Cue-induced craving to paraphernalia and drug images in opioid dependence

rTMS effects on urges and severity of tobacco use disorder operate independently of a retrieval-extinction component and involve frontal-striatal pathways

BACKGROUND

Although smoking remains a leading cause of preventable disease, the treatment options for smoking are limited. The present study evaluated the neural features underlying effects of repetitive transcranial magnetic stimulation (rTMS) for reducing smoking cravings. In addition, the efficacy of a simulated retrieval-extinction procedure to augment rTMS efficacy was examined.

METHODS

Sixty-one individuals with tobacco use disorder (TUD) were randomized into three groups: classic rTMS, retrieval rTMS (viewed smoking videos before rTMS), and sham rTMS. rTMS was performed on the left dorsolateral prefrontal cortex (DLPFC) over 5 days using a standard figure-8 coil. Smoking cravings and brain responses to smoking cues were measured before and after rTMS treatment. Changes in functional connectivity (FC) among different brain regions were calculated.

RESULTS

rTMS reduced smoking urges in TUD. Both active-rTMS groups demonstrated greater activations of the DLPFC, caudate, and bilateral insula relative to the sham group. Increased FC was observed between executive and reward network brain regions, and decreased FC was observed within reward network regions. Compared with standard rTMS, retrieval-extinction rTMS demonstrated similar outcomes and was associated with less activation of the medial frontal gyrus.

CONCLUSIONS

rTMS increased activations in brain regions implicated in executive control and reward processing. Strengthened prefrontal-striatal pathway suggests that rTMS enhanced top-down control over smoking cravings. The retrieval-extinction process, although associated with some different and multiple similar neural correlates as the standard rTMS, did not enhance cessation outcomes.

The relationship between beliefs in substance craving and quality of life among narcotics anonymous: a cross-sectional study in southeastern Iran

BACKGROUND

Addiction is a chronic and relapsing disorder characterized by compulsive drug seeking and lasting changes in the brain. Low quality of life may influence the substance craving, which leads to relapsing. Therefore, the present study aimed to investigate the relationship between beliefs in substance craving and quality of life among narcotics anonymous.

METHODS

This cross-sectional study was performed on 202 narcotics anonymous in Kerman, southeastern Iran. Convenience sampling was used to select anonymous patients in the Narcotics Anonymous (NA) association in Kerman city. Narcotics anonymous completed the demographic questionnaire, the Craving Beliefs Questionnaire (CBQ), and the World Health Organization Quality of Life-BREF (WHOQOL-BREF). Multiple linear regression model was used to determine the predictors of craving beliefs. The data were then analyzed using SPSS 22.

RESULTS

The mean age of the participants was 38.48 ± 11.32 years. The majority of the samples were male (86.1%), married (65.4%), educated (93.6%) and urban (86.1%). The mean scores of craving beliefs and overall Quality of Life (QOL) were 77.58 ± 20.70 and 64.42 ± 23.13, respectively. Forty-two-point 1% had high level of craving beliefs. We found a significant negative and weak correlation between beliefs in substance craving, physical health domain (r = -0.16, p = 0.02), and overall quality of life (r = -0.15, p = 0.03). History of crack use, job, and physical health domain of QOL were predictors of beliefs in substance craving among the NAs.

CONCLUSION

Based on the study results, the participants had a high level of substance craving, and some aspects of the quality of life had an impact on the beliefs of addiction. However, it is necessary to conduct more studies in this field; psychological interventions and programs to increase the quality of life may reduce the substance craving.

Effects of buprenorphine on opioid craving in comparison to other medications for opioid use disorder: A systematic review of randomized controlled trials

BACKGROUND

Craving is a distressing symptom of opioid use disorder (OUD) that can be alleviated with medications for OUD (MOUD). Buprenorphine is an effective MOUD that may suppress craving; however, treatment discontinuation and resumed opioid use is common during the early phases of treatment. More information on the craving response through the high-risk period of initiating buprenorphine may provide meaningful information on how to better target craving, which in turn may enhance outcomes. This systematic review investigated buprenorphine doses and formulations on craving during the induction and maintenance phases of treatment, and for context also compared the craving response to other MOUD (i.e., methadone, extended-release naltrexone [XR-NTX]).

METHODS

PubMed, PsycInfo, Embase, and Cochrane Central databases were searched for randomized trials of buprenorphine versus placebo, various buprenorphine formulations/doses, or other MOUD that included a measure of opioid craving.

RESULTS

A total of 10 studies were selected for inclusion. Buprenorphine and buprenorphine/naloxone (BUP/NAL) were each associated with lower craving than placebo over time. Craving was greater among those prescribed lower versus higher buprenorphine doses. In comparison to other MOUD, buprenorphine or BUP/NAL was linked to greater craving than methadone in 3 of the 6 studies. BUP/NAL was associated with greater reported craving than XR-NTX.

DISCUSSION

Craving is reduced over time with buprenorphine and BUP/NAL, although other MOUD may provide greater reductions in craving. Although there is currently considerable variability in the measurement of craving, it may be a valuable concept to address with individuals receiving MOUD, especially early in treatment.

Impact of cannabidiol on reward- and stress-related neurocognitive processes among individuals with opioid use disorder: A pilot, double-blind, placebo-controlled, randomized cross-over trial

Introduction

Opioid use disorder (OUD) continues to be a significant public health concern. Medications for OUD (MOUD) such as buprenorphine reduce overdose mortality, but relapses occur often, leading to adverse outcomes. Preliminary data suggest that cannabidiol (CBD) may be a potential adjunctive treatment to MOUD by attenuating cue-reactivity. This pilot study sought to evaluate the impact of a single dose of CBD on reward- and stress-related neurocognitive processes implicated in relapse among those with OUD.

Methods

The study was a pilot, double-blind, placebo-controlled, randomized cross-over trial aimed at assessing the effects of a single dose of CBD (Epidiolex®) 600 mg or matching placebo administered to participants with OUD receiving either buprenorphine or methadone. Vital signs, mood states, pain, opioid withdrawal, cue-induced craving, attentional bias, decision-making, delayed discount, distress tolerance, and stress-reactivity were examined at each testing session on two separate testing days at least 1 week apart.

Results

Ten participants completed all study procedures. Receipt of CBD was associated with a significant decrease in cue-induced craving (0.2 vs. 1.3, p = 0.040), as well as reduced attentional bias toward drug-related cues as measured by the visual probe task (-80.4 vs. 100.3, p = 0.041). No differences were found among all the other outcomes examined.

Discussion

CBD may have promise as an adjunct to MOUD treatment by attenuating the brain response to drug-related cues, which, in turn, may reduce the risk of relapse and overdoses. Further research is warranted to evaluate the potential for CBD as an adjunctive therapy for individuals in treatment for OUD.

Clinical Trial Registration

https://clinicaltrials.gov/ct2/show/NCT04982029.

Learning from addiction: Craving of prescription opioids in chronic pain sufferers

Prescription opioids are a primary driver of opioid-related deaths. Although craving is a substantial component of OUD, the degree to which craving leads to misuse among chronic pain patients on long-term prescription opioids is unknown. A clear understanding of the factors that lead to misuse in this vulnerable population is needed for the development of safe and effective practices for opioid taper. This narrative review summarizes the relevant literature on the role of craving in addiction and chronic pain through epidemiological and behavioral studies. The first part of this review examines the role of craving in predicting opioid use/misuse in individuals with chronic pain with and without OUD. The second part covers methods on how craving is evaluated experimentally using both subjective and objective measures and provides related findings. The overall goal of this review is to facilitate the development of a population-specific description of craving in those who use opioids to control chronic pain and to describe how it may be mechanistically linked to patterns of opioid (mis)use.

Buprenorphine/naloxone and methadone effectiveness for reducing craving in individuals with prescription opioid use disorder: Exploratory results from an open-label, pragmatic randomized controlled trial

BACKGROUND

Craving reduction is an important target in the treatment of prescription-type opioid use disorder (POUD). In this exploratory analysis, we compared the effectiveness of BUP/NX flexible model of care relative to methadone for craving reduction in individuals with POUD.

METHODS

We analyzed data from a multicentric, pragmatic, 24-week open-label randomized controlled trial conducted in participants with POUD (N = 272) who were randomly assigned to BUP/NX model of care with flexible take-home dosing (n = 138) or the standard model of care with closely supervised methadone (n = 134). Treatments were prescribed and administered according to local guidelines, in diverse clinical settings. Craving was measured using the Brief Substance Craving Scale at baseline, week 2, 6, 10, 14, 18 and 22.

RESULTS

Cravings decreased in both treatment groups over 22 weeks (BUP/NX adjusted mean difference = -5.52, 95% CI = -6.91 to -4.13; methadone adjusted mean difference = -3.95, 95% CI = -5.28 to -2.63; p < 0.001), and were overall lower in the BUP/NX group (adjusted mean = 4.04, 95% CI = 3.43-4.64) than the methadone group (adjusted mean = 5.13, 95% CI = 4.51-5.74; p < 0.001). The time by treatment group interaction (favoring BUP/NX) was statistically significant at week 2 (adjusted mean difference = -1.58, 95% CI = -3.13 to -0.03; p = 0.041).

CONCLUSIONS

Compared to the standard methadone model of care, flexible take-home dosing of BUP/NX was associated with lower craving in individuals with POUD. These findings can contribute to guiding shared decision-making regarding OAT treatment in this population.

Cannabidiol Effect on Cue-Induced Craving for Individuals with Opioid Use Disorder Treated with Buprenorphine: A Small Proof-of-Concept Open-Label Study

Background:

Opioid use disorder (OUD) remains a major public health concern. Despite the use of medications for OUD such as buprenorphine, the current gold-standard treatment, relapse in the context of increased craving remains common. Cannabidiol (CBD) has been shown to reduce cue-induced craving in individuals with OUD, but among those who were not receiving any buprenorphine treatment. This small proof-of-concept open-label study sought to evaluate the effect of CBD on cue-induced craving among individuals with OUD who were being actively treated with buprenorphine.

Methods:

Participants (n = 5) received CBD (Epidiolex^®) 600 mg once daily for 3 consecutive days in an open-label manner. Primary outcome was cue-induced craving measured on a visual analog scale of 0 to 10, calculated as the difference in craving in response to drug-related versus neutral cues. The cue-reactivity paradigm was performed at baseline before CBD administration, and was repeated after 3 days of CBD. Secondary outcomes included scores on depression, anxiety, pain, opioid withdrawal, and side effects.

Results:

All participants were actively taking buprenorphine for an average of 37.8 months (range 1–120 months). Cue-induced craving was significantly lower after CBD dosing compared with baseline (0.4 vs. 3.2, paired t-test, p = 0.0046). No significant changes in scores for depression, anxiety, pain, or opioid withdrawal were noted. CBD was well tolerated, although one participant experienced moderate sedation; otherwise, no other adverse effects were reported.

Conclusions:

Given the high risk for bias in a small uncontrolled open label study such as this, results must be interpreted with caution. A larger adequately powered trial with a suitable control group is needed to confirm the finding that CBD may help to reduce cue-induced craving among individuals with OUD currently on buprenorphine treatment. Research should further evaluate whether adjunctive use of CBD can improve clinical outcomes for individuals with OUD maintained on buprenorphine. ClinicalTrials.gov (NCT04192370).

A neuroeconomic signature of opioid craving: How fluctuations in craving bias drug-related and nondrug-related value

How does craving bias decisions to pursue drugs over other valuable, and healthier, alternatives in addiction? To address this question, we measured the in-the-moment economic decisions of people with opioid use disorder as they experienced craving, shortly after receiving their scheduled opioid maintenance medication and ~24 h later. We found that higher cravers had higher drug-related valuation, and that moments of higher craving within-person also led to higher drug-related valuation. When experiencing increased opioid craving, participants were willing to pay more for personalized consumer items and foods more closely related to their drug use, but not for alternative "nondrug-related" but equally desirable options. This selective increase in value with craving was greater when the drug-related options were offered in higher quantities and was separable from the effects of other fluctuating psychological states like negative mood. These findings suggest that craving narrows and focuses economic motivation toward the object of craving by selectively and multiplicatively amplifying perceived value along a "drug relatedness" dimension.

Diels–Alder Adducts of Morphinan-6,8-Dienes and Their Transformations

6,14-ethenomorphinans are semisynthetic opiate derivatives containing an ethylene bridge between positions 6 and 14 in ring-C of the morphine skeleton that imparts a rigid molecular structure. These compounds represent an important family of opioid receptor ligands in which the 6,14-etheno bridged structural motif originates from a [4 + 2] cycloaddition of morphinan-6,8-dienes with dienophiles. Certain 6,14-ethenomorphinans having extremely high affinity for opioid receptors are often non-selective for opioid receptor subtypes, but this view is now undergoing some revision. The agonist 20R-etorphine and 20R-dihydroetorphine are several thousand times more potent analgesics than morphine, whereas diprenorphine is a high-affinity non-selective antagonist. The partial agonist buprenorphine is used as an analgesic in the management of post-operative pain or in substitution therapy for opiate addiction, sometimes in combination with the non-selective antagonist naloxone. In the context of the current opioid crisis, we communicated a summary of several decades of work toward generating opioid analgesics with lesser side effects or abuse potential. Our summary placed a focus on Diels–Alder reactions of morphinan-6,8-dienes and subsequent transformations of the cycloadducts. We also summarized the pharmacological aspects of radiolabeled 6,14-ethenomorphinans used in molecular imaging of opioid receptors.

Emotional distress and pain catastrophizing predict cue-elicited opioid craving among chronic pain patients on long-term opioid therapy

BACKGROUND

Individuals who use illicit substances exhibit cue-elicited craving and autonomic cue-reactivity when exposed to cues associated with past drug use. However, little is known about this phenomenon among chronic pain patients on long-term opioid therapy (LTOT). Negative cognitive-emotional reactivity in general (e.g., distress) and cognitive-emotional reactivity specific to pain (e.g., pain catastrophizing) might drive cue-reactivity independent of pain severity. Here we examined emotional distress and pain catastrophizing as predictors of cue-reactivity among a sample of chronic pain patients receiving LTOT. We also tested whether associations between distress, catastrophizing, and cue-reactivity differed as a function of opioid misuse status.

MATERIALS AND METHODS

Patients receiving LTOT (N = 243) were classified as exhibiting aberrant behavior consistent with opioid misuse (MISUSE+, n = 145) or as using opioids as prescribed (MISUSE-, n = 97). Participants completed assessments of pain catastrophizing and emotional distress and then participated in an opioid cue-reactivity task one week later. Cue-elicited opioid craving and autonomic cue-reactivity were measured with craving ratings and high-frequency heart rate variability (HRV), respectively.

RESULTS

Distress and catastrophizing predicted cue-elicited craving and HRV, whereas pain severity did not. Misuser status moderated the relationship between emotional distress and self-reported craving, such that higher levels of distress predicted craving among the MISUSE+ group, but not among the MISUSE- group. No moderating effects were found for catastrophizing.

CONCLUSIONS

Findings suggest that although opioids are prescribed for analgesia, the exacerbating influence of negative cognitive-emotional reactivity, both in general and specific to pain, on cue-elicited opioid craving extends beyond the effects of pain severity alone.

A methodological checklist for fMRI drug cue reactivity studies: development and expert consensus

Cue reactivity is one of the most frequently used paradigms in functional magnetic resonance imaging (fMRI) studies of substance use disorders (SUDs). Although there have been promising results elucidating the neurocognitive mechanisms of SUDs and SUD treatments, the interpretability and reproducibility of these studies is limited by incomplete reporting of participants' characteristics, task design, craving assessment, scanning preparation and analysis decisions in fMRI drug cue reactivity (FDCR) experiments. This hampers clinical translation, not least because systematic review and meta-analysis of published work are difficult. This consensus paper and Delphi study aims to outline the important methodological aspects of FDCR research, present structured recommendations for more comprehensive methods reporting and review the FDCR literature to assess the reporting of items that are deemed important. Forty-five FDCR scientists from around the world participated in this study. First, an initial checklist of items deemed important in FDCR studies was developed by several members of the Enhanced NeuroImaging Genetics through Meta-Analyses (ENIGMA) Addiction working group on the basis of a systematic review. Using a modified Delphi consensus method, all experts were asked to comment on, revise or add items to the initial checklist, and then to rate the importance of each item in subsequent rounds. The reporting status of the items in the final checklist was investigated in 108 recently published FDCR studies identified through a systematic review. By the final round, 38 items reached the consensus threshold and were classified under seven major categories: 'Participants' Characteristics', 'General fMRI Information', 'General Task Information', 'Cue Information', 'Craving Assessment Inside Scanner', 'Craving Assessment Outside Scanner' and 'Pre- and Post-Scanning Considerations'. The review of the 108 FDCR papers revealed significant gaps in the reporting of the items considered important by the experts. For instance, whereas items in the 'General fMRI Information' category were reported in 90.5% of the reviewed papers, items in the 'Pre- and Post-Scanning Considerations' category were reported by only 44.7% of reviewed FDCR studies. Considering the notable and sometimes unexpected gaps in the reporting of items deemed to be important by experts in any FDCR study, the protocols could benefit from the adoption of reporting standards. This checklist, a living document to be updated as the field and its methods advance, can help improve experimental design, reporting and the widespread understanding of the FDCR protocols. This checklist can also provide a sample for developing consensus statements for protocols in other areas of task-based fMRI.

Connectome-based prediction of craving for gaming in internet gaming disorder

BACKGROUND

Craving-related brain responses have been associated with the emergence and maintenance of addictions. However, little is known about brain network organizations underlying cravings in internet gaming disorder (IGD).

METHODS

Sixty-six IGD subjects and 61 matched individuals with recreational game use (RGU) were scanned while performing a cue-craving task. A recently developed whole-brain analysis approach, connectome-based predictive modelling (CPM) with leave-one-out cross-validation was conducted to identify networks that predicted craving responses in IGD. Then, the craving network was tested in different brain states (cue-craving under deprivation) to investigate replicability.

RESULTS

CPM identified an IGD craving network, as indicated by a significant correspondence between predicted and actual craving values (r = 0.49, p < 0.001), characterized by within-network default mode (DMN) connectivity and connectivity between canonical networks implicated in executive/cognitive control (frontoparietal, medial frontal, DMN) and reward responsiveness (subcortical, motor/sensory). Network strength in the cue-craving task during gaming deprivation also predicted IGD craving scores (r = 0.43, p = 0.017), indicating network replication across brain states.

CONCLUSIONS

The CPM results demonstrate that individual differences in cognitive, attention, and control network function can predict craving intensities in IGD subjects. These networks may be targets for potential interventions using brain modulation.

Effects of acupuncture stimulation on brain activation induced by cue-elicited alcohol craving

Acupuncture has been shown to be effective on alcohol use disorder. However, the underlying mechanism remains poorly understood. To investigate the effects of Shenmen (HT7) acupoint on brain activation induced by cue-elicited alcohol craving, 30 right-handed healthy light to moderate alcohol drinkers were recruited from the community. They were randomly assigned to undergo acupuncture either at HT7 (experimental acupoint, n = 15) or Jingqu (LU8, control acupoint, n = 15) acupoints. This randomized controlled study was performed in Daegu Haany University and Daegu-Gyeongbuk Medical Innovation Foundation, Republic of Korea. Recruitment and data collection were conducted from December 2018 to May 2019. The results showed that after acupuncture at HT7 acupoint, the activation of orbitofrontal cortex and dorsolateral prefrontal cortex was greatly increased, while the activation of dorsolateral prefrontal cortex was obviously reduced, and subject's craving for alcohol was reduced when he/she seeing alcohol-related video clips involving various alcohols (beer, wine, or soju) or drinking scenarios. Acupuncture at HT7 more greatly reduced subject's alcohol cravings than acupuncture at LU8 acupoint. These findings suggest that acupuncture can improve the self-control of mild to moderate social drinkers through the activation of the orbitofrontal cortex and dorsolateral prefrontal cortex, thereby reducing the craving for alcohol. The study protocol was approved by the Institutional Review Board of Daegu Haany University Korean Medicine Hospital, Republic of Korea (approval No. DHUMC-D-18026-PRO-02) on November 30, 2018.

Disturbed craving regulation to gaming cues in internet gaming disorder: Implications for uncontrolled gaming behaviors

BACKGROUND

The ability to control craving for games is very important to abstain from Internet gaming disorder (IGD) and abundant clinical evidence has suggested that craving dysregulation is the essential pathogenesis for IGD. However, the neural mechanism underlying this feature remains unclear.

METHODS

Subjective evaluation and fMRI data from 44 participants (IGD participants: 21; recreational Internet game users (RGUs): 23) were collected while they were performing a regulation of craving task. We analyzed and compared their brain features while they regulated cravings to gaming stimuli.

RESULTS

Compared to RGUs, IGD participants showed enhanced brain activation in the right anterior cingulate cortex, posterior cingulate cortex (PCC), orbitofrontal cortex and middle temporal gyrus and in the left dorsolateral prefrontal cortex and thalamus during the regulation of craving task. Generalized psychophysiological interaction (gPPI) analysis revealed that IGD participants showed decreased functional connectivity between the right PCC and right inferior parietal lobule compared to that in RGU participants.

CONCLUSIONS

The results suggested that deficits of craving regulation in IGD participant were associated with the imbalanced coordination between the reward network and the executive network. Enhanced game-seeking motivation and disturbed executive control are responsible for craving dysregulation in IGD participants. These findings suggest a biological mechanism for IGD that may help in finding potential interventions.

The role of withdrawal in mesocorticolimbic drug cue reactivity in opioid use disorder

Opioid use disorder (OUD) is characterized by heightened cognitive, physiological, and neural responses to opioid-related cues that are mediated by mesocorticolimbic brain pathways. Craving and withdrawal are key symptoms of addiction that persist during physiological abstinence. The present study evaluated the relationship between the brain response to drug cues in OUD and baseline levels of craving and withdrawal. We used functional magnetic resonance imaging (fMRI) to examine brain responses to opioid-related pictures and control pictures in 29 OUD patients. Baseline measures of drug use severity, opioid craving, and withdrawal symptoms were assessed prior to cue exposure and correlated with subsequent brain responses to drug cues. Mediation analysis was conducted to test the indirect effect of drug use severity on brain cue reactivity through craving and withdrawal symptoms. We found that baseline drug use severity and opioid withdrawal symptoms, but not craving, were positively associated with the neural response to drug cues in the nucleus accumbens, orbitofrontal cortex, and amygdala. Withdrawal, but not craving, mediated the effect of drug use severity on the nucleus accumbens' response to drug cues. We did not find similar effects for the neural responses to stimuli unrelated to drugs. Our findings emphasize the central role of withdrawal symptoms as the mediator between the clinical severity of OUD and the brain correlates of sensitization to opioid-related cues. They suggest that in OUD, baseline withdrawal symptoms signal a high vulnerability to drug cues.

Pharmacological treatment of pain among persons with opioid addiction: A systematic review and meta-analysis with implications for drug development

The clinical features and neurobiology of pain and opioid use disorder (OUD) are inextricably linked. Despite emerging evidence supporting the negative impact of ongoing pain in the treatment of OUD, the pharmacological management of pain in the presence of OUD has received limited attention. We sought to systematically review the studies investigating pharmacotherapies for pain among persons with OUD. Eligible studies had participants with OUD and outcomes including evoked or spontaneous pain. We searched Scopus, Cochrane Database of Systematic Reviews, Medline, and Embase. Out of 1,097 studies that met the search criteria, 12 studies provided data relevant to the research question-five laboratory studies and seven clinical trials. Random effects pooled estimates suggested no significant difference between groups at baseline but a response favoring the active treatment group over placebo, with nonsignificant heterogeneity between studies. Findings from these studies provide preliminary evidence for analgesic and antihyperalgesic effects of gabapentin, GABA agonists, and NMDA antagonists among persons with OUD. To establish the tradeoffs between the analgesic effects and abuse liability of these compounds, further well-controlled clinical trials are required among persons with OUD. This review also underscores the need for methodological enhancement in drug development for pain in OUD. Future research should address the clinical and neurobiological overlap between pain- and addiction-related phenomena. Transdisciplinary approaches may identify biomarkers of these shared phenomena and their neural substrates. The development of novel therapeutics for pain in OUD may be accelerated by such integration of pain and addiction research.

Oral prescription opioid-seeking behavior in male and female mice

A significant portion of prescription opioid users self-administer orally rather than intravenously. Animal models of opioid addiction have demonstrated that intravenous cues are sufficient to cause drug seeking. However, intravenous models may not characterize oral users, and the preference to self-administer orally appears to be partially influenced by the user's sex. Our objectives were to determine whether oral opioid-associated cues are sufficient for relapse and whether sex differences exist in relapse susceptibility. Mice orally self-administered escalating doses of oxycodone under postprandial (prefed) or non-postprandial (no prefeeding) conditions. Both sexes demonstrated cue-induced reinstatement following abstinence. In separate mice, we found that oral oxycodone cues were sufficient to reinstate extinguished oral oxycodone-seeking behavior following abstinence without prior postprandial or water self-administration training. During self-administration, we incidentally found that female mice earned significantly more mg/kg oxycodone than male mice. Follow-up studies indicated sex differences in psychomotor stimulation and plasma oxycodone/oxymorphone following oral oxycodone administration. In addition, gonadal studies were performed in which we found divergent responses where ovariectomy-enhanced and orchiectomy-suppressed oral self-administration. While the suppressive effects of orchiectomy were identified across doses and postprandial conditions, the enhancing effects of ovariectomy were selective to non-postprandial conditions. These studies establish that (a) oral drug cues are sufficient to cause reinstatement that is independent of prandial conditions and water-seeking behavior, (b) earned oral oxycodone is larger in female mice compared with male mice potentially through differences in psychomotor stimulation and drug metabolism, and (c) gonadectomy produces divergent effects on oral oxycodone self-administration between sexes.

Traumatic brain injury substantially reduces the conditioned reinforcing effects of environmental cues in rats

Traumatic brain injury affects millions of people each year and is an established risk factor for addiction. Recent animal studies have causally demonstrated that injuries can increase drug self-administration across a variety of substances. One potential behavioral mediator for this finding is an increased responsivity to drug-associated cues. This endophenotype can be identified by profiling non-drug-related behaviors. The current study evaluated several paradigms (conditioned approach, conditioned reinforcement, extinction from variable interval responding, conditioned facilitation) to determine how rats with a frontal TBI differed in their response to Pavlovian conditioning in response to food-paired cues. Surprisingly, rats with a TBI demonstrated increased goal-tracking in a conditioned approach paradigm and exerted less effort for a conditioned reinforcer. Moreover, they had slightly facilitated extinction (as demonstrated by significantly larger interresponse times) in the face of reinforcer-associated cues. Despite these effects, TBI rats still demonstrated conditioned facilitation to an auditory stimulus. Together, these effects suggest a phenotype in the opposite direction of what might be anticipated. Cues still served a strong discriminative function and altered behavior; however, they did not function as strong conditioned reinforcers for TBI animals. One potential reason for this is that substantial changes to the dopamine system after TBI may reduce the conditioned reinforcing effects of cues, but sensitize the brain to potent drugs of abuse. More research will be needed to determine whether this is the case.

Opioid Craving in Human Laboratory Settings: a Review of the Challenges and Limitations

There are many factors that need to be taken into consideration when measuring craving in a human laboratory study. This review summarizes and discusses some of the major challenges researchers are faced with when assessing opioid craving in clinical research. First, there are wide range of available assessments that have been developed for measuring craving and depending on the research questions or the underlying constructs targeted, some may be more appropriate than others. In addition to establishing the methodological point of departure for designing a study with craving, there are also different participant conditions and characteristics that need to be evaluated when selecting among the large selection of assessments available. Participant conditions/characteristics can influence the degree or frequency of opioid craving experienced. Lastly, there can be contextual conditions that affect opioid cravings such as a stressful environment that may alter cue saliency. It is recommended that researchers carefully consider the different constituents that contribute to opioid craving and to ensure a comprehensive evaluation when assessing each participant. A more thorough consideration of these challenges can help us to understand the optimal ways to measure one important and complex component of addiction.

Craving and opioid use disorder: A scoping review

INTRODUCTION

The subjective experience of drug craving is a prominent and common clinical phenomenon for many individuals diagnosed with opioid use disorder (OUD), and could be a valuable clinical endpoint in medication development studies. The purpose of this scoping review is to provide an overview and critical analysis of opioid craving assessments located in the published literature examining OUD.

METHOD

Studies were identified through a search of PubMed, Embase, and PsychInfo databases and included for review if opioid craving was the focus and participants were diagnosed with or in treatment for OUD.

RESULTS

Fifteen opioid craving assessment instruments were identified across the 87 studies included for review. The most common were the Visual Analog Scale (VAS, 41 studies), Desires for Drug Questionnaire (DDQ, 12 studies), Heroin Craving Questionnaire (HCQ, 10 studies), and Obsessive-Compulsive Drug Use Scale (OCDUS, 10 studies). Craving assessments varied considerably in their format, content, time frame, and underlying subscales, and only 6 of 15 had been psychometrically evaluated.

DISCUSSION

This review identified a variety of opioid craving assessments, but few had been evaluated for their psychometric properties making it difficult to ascertain whether craving is being assessed optimally in studies of OUD. Thus, the development of a reliable and valid opioid craving assessment would be worthwhile and could be guided by recently published Food and Drug Administration Clinical Outcome Assessment (COA) guidelines. Importantly, a COA focused on opioid craving could be a valuable addition to research studies designed to evaluate novel treatments for OUD.

Cannabidiol for the Reduction of Cue-Induced Craving and Anxiety in Drug-Abstinent Individuals With Heroin Use Disorder: A Double-Blind Randomized Placebo-Controlled Trial

OBJECTIVE

Despite the staggering consequences of the opioid epidemic, limited nonopioid medication options have been developed to treat this medical and public health crisis. This study investigated the potential of cannabidiol (CBD), a nonintoxicating phytocannabinoid, to reduce cue-induced craving and anxiety, two critical features of addiction that often contribute to relapse and continued drug use, in drug-abstinent individuals with heroin use disorder.

METHODS

This exploratory double-blind randomized placebo-controlled trial assessed the acute (1 hour, 2 hours, and 24 hours), short-term (3 consecutive days), and protracted (7 days after the last of three consecutive daily administrations) effects of CBD administration (400 or 800 mg, once daily for 3 consecutive days) on drug cue-induced craving and anxiety in drug-abstinent individuals with heroin use disorder. Secondary measures assessed participants' positive and negative affect, cognition, and physiological status.

RESULTS

Acute CBD administration, in contrast to placebo, significantly reduced both craving and anxiety induced by the presentation of salient drug cues compared with neutral cues. CBD also showed significant protracted effects on these measures 7 days after the final short-term (3-day) CBD exposure. In addition, CBD reduced the drug cue-induced physiological measures of heart rate and salivary cortisol levels. There were no significant effects on cognition, and there were no serious adverse effects.

CONCLUSIONS

CBD's potential to reduce cue-induced craving and anxiety provides a strong basis for further investigation of this phytocannabinoid as a treatment option for opioid use disorder.

Craving in Opioid Use Disorder: From Neurobiology to Clinical Practice

Opioid use disorder (OUD) is a major public health issue that has reached epidemic levels in some parts of the world. It is a chronic and complex neurobiological disease associated with frequent relapse to drug taking. Craving, defined as an overwhelmingly strong desire or need to use a drug, is a central component of OUD and other substance use disorders. In this review, we describe the neurobiological and neuroendocrine pathways that underpin craving in OUD and also focus on the importance of assessing and treating craving in clinical practice. Craving is strongly associated with patients returning to opioid misuse and is therefore an important treatment target to reduce the risk of relapse and improve patients' quality of life. Opioid agonist therapies (OAT), such as buprenorphine and methadone, can significantly reduce craving and relapse risk, and it is essential that patients are treated optimally with these therapies. There is also evidence to support the benefits of non-pharmacological approaches, such as cognitive behavioral therapy and mindfulness-based interventions, as supplementary treatments to opioid agonist therapies. However, despite the positive impact of these treatments on craving, many OUD patients continue to suffer with negative affect and dysphoria. There is a clear need for further studies to progress our understanding of the neurobiological basis of craving and addiction and to identify novel therapeutic strategies as well as to optimize the use of existing treatments to improve outcomes for the growing numbers of patients affected by OUD.

Arc reactivity in accumbens nucleus, amygdala and hippocampus differentiates cue over context responses during reactivation of opiate withdrawal memory

Opiate withdrawal induces an early aversive state which can be associated to contexts and/or cues, and re-exposure to either these contexts or cues may participate in craving and relapse. Nucleus accumbens (NAC), hippocampus (HPC) and basolateral amygdala (BLA) are crucial substrates for acute opiate withdrawal, and for withdrawal memory retrieval. Also HPC and BLA interacting with the NAC are suggested to respectively mediate the processing of context and cue representations of drug-related memories. Here we used a paradigm of conditioned suppression of operant food seeking, allowing to differentiate context and cue related responses, to study the influence of withdrawal memories on operant behavior and the underlying neural substrates. catFISH for Arc mRNA expression was used to discriminate cellular responses during context and cue (flashing light) periods in this paradigm. We show that reactivation of the memory of the negative affective state of withdrawal suppresses active lever pressing for food, and this conditioned suppression is generalized to the context. Interestingly the behavioral responses during the context and cue light periods are associated with differential Arc mRNA activations within the NAC, BLA, and HPC. Indeed both periods led to NAC shell activation whereas the NAC core was responsive only following the cue light period. Moreover, BLA and HPC were more responsive during cue-light and context period respectively. These data further support the already reported differential role of these brain structures on cue vs context-induced reinstatement of operant behaviors, and highlight the existence of common mechanisms for the processing of positive and aversive emotional memories.

Attentional bias in opioid users: A systematic review and meta-analysis

BACKGROUND

Opioid use in the United States is a national public health emergency. The primary treatment for opioid use disorder (OUD) is medication assisted treatment (MAT). Although effective in improving treatment outcomes in OUD, there is a need to develop behavioral treatments adjunctive to MAT. The current study investigates attentional bias in OUD as a possible target for adjunctive behavioral treatments.

METHODS

Comprehensive literature searches of psychological, medical, and educational databases were conducted through October 2017. Eligible peer-reviewed studies evaluated attentional bias in opioid users, used a task to evaluate attentional bias that included active response to study stimuli, calculated attention bias by comparing response to drug and neutral stimuli, and could isolate attentional bias specific to opioid versus neutral stimuli from bias to other salient stimuli.

CONCLUSIONS

The results of our systematic review and meta-analysis suggest that individuals with OUD exhibit robust attentional bias to opioid cues, even when engaged in MAT. Interventions that reduce attentional bias may be a useful adjunct to MAT.