The neurobiology of addiction: a neuroadaptational view relevant for diagnosis

Using Measurement-Based Care as a Precision Medicine Strategy for Substance Use Disorders

PURPOSE OF REVIEW

Precision medicine prioritizes characterization of individual patient parameters to optimize care and this review evaluates measurement-based care (MBC) as a strategy for doing so in the treatment of substance use disorders (SUD). Measurement-based care refers to the systematic use of validated assessments to inform diagnosis and treatment planning, with varying frequency of assessments. Despite the seemingly obvious grounds for the use of MBC in treating SUD, systematic implementation to date has been limited. Thus, the goal of this review is to evaluate efforts to date and to stimulate greater consideration of MBC models in addictions programs.

RECENT FINDINGS

Data from two published randomized controlled trials and findings from pragmatic clinical research highlight the potential utility of MBC in the SUD treatment settings. Despite these findings, the existing literature indicates the high need for larger-scale clinical trials and quality improvement programs. Potential barriers to the implementation of MBC for SUD are outlined at the patient, provider, organization, and system levels, as well as the challenges associated with the use of MBC programs for clinical research. Critical thinking considerations and risk mitigation strategies are offered toward advancing MBC for SUD beyond the current nascent state. Collectively, the existing data confirm that MBC is a suitable and promising strategy for applying a precision medicine approach in SUD treatment, warranting further implementation efforts and scientific inquiry.

Modeling Idiographic Longitudinal Relationships between Affect and Cigarette Use: An Ecological Momentary Assessment Study

Background: Despite public knowledge of the adverse health effects of tobacco use, cigarettes remain widely used due to the addictive nature of nicotine. Physiologic adaptation to the presence of nicotine over time leads to unpleasant effects during withdrawal periods. Alongside these physiological effects, tobacco users often report changes in their consumption of tobacco in response to their emotional state. Objectives: We hypothesized that idiographic, or person-specific level, increases in participants' negative affect (NA) and positive affect (PA) ratings at a given time point would be associated with higher and lower craving and smoking over the following several hours, respectively. Fifty-two participants completed block randomized ecological momentary assessment surveys on their smartphones 4 times per day for 30 days, reporting from 0-100 their level of seven discrete emotions, stress, current craving, and smoking behavior. We analyzed the relationships between affect and smoking and craving using idiographic generalized linear models. Results: While some participants exhibited the hypothesized relationships, each participant varied in the strength and direction of the relationships between affect and craving/smoking. These outcomes were partially moderated at the group level by anxiety/depression at baseline, but not by level of nicotine dependence or sex. Conclusions: This suggests that the factors driving cigarette use vary significantly between individuals.

Cannabidiol attenuates the expression of conditioned place aversion induced by naloxone-precipitated morphine withdrawal through the activation of 5-HT1A receptors

The misuse of and addiction to opioids are serious public health problems in some countries, such as the USA. Drug addiction is a chronic and relapsing medical condition that involves motivational and memory-related processes due to the strong associations between drugs and consuming-related stimuli. These stimuli usually trigger continuous and compulsive use and are associated with relapses after periods of withdrawal. Several factors contribute to relapse, including withdrawal-induced mood changes. Therefore, drugs attenuating withdrawal-induced affective alterations could be useful alternative treatments for relapse prevention. Cannabidiol (CBD), a non-psychotomimetic component from the Cannabis sativa plant, has anti-anxiety and anti-stress properties and has been investigated as an alternative for the treatment of several mental disorders, including drug addiction. Here, we evaluated if CBD administered 30min prior to test for a conditioned place aversion (CPA) would attenuate the aversion induced by morphine withdrawal precipitated by the opioid receptor antagonist naloxone in male C57BL/6 mice. We also investigated if this effect involves the activation of 5-HT1A receptors, a mechanism previously associated with CBD anti-aversive effects. As expected, morphine-treated mice spent less time exploring the compartment paired with the naloxone-induced withdrawal, indicating a CPA induced by naloxone-precipitated morphine withdrawal. This effect was not observed in animals treated with CBD, at 30 and 60mg/kg, prior to the CPA test, indicating that CBD attenuated the expression of CPA induced by naloxone-precipitated morphine withdrawal. Pretreatment with the 5-HT1A receptor antagonist WAY100635 (0.3mg/kg) blocked CBD effects. Our findings suggest that CBD may reduce the expression of a previously established conditioned aversion induced by morphine withdrawal by a mechanism involving the activation of 5-HT1A receptors. Thus, CBD may be a therapeutic alternative for preventing relapse to opioid addiction by decreasing withdrawal-induced negative affective changes.

Understanding the habenula: A major node in circuits regulating emotion and motivation

Over the last decade, the understanding of the habenula has rapidly advanced from being an understudied brain area with the Latin name 'habena" meaning "little rein", to being considered a "major rein" in the control of key monoaminergic brain centers. This ancient brain structure is a strategic node in the information flow from fronto-limbic brain areas to brainstem nuclei. As such, it plays a crucial role in regulating emotional, motivational, and cognitive behaviors and has been implicated in several neuropsychiatric disorders, including depression and addiction. This review will summarize recent findings on the medial (MHb) and lateral (LHb) habenula, their topographical projections, cell types, and functions. Additionally, we will discuss contemporary efforts that have uncovered novel molecular pathways and synaptic mechanisms with a focus on MHb-Interpeduncular nucleus (IPN) synapses. Finally, we will explore the potential interplay between the habenula's cholinergic and non-cholinergic components in coordinating related emotional and motivational behaviors, raising the possibility that these two pathways work together to provide balanced roles in reward prediction and aversion, rather than functioning independently.

Substance Use Disorders and Role of Complementary and Integrative Medicine/Functional Medicine

Substance use disorders are a growing concern for all ages, including adolescents. Even though there is an increase in recreational substance use and a wider variety of drugs is available to this young population, treatment options remain scarce. Most medications have limited evidence in this population. Few specialists treat individuals struggling with addiction along with mental health disorders. As the evidence grows, these treatments are usually included in complementary and integrative medicine. This article discusses available evidence for many complementary and integrative treatment approaches while briefly describing existing psychotherapeutic and psychotropic medications.

Ghrelin/GHS-R1A antagonism in memory test and its effects on central molecular signaling involved in addiction in rats

Central ghrelin signaling seems to play important role in addiction as well as memory processing. Antagonism of the growth hormone secretagogue receptor (GHS-R1A) has been recently proposed as a promising tool for the unsatisfactory drug addiction therapy. However, molecular aspects of GHS-R1A involvement in specific brain regions remain unclear. The present study demonstrated for the first time that acute as well as subchronic (4 days) administration of the experimental GHS-R1A antagonist JMV2959 in usual intraperitoneal doses including 3 mg/kg, had no influence on memory functions tested in the Morris Water Maze in rats as well as no significant effects on the molecular markers linked with memory processing in selected brain areas in rats, specifically on the β-actin, c-Fos, two forms of the calcium/calmodulin-dependent protein kinase II (CaMKII, p-CaMKII) and the cAMP-response element binding protein (CREB, p-CREB), within the medial prefrontal cortex (mPFC), nucleus accumbens (NAc), dorsal striatum, and hippocampus (HIPP). Furthermore, following the methamphetamine intravenous self-administration in rats, the 3 mg/kg JMV2959 pretreatment significantly reduced or prevented the methamphetamine-induced significant decrease of hippocampal β-actin and c-Fos as well as it prevented the significant decrease of CREB in the NAC and mPFC. These results imply, that the GHS-R1A antagonist/JMV2959 might reduce/prevent some of the memory-linked molecular changes elicited by methamphetamine addiction within brain structures associated with memory (HIPP), reward (NAc), and motivation (mPFC), which may contribute to the previously observed significant JMV2959-induced reduction of the methamphetamine self-administration and drug-seeking behavior in the same animals. Further research is necessary to corroborate these results.

Neurocognitive Impulsivity in Opiate Users at Different Lengths of Abstinence

The aim of the current study was to examine the effects of length of abstinence on decision making (impulsive choice) and response inhibition (impulsive action) in former opiate users (OU). Participants included 45 OU in early remission [0−12 months of abstinence], 68 OU in sustained remission [>12 months of abstinence], and 68 control participants. Decision making was assessed with the Iowa Gambling Task (IGT), the Cambridge Gambling Task (CGT), and the Monetary Choice Questionnaire (MCQ). Response inhibition was examined with the Stop Signal Task (SST), and the Go/No-Go Task (GNG). Results revealed group differences in decision making under risk (CGT) and ambiguity (IGT), where control participants displayed better decision making compared to OU in early remission. Both groups of former OU were also characterized by higher discounting of delayed rewards (MCQ). Regression analyses revealed minimal effects of length of abstinence on performance on decision-making tasks and no effects on delay discounting. In addition, both OU groups showed reduced action inhibition (GNG) relative to controls and there were no group differences in action cancellation (SST). Length of abstinence had no effect on response inhibition. Overall, our findings suggest that neurocognitive function may not fully recover even with protracted abstinence, which should be addressed by relapse prevention and cognitive remediation programs for OU.

The Longitudinal Association of Childhood and Adolescent Television Viewing with Substance Use Disorders and Disordered Gambling in Adulthood up to Age 45

Excessive leisure-time television viewing in childhood has been associated with a range of poorer outcomes in adulthood and may represent an early form of addictive disorder. As addictive disorders are often correlated, we tested the hypothesis that television viewing in childhood and adolescence would be longitudinally associated with adulthood substance-related and behavioural addictive disorders in a population-based cohort born in 1972/1973. Weekday television viewing time was reported at multiple ages from 5 to 15 years, and criteria for alcohol, cannabis, and tobacco use disorders and disordered gambling were assessed at multiple adult ages up to 45 years. Higher television viewing times were associated with a greater likelihood of meeting diagnostic criteria for all substance-related disorders and disordered gambling in models that were adjusted for sex (p values < 0.05). After adjustment for childhood socioeconomic status and childhood self-control, mean television viewing time (hours/day) remained associated with tobacco use disorder (OR = 1.22, 95% CI = 1.04–1.42, p = 0.017) and disordered gambling (OR = 1.33, 95% CI = 1.07–1.66, p = 0.010). Excessive, leisure-time television viewing in childhood and adolescence may be a modifiable risk factor for tobacco use disorder and/or disordered gambling in later life.

Effects of cigarette abstinence on negative and positive affect by depression symptom levels: A lab study

BACKGROUND

High negative affect and low positive affect are key depression-related states that may be greater following acute tobacco abstinence. This study aimed to test associations between depression symptom levels and acute tobacco abstinence with negative affect and positive affect.

METHODS

Following a baseline session, participants attended two counterbalanced laboratory sessions (non-abstinent, abstinent) and completed measures of positive and negative affect at rest (i.e., when not completing a task) and during a film clip task.

RESULTS

Individuals with elevated depression symptoms had higher negative affect and lower positive affect at rest and during the film clip task compared to individuals with low depression symptoms. There was no interaction of depression symptom levels and abstinence on negative and positive affect at rest. There was an interaction of depression symptom level and abstinence on negative and positive affect during the film clip task. Individuals with elevated depression showed significant differences in positive and negative affect between the abstinent and non-abstinent session, but no significant abstinence effects were noted in individuals with low depression symptoms.

LIMITATIONS

The study included a non-treatment seeking sample and experimentally induced acute cigarette abstinence. We excluded for the use of smoking cessation medications that are also used to treat depression, classified depression levels using dichotomized CES-D scores, and used self-report measures of affect.

CONCLUSIONS

Results of this study suggest individuals with elevated depression symptoms who smoke experience elevated negative affect and lower positive affect and cigarette abstinence may uniquely alter affective reactivity in individuals with elevated depression symptoms.

Association of depression symptom level with smoking urges, cigarette withdrawal, and smoking reinstatement: A preliminary laboratory study

BACKGROUND

Cigarette smoking urges, withdrawal, and smoking reinstatement may be especially relevant to people with elevated depression symptoms who smoke. This laboratory study aimed to assess relations between depression symptom level and smoking urges for reward and relief, cigarette withdrawal, and smoking reinstatement in people who smoke cigarettes daily during acute abstinence and while smoking as usual.

METHODS

Participants with low (n = 51) or elevated (n = 29) baseline depression symptoms underwent two counterbalanced laboratory sessions (i.e., abstinent, non-abstinent). At each session, they completed subjective measures of smoking urges for reward and relief, and withdrawal. They also completed a laboratory smoking reinstatement task measuring whether they would delay smoking and the number of cigarettes smoked.

RESULTS

The elevated depression symptom group reported significantly higher withdrawal (p = .01) and smoked more cigarettes than the low depression symptoms group during the smoking reinstatement task self-administration period at the abstinent session (p = .04). Smoking urges for reward and relief were not significantly different by depression symptom group. There were no significant interactions of depression and abstinence with any outcomes.

CONCLUSIONS

As outcomes were measured at both an abstinent and non-abstinent session, findings identify factors for people with elevated depression symptoms who smoke which may drive smoking behavior and impede smoking cessation efforts. This study provides evidence that people with elevated depression symptoms who smoke may need additional/more pharmacological or behavioral smoking cessation aids targeted at reducing withdrawal and number of cigarettes smoked.

Affect and subjective cognitive functioning by depression symptom levels during naturalistic cigarette smoking in premenopausal females who smoke daily

Objective: High negative affect, low positive affect, and low cognitive functioning are depression-related states that may be particularly relevant to females who smoke cigarettes and may be more prominent following overnight tobacco abstinence. This study aimed to assess relations between depression symptom levels and negative affect, positive affect, and subjective cognitive functioning in premenopausal females who smoke. Methods: Premenopausal females who smoke daily with low (n = 66) or elevated (n = 33) baseline depression symptoms completed subjective ratings of negative affect, positive affect, and cognitive functioning pre-first cigarette (i.e., after overnight tobacco abstinence) and at random prompts throughout the day via ecological momentary assessment (EMA) for 35 days. Results: Participants with elevated depression symptoms reported overall higher negative affect (p = .01). Positive affect was significantly lower prior to the first cigarette of the day (p < .001), but did not significantly differ between depression symptom groups. Subjective cognitive functioning was significantly lower pre-first cigarette of the day (p < .001). There was a significant Depression Symptom × Prompt Type interaction for subjective cognitive functioning (p = .01). Subjective cognitive functioning did not significantly differ by depression symptom group pre-first cigarette of the day but was significantly different at random prompts throughout the day. Conclusions: As participants smoked as usual, findings identify naturalistic factors which may influence smoking behavior among premenopausal females who smoke with elevated depression symptoms. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Relating Compulsivity and Impulsivity With Severity of Behavioral Addictions: A Dynamic Interpretation of Large-Scale Cross-Sectional Findings

BACKGROUND AND AIM

Impulsivity and compulsivity are two key temperament traits involved in behavior regulation. The aim of this study was to test several existing theories in explaining the role of impulsivity and compulsivity in symptom severity in various behavioral addictions.

METHODS

Data were collected from a (representative) general population sample (N = 2,710, mean age:39.8 years (SD:13.6), 51% woman), and from people who are at increased risk of having a behavioral addiction (N = 9,528 in total, mean age: 28.11 (SD:8.3), 34.3% woman), including people with problematic gaming and internet use, pathological gambling, exercise dependence, compulsive buying and work addiction. Symptom severity, reward driven impulsivity and relief driven compulsivity were assessed.

RESULTS

For non-problematic groups, impulsivity is present to about the same extent as compulsivity, whereas for problematic groups, compulsivity dominates over impulsivity in all groups (except for gambling). The strength of the correlation between impulsivity and compulsivity is higher in more severe forms of the disorders (from r = 0.18 to r = 0.59 in the representative population).

DISCUSSION

Based on these data, it appears that relief-driven behavior (negative reinforcement) dominates over reward-driven behavior (positive reinforcement) in more severe cases of a behavioral addiction.

CONCLUSION

This is the first large-scale study to find empirical support for the neuroscientific theory on the dominance of compulsivity ("needing") over impulsivity ("wanting") in more severe cases of a behavioral addiction. Although longitudinal research is needed, a possible shift from impulsivity to compulsivity takes place, similar to substance use addictions, which maintains the circle of addiction.

Effects of docosanyl ferulate, a constituent of Withania somnifera, on ethanol- and morphine-elicited conditioned place preference and ERK phosphorylation in the accumbens shell of CD1 mice

BACKGROUND

Docosanyl ferulate (DF) is a behaviourally active GABA_A receptor complex (GABA_AR) agonist, recently isolated from the standardized methanolic extract of Withania somnifera Dunal (WSE) root. Previous studies have shown that WSE prevents both ethanol- and morphine-dependent acquisition and expression of conditioned place preference (CPP) and stimulation of dopamine release in the nucleus accumbens shell (AcbSh).

AIMS

The study aimed at determining (a) whether DF contributes to WSE's ability to affect the acquisition and expression of ethanol- and morphine-elicited CPP and, given that phosphorylation of extracellular signal-regulated kinase (pERK) in the AcbSh is involved in associative learning and motivated behaviours, (b) whether WSE and DF may affect ethanol- and morphine-induced ERKs phosphorylation in the AcbSh.

METHODS

In adult male CD1 mice, DF's effects on the acquisition and expression of ethanol- and morphine-elicited CPP were evaluated by a classical place conditioning paradigm, whereas the effects of WSE and DF on ethanol- and morphine-elicited pERK in the AcbSh were evaluated by immunohistochemistry.

RESULTS AND CONCLUSIONS

The study shows that DF, differently from WSE, affects only the acquisition but not the expression of ethanol- and morphine-induced CPP. Moreover, the study shows that both WSE and DF can prevent ethanol- and morphine-elicited pERK expression in the AcbSh. Overall, these results highlight subtle but critical differences for the role of GABA_ARs in the mechanism by which WSE affects these ethanol- and morphine-dependent behavioural and molecular/cellular responses and support the suggestion of WSE and DF for the control of different components of drug addiction.

Relentless Stigma: A Qualitative Analysis of a Substance Use Recovery Needs Assessment

Substance use disorders (SUD) pose emotional, mental, and physical threats to persons worldwide. There is a paucity of research focused on capturing individual perspectives on supports and barriers to recovery from a SUD. This need has been identified in areas of Minnesota where a gap in evidence-based substance use support exists. A team of interdisciplinary professionals distributed a qualitative survey assessing supports and barriers to SUD recovery within recovery circles in order to inform the efforts of local organizations. This paper and online access survey was adapted from an existing survey created by Faces and Voices of Recovery. The online survey was accessed by a link and distributed to persons in recovery across Minnesota over 7 months. Data from this survey were analyzed through a consensual qualitative research (CQR) coding method. Notable themes emerged in the following domains: healthcare, environment, individual, and community. Community-wide stigma was an overarching concern, and the study yielded unique insights into stigma within healthcare and the community at-large. Barriers and support to recovery were reported. Barriers included experiencing high levels of stigma and identifying a need for community education on SUDs and recovery. Support included local recovery groups, peer recovery support, and access to healthcare and medication. Our findings illuminate the needs of the recovery community from the perspective of individuals with lived experience and will inform local organizations in specifying resources to help meet the identified needs. This survey may also be adapted and used around the world to inform substance use prevention, treatment, and recovery programing.

Non-invasive and invasive brain stimulation in alcohol use disorders: A critical review of selected human evidence and methodological considerations to guide future research

INTRODUCTION

Alcohol use disorder (AUD) ranks among the leading causes of decrements in disability-adjusted life-years. Long-term exposure to alcohol leads to an imbalance of activity between frontal cortical systems and the striatum, thereby enhancing impulsive behaviours and weakening inhibitory control. Alternative therapeutic approaches such as non-invasive and invasive brain stimulation have gained some momentum in the field of addictology by capitalizing on their ability to target specific anatomical structures and correct abnormalities in dysfunctional brain circuits.

MATERIALS AND METHODS

The current review, covers original peer-reviewed published research on the use of brain stimulation methods for the rehabilitation of AUD. A broad and systematic search was carried out on four electronic databases: NCBI PubMed, Web of Science, Handbooks and the Cochrane Library. Any original article in English or French language, without restrictions of patient age or gender, article type and publication outlet, were included in the final pool of selected studies.

RESULTS

The outcomes of this systematic review suggest that the dorsolateral prefrontral cortex (DLPFC) is a promising target for treating AUD with high frequency repetitive transcranial magnetic stimulation. Such effect would reduce feelings of craving by enhancing cognitive control and modulating striatal function. Existing literature also supports the notion that changes of DLPFC activity driven by transcranial direct current stimulation, could decrease alcohol craving and consumption. However, to date, no major differences have been found between the efficacy of these two non-invasive brain-stimulation approaches, which require further confirmation. In contrast, beneficial stronger evidence supports an impact of deep brain stimulation reducing craving and improving quality of life in AUD, effects that would be mediated by an impact on the nucleus accumbens, a central structure of the brain's reward circuitry. Overall, neurostimulation shows promise contributing to the treatment of AUD. Nonetheless, progress has been limited by a number of factors such as the low number of controlled randomized trials, small sample sizes, variety of stimulation parameters precluding comparability and incomplete or questionable sham-conditions. Additionally, a lack of data concerning clinical impact on the severity of AUD or craving and the short follow up periods precluding and accurate estimation of effect duration after discontinuing the treatment, has also limited the clinical relevance of final outcomes.

CONCLUSION

Brain stimulation remains a promising approach to contribute to AUD therapy, co-adjuvant of more conventional procedures. However, a stronger therapeutic rational based on solid physio-pathological evidence and accurate estimates of efficacy, are still required to achieve further therapeutic success and expand clinical use.

Abnormal white matter within brain structural networks is associated with high-impulse behaviour in codeine-containing cough syrup dependent users

Codeine-containing cough syrup (CCS) is considered as one of the most popular drug of dependence among adolescents because of its inexpensiveness and easy availability. However, its relationship with neurobiological effects remains sparsely explored. Herein, we examined how high-impulse behaviours relate to changes in the brain structural networks. Forty codeine-containing cough syrup dependent (CCSD) users and age-, gender-, and number of cigarettes smoked per day -matched forty healthy control (HC) subjects underwent structural brain imaging via MRI. High-impulse behaviour was assessed using the 30-item self-rated Barratt Impulsiveness Scale (BIS-11), and structural networks were constructed using diffusion tensor imaging and AAL-90 template. Between-group topological metrics were compared using nonparametric permutations. Benjamin-Hochberg false discovery rate correction was used to correct for multiple comparisons (P < 0.05). The relationships between abnormal network metrics and clinical characteristics of CCS dependent (BIS-11 total score, CCS- dependent duration and mean dose) were examined by Spearman's correlation. Structural networks of the CCSD group demonstrated lower small-world properties than those of the HC group. Abnormal changes in nodal properties among CCSD users were located mainly in the frontal gyrus, inferior parietal lobe and olfactory cortex. NBS analysis further indicated disrupted structural connections between the frontal gyrus and multiple brain regions. There were significant correlations between abnormal nodal properties of the frontal gyrus and clinical characteristics (BIS-11 total score, CCS dependent duration and mean dose) in the CCSD group. These findings suggest that the high-impulse behavioural expression in CCS addiction is associated with widespread brain regions, particularly within those in the frontal cortex. Aberrant brain regions and disrupted connectivity of structural network may be the bases of neuropathology for underlying symptoms of high-impulse behaviours in CCSD users, which may provide a novel sight to better treat and prevent codeine dependency in adolescents.

Effects of Multiple Detoxifications on Withdrawal Symptoms, Psychiatric Distress and Alcohol-Craving in Patients with an Alcohol Use Disorder

Previous studies have shown an association between the number of withdrawal attempts and increased severity of withdrawal symptoms in patients with an alcohol use disorder (AUD). An underlying allostatic neuroadaptive response may negatively affect the withdrawal pathology after alcohol discontinuation. The objective of the present research is to examine the intensification of psychiatric distress, craving, and post-detoxification drinking outcomes, which may result from these neurobehavioral alternations. Fifty-two AUD inpatients were divided into two groups: <2 previous detoxifications and ≥2 previous detoxifications. Patients completed the Dutch version of the Severity of Withdrawal Scale (SWS), Depression Anxiety Stress Scales (DASS-21), VAS Craving, and Desires for Alcohol Questionnaire (DAQ). Linear mixed effects models were applied, controlling for the number of drinks consumed in the past 30 days and alcohol drinking history (years). Patients who had undergone ≥2 detoxifications reported statistically significantly higher scores on SWS withdrawal and DASS psychiatric symptoms. Also, craving patterns were different between groups, as shown by a statistically significant interaction effect for VAS craving for the time of day factor (morning vs. evening). No statistically significant group differences were found for DAQ scores and post-detoxification drinking outcomes. Due to relatively low 1-month follow-up rates our power was limited to detect such a difference. The present study contributes to the existing body of evidence that multiple detoxifications are associated with aggravated withdrawal/psychiatric pathology, and distinct diurnal patterns of VAS craving. Several clinical implications are discussed and alternative strategies are provided to manage repeated cycles of detoxifications.

Synaptic Adaptations at the Rostromedial Tegmental Nucleus Underlie Individual Differences in Cocaine Avoidance Behavior

Although cocaine is powerfully rewarding, not all individuals are equally prone to abusing this drug. We postulate that these differences arise in part because some individuals exhibit stronger aversive responses to cocaine that protect them from cocaine seeking. Indeed, using conditioned place preference (CPP) and a runway operant cocaine self-administration task, we demonstrate that avoidance responses to cocaine vary greatly between individual high cocaine-avoider and low cocaine-avoider rats. These behavioral differences correlated with cocaine-induced activation of the rostromedial tegmental nucleus (RMTg), measured using both in vivo firing and c-fos, whereas slice electrophysiological recordings from ventral tegmental area (VTA)-projecting RMTg neurons showed that relative to low avoiders, high avoiders exhibited greater intrinsic excitability, greater transmission via calcium-permeable AMPA receptors (CP-AMPARs), and higher presynaptic glutamate release. In behaving animals, blocking CP-AMPARs in the RMTg with NASPM reduced cocaine avoidance. Hence, cocaine addiction vulnerability may be linked to multiple coordinated synaptic differences in VTA-projecting RMTg neurons.SIGNIFICANCE STATEMENT Although cocaine is highly addictive, not all individuals exposed to cocaine progress to chronic use for reasons that remain unclear. We find that cocaine's aversive effects, although less widely studied than its rewarding effects, show more individual variability, are predictive of subsequent propensity to seek cocaine, and are driven by variations in RMTg in response to cocaine that arise from distinct alterations in intrinsic excitability and glutamate transmission onto VTA-projecting RMTg neurons.

Lower regional grey matter in alcohol use disorders: evidence from a voxel-based meta-analysis

BACKGROUND

Previous research using whole-brain neuroimaging techniques has revealed structural differences of grey matter (GM) in alcohol use disorder (AUD) patients. However, some of the findings diverge from other neuroimaging studies and require further replication. The quantity of relevant research has, thus far, been limited and the association between GM and abstinence duration of AUD patients has not yet been systematically reviewed.

METHODS

The present research conducted a meta-analysis of voxel-based GM studies in AUD patients published before Jan 2021. The study utilised a whole brain-based d-mapping approach to explore GM changes in AUD patients, and further analysed the relationship between GM deficits, abstinence duration and individual differences.

RESULTS

The current research included 23 studies with a sample size of 846 AUD patients and 878 controls. The d-mapping approach identified lower GM in brain regions including the right cingulate gyrus, right insula and left middle frontal gyrus in AUD patients compared to controls. Meta-regression analyses found increasing GM atrophy in the right insula associated with the longer mean abstinence duration of the samples in the studies in our analysis. GM atrophy was also found positively correlated with the mean age of the samples in the right insula, and positively correlated with male ratio in the left middle frontal gyrus.

CONCLUSIONS

GM atrophy was found in the cingulate gyrus and insula in AUD patients. These findings align with published meta-analyses, suggesting they are potential deficits for AUD patients. Abstinence duration, age and gender also affect GM atrophy in AUD patients. This research provides some evidence of the underlying neuroanatomical nature of AUD.

Cannabidiol enhanced the development of sensitization to the expression of methamphetamine-induced conditioned place preference in male rats

Cannabis and ecstasy are illicit substances, and currently, there are no approved treatments for methamphetamine (METH) use disorder. Some studies have proposed that cannabidiol (CBD) decreases the motivation for METH seeking, but reports indicate that the therapeutic benefits are only for heroin. Here, we studied the interaction between CBD and METH during the sensitization phase on the rewarding effect of METH, using the conditioned place preference (CPP) paradigm to measure possible alterations in sensitivity. Our data showed that i. p. injection of METH created METH-induced CPP at two of the highest applied doses (1 and 2 mg/kg), and injection of METH during the sensitization period caused an establishment of METH-induced CPP at lower doses (0.25 and 0.5 mg/kg). Data also revealed that i. c.v. administration of CBD during the sensitization phase, shifted the establishment of METH-induced CPP toward a lower dose (0.5 mg/kg). Concurrent administration of CBD (10 μg/5 μl, i. c.v.) and METH (0.25 mg/kg, i. p.) during sensitization phase established METH-induced CPP with sub-threshold doses of METH (0.125, 0.25, and 0.5 mg/kg). Our results suggest the involvement of CBD and prior exposure to METH in creating sensitization to METH CPP.

Spectral power and theta-gamma coupling in the basolateral amygdala related with methamphetamine conditioned place preference in mice

The basolateral amygdala (BLA) plays a crucial role in conditioned place preference (CPP) for addictive drugs. However, neural signaling associated with methamphetamine (METH) craving and seeking remained to be investigated. This study characterized local field potential (LFP) oscillatory patterns in the BLA and conditioned place preference induced by METH-related context. Male Swiss albino ICR mice were deeply anesthetized for LFP intracranial electrode implantation in the BLA. Control and METH groups received sessions to learn to associate saline-paired and METH-paired compartments of the CPP apparatus with saline and METH injections, respectively, for 10 days. LFP signals and exploring behavior were recorded simultaneously during pre- and post-conditioning phases. Time spent in METH-paired compartment was normalized and expressed as CPP scores. Fast Fourier Transform (FFT) algorithm was used to analyze LFP powers of 8 discrete frequency ranges (delta, theta, alpha, beta, gamma I-IV). During post-conditioning phase of METH CPP with METH cues, statistical analysis revealed that METH group significantly increased time spent in METH-paired compartment. Significant suppressions of theta and alpha powers were observed. Phase-amplitude cross frequency coupling analyses confirmed significant increases in maximal modulation index (MI), frequency for phase of slow wave and MI of theta-gamma II coupling. Taken together, LFP oscillation in the BLA was sensitive in association with METH CPP. These research findings might suggest the underlying mechanisms of drug reward learning and adaptive changes in the BLA in acquisition of METH CPP and dependence.

Molecular Docking and Molecular Dynamics Simulation Studies of Triterpenes from Vernonia patula with the Cannabinoid Type 1 Receptor

A molecular docking approach was employed to evaluate the binding affinity of six triterpenes, namely epifriedelanol, friedelin, α-amyrin, α-amyrin acetate, β-amyrin acetate, and bauerenyl acetate, towards the cannabinoid type 1 receptor (CB1). Molecular docking studies showed that friedelin, α-amyrin, and epifriedelanol had the strongest binding affinity towards CB1. Molecular dynamics simulation studies revealed that friedelin and α-amyrin engaged in stable non-bonding interactions by binding to a pocket close to the active site on the surface of the CB1 target protein. The studied triterpenes showed a good capacity to penetrate the blood–brain barrier. These results help to provide some evidence to justify, at least in part, the previously reported antinociceptive and sedative properties of Vernonia patula.

Why Some Sports Bettors Think Gambling Addiction Prevented Them from Becoming Winners? A Qualitative Approach to Understanding the Role of Knowledge in Sports Betting Products

Sports betting products rely upon a balance between their knowledge and chance based structural characteristics. The emphasis by bookmakers on mastering the knowledge-based elements to become winners poses significant challenges for those seeking help for gambling disorder. Bettors find difficulties in integrating their preconceptions about the role of knowledge and skills in winning, into the new cognitive restructuring fostered by cognitive-behavioural therapy. Using a grounded theory approach, this study collected data from 43 Spanish sports bettors undergoing treatment for gambling disorder. The results suggest sports bettors neutralize some gambling-related cognitive distortions during CBT but retain others. Sports bettors try to eliminate them but encounter external validation to retain them, as well as internal incongruences to integrate them into a coherent understanding of how gambling works. The results are discussed with the aim of providing practical guidance as to how skill versus chance related persistent cognitions can be addressed in CBT.

Antinociceptive and sedative activity of Vernonia patula and predictive interactions of its phenolic compounds with the cannabinoid type 1 receptor

When tested in the acetic acid-induced writhing and formalin-induced paw-licking tests, the ethanol extract of Vernonia patula (VP) aerial parts showed significant antinociceptive activity. In neuropharmacological tests, it also significantly delayed the onset of sleep, increased the duration of sleeping time, and significantly reduced the locomotor activity and exploratory behaviour of mice. Five phenolic compounds, namely gallic acid, vanillic acid, caffeic acid, quercetin and kaempferol, were detected in VP following HPLC-DAD analysis. The presence of these phenolic compounds in VP provides some support for the observed antinociceptive and sedative effects. A computational study was performed to predict the binding affinity of gallic acid, vanillic acid, caffeic acid, quercetin and kaempferol towards the cannabinoid type 1 (CB1) receptor. Caffeic and vanillic acid showed the highest probable ligand efficiency indices towards the CB1 target. Vanillic acid displayed the best blood-brain barrier penetration prediction score. These findings provide some evidence for the traditional use of VP to treat pain.

Pilot trial investigating a brief behavioral economic intervention as an adjunctive treatment for alcohol use disorder

OBJECTIVE

Behavioral economic research suggests that increasing the salience of a delayed reward may improve capacity for delaying gratification and increase behavior allocated toward obtaining larger, delayed substance-free reward rather than smaller, more immediate reward such as alcohol use. This study aimed to improve the efficacy of outpatient alcohol use disorder (AUD) treatment by adding elements that target behavioral economic mechanisms of change.

METHOD

Forty-one (N = 41) adults in outpatient AUD treatment were recruited and 37 participants were retained at follow-up. Following baseline assessment, participants received either the Substance Free Activity Session (SFAS), a single-session behavioral economic-informed intervention focused on increasing future orientation and engagement in values-based substance-free activities or a health education control intervention. Participants in both conditions received weekly prompts (via text or email) relevant to their respective intervention for four weeks. Participants (68.3% male; 70.7% Caucasian, M age = 38.24, SD = 12.69) reported an average of 3.95 (SD = 4.72) binge drinking episodes (4/5 drinks per occasion for a woman/man) and 5.05 (SD = 5.32) drinks per drinking day 30-days prior to treatment entry.

RESULTS

The study provided initial support for the feasibility and acceptability of implementing the SFAS within a treatment setting. Participants reported high levels of satisfaction with the SFAS (M = 9.08 (SD = 0.94), on a scale of 1-10). At 3-month follow-up, the SFAS was associated with reductions in the proportion of activity participation and enjoyment (reinforcement) related to substance-use relative to substance-free activities and in alcohol demand compared to control.

CONCLUSION

These preliminary results provide initial support for targeting behavioral economic mechanisms of change in an outpatient AUD treatment with a single-session intervention plus remote delivery of booster prompts.

Treatment resistant opioid use disorder (TROUD): Definition, rationale, and recommendations

The opioid overdose epidemic kills about 130 people a day in the United States and it is estimated that there are about 2.1 million people who suffer from an opioid use disorder (OUD). Academic neuroscientists, psychiatrists and the National Institute of Drug Abuse have spent the last forty-years establishing the foundation of addiction as a brain disorder. It is now clear that extended opioid use causes multiple important and at times, irreversible changes to the brain, especially to its dopamine and opioid systems. With our recognized criteria for diagnosis and the accepted multifaceted treatment approach of both professional psychotherapy and medications that assist treatments, treatment failures should be limited. Unfortunately, this is not the case. Slips, relapses, overdose and multiple failures are all too common. Similar to treatment resistant depression there is a subpopulation who do not respond to standard OUD treatments. However, the field has suggested that if a treatment does not work, it is either the patients fault, they have not hit bottom or simply we need to try the same treatment again. There is a rational to consider this a new category of OUD, treatment resistant opioid use disorder (TROUD). This paper explores past treatment attempts data from OUD patients entering traditional outpatient treatment and makes recommendations how TROUD can be defined. It challenges the addiction research and treatment providers to change its focus from individuals being resistant to the unique conditions associated with this brain disorder as being resistant to treatment as usual.

Critical View on the Usage of Ribavirin in Already Existing Psychostimulant-Use Disorder

Substance-use disorder represents a frequently hidden non-communicable chronic disease. Patients with intravenous drug addiction are at high risk of direct exposure to a variety of viral infections and are considered to be the largest subpopulation infected with the hepatitis C virus. Ribavirin is a synthetic nucleoside analog that has been used as an integral component of hepatitis C therapy. However, ribavirin medication is quite often associated with pronounced psychiatric adverse effects. It is not well understood to what extent ribavirin per se contributes to changes in drug-related neurobehavioral disturbances, especially in the case of psychostimulant drugs, such as amphetamine. It is now well-known that repeated amphetamine usage produces psychosis in humans and behavioral sensitization in animals. On the other hand, ribavirin has an affinity for adenosine A1 receptors that antagonistically modulate the activity of dopamine D1 receptors, which play a critical role in the development of behavioral sensitization. This review will focus on the current knowledge of neurochemical/ neurobiological changes that exist in the psychostimulant drug-addicted brain itself and the antipsychotic-like efficiency of adenosine agonists. Particular attention will be paid to the potential side effects of ribavirin therapy, and the opportunities and challenges related to its application in already existing psychostimulant-use disorder.

Intranasal Insulin: a Treatment Strategy for Addiction

Addiction to substances such as alcohol, cocaine, opioids, and methamphetamine poses a continuing clinical and public challenge globally. Despite progress in understanding substance use disorders, challenges remain in their treatment. Some of these challenges include limited ability of therapeutics to reach the brain (blood-brain barrier), adverse systemic side effects of current medications, and importantly key aspects of addiction not addressed by currently available treatments (such as cognitive impairment). Inability to sustain abstinence or seek treatment due to cognitive deficits such as poor decision-making and impulsivity is known to cause poor treatment outcomes. In this review, we provide an evidenced-based rationale for intranasal drug delivery as a viable and safe treatment modality to bypass the blood-brain barrier and target insulin to the brain to improve the treatment of addiction. Intranasal insulin with improvement of brain cell energy and glucose metabolism, stress hormone reduction, and improved monoamine transmission may be an ideal approach for treating multiple domains of addiction including memory and impulsivity. This may provide additional benefits to enhance current treatment approaches.

Extinction training following cocaine or MDMA self-administration produces discrete changes in D2-like and mGlu5 receptor density in the rat brain

BACKGROUND

Several studies strongly support the role of the dopamine D2-like and glutamate mGlu5 receptors in psychostimulant reward and relapse.

METHODS

The present study employed cocaine or MDMA self-administration with yoked-triad procedure in rats to explore whether extinction training affects the drug-seeking behavior and the D2-like and mGlu5 receptor Bmax and Kd values in several regions of the animal brain.

RESULTS

Both cocaine and MDMA rats developed maintenance of self-administration, but MDMA evoked lower response rates and speed of self-administration acquisition. During reinstatement tests, cocaine or MDMA seeking behavior was produced by either exposure to the drug-associated cues or drug-priming injections. The extinction training after cocaine self-administration did not alter significantly D2-like receptor expression the in the limbic and subcortical brain areas, while MDMA yoked rats showed a decrease of the D2-like binding density in the nucleus accumbens and increase in the hippocampus and a rise of affinity in the striatum and hippocampus. Interestingly, in the prefrontal cortex a reduction in the mGlu5 receptor density in cocaine- or MDMA-abstinent rats was demonstrated, with significant effects being observed after previous MDMA exposure. Moreover, rats self-administered cocaine showed a rise in the density of mGlu5 receptor for the nucleus accumbens.

CONCLUSION

This study first time shows that abstinence followed extinction training after cocaine or MDMA self- or passive-injections changes the D2-like and mGlu5 density and affinity. The observed changes in the expression of both receptors are brain-region specific and related to either pharmacological and/or motivational features of cocaine or MDMA.

Brain ethanol-metabolizing enzymes are differentially expressed in lead-exposed animals after voluntary ethanol consumption: Pharmacological approaches

Developmentally-lead (Pb)-exposed rats showed an enhanced vulnerability to the stimulating and motivational effects of ethanol (EtOH). This is accompanied by differential activity of the brain EtOH-metabolizing enzymes catalase (CAT) and mitochondrial aldehyde dehydrogenase (ALDH2). Based on the theory that brain acetaldehyde accumulation is associated with the reinforcing properties of EtOH, this study sought to determine brain CAT and ALDH2 expression in limbic areas of control and Pb-exposed animals after voluntary EtOH intake. Thirty-five-day-old rats perinatally exposed to 220 ppm Pb were offered with water or increasing EtOH solutions (2-10% v/v) during 28 days until postnatal day (PND) 63. Once intake was stable, the animals were administered: 1) saline (SAL; test days 21-24 or 21-28, as corresponds), or 2) a CAT inhibitor: 3-amine 1, 2, 4-triazole (AT; 250 mg/kg intraperitoneally [i.p.], 5 h before the last eight EtOH intake sessions -test days 21-24 and 25-28), or 3) a CAT booster: 3-nitropropionic acid (3NPA; 20 mg/kg subcutaneously [s.c.], 45 min before the last four EtOH intake sessions -test days 25-28). Two additional groups were centrally-administered cyanamide (CY, an ALDH2 inhibitor, 0.3 mg i.c.v. immediately before the last four EtOH sessions, test days 25-28) or its corresponding vehicle (VEH). Lead exposure increased EtOH intake, an effect potentiated in both groups by 3NPA or CY pretreatments and reduced by AT, albeit selectivity in the Pb group. Catalase abundance in limbic areas parallels these observations in the Pb group, showing higher CAT expression in all areas after EtOH consumption respect to the controls, an effect prevented by AT administration. In contrast, ALDH2 expression was reduced in the Pb animals after EtOH intake, with CY potentiating this effect in all brain areas under study. Based on these results and on previous evidences, we suggest that Pb exposure promotes acetaldehyde accumulation in limbic regions, providing some insights into the mechanism of action that underlies the vulnerability to the excessive EtOH consumption reported in these animals.

Involvement of neural substrates in reward and aversion to methamphetamine addiction: Testing the reward comparison hypothesis and the paradoxical effect hypothesis of abused drugs

Clinical studies of drug addiction focus on the reward impact of abused drugs that produces compulsive drug-seeking behavior and drug dependence. However, a small amount of research has examined the opposite effect of aversion to abused drugs to balance the reward effect for drug taking. An aversive behavioral model of abused drugs in terms of conditioned taste aversion (CTA) was challenged by the reward comparison hypothesis (Grigson, 1997). To test the reward comparison hypothesis, the present study examined the rewarding or aversive neural substrates involved in methamphetamine-induced conditioned suppression. The behavioral data showed that methamphetamine induced conditioned suppression on conditioning and reacquisition but extinguished it on extinction. A higher level of stressful aversive corticosterone occurred on conditioning and reacquisition but not extinction. The c-Fos or p-ERK immunohistochemical activity showed that the cingulated cortex area 1 (Cg1), infralimbic cortex (IL), prelimbic cortex (PrL), basolateral amygdala (BLA), nucleus accumbens (NAc), and dentate gyrus (DG) of the hippocampus were overexpressed in aversive CTA induced by methamphetamine. These data may indicate that the Cg1, IL, PrL, BLA, NAc, and DG probably mediated the paradoxical effect-reward and aversion. Altogether, our data conflicted with the reward comparison hypothesis, and methamphetamine may simultaneously induce the paradoxical effect of reward and aversion in the brain to support the paradoxical effect hypothesis of abused drugs. The present data implicate some insights for drug addiction in clinical aspects.

Neuropsychiatric implications of transient receptor potential vanilloid (TRPV) channels in the reward system

Neuropsychiatric disorders (NPDs) exert a devastating impact on an individual's personal and social well-being, encompassing various conditions and brain anomalies that influence affect, cognition, and behavior. Because the pathophysiology of NPDs is multifactorial, the precise mechanisms underlying the development of such disorders remain unclear, representing a unique challenge in current neuropsychopharmacotherapy. Transient receptor potential vanilloid (TRPV) type channels are a family of ligand-gated ion channels that mainly include sensory receptors that respond to thermal, mechanical and chemical stimuli. TRPV channels are abundantly present in dopaminergic neurons, thus playing a pivotal role in the modulation of the reward system and in pathophysiology of diseases such as stress, anxiety, depression, schizophrenia, neurodegenerative disorders and substance abuse/addiction. Recent evidence has highlighted TRPV channels as potential targets for understanding modulation of the reward system and various forms of addiction (opioids, cocaine, amphetamines, alcohol, nicotine, cannabis). In this review, we discuss the distribution, physiological roles, ligands and therapeutic importance of TRPV channels with regard to NPDs and addiction biology.

Dysregulation as a correlate of cannabis use and problem use

OBJECTIVE

Cannabis users with a dysregulatory risk factor may be particularly vulnerable to engaging in more frequent and problematic cannabis use. Contemporary models of dysregulated behavior suggest that dysregulation emerges due to distinct mechanisms. The current study seeks to examine the dysregulatory correlates of cannabis involvement, including working memory capacity, delay discounting, impulsivity, and reward sensitivity.

METHOD

Participants were 104 non-treatment seeking frequent cannabis users (the average participant used cannabis 71% of the days/past 60 days [SD = 22%], with an average of two uses per day [SD = 1.2]). Mean age was 21.3 (SD = 4.3); 36.5% were female. Working memory was assessed via the Trail-Making Test-B and the Digit Span subtests of the WAIS-III, delay discounting was assessed via a computer-based task, trait impulsivity was self-reported via the Barratt Impulsiveness Scale, and reward sensitivity was self-reported via the Reward Dependence Scale and the Snaith-Hamilton Pleasure Scale.

RESULTS

Structural equation modeling estimated the associations between different facets of dysregulation and cannabis involvement. Results suggest that poor working memory capacity and high trait impulsivity were associated with both use and problem use. Greater delay discounting was associated with problem use, but not with frequency of use. Low reward sensitivity was associated with more frequent cannabis use, but not with problem use.

CONCLUSIONS

Results confirm that the dysregulatory correlates of cannabis involvement consist of multiple dimensions of functioning. Prospective studies that assess the multidimensional structure of dysregulation and cannabis involvement are needed in order to disaggregate the dysregulatory antecedents and consequences of cannabis involvement.

Affective temperaments in Lebanese people with substance use disorder

PURPOSE

To examine these temperaments among patients with substance use disorder (SUD) in the Lebanese population.

DESIGN

Case-control.

METHODS

Fifty-seven controls and 57 patients with SUD were enrolled between April and September 2017.

RESULTS

A significantly higher mean of depressive, irritable, and anxious temperaments was found in addicted patients as compared with the nonaddicts. However, the results of the multivariate analysis showed that anxious, hyperthymic, irritable temperaments would significantly increase the odds of addiction in participants (ORa = 25.20, 1.057, 1.168, 1.241, and 1.275). Cyclothymic temperament would significantly decrease the odds of addiction in participants (ORa = 0.817). Furthermore, suicidality was associated with depressive, anxious, and irritable temperaments.

PRACTICE IMPLICATIONS

Hyperthymic, irritable, and anxious temperaments were the main temperaments found in patients with SUD in Lebanon.

A comparison of implicit and explicit reward learning in low risk alcohol users versus people who binge drink and people with alcohol dependence

Chronic alcohol use leads to specific neurobiological alterations in the dopaminergic brain reward system, which probably are leading to a reward deficiency syndrome in alcohol dependence. The purpose of our study was to examine the effects of such hypothesized neurobiological alterations on the behavioral level, and more precisely on the implicit and explicit reward learning. Alcohol users were classified as dependent drinkers (using the DSM-IV criteria), binge drinkers (using criteria of the USA National Institute on Alcohol Abuse and Alcoholism) or low-risk drinkers (following recommendations of the Scientific board of trustees of the German Health Ministry). The final sample (n = 94) consisted of 36 low-risk alcohol users, 37 binge drinkers and 21 abstinent alcohol dependent patients. Participants were administered a probabilistic implicit reward learning task and an explicit reward- and punishment-based trial-and-error-learning task. Alcohol dependent patients showed a lower performance in implicit and explicit reward learning than low risk drinkers. Binge drinkers learned less than low-risk drinkers in the implicit learning task. The results support the assumption that binge drinking and alcohol dependence are related to a chronic reward deficit. Binge drinking accompanied by implicit reward learning deficits could increase the risk for the development of an alcohol dependence.

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Alcohol dependent patients were impaired in implicit and explicit reward learning.

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Alcohol dependence may lead to implicit and explicit reward learning deficits.

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Binge drinkers learned less than low-risk drinkers in the implicit learning task.

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Binge drinking is related to implicit reward learning deficits.

Calcium Sensors in Neuronal Function and Dysfunction

Calcium signaling in neurons as in other cell types can lead to varied changes in cellular function. Neuronal Ca²⁺ signaling processes have also become adapted to modulate the function of specific pathways over a wide variety of time domains and these can have effects on, for example, axon outgrowth, neuronal survival, and changes in synaptic strength. Ca²⁺ also plays a key role in synapses as the trigger for fast neurotransmitter release. Given its physiological importance, abnormalities in neuronal Ca²⁺ signaling potentially underlie many different neurological and neurodegenerative diseases. The mechanisms by which changes in intracellular Ca²⁺ concentration in neurons can bring about diverse responses is underpinned by the roles of ubiquitous or specialized neuronal Ca²⁺ sensors. It has been established that synaptotagmins have key functions in neurotransmitter release, and, in addition to calmodulin, other families of EF-hand-containing neuronal Ca²⁺ sensors, including the neuronal calcium sensor (NCS) and the calcium-binding protein (CaBP) families, play important physiological roles in neuronal Ca²⁺ signaling. It has become increasingly apparent that these various Ca²⁺ sensors may also be crucial for aspects of neuronal dysfunction and disease either indirectly or directly as a direct consequence of genetic variation or mutations. An understanding of the molecular basis for the regulation of the targets of the Ca²⁺ sensors and the physiological roles of each protein in identified neurons may contribute to future approaches to the development of treatments for a variety of human neuronal disorders.

Treatment for Substance Use Disorder With Co-Occurring Mental Illness

Substance use disorder is a highly prevalent condition, leading to significant morbidity, mortality, and burden on the health care system. Substance use disorders are overrepresented among individuals with a mental illness. The term "dual diagnosis" was introduced by the World Health Organization in the mid-1990s and refers to the co-occurrence of a substance use disorder with mental illness-a more recently used term is "co-occurring disorders." In the past decade, substantial progress has been made toward expanding psychotherapeutic and pharmacotherapeutic treatments for treating co-occurring disorders. Yet management remains a challenge among clinicians and has been a source of confusion and considerable controversy. This review describes the epidemiology and treatment of co-occurring disorders, with a focus on major depressive disorder, anxiety disorders, and attention-deficit hyperactivity disorder. Substance use may make diagnosis of the underlying psychiatric condition difficult, and a period of abstinence may be necessary. Findings from efficacy studies of medications used to treat co-occurring disorders are reviewed, as are results of preliminary studies of newer treatments, such as topiramate, ketamine, noninvasive brain stimulation, and deep brain stimulation. Treatment recommendations that combine medications and psychosocial interventions are summarized.

Diagnostic and Classification Considerations Regarding Gaming Disorder: Neurocognitive and Neurobiological Features

Video gaming and Internet use have become a part of the everyday lives of many individuals, especially during adolescence. Given the health concerns related to problematic gaming behaviors, gaming disorder (GD) has been included in the version of the 11th edition of The International Classification of Diseases (ICD-11) ratified by the secretariat of the World Health Organization. Given these considerations and others (including debate regarding the most appropriate classification of GD and how best to prevent and treat the condition), there is a need for further research into GD. Specifically, we suggest that researching intermediate phenotypes focusing on cognitive and neurobiological function may help clarify GD's relationships to other addictive disorders and more accurately define their relationships with core and associated features of GD. Overlaps in neural activity, cognitive functioning, and other features suggest that GD shares similarities with gambling and substance-use disorders and may best be classified as an addictive disorder. Individuals with GD differ from those with regular game use (RGU) on neurocognitive levels. However, concerns have been raised with respect to the differences between GD and substance-use disorders in certain dimensional features, such as tolerance. Additionally, it has been argued that differences between GD and RGU may not be fully captured by nomenclature systems like the ICD-11. Nonetheless, individuals seek treatment for help with GD, despite the limited data available for effective treatments. As more data are gathered from investigations of GD, they should be translated into refining criteria for GD and optimizing interventions.

Genetic Markers in Psychiatry

Psychiatric disorders such as addiction (substance use and addictive disorders), depression, eating disorders, schizophrenia, and post-traumatic stress disorder (PTSD) are severe, complex, multifactorial mental disorders that carry a high social impact, enormous public health costs, and various comorbidities as well as premature morbidity. Their neurobiological foundation is still not clear. Therefore, it is difficult to uncover new set of genes and possible genetic markers of these disorders since the understanding of the molecular imbalance leading to these disorders is not complete. The integrative approach is needed which will combine genomics and epigenomics; evaluate epigenetic influence on genes and their influence on neuropeptides, neurotransmitters, and hormones; examine gene × gene and gene × environment interplay; and identify abnormalities contributing to development of these disorders. Therefore, novel genetic approaches based on systems biology focused on improvement of the identification of the biological underpinnings might offer genetic markers of addiction, depression, eating disorders, schizophrenia, and PTSD. These markers might be used for early prediction, detection of the risk to develop these disorders, novel subtypes of the diseases and tailored, personalized approach to therapy.

Dopamine and addiction: what have we learned from 40 years of research

Among the neurotransmitters involved in addiction, dopamine (DA) is clearly the best known. The critical role of DA in addiction is supported by converging evidence that has been accumulated in the last 40 years. In the present review, first we describe the dopaminergic system in terms of connectivity, functioning and involvement in reward processes. Second, we describe the functional, structural, and molecular changes induced by drugs within the DA system in terms of neuronal activity, synaptic plasticity and transcriptional and molecular adaptations. Third, we describe how genetic mouse models have helped characterizing the role of DA in addiction. Fourth, we describe the involvement of the DA system in the vulnerability to addiction and the interesting case of addiction DA replacement therapy in Parkinson's disease. Finally, we describe how the DA system has been targeted to treat patients suffering from addiction and the result obtained in clinical settings and we discuss how these different lines of evidence have been instrumental in shaping our understanding of the physiopathology of drug addiction.

Symptoms of anhedonia, not depression, predict the outcome of treatment of cocaine dependence

The purpose of this paper is to reanalyze data from two studies to determine if anhedonia specifically, rather than depression overall, predicts treatment outcome for patients with cocaine use disorders. Measures of baseline anhedonia symptoms were created using anhedonia items from the Beck Depression Inventory (BDI) to re-examine National Institute on Drug Abuse Cocaine Collaborative Treatment study data (Crits-Christoph et al., 1999) and the contingency management group from the McKay et al. (2010) trial. Baseline anhedonia was used to predict cocaine abstinence rates across the treatment period in both studies. Anhedonia was a significant predictor of cocaine abstinence, even when overall depression scores excluding anhedonia were included in the models. The development of treatments to target individuals with cocaine use disorder who have symptoms of anhedonia has the potential to improve overall outcomes for those with this disorder.

Neuroimaging, neuromodulation, and population health: the neuroscience of chronic disease prevention

Preventable chronic diseases are the leading cause of death in the majority of countries throughout the world, and this trend will continue for the foreseeable future. The potential to offset the social, economic, and personal burdens associated with such conditions depends on our ability to influence people's thought processes, decisions, and behaviors, all of which can be understood with reference to the brain itself. Within the health neuroscience framework, the brain can be viewed as a predictor, mediator, moderator, or outcome in relation to health-related phenomena. This review explores examples of each of these, with specific reference to the primary prevention (i.e., prevention of initial onset) of chronic diseases. Within the topic of primary prevention, we touch on several cross-cutting themes (persuasive communications, delay discounting of rewards, and self-control), and place a special focus on obesity as a disorder influenced by both eating behavior and exercise habits.

Chasing the addicted engram: identifying functional alterations in Fos-expressing neuronal ensembles that mediate drug-related learned behavior

Given that addiction has been characterized as a disorder of maladaptive learning and memory, one critical question is whether there are unique physical adaptations within neuronal ensembles that support addiction-related learned behavior. The search for the physical mechanisms of encoding these and other memories in the brain, often called the engram as a whole, continues despite decades of research. As we develop new technologies and tools that allow us to study cue- and behavior-activated Fos-expressing neuronal ensembles, the possibility of identifying the engrams of learning and memory is moving into the realm of reality rather than speculation. It has become clear from recent studies that there are specific functional, electrophysiological alterations unique to Fos-expressing ensemble neurons that may participate in encoding memories. The ultimate goal is to identify the addicted engram and reverse the physical changes that support this maladaptive form of learning.

High-intensity binge drinking is associated with alterations in spontaneous neural oscillations in young adults

Heavy episodic alcohol consumption (also termed binge drinking) contributes to a wide range of health and cognitive deficits, but the associated brain-based indices are poorly understood. The current study used electroencephalography (EEG) to examine spontaneous neural oscillations in young adults as a function of quantity, frequency, and the pattern of their alcohol consumption. Sixty-one young adults (23.4 ± 3.4 years of age) were assigned to binge drinking (BD) and light drinking (LD) groups that were equated on gender, race/ethnic identity, age, educational background, and family history of alcoholism. EEG activity was recorded during eyes-open and eyes-closed resting conditions. Each participant's alpha peak frequency (APF) was used to calculate absolute power in individualized theta and alpha frequency bands, with a canonical frequency range used for beta. APF was slower by 0.7 Hz in BD, especially in individuals engaging in high-intensity drinking, but there were no changes in alpha power. BD also exhibited higher frontal theta and beta power than LD. Alpha slowing and increased theta power in BD remained after accounting for depression, anxiety, and personality characteristics, while elevated beta power covaried with sensation seeking. Furthermore, APF slowing and theta power correlated with various measures of alcohol consumption, including binge episodes and blackouts, but not with measures of working and episodic memory, cognitive flexibility, processing speed, or personality variables, suggesting that these physiological changes may be modulated by high-intensity alcohol intake. These results are consistent with studies of alcohol-use disorder (AUD) and support the hypothesis that binge drinking is a transitional stage toward alcohol dependence. The observed thalamocortical dysrhythmia may be indicative of an excitatory-inhibitory imbalance in BD and may potentially serve as an index of the progressive development of AUD, with a goal of informing possible interventions to minimize alcohol's deleterious effects on the brain.

Anti-nociceptive interactions between opioids and a cannabinoid receptor 2 agonist in inflammatory pain

The cannabinoid 1 receptor and cannabinoid 2 receptor can both be targeted in the treatment of pain; yet, they have some important differences. Cannabinoid 1 receptor is expressed at high levels in the central nervous system, whereas cannabinoid 2 receptor is found predominantly, although not exclusively, outside the central nervous system. The objective of this study was to investigate potential interactions between cannabinoid 2 receptor and the mu-opioid receptor in pathological pain. The low level of adverse side effects and lack of tolerance for cannabinoid 2 receptor agonists are attractive pharmacotherapeutic traits. This study assessed the anti-nociceptive effects of a selective cannabinoid 2 receptor agonist (JWH-133) in pathological pain using mice subjected to inflammatory pain using the formalin test. Furthermore, we examined several ways in which JWH-133 may interact with morphine. JWH-133 produces dose-dependent anti-nociception during both the acute and inflammatory phases of the formalin test. This was observed in both male and female mice. However, a maximally efficacious dose of JWH-133 (1 mg/kg) was not associated with somatic withdrawal symptoms, motor impairment, or hypothermia. After eleven once-daily injections of 1 mg/JWH-133, no tolerance was observed in the formalin test. Cross-tolerance for the anti-nociceptive effects of JWH-133 and morphine were assessed to gain insight into physiologically relevant cannabinoid 2 receptor and mu-opioid receptor interaction. Mice made tolerant to the effects of morphine exhibited a lower JWH-133 response in both phases of the formalin test compared to vehicle-treated morphine-naïve animals. However, repeated daily JWH-133 administration did not cause cross-tolerance for morphine, suggesting opioid and cannabinoid 2 receptor cross-tolerance is unidirectional. However, preliminary data suggest co-administration of JWH-133 with morphine modestly attenuates morphine tolerance. Isobolographic analysis revealed that co-administration of JWH-133 and morphine has an additive effect on anti-nociception in the formalin test. Overall these findings show that cannabinoid 2 receptor may functionally interact with mu-opioid receptor to modulate anti-nociception in the formalin test.