined, but each field had its own preference for projection targets. Frontal and parietal regions were the major cortical targets: in the frontal cortex, A1 and AAF showed dominant projections to the anterior cingulate cortex Cg1 and the secondary motor cortex (M2), respectively; in the parietal cortex, A1 and AAF exhibited dense projections to the medial secondary visual cortex and the posterior parietal cortex (PPC), respectively. Although M2 and PPC received considerable input from A1 as well, A1 innervated the medial part whereas AAF innervated the lateral part of these cortical regions. A1 also projected to the orbitofrontal cortex, while AAF also projected to the primary somatosensory cortex and insular auditory cortex. As for subcortical projections, A1 and AAF projected to a common ventromedial region in the caudal striatum with a comparable strength; they also both projected to the medial geniculate body and the inferior colliculus, innervating common and distinct divisions of the nuclei. A1 also projected to visual subcortical structures, such as the superior colliculus and the lateral posterior nucleus of the thalamus, where fibres from AAF were sparse. Our results demonstrate the preference of A1 and AAF for cortical and subcortical targets, and for divisions in individual target. The preference of A1 and AAF for sensory-related structures suggest a role for A1 in providing auditory information for audio-visual association at both the cortical and subcortical level, and a distinct role of AAF in providing auditory information for association with somatomotor information in the cortex.

Decision making of forensic psychiatric inpatients deemed incompetent to stand trial

This study examined decision making and its correlates among forensic psychiatric inpatients deemed incompetent to stand trial (IST). This study utilized archival data (n = 41; Mean Age = 44.27, SD = 15.89, 79.1% Male; 34.1% Caucasian). Decision making was measured using the Iowa Gambling Task (IGT), which is purported to simulate real-life decision making. Correlates included cognitive functioning, psychiatric symptom severity, and impulsivity. Participants selected more frequently from disadvantageous decks, which yield larger immediate monetary gains with a larger long-term monetary losses (Mean NET = -9.51, SD = 26.70), but avoided decks yielding frequent monetary losses (Mean GLF = 10.10, SD = 26.70). Consistently, participants selected most frequently from a deck yielding the most immediate monetary gains and the least frequent monetary losses compared to other decks (ps < 0.05). Based upon their selections, participants lost a significant amount of money (M = -$1,493.22, SD = $1,182.26). IGT outcomes were differentially associated with cognitive functioning (rs = -0.26 to 0.47), psychiatric symptom severity (rs = -0.41 to 0.37), and impulsivity (rs = -0.47 to 0.28; all ps = 0.003-0.98). Findings can guide future research, as well as guide competency restoration and decision-making interventions, for this population.

Consortium on Vulnerability to Externalizing Disorders and Addictions (cVEDA): A developmental cohort study protocol

BACKGROUND

Low and middle-income countries like India with a large youth population experience a different environment from that of high-income countries. The Consortium on Vulnerability to Externalizing Disorders and Addictions (cVEDA), based in India, aims to examine environmental influences on genomic variations, neurodevelopmental trajectories and vulnerability to psychopathology, with a focus on externalizing disorders.

METHODS

cVEDA is a longitudinal cohort study, with planned missingness design for yearly follow-up. Participants have been recruited from multi-site tertiary care mental health settings, local communities, schools and colleges. 10,000 individuals between 6 and 23 years of age, of all genders, representing five geographically, ethnically, and socio-culturally distinct regions in India, and exposures to variations in early life adversity (psychosocial, nutritional, toxic exposures, slum-habitats, socio-political conflicts, urban/rural living, mental illness in the family) have been assessed using age-appropriate instruments to capture socio-demographic information, temperament, environmental exposures, parenting, psychiatric morbidity, and neuropsychological functioning. Blood/saliva and urine samples have been collected for genetic, epigenetic and toxicological (heavy metals, volatile organic compounds) studies. Structural (T1, T2, DTI) and functional (resting state fMRI) MRI brain scans have been performed on approximately 15% of the individuals. All data and biological samples are maintained in a databank and biobank, respectively.

DISCUSSION

The cVEDA has established the largest neurodevelopmental database in India, comparable to global datasets, with detailed environmental characterization. This should permit identification of environmental and genetic vulnerabilities to psychopathology within a developmental framework. Neuroimaging and neuropsychological data from this study are already yielding insights on brain growth and maturation patterns.

DRD2 methylation is associated with executive control network connectivity and severity of alcohol problems among a sample of polysubstance users

Chronic exposure to alcohol and other drugs of abuse has been associated with deleterious consequences, including functional connectivity deficits within neural networks associated with executive control. Altered functional connectivity within the executive control network (ECN) might underlie the progressive inability to control consumption of alcohol and other drugs as substance use disorders progress. Genetic and epigenetic factors have been associated with substance use disorders (SUDs). For example, dopamine receptor 2 (DRD2) functioning has been associated with alcohol use disorder (AUD) and related phenotypes, including correlates of executive functioning. The present study aims to explore the relationship between a continuous measure of alcohol-related problems, epigenetic markers (methylation) within the DRD2 gene, and functional connectivity within the ECN among a sample of polysubstance users. A community sample of 658 subjects, whose consumption of alcohol, nicotine, and cannabis span across a spectrum of quantity and frequency of use, were obtained across previous studies in polysubstance using populations. Resting state functional magnetic resonance imaging was analyzed to identify intrinsic connectivity networks using a priori regions of interest. Methylation measurement of functionally relevant sites within the DRD2 gene was achieved via pyrosequencing. Regression-based models, including mediation and moderation models, tested the association between DRD2 methylation, functional connectivity within intrinsic neural networks (including the ECN), and severity of alcohol problems. Results suggest that average DRD2 methylation was negatively associated with right ECN (RECN) and left ECN (LECN) connectivity, but not associated with other networks tested, and DRD2 methylation was significantly associated with alcohol problems severity. Mediation models were not supported, although moderation models suggested that connectivity between edges within the RECN moderated the relationship between DRD2 methylation and AUD severity. Results support a theoretical model in which epigenetic factors are associated with neurobiological correlates of alcohol consumption among a sample of polysubstance users.

mTORC1 in the orbitofrontal cortex promotes habitual alcohol seeking

The mechanistic target of rapamycin complex 1 (mTORC1) plays an important role in dendritic translation and in learning and memory. We previously showed that heavy alcohol use activates mTORC1 in the orbitofrontal cortex (OFC) of rodents (Laguesse et al., 2017a). Here, we set out to determine the consequences of alcohol-dependent mTORC1 activation in the OFC. We found that inhibition of mTORC1 activity in the OFC attenuates alcohol seeking and restores sensitivity to outcome devaluation in rats that habitually seek alcohol. In contrast, habitual responding for sucrose was unaltered by mTORC1 inhibition, suggesting that mTORC1’s role in habitual behavior is specific to alcohol. We further show that inhibition of GluN2B in the OFC attenuates alcohol-dependent mTORC1 activation, alcohol seeking and habitual responding for alcohol. Together, these data suggest that the GluN2B/mTORC1 axis in the OFC drives alcohol seeking and habit.

Decision making of individuals with heroin addiction receiving opioid maintenance treatment compared to early abstinent users

BACKGROUND AND AIMS

Individuals with heroin addiction are prone to dysfunctional decision-making. They frequently choose the short-term rewarding option of drug intake despite experiencing long-term negative consequences. Opioid maintenance treatment (OMT) is the most common treatment of heroin addiction.

METHODS

In this study, 38 individuals in an early stage of abstinence from heroin addiction (ESA-HA individuals) at the end of inpatient detoxification treatment and 41 individuals in long-term OMT were examined. Decision-making was assessed by (I) a modified version of the Iowa Gambling Task (IGT) with drug-related stimuli focusing on decision-making under ambiguity and (II) the Game of Dice Task (GDT) assessing decision-making under objective risk.

RESULTS

OMT-individuals showed significantly better performance in the IGT than the ESA-HA-individuals. They also showed significantly less craving under exposure of drug-related pictures. In the GDT, OMT-individuals showed significantly less risky decision-making than ESA-HA-individuals.

CONCLUSION

The results suggest that patients receiving OMT show better functional decision-making and lower craving reactions. It could be assumed that the effectiveness of OMT in preventing relapse is linked to better decision-making and lower craving among these patients.

Withdrawal from escalated cocaine self-administration impairs reversal learning by disrupting the effects of negative feedback on reward exploitation: a behavioral and computational analysis

Addiction is regarded as a disorder of inflexible choice with behavior dominated by immediate positive rewards over longer-term negative outcomes. However, the psychological mechanisms underlying the effects of self-administered drugs on behavioral flexibility are not well understood. To investigate whether drug exposure causes asymmetric effects on positive and negative outcomes we used a reversal learning procedure to assess how reward contingencies are utilized to guide behavior in rats previously exposed to intravenous cocaine self-administration (SA). Twenty-four rats were screened for anxiety in an open field prior to acquisition of cocaine SA over six daily sessions with subsequent long-access cocaine SA for 7 days. Control rats (n = 24) were trained to lever-press for food under a yoked schedule of reinforcement. Higher rates of cocaine SA were predicted by increased anxiety and preceded impaired reversal learning, expressed by a decrease in lose-shift as opposed to win-stay probability. A model-free reinforcement learning algorithm revealed that rats with high, but not low cocaine escalation failed to exploit previous reward learning and were more likely to repeat the same response as the previous trial. Eight-day withdrawal from high cocaine escalation was associated, respectively, with increased and decreased dopamine receptor D2 (DRD2) and serotonin receptor 2C (HTR2C) expression in the ventral striatum compared with controls. Dopamine receptor D1 (DRD1) expression was also significantly reduced in the orbitofrontal cortex of high cocaine-escalating rats. These findings indicate that withdrawal from escalated cocaine SA disrupts how negative feedback is used to guide goal-directed behavior for natural reinforcers and that trait anxiety may be a latent variable underlying this interaction.

Enhanced methamphetamine-induced conditioned place preference in risk-taking rats

Patients with psychiatric disorders, such as gambling and substance use, tend to exhibit maladaptive decision-making. In this study, we assessed individual differences in risk-taking behaviors using a rat gambling task (GT) and investigated the relationship between risk-taking behaviors and vulnerability to drug dependence using methamphetamine (METH)-induced conditioned place preference (CPP). In the GT using a radial arm maze, male Long-Evans rats were trained to choose one of three choice arms (a low-risk/low reward (L-L), a high-risk/high reward (H-H), and an empty arm) in 16 trials per day for 14 days. METH-induced CPP consisted of 6 sessions: habituation, conditioning, preference test (Test I), extinction, extinction test (Test II), and reinstatement test (Test III). Results demonstrated that the percentage of choosing the H-H arm was significantly positively correlated with the percentage of time spent in the METH-paired compartment in the preference test, but not with the extinction and reinstatement tests, suggesting that risk-taking rats are more vulnerable to drug dependence.

Adolescent Brain Surface Area Pre- and Post-Cannabis and Alcohol Initiation

OBJECTIVE

Changes in gray matter volume and thickness are associated with adolescent alcohol and cannabis use, but the impact of these substances on surface area remains unclear. The present study expands on previous findings to examine the impact of alcohol and cannabis on surface area before and after use initiation.

METHOD

Scans for 69 demographically similar youth were obtained at baseline (ages 12-14 years; before substance use) and at 6-year follow-up (ages 17-21 years). Participants were classified into three groups based on substance use: alcohol use initiators (ALC, n = 23), alcohol and cannabis use initiators (ALC+CU, n = 23), and individuals with minimal substance use (<3 lifetime alcohol and 0 marijuana use episodes; CON, n = 23). For each hemisphere, group differences in surface area across time (pre- and post-substance use initiation) and significant group-by-time interactions were examined individually for 34 cortical regions using repeated measures analysis of covariance. A vertex-wise analysis assessed group differences in surface area percent change.

RESULTS

A significant group-by-time interaction was found in three regions, bilateral medial orbitofrontal cortices and right insula. Although all regions showed decreases in surface area over time (ps < .05), a more substantial decrease was identified in the ALC group. Of note, the right medial orbitofrontal cortex survived the conservative vertex-wise analyses (p < .001), as a more substantial decrease was found in the ALC compared to the ALC+CU group in this region.

CONCLUSIONS

Surface area in the medial orbitofrontal cortex may be a useful intermediate phenotype for exploring the mechanisms underlying the effects of substance use on brain development.

Brain Gray Matter Volume and Functional Connectivity Are Associated With Smoking Cessation Outcomes

Smoking cessation is critical for reducing the risk of respiratory, cardiovascular diseases and cancers. However, most cessation attempts resulted in failure. In the present study, we aim to explore whether alterations of brain gray matter (GM) volume and functional connectivity (FC) are related to cessation outcomes, in hope of providing evidence for improving smoking cessation outcomes. Seventy-three smokers and 41 non-smokers were enrolled in the present study. All smokers participated in a 12-week smoking cessation treatment during which Varenicline was used to aid cessation. At the end of treatment, the smokers were divided into quitters and relapsers based on their abstinence performance. Structural magnetic resonance imaging (MRI) and voxel-based morphometry were applied to quantify the differences of regional brain volumes among the three groups at baseline. In addition, resting-state FC was used to investigate the related functional changes. In comparison with non-smokers, the smokers showed smaller GM volume in the left dorsal medial thalamus. Among the 73 smokers, 29 subjects successfully quitted smoking. The quitters showed greater GM volume than the relapsers in the right postcentral gyrus, right putamen\caudate nucleus and left orbitofrontal cortex (OFC). The GM volume in the left OFC was found to be negatively correlated with the pack years and daily smoking amount in the quitters. Furthermore, we found significantly reduced FC between left thalamus and left cerebellum in the relapsers. These findings extended our knowledge of the neural mechanism of smoking cessation, and suggested that brain structural and functional changes were related to smoking cessation outcomes.

Orbitofrontal cortex volume prospectively predicts cannabis and other substance use onset in adolescents

BACKGROUND

Identifying neural characteristics that predict cannabis initiation is important for prevention efforts. The orbitofrontal cortex is critical for reward response and may be vulnerable to substance-induced alterations.

AIMS

We measured orbitofrontal cortex thickness, surface area, and volume prior to the onset of use to predict cannabis involvement during an average nine-year follow-up.

METHODS

Adolescents (n=118) aged 12-15 years completed baseline behavioral assessment and magnetic resonance imaging scans, then were followed up to 13 years with annual substance use interviews. Logistic regression examined baseline (pre-substance use) bilateral medial and lateral orbitofrontal cortex characteristics (volume, surface area, or cortex thickness) as predictors of regular cannabis use by follow-up. Post-hoc multinomial logistic regression assessed whether orbitofrontal cortex characteristics significantly predicted either alcohol use alone or cannabis+alcohol co-use. Brain-behavior relationships were assessed through follow-up correlations of baseline relationships between orbitofrontal cortex and executive functioning, reward responsiveness, and behavioral approach traits.

RESULTS

Larger left lateral orbitofrontal cortex volume predicted classification as cannabis user by follow-up (p=0.025, odds ratio=1.808). Lateral orbitofrontal cortex volume also predicted cannabis+alcohol co-user status (p=0.008, odds ratio=2.588), but not alcohol only status. Larger lateral orbitofrontal cortex volume positively correlated with greater baseline reward responsiveness (p=0.030, r=0.348). There were no significant results by surface area or cortex thickness (ps>0.05).

CONCLUSIONS

Larger left lateral orbitofrontal cortex measured from ages 12-15 years and prior to initiation of substance use was related to greater reward responsiveness at baseline and predicted classification as a cannabis user and cannabis+alcohol co-user by final follow-up. Larger lateral orbitofrontal cortex volume may represent aberrant orbitofrontal cortex maturation and increasing vulnerability for later substance use.

Predictors of empirically derived substance use patterns among sexual minority groups presenting at an emergency department

AIM

Minority sexual orientation (i.e., Lesbian, Gay, Bisexual; LGB) is a risk indicator for mental health and substance use problems. Findings are inconsistent across studies investigating LGB substance use and risk factors, possibly due to heterogeneity in LGB subgroups. To inform models of substance use risk, we identified empirical patterns of substance use and related risk behaviors among LGB individuals.

METHOD

LGB participants (N = 343; Mage = 35.5, SD = 11.8; 71.4% = Female; 80.5% = White) were screened in an Emergency Department as part of a randomized controlled trial of an alcohol brief intervention. We conducted latent class analyses using the AUDIT-C (12 month; frequency, quantity, & binge) and ASSIST (12 month; illicit or misused prescription substance). Multinomial regression was performed to test predictors of class membership including depression symptoms, driving after alcohol or marijuana, and sexually transmitted infection (STI) history.

RESULTS

A 3-class model fit best and included "low use alcohol, marijuana, and tobacco users," (Low use; n = 244) "hazardous alcohol, tobacco and marijuana users," (Hazardous; n = 74) and "high-risk polysubstance users" (HPU; n = 25). The Low use class comprised the largest proportion of the sample across age, race/ethnicity, and sexual orientation. Compared to the Low use class, higher likelihood of depression symptoms, driving after alcohol or marijuana use, and STI was found for both Hazardous and HPU classes.

CONCLUSION

Researchers and clinicians should consider substance use patterns within the LGB population to inform interventions that address a variety of complex needs such as allocating more support for LGB individuals endorsing high-risk polysubstance use.

Linking genes, circuits, and behavior: network connectivity as a novel endophenotype of externalizing

BACKGROUND

Externalizing disorders are known to be partly heritable, but the biological pathways linking genetic risk to the manifestation of these costly behaviors remain under investigation. This study sought to identify neural phenotypes associated with genomic vulnerability for externalizing disorders.

METHODS

One-hundred fifty-five White, non-Hispanic veterans were genotyped using a genome-wide array and underwent resting-state functional magnetic resonance imaging. Genetic susceptibility was assessed using an independently developed polygenic score (PS) for externalizing, and functional neural networks were identified using graph theory based network analysis. Tasks of inhibitory control and psychiatric diagnosis (alcohol/substance use disorders) were used to measure externalizing phenotypes.

RESULTS

A polygenic externalizing disorder score (PS) predicted connectivity in a brain circuit (10 nodes, nine links) centered on left amygdala that included several cortical [bilateral inferior frontal gyrus (IFG) pars triangularis, left rostral anterior cingulate cortex (rACC)] and subcortical (bilateral amygdala, hippocampus, and striatum) regions. Directional analyses revealed that bilateral amygdala influenced left prefrontal cortex (IFG) in participants scoring higher on the externalizing PS, whereas the opposite direction of influence was observed for those scoring lower on the PS. Polygenic variation was also associated with higher Participation Coefficient for bilateral amygdala and left rACC, suggesting that genes related to externalizing modulated the extent to which these nodes functioned as communication hubs.

CONCLUSIONS

Findings suggest that externalizing polygenic risk is associated with disrupted connectivity in a neural network implicated in emotion regulation, impulse control, and reinforcement learning. Results provide evidence that this network represents a genetically associated neurobiological vulnerability for externalizing disorders.

Dealing with gender-related and general stress: Substance use among Brazilian transgender youth

INTRODUCTION

Adolescent substance use is a major public health concern since it enhances adolescent morbidity and mortality, affecting adulthood health and well-being. Although current evidence shows a high risk for substance use among transgender populations, to date, few studies evaluate substance use among transgender youth.

METHOD

Brazilian transgender youth (ages between 16 and 25 years old) answered an online questionnaire measuring demographics, substance use and modifiable factors associated with drug use to deal with general stress, gender-related stress, and recreational use.

RESULTS

Cannabis was the most frequent substance used among transgender youth (20.88%; CI 95% 23.71-36.19), whereas 11.45% (CI 95% 11.38-21.47) of volunteers disclosed use of pain medication, such as codeine, and 5.05% (CI 95% 3.71-10.78) revealed use of sedatives and tranquilizers in the last 30 days. ADH medication (not prescribed), as well as cocaine and other drugs (such as antihistamines and Hookah), was also reported by 2.36% (CI 95% 0.92-5.84), 2.69% (CI 95% 1.24-6.49) and 4.04% (CI 95% 2.61-8.98) of transgender youth.

CONCLUSION

A logistic regression model showed that discrimination and home instability were the primary determinants of vulnerable to substance use among youth. Therefore, the harm reduction strategies must affect the social and physical aspects of transgender youth lives.

[Physiological centers of decision-making: manipulation of neural activity in insular cortex by AAV]

Decision-making is a key activity process that influences many aspects of daily living and both mental and physical health. In general, healthy participants reveal rational choice, but patients with neuropsychiatric disorders reveal irrational and risky choice in decision-making. Addiction is one of typical diseases revealed risky decision-making, addicts select risky action and options that confer short-term rewards at the cost of long-term disadvantages. Thus, irrational and risky decision-making is recognized as a core problem in patients with neuropsychiatric disorders, and a better understanding of the mechanisms underlying altered decision-making would provide insights into potential therapeutic approaches for these diseases. However, the neural pathway and substrates underlying these deficits are particularly unknown. Recently, we found that insular cortex is one of key regions for risky decision-making in an animal model of methamphetamine addiction, by using the designer receptor exclusively activated by designer drug (DREADD) technology, and that GABAergic dysfunction in insular cortex is involved in evaluating the subjective value of reward and reward prediction error. These brain dysfunctions would be related to risk taking behavior in addiction. In this review, we introduced the possible neural pathway related to risky decision-making and behavioral changes in choice strategy using adeno associated virus (AAV).

Negative Short-Term Outcome of Detoxification Therapy in Chronic Migraine With Medication Overuse Headache: Role for Early Life Traumatic Experiences and Recent Stressful Events

Background: Early traumatic experiences and Stressful episodes appear to be associated to the development and perpetuation of chronic pain disorders and to dependence-related behaviors. Objective: The present study evaluated whether these factors can be predictors, together with psychiatric conditions, of the outcome of a detoxification treatment in patients suffering from chronic migraine and medication-overuse headache in a 2-month follow-up. Methods: Consecutive patients undergoing a detoxification program as therapy for treating chronic migraine and medication overuse headache at the Pavia Headache Center were analyzed. During this program, lasting about 1 week, all patients received the standard CARE in-patient withdrawal protocol, which consisted in discontinuing abruptly the overused drug(s) and receiving daily detoxification therapy. Data on childhood traumatic events and recent stressful ones were analyzed by means of the Childhood Trauma Questionnaire and Stressful life-events Questionnaire. Psychiatric conditions were evaluated using the Structured Clinical Interview for Diagnostic and Statistical Manual of mental disorders. Results: A total of 166 (80% females; mean age 44.7) patients completed the follow-up at 2 months after the detoxification program: of these 118 (71%) (78% females; mean age 44.7) stopped overuse and reverted to an episodic pattern of headache (Group A); 19 (11%) (89% females; mean age 41.3) kept overusing and maintained a chronic pattern of headache (Group B); and 29 (18%) (79% females; mean age 46.9) stopped overuse without any benefit on headache frequency (Group C). At the multivariate analyses, a higher number of early life emotional distress (Odds Ratio 11.096; p = 0.037) arose as a prognostic factor for the outcome in Group B, while major depression during life-time (Odds Ratio 3.703; p = 0.006) and higher number of severe stressful episodes in the past 10 years (Odds Ratio 1.679; p = 0.045) were prognostic factors for the outcome of Group C. Conclusions: Data suggest that early life traumas and stressful events have a negative impact on the outcome of the detoxification program in subjects overusing acute medication for headache. The history of emotional childhood traumas is associated to the failure to cease overuse, whereas recent very serious life events are associated to the persistence of headache chronicity.

An investigation of the effect of trauma script exposure on risk-taking among patients with substance use disorders and posttraumatic stress disorder

Studies show that patients with substance use disorders (SUD) and posttraumatic stress disorder (PTSD) are at high risk for engaging in risky behaviors. However, these studies do not speak to the context in which these behaviors are more likely to occur. This study examined whether SUD patients with current PTSD, compared to those without a history of PTSD, are more likely to exhibit risk-taking on a laboratory-based risk-taking task, the Iowa Gambling Task (IGT), following exposure to a personalized trauma script versus a neutral script. The sample consisted of 122 trauma-exposed SUD patients with and without PTSD. Participants were administered a series of diagnostic interviews and personalized trauma scripts were created. On separate days, participants were exposed to a neutral or trauma script, followed by the IGT. Contrary to expectations, PTSD-SUD patients exhibited significantly greater risk-taking after the neutral (vs. trauma) script than those without PTSD. Moreover, whereas SUD patients without PTSD evidenced stability in IGT performance across scripts, those with PTSD exhibited significantly lower risk-taking on the IGT following the trauma (vs. neutral) script. Results provide support for the context dependent nature of risk-taking in PTSD-SUD patients and suggest they may become more risk averse in the context of trauma-related distress.

The role of the orbitofrontal cortex in alcohol use, abuse, and dependence

One of the major functions of the orbitofrontal cortex (OFC) is to promote flexible motivated behavior. It is no surprise, therefore, that recent work has demonstrated a prominent impact of chronic drug use on the OFC and a potential role for OFC disruption in drug abuse and addiction. Among drugs of abuse, the use of alcohol is particularly salient with respect to OFC function. Although a number of studies in humans have implicated OFC dysregulation in alcohol use disorders, animal models investigating the association between OFC and alcohol use are only beginning to be developed, and there is still a great deal to be revealed. The goal of this review is to consider what is currently known regarding the role of the OFC in alcohol use and dependence. I will first provide a brief, general overview of current views of OFC function and its contributions to drug seeking and addiction. I will then discuss research to date related to the OFC and alcohol use, both in human clinical populations and in non-human models. Finally I will consider issues and strategies to guide future study that may identify this brain region as a key player in the transition from moderated to problematic alcohol use and dependence.

Effects of neuromodulation on cognitive performance in individuals exhibiting addictive behaviors: A systematic review

BACKGROUND

There is growing interest in non-invasive brain stimulation techniques as treatments for addictive disorders. While multiple reviews have examined the effects of neuromodulation on craving and consumption, there has been no review of how neuromodulation affects cognitive functioning in addiction. This systematic review examined studies of the cognitive effects of transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS) in individuals exhibiting addictive behavior.

METHODS

Articles were identified through searches in PubMed and PsycINFO conducted in October 2017. Eligible studies investigated the effects of tDCS or TMS on cognitive task performance in participants reporting substance use (e.g., alcohol, tobacco, or drugs) or addictive behaviors (e.g., gambling). Tasks were organized into five domains: (1) Inhibitory control, (2) Risk-taking, (3) Impulsive choice (delay discounting), (4) Executive function, and (5) Implicit biases.

RESULTS

Twenty-four articles met the inclusion criteria. Fifty-seven percent of studies used tDCS and 43% used TMS, with nearly all studies (96%) targeting the dorsolateral prefrontal cortex. Ten studies reported significant within-subject modulation of cognitive functioning associated with active TMS or tDCS, with the same number reporting no change in cognitive performance. Of four studies that included both an experimental and control participant group, three showed between-group differences in the effects of neuromodulation.

CONCLUSIONS

While positive effects in several studies suggest that tDCS and TMS improve cognitive functioning in addiction, there is substantial heterogeneity across studies. We discuss person-related and methodological factors that could explain inconsistencies, and propose individualized stimulation protocols may sharpen the cognitive effects of neuromodulation in addiction.

The neurobiology of impulsivity and substance use disorders: implications for treatment

Impulsivity is strongly associated with substance use disorders (SUDs). Our review discusses impulsivity as an underlying vulnerability marker for SUDs, and treatment of co-occurring impulsivity in SUDs. Three factors should be considered for the complex relationship between impulsivity and a SUD: (1) the trait effect of impulsivity, centering on decreased cognitive and response inhibition, (2) the state effect resulting from either acute or chronic substance use on brain structure and function, and (3) the genetic and environmental factors (e.g., age and sex) may influence impulsive behavior associated with SUDs. Both subjective and objective measures are used to assess impulsivity. Together, treatment developments (pharmacological, behavioral, and neurophysiological) should consider these clinically relevant dimensions assessed by a variety of measures, which have implications for treatment matching in individuals with SUD. Despite its heterogeneity, impulsivity is a marker associated with SUDs and may be understood as an imbalance of bottom-up and top-down neural systems. Further investigation of these relationships may lead to more effective SUD treatments.

Effects of neuromodulation on cognitive performance in individuals exhibiting addictive behaviour: a systematic review protocol

BACKGROUND

Individuals with substance use and addictive disorders often display greater risk-taking behaviour, higher impulsivity, and altered reward processing compared to individuals without these disorders. While it is not known whether cognitive biases precede or result from addictive behaviour, they likely influence addiction-related decision-making, and may facilitate pathological behaviour. There is evidence that cognitive functions-including those shown to be altered in substance use and addictive disorders-can be influenced by neuromodulation techniques (specifically, transcranial direct current stimulation and transcranial magnetic stimulation). Much of this work has been conducted in healthy populations, however, making it unclear whether these methods can be used effectively to modulate cognitive functioning in individuals with substance use and addictive disorders. The purpose of the current review is to shed light on the potential effectiveness and feasibility of neuromodulation as a means to improve cognitive deficits in substance use disorders.

METHODS

The review will identify and evaluate studies that have examined the effects of transcranial direct current stimulation (tDCS) or transcranial magnetic stimulation (TMS) on cognitive task performance in individuals with chronic substance use or dependence. Relevant studies will be identified through searches in PubMed, PsycINFO, Scopus, and Embase, and narrative review will be used to explore evidence that these techniques can be used successfully to modulate cognitive performance in populations exhibiting addictive behaviour. Assessing individual cognitive domains in turn (e.g. risk-taking, impulsivity, attention), we will critically evaluate the validity and reliability of relevant studies and draw conclusions about the strength of evidence for effective use of neuromodulation in that domain. This protocol is not yet registered with PROSPERO.

DISCUSSION

To determine whether neuromodulation holds promise as an effective treatment for neurocognitive deficits in substance use and addictive disorders, it is essential to look carefully at previous studies using this approach in addiction samples. This review will provide an objective and informative description of what is currently known about the efficacy of these techniques, shed light on the feasibility and potential challenges of using neuromodulation in individuals who exhibit addictive behaviour, and identify the most valuable next steps for future research.

Lateral orbitofrontal cortex partitions mechanisms for fear regulation and alcohol consumption

Anxiety disorders and alcohol use disorder are highly comorbid, yet identifying neural dysfunction driving comorbidity has been challenging. Lateral orbitofrontal cortex (lOFC) dysfunction has been independently observed in each disorder. Here we tested the hypothesis that the lOFC is essential to partition mechanisms for fear regulation and alcohol consumption. Specifically, the capacity to regulate fear and the propensity to consume alcohol are unrelated when lOFC is intact, but become linked through lOFC dysfunction. Male Long Evans rats received bilateral, neurotoxic lOFC lesions or sham surgery. Fear regulation was determined by establishing discrimination to danger, uncertainty, and safety cues then shifting the shock probability of the uncertainty cue. Alcohol consumption was assessed through voluntary, intermittent access to 20% ethanol. The neurotoxic lesion approach ensured lOFC dysfunction spanned testing in fear regulation and alcohol consumption. LOFC-lesioned rats demonstrated maladaptive fear generalization during probability shifts, inverting normal prediction error assignment, and subsequently consumed more alcohol. Most novel, fear regulation and alcohol consumption were inextricably linked only in lOFC-lesioned rats: extreme fear regulation predicted excessive alcohol consumption. The results reveal the lOFC is essential to partition mechanisms for fear regulation and alcohol consumption and uncover a plausible source of neural dysfunction contributing to comorbid anxiety disorders and alcohol use disorder.

Assessment tools for screening and clinical evaluation of psychosocial aspects in addictive disorders

This article provides an overview of the tools for psychosocial assessment of substance use disorders. Various psychosocial factors need to be assessed for effective management of individuals and to carry out research in the field. These factors include socio-demographic characteristics, neuropsychological functions, psychiatric co-morbidities, psychological vulnerabilities such as personality traits, motivation, and cognitions related to drug use, and the psychosocial functioning of the individual and his family. The various tools used to assess these aspects have been outlined below and the brief descriptions provided can help in choosing the right tool based on the characteristics that need to be measured and logistics.

Problematic internet use is associated with structural alterations in the brain reward system in females

Neuroimaging findings suggest that excessive Internet use shows functional and structural brain changes similar to substance addiction. Even though it is still under debate whether there are gender differences in case of problematic use, previous studies by-passed this question by focusing on males only or by using gender matched approach without controlling for potential gender effects. We designed our study to find out whether there are structural correlates in the brain reward system of problematic Internet use in habitual Internet user females. T1-weighted Magnetic Resonance (MR) images were collected in 82 healthy habitual Internet user females. Structural brain measures were investigated using both automated MR volumetry and voxel based morphometry (VBM). Self-reported measures of problematic Internet use and hours spent online were also assessed. According to MR volumetry, problematic Internet use was associated with increased grey matter volume of bilateral putamen and right nucleus accumbens while decreased grey matter volume of orbitofrontal cortex (OFC). Similarly, VBM analysis revealed a significant negative association between the absolute amount of grey matter OFC and problematic Internet use. Our findings suggest structural brain alterations in the reward system usually related to addictions are present in problematic Internet use.

Altered White Matter Integrity in Smokers Is Associated with Smoking Cessation Outcomes

Smoking is a significant cause of preventable mortality worldwide. Understanding the neural mechanisms of nicotine addiction and smoking cessation may provide effective targets for developing treatment strategies. In the present study, we explored whether smokers have white matter alterations and whether these alterations are related to cessation outcomes and smoking behaviors. Sixty-six smokers and thirty-seven healthy non-smokers were enrolled. The participants underwent magnetic resonance imaging scans and smoking-related behavioral assessments. After a 12-week treatment with varenicline, 28 smokers succeeded in quitting smoking and 38 failed. Diffusion parameter maps were compared among the non-smokers, future quitters, and relapsers to identify white matter differences. We found that the future relapsers had significantly lower fractional anisotropy (FA) in the orbitofrontal area than non-smokers, and higher FA in the cerebellum than non-smokers and future quitters. The future quitters had significantly lower FA in the postcentral gyrus compared to non-smokers and future relapsers. Compared to non-smokers, pooled smokers had lower FA in bilateral orbitofrontal gyrus and left superior frontal gyrus. In addition, regression analysis showed that the left orbitofrontal FA was correlated with smoking-relevant behaviors. These results suggest that white matter alterations in smokers may contribute to the formation of aberrant brain circuits underlying smoking behaviors and are associated with future smoking cessation outcomes.