The association of pain impact and sleep disruption with opioid withdrawal during opioid-use disorder treatment.

AIMS: Persons with opioid-use disorder (OUD) often experience opioid withdrawal and opioid craving, which can drive continued opioid use and treatment discontinuation. In addition, hyperalgesia is common among persons with OUD, yet few studies have examined the role of pain impact during OUD treatment. The purpose of the present study was to test whether opioid withdrawal and craving were elevated in the context of greater pain impact (i.e. greater pain intensity and interference), and whether these associations changed throughout treatment. METHODS: Participants in residential OUD treatment (n = 24) wore wrist actigraphy to measure sleep and completed daily measures of pain impact, opioid withdrawal and opioid craving for up to 28 days. Mixed effects models were used to examine whether daily elevations in pain impact and sleep continuity were associated with withdrawal severity and opioid craving. RESULTS: Elevations in withdrawal, but not craving, occurred on days when individuals reported higher scores on the pain impact scale. Associations between pain impact and withdrawal were present throughout treatment, but stronger during early treatment. In contrast, both withdrawal and opioid craving were elevated following nights of greater wake after sleep onset and awakenings, but these findings were often more pronounced in early treatment. CONCLUSIONS: Pain impact and sleep disturbance are 2 factors associated with opioid withdrawal and opioid craving. Novel pharmacotherapies and scalable adjunctive interventions targeting sleep and pain impact should be tested in future work to improve OUD treatment outcomes.

Characterizing reward and relief/habit drinking profiles in a study of naltrexone, varenicline, and placebo.

INTRODUCTION: This study aims to clarify differences in mood, craving, and treatment response between reward and relief/habit individuals in a study of naltrexone, varenicline, and placebo. We hypothesized that relief/habit individuals would have a poorer mood during early abstinence and higher levels of alcohol craving than reward individuals. We hypothesized that reward individuals would demonstrate better drinking outcomes on naltrexone versus placebo. METHODS: Data were culled from a randomized, double-blind, placebo-controlled human trial of 53 individuals (18F/16M) with alcohol use disorder randomized to varenicline (n = 19), naltrexone (n = 15), or matched placebo (n = 19). In this 6-day practice quit trial, participants attempted to abstain from drinking and completed daily diaries. Participants were classified into reward or relief/habit subgroups based on self-reported motivation for drinking. Multilinear models tested differences in mood and alcohol craving between reward and relief/habit individuals. General linear models tested differences between reward and relief/habit individuals' drinking outcomes on each medication versus placebo. RESULTS: Relief/habit individuals showed decreases in positive mood and increases in negative mood over the quit attempt across medications, compared to reward individuals (P's < .05). Reward individuals' tension decreased on naltrexone, while relief/habit individuals' tension remained stable (F = 3.64, P = .03). Reward individuals in the placebo group had higher percent days abstinent than relief individuals in the placebo group (P < .001). DISCUSSION: This study suggests relief/habit individuals' mood worsens during early abstinence. Our finding that reward individuals' tension decreased on naltrexone and increased on placebo may suggest a clinical response to the medication.

Orbitofrontal cortex to dorsal striatum circuit is critical for incubation of oxycodone craving after forced abstinence.

Relapse is a major challenge in treating opioid addiction, including oxycodone. During abstinence, oxycodone seeking progressively increases, a phenomenon termed incubation of oxycodone craving. We previously demonstrated a causal role of orbitofrontal cortex (OFC) in this incubation. Here, we studied the interaction between glutamatergic projections from OFC and dopamine 1-family receptor (D1R) signaling in dorsal striatum (DS) in this incubation in male rats. We first examined the causal role of D1R signalling in DS in incubated oxycodone seeking. Next, we combined fluorescence-conjugated cholera toxin subunit B (CTb-555, a retrograde tracer) with Fos (a neuronal activity marker) to assess whether the activation of OFC→DS projections was associated with incubated oxycodone seeking. We then used a pharmacological asymmetrical disconnection procedure to examine the role of the interaction between projections from OFC and D1R signalling in DS in incubated oxycodone seeking. We also tested the effect of unilateral pharmacological inactivation of OFC or unilateral D1R blockade of DS on incubated oxycodone seeking. Finally, we assessed whether contralateral disconnection of OFC→DS projections impacted non-incubated oxycodone seeking on abstinence day 1. We found that D1R blockade in DS decreased incubated oxycodone seeking and OFC→DS projections were activated during incubated oxycodone seeking. Moreover, anatomical disconnection of OFC→DS projections, but not unilateral inactivation of OFC or unilateral D1R blockade in DS, decreased incubated oxycodone seeking. Lastly, contralateral disconnection of OFC→DS projections had no effect on oxycodone seeking on abstinence day 1. Together, these results demonstrated a causal role of OFC→DS projections in incubation of oxycodone craving.

Systematic review and meta-analysis: Combining transcranial magnetic stimulation or direct current stimulation with pharmacotherapy for treatment of substance use disorders.

BACKGROUND AND OBJECTIVES: Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) have evidence for their potential in the treatment of substance use disorders (SUD). Medication for addiction treatment (MAT) is underutilized and not always effective. We identified randomized controlled trials (RCTs) and case studies that evaluated the effectiveness of TMS or tDCS used concurrently with MAT in SUD treatment. METHODS: A systematic review of published literature following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was conducted on 6/1/2023 by a medical librarian. Craving-related scales were extracted for an effect size calculation. The Physiotherapy Evidence Database (PEDro) scale assessed study quality. RESULTS: Eight studies (7 RCT, 1 case) including 253 individuals were published from 2015 to 2022, 5 of which had available data for meta-analysis. TMS or tDCS combined with MAT significantly reduced craving-related measures relative to sham stimulation (Hedges' g = -0.42, confidence interval: -0.73 to -0.11, p < .01). Opioid use disorder, methadone, and the dorsolateral prefrontal cortex were the most commonly studied SUD, MAT, and target region. DISCUSSION AND CONCLUSIONS: Our results show a significant effect; however, is limited by a small number of studies with heterogeneous methodology across intervention methods and SUDs. Additional trials are needed to fully assess the clinical impact and mechanisms of combined brain stimulation and pharmacotherapy. We discuss a possible mechanism for synergism from these treatment combinations. SCIENTIFIC SIGNIFICANCE: Adds the first systematic review of combination treatment with TMS or tDCS and MAT in SUD patients to the literature and estimates its overall effect size.

Impact of MAOA Gene Polymorphism on the Efficacy of Antidepressant Treatment and Craving Severity for Betel Quid Use Disorder.

Betel quid (BQ) use disorder (BUD) is prevalent in many Asian countries, impacting approximately 600 million people. We conducted a randomized clinical trial to analyze the impact of MAOA genetic variations on the severity of BQ craving. This was measured using DSM-5 criteria and the Yale-Brown Obsessive-Compulsive Scale modified for betel quid use (Y-BOCS-BQ). Participants were grouped according to the severity of BUD and MAOA gene single-nucleotide polymorphism (SNP) rs5953210 genotypes. The Y-BOCS-BQ scores were assessed at baseline (week 0) and during follow-up at weeks 2, 4, 6, and 8. The AA genotype group showed significantly greater reductions in Y-BOCS-BQ at weeks 2 (p = 0.0194), 4 (p = 0.0078), 6 (p = 0.0277), and 8 (p = 0.0376) compared to the GG genotype group. Additionally, within the antidepressant group, the AA genotype showed significant reductions in the Y-BOCS-BQ scores at weeks 2 (p = 0.0313), 4 (p = 0.0134), 6 (p = 0.0061), and 8 (p = 0.0241) compared to the GG genotype. The statistical analysis revealed a significant interaction between the treatment and placebo groups based on MAOA genotypes, with the AA genotype in the treatment group exhibiting a more pronounced decrease in Y-BOCS-BQ score (p interaction <0.05) at week 6. Our study highlights the importance of considering genetic factors when developing personalized treatment plans for BUD.

GluN3-Containing NMDA Receptors in the Rat Nucleus Accumbens Core Contribute to Incubation of Cocaine Craving.

Cue-induced cocaine craving progressively intensifies (incubates) after withdrawal from cocaine self-administration in rats and humans. In rats, the expression of incubation ultimately depends on Ca2+-permeable AMPARs that accumulate in synapses onto medium spiny neurons (MSNs) in the NAc core. However, the delay in their accumulation (∼1 month after drug self-administration ceases) suggests earlier waves of plasticity. This prompted us to conduct the first study of NMDAR transmission in NAc core during incubation, focusing on the GluN3 subunit, which confers atypical properties when incorporated into NMDARs, including insensitivity to Mg2+ block and Ca2+ impermeability. Whole-cell patch-clamp recordings were conducted in MSNs of adult male rats 1-68 d after discontinuing extended-access saline or cocaine self-administration. NMDAR transmission was enhanced after 5 d of cocaine withdrawal, and this persisted for at least 68 d of withdrawal. The earliest functional alterations were mediated through increased contributions of GluN2B-containing NMDARs, followed by increased contributions of GluN3-containing NMDARs. As predicted by GluN3-NMDAR incorporation, fewer MSN spines exhibited NMDAR-mediated Ca2+ entry. GluN3A knockdown in NAc core was sufficient to prevent incubation of craving, consistent with biotinylation studies showing increased GluN3A surface expression, although array tomography studies suggested that adaptations involving GluN3B also occur. Collectively, our data show that a complex cascade of NMDAR and AMPAR plasticity occurs in NAc core, potentially through a homeostatic mechanism, leading to persistent increases in cocaine cue reactivity and relapse vulnerability. This is a remarkable example of experience-dependent glutamatergic plasticity evolving over a protracted window in the adult brain.SIGNIFICANCE STATEMENT "Incubation of craving" is an animal model for the persistence of vulnerability to cue-induced relapse after prolonged drug abstinence. Incubation also occurs in human drug users. AMPAR plasticity in medium spiny neurons (MSNs) of the NAc core is critical for incubation of cocaine craving but occurs only after a delay. Here we found that AMPAR plasticity is preceded by NMDAR plasticity that is essential for incubation and involves GluN3, an atypical NMDAR subunit that markedly alters NMDAR transmission. Together with AMPAR plasticity, this represents profound remodeling of excitatory synaptic transmission onto MSNs. Given the importance of MSNs for translating motivation into action, this plasticity may explain, at least in part, the profound shifts in motivated behavior that characterize addiction.

Granulocyte-Colony Stimulating Factor Reduces Cocaine-Seeking and Downregulates Glutamatergic Synaptic Proteins in Medial Prefrontal Cortex.

Psychostimulant use disorder is a major public health issue, and despite the scope of the problem there are currently no Food and Drug Administration (FDA)-approved treatments. There would be tremendous utility in development of a treatment that could help patients both achieve and maintain abstinence. Previous work from our group has identified granulocyte-colony stimulating factor (G-CSF) as a neuroactive cytokine that alters behavioral response to cocaine, increases synaptic dopamine release, and enhances cognitive flexibility. Here, we investigate the role of G-CSF in affecting extinction and reinstatement of cocaine-seeking and perform detailed characterization of its proteomic effects in multiple limbic substructures. Male Sprague Dawley rats were injected with PBS or G-CSF during (1) extinction or (2) abstinence from cocaine self-administration, and drug seeking behavior was measured. Quantitative assessment of changes in the proteomic landscape in the nucleus accumbens (NAc) and medial prefrontal cortex (mPFC) were performed via data-independent acquisition (DIA) mass spectrometry analysis. Administration of G-CSF during extinction accelerated the rate of extinction, and administration during abstinence attenuated cue-induced cocaine-seeking. Analysis of global protein expression demonstrated that G-CSF regulated proteins primarily in mPFC that are critical to glutamate signaling and synapse maintenance. Taken together, these findings support G-CSF as a viable translational research target with the potential to reduce drug craving or seeking behaviors. Importantly, recombinant G-CSF exists as an FDA-approved medication which may facilitate rapid clinical translation. Additionally, using cutting-edge multiregion discovery proteomics analyses, these studies identify a novel mechanism underlying G-CSF effects on behavioral plasticity.SIGNIFICANCE STATEMENT Pharmacological treatments for psychostimulant use disorder are desperately needed, especially given the disease's chronic, relapsing nature. However, there are currently no Food and Drug Administration (FDA)-approved pharmacotherapies. Emerging evidence suggests that targeting the immune system may be a viable translational research strategy; preclinical studies have found that the neuroactive cytokine granulocyte-colony stimulating factor (G-CSF) alters cocaine reward and reinforcement and can enhance cognitive flexibility. Given this basis of evidence we studied the effects of G-CSF treatment on extinction and reinstatement of cocaine seeking. We find that administration of G-CSF accelerates extinction and reduces cue-induced drug seeking after cocaine self-administration. In addition, G-CSF leads to downregulation of synaptic glutamatergic proteins in medial prefrontal cortex (mPFC), suggesting that G-CSF influences drug seeking via glutamatergic mechanisms.

Cocaine cue-induced mesocorticolimbic activation in cocaine users: Effects of personality traits, lifetime drug use, and acute stimulant ingestion.

Stimulant drug-paired cues can acquire the ability to activate mesocorticolimbic pathways and lead to new bouts of drug use. Studies in laboratory animals suggest that these effects are augmented by progressively greater drug use histories, impulsive personality traits, and acute drug ingestion. As a preliminary test of these hypotheses in humans, we exposed cocaine users (n = 14) and healthy volunteers (n = 10) to cocaine-related videos during two functional magnetic resonance imaging (fMRI) sessions, once following acute administration of placebo and once following d-amphetamine (0.3 mg/kg, p.o.). Across sessions, cocaine users showed larger cocaine cue-induced responses than healthy controls in the associative striatum and midbrain. Among the cocaine users, larger drug cue-induced responses during the placebo session were correlated with higher Barratt Impulsiveness Scale (BIS-11) nonplanning scores (associative striatum) and greater lifetime use of stimulant drugs (limbic, associative, and sensorimotor striatum). The administration of d-amphetamine did not augment the cue-induced activations, but, in cocaine users, drug cue-induced striatal activations were more widespread following prolonged cocaine cue exposure. Together, these effects of past and present drug use might aggravate the risk for stimulant drug use problems.

Synaptic mechanisms underlying persistent cocaine craving.

Although it is challenging for individuals with cocaine addiction to achieve abstinence, the greatest difficulty is avoiding relapse to drug taking, which is often triggered by cues associated with prior cocaine use. This vulnerability to relapse persists for long periods (months to years) after abstinence is achieved. Here, I discuss rodent studies of cue-induced cocaine craving during abstinence, with a focus on neuronal plasticity in the reward circuitry that maintains high levels of craving. Such work has the potential to identify new therapeutic targets and to further our understanding of experience-dependent plasticity in the adult brain under normal circumstances and in the context of addiction.

Neuroendocrine Response to Exogenous Ghrelin Administration, Combined With Alcohol, in Heavy-Drinking Individuals: Findings From a Randomized, Double-Blind, Placebo-Controlled Human Laboratory Study.

BACKGROUND: Accumulating evidence has established a role for the orexigenic hormone ghrelin in alcohol-seeking behaviors. Accordingly, the ghrelin system may represent a potential pharmacotherapeutic target for alcohol use disorder. Ghrelin modulates several neuroendocrine pathways, such as appetitive, metabolic, and stress-related hormones, which are particularly relevant in the context of alcohol use. The goal of the present study was to provide a comprehensive assessment of neuroendocrine response to exogenous ghrelin administration, combined with alcohol, in heavy-drinking individuals. METHODS: This was a randomized, crossover, double-blind, placebo-controlled human laboratory study, which included 2 experimental alcohol administration paradigms: i.v. alcohol self-administration and i.v. alcohol clamp. Each paradigm consisted of 2 counterbalanced sessions of i.v. ghrelin or placebo administration. Repeated blood samples were collected during each session, and peripheral concentrations of the following hormones were measured: leptin, glucagon-like peptide-1, pancreatic polypeptide, gastric inhibitory peptide, insulin, insulin-like growth factor-1, cortisol, prolactin, and aldosterone. RESULTS: Despite some statistical differences, findings were consistent across the 2 alcohol administration paradigms: i.v. ghrelin, compared to placebo, increased blood concentrations of glucagon-like peptide-1, pancreatic polypeptide, cortisol, and prolactin, both acutely and during the whole session. Lower levels of leptin and higher levels of aldosterone were also found during the ghrelin vs placebo session. CONCLUSION: These findings, gathered from a clinically relevant sample of heavy-drinking individuals with alcohol use disorder, provide a deeper insight into the complex interplay between ghrelin and appetitive, metabolic, and stress-related neuroendocrine pathways in the context of alcohol use.

The Effect of Add-on Buprenorphine to Matrix Program in Reduction of Craving and Relapse Among People With Methamphetamine Use Disorder: A Randomized Controlled Trial.

BACKGROUND: Methamphetamine addiction is a global issue. Buprenorphine might have beneficial roles in reducing craving to methamphetamine use via altering neurotransmission signaling and dopaminergic system-related reward mechanisms. PROCEDURES: This clinical trial was performed in 2019 to 2020 in Khorshid Hospital, Isfahan, Iran. The study was conducted on patients with methamphetamine use disorder. The intervention group received sublingual buprenorphine for 8 weeks, and the other group also received placebo tablets. Patients were followed up and visited every month for the next 4 months. Both groups were treated simultaneously by matrix program for 2 months and observed for the next 4 months. Patients filled out the Cocaine Craving Questionnaire-Brief (CCQ-Brief) every week during intervention time (first 2 months) and every month during follow up visits (4 months). The Depression Anxiety Stress Scale (DASS-21) was also filled out before and after interventions for all of the patients. Data were analyzed using SPSS software using χ2, independent t test and repeated-measure analysis of variance tests. RESULTS: Our data indicated significantly lower CCQ-Brief scores in the intervention group compared with the placebo group (P < 0.05). It was also indicated that changes in CCQ-Brief scores were also significant among both groups (P < 0.001). We also showed that the anxiety, depression, and stress scores reduced significantly after interventions (P < 0.001). These scores were also significantly lower in the intervention group compared with placebo group (P < 0.05). CONCLUSIONS: Buprenorphine may be effective and may have positive potential roles in reducing methamphetamine craving. This drug is also helpful in reducing the anxiety, depression, and stress of patients with methamphetamine use disorders.

Effect of intravenous ghrelin administration, combined with alcohol, on circulating metabolome in heavy drinking individuals with alcohol use disorder.

BACKGROUND: Ghrelin may influence several alcohol-related behaviors in animals and humans by modulating central and/or peripheral biological pathways. The aim of this exploratory analysis was to investigate associations between ghrelin administration and the human circulating metabolome during alcohol exposure in nontreatment seeking, heavy drinking individuals with alcohol use disorder (AUD). METHODS: We used serum samples from a randomized, crossover, double-blind, placebo-controlled human laboratory study with intravenous (IV) ghrelin or placebo infusion in two experiments. During each session, participants received a loading dose (3 µg/kg) followed by continuous infusion (16.9 ng/kg/min) of acyl ghrelin or placebo. The first experiment included an IV alcohol self-administration (IV-ASA) session and the second experiment included an IV alcohol clamp (IV-AC) session, both with the counterbalanced infusion of ghrelin or placebo. Serum metabolite profiles were analyzed from repeated blood samples collected during each session. RESULTS: In both experiments, ghrelin infusion was associated with an altered serum metabolite profile, including significantly increased levels of cortisol (IV-ASA q-value = 0.0003 and IV-AC q < 0.0001), corticosterone (IV-ASA q = 0.0202 and IV-AC q < 0.0001), and glycochenodeoxycholic acid (IV-ASA q = 0.0375 and IV-AC q = 0.0013). In the IV-ASA experiment, ghrelin infusion increased levels of cortisone (q = 0.0352) and fatty acids 18:1 (q = 0.0406) and 18:3 (q = 0.0320). Moreover, in the IV-AC experiment, ghrelin infusion significantly increased levels of glycocholic acid (q < 0.0001) and phenylalanine (q = 0.0458). CONCLUSION: IV ghrelin infusion, combined with IV alcohol administration, was associated with increases in the circulating metabolite levels of corticosteroids and glycine-conjugated bile acids, among other changes. Further research is needed to understand the role that metabolomic changes play in the complex interaction between ghrelin and alcohol.

A meta-regression of methodological features that predict the effects of medications on the subjective response to alcohol.

BACKGROUND: Alcohol administration paradigms have been used for early efficacy testing of novel compounds for alcohol use disorder (AUD). There has been an ongoing debate about sample characteristics and methodological features that affect the likelihood of detecting an early efficacy signal for AUD medications. We conducted a meta-regression to test whether the drinking level of the study sample and the peak breath alcohol concentration (BrAC) in the alcohol administration study predict the efficacy of AUD pharmacotherapies on the subjective responses to alcohol. METHODS: We computed the effects of 21 medications on alcohol-induced stimulation, sedation, negative mood, and craving during alcohol administration in 49 studies. RESULTS: Meta-regression analyses indicated a significant and positive effect of pre-study drinks per month on alcohol-induced stimulation (ß = 0.142, p < 0.0001), such that as drinking increases, the benefit of medication over placebo decreases. There was an effect of drinks per month on negative mood (ß = -0.164, p = 0.0248), such that at higher levels of drinks per month, the effects of medications on negative mood are stronger. For sedation, there was an effect of peak BrAC (ß = 0.119, p = 0.0002), such that at low levels of peak BrAC, the effects of medication on sedation were null. For craving, there was a peak BrAC × drinks per month interaction such that at low levels of BrAC, a heavier drinking sample is required to detect the effects of medication on craving. Sensitivity analyses comparing naltrexone studies and non-naltrexone studies suggested that naltrexone was less sensitive to drinks per month across subjective response domains. CONCLUSIONS: These analyses show that design features are critical in studies that test the effects of medications on the subjective responses to alcohol. By specifying the significance and directionality of these effects, as well as the specific points in BrAC or drinks per month at which medication effects are detectable, the study offers recommendations for design features of alcohol administration studies that aim to inform AUD medication development.

Efficacy of Self-Administered Intranasal Oxytocin on Alcohol Use and Craving After Detoxification in Patients With Alcohol Dependence. A Double-Blind Placebo-Controlled Trial.

AIMS: The aim of this study was to assess the efficacy of self-administered intranasal oxytocin on alcohol dependence after detoxification. METHODS: In a double-blind, randomized, placebo-controlled trial, 38 patients fulfilling the criteria for ICD-10 diagnosis of alcohol dependence received either 8 IU oxytocin or placebo at their own discretion up to thrice daily for 4 weeks, after completing detoxification. Primary outcome was alcohol intake specified as the amount of alcohol consumed, the number of days to relapse into alcohol use and the proportion of subjects relapsing. Secondary outcomes were self-reported symptoms of craving, sleep and mental distress. RESULTS: There were no significant differences between the oxytocin group and the placebo group in daily alcohol intake in total (mean 1.3 ± 2.9 vs. 2.0 ± 5.0 units; P = 0.63) or on drinking days (mean 8.4 ± 2.7 vs. 7.7 ± 6.0 units; P = 0.76), in the number of days until relapse (P = 0.91) or in the proportion of subjects relapsing (37.5 vs. 41.2%; P = 0.84). Neither were there any statistically significant differences in any other outcomes, except a larger decrease in self-reported nervousness in the oxytocin group (P = 0.022). CONCLUSION: The results were inconclusive as to whether intranasal oxytocin reduced the time to relapse, degree of craving or total amount of alcohol consumed after detoxification. However, the oxytocin group had a larger decrease in self-reported nervousness.

Effects of Acute Alcohol Consumption on Food Intake and Pictorial Stroop Response to High-Calorie Food Cues.

AIMS: We examined (a) the effect of an acute dose of alcohol on the consumption of energy-dense food and (b) on cognitive bias towards high-energy-dense food cues and (3) whether the effect of an acute dose of alcohol on the consumption of energy-dense food would be mediated by cognitive bias towards high-energy-dense food cues. METHODS: Heavy social drinkers (n = 40) abstained from drinking for 12 hours before testing. On the test day, participants completed pre-challenge measures of alcohol and food craving, and cognitive bias towards alcohol in a placebo-controlled, double-blind design. Participants performed post-challenge measures of alcohol and food craving, ad lib energy-dense food consumption and cognitive bias. RESULTS: We did not observe any of the hypothesized interactions between challenge condition, consumption of energy-dense food and cognitive bias towards high-energy-dense food cues. CONCLUSIONS: Our data suggest that acute alcohol consumption does not influence the consumption of energy-dense food or cognitive bias towards high-energy-dense food cues. These findings may reflect that alcohol does not increase the appetitive value of food and food-related cues or that the measures used in this study were not sensitive to detect an effect. Further research is required to determine whether alcohol at higher doses and/or food cues that are frequently paired with alcohol intake stimulates changes in food intake and the reward value of food cues.

Dorsal and ventral striatum activity in individuals with buying-shopping disorder during cue-exposure: A functional magnetic resonance imaging study.

BACKGROUND AND AIMS: Buying-shopping disorder (BSD) is a clinical condition in which individuals lose control over their buying behaviour and continue buying despite negative consequences such as indebtedness, loss of family and friends. BSD has been considered a behavioural addiction and first studies provide evidence for cue-reactivity and craving as potential pathomechanisms. The current study aimed at investigating neural correlates of cue-reactivity and craving in individuals with BSD using functional magnetic resonance imaging (fMRI). METHODS: A cue-reactivity paradigm comprising individualised shopping-related and control cues was applied in n = 18 individuals diagnosed with BSD and n = 18 gender, age, and handedness matched control participants using fMRI. Outside the scanner, symptoms of BSD and craving reactions towards shopping (before and after the cue-reactivity paradigm) were assessed via questionnaires. FINDINGS: Higher subjective craving reactions towards shopping, prior and after exposure to shopping cues, were observed in individuals with BSD compared to control participants. Consistent with studies in addiction research, we found increased activations in the dorsal striatum for individuals with BSD compared to control participants during exposure to shopping cues. Activity in the ventral striatum was associated with symptoms of BSD in affected individuals, but not in control participants. CONCLUSIONS: Consistent with studies investigating cue-reactivity in substance-use and behavioural addictions, the association between cue-exposure and activities in reward-related brain structures such as the dorsal and ventral striatum in BSD participants may contribute to a neural explanation of why individuals experience irresistible urges to buy and lose control over their behaviour.

Modeling motivation for alcohol in humans using traditional and machine learning approaches.

Given the significant cost of alcohol use disorder (AUD), identifying risk factors for alcohol seeking represents a research priority. Prominent addiction theories emphasize the role of motivation in the alcohol seeking process, which has largely been studied using preclinical models. In order to bridge the gap between preclinical and clinical studies, this study examined predictors of motivation for alcohol self-administration using a novel paradigm. Heavy drinkers (n = 67) completed an alcohol infusion consisting of an alcohol challenge (target breath alcohol = 60 mg%) and a progressive-ratio alcohol self-administration paradigm (maximum breath alcohol 120 mg%; ratio requirements range = 20-3 139 response). Growth curve modeling was used to predict breath alcohol trajectories during alcohol self-administration. K-means clustering was used to identify motivated (n = 41) and unmotivated (n = 26) self-administration trajectories. The data were analyzed using two approaches: a theory-driven test of a-priori predictors and a data-driven, machine learning model. In both approaches, steeper delay discounting, indicating a preference for smaller, sooner rewards, predicted motivated alcohol seeking. The data-driven approach further identified phasic alcohol craving as a predictor of motivated alcohol self-administration. Additional application of this model to AUD translational science and treatment development appear warranted.

Role of orbitofrontal cortex in incubation of oxycodone craving in male rats.

One of the main challenges in treating opioid-use disorders is relapse during abstinence, triggered by re-exposure to drug-associated cues. Previous studies have demonstrated that drug-seeking in rats progressively increases over time during withdrawal (incubation of drug craving). Here, we used male rats and examined neural mechanisms underlying incubation of craving to oxycodone, a commonly abused prescription opioid, and we focused on orbitofrontal cortex (OFC), a brain region previously implicated in incubation of heroin craving. We first used neuronal activity marker Fos and measured neuronal activation in OFC (ventral and lateral OFC) associated with day-1 and day-15 relapse tests. Next, we determined the effect of pharmacological reversible inactivation of OFC on incubated oxycodone seeking on withdrawal day 15. Finally, we determined the effect of reversible inactivation of OFC on nonincubated oxycodone seeking on withdrawal day 1. We found that lever presses during relapse tests were higher on withdrawal day 15 than on withdrawal day 1 (incubation of oxycodone craving). Incubation of oxycodone craving is accompanied with a time-dependent increase of Fos protein expression in both ventral and lateral OFC. Lastly, OFC inactivation decreased oxycodone seeking on withdrawal day 15 but had no effect on withdrawal day 1. Together with the previous heroin study, results here show that OFC plays a critical role in incubation of opioid craving.

5HT-2C agonist lorcaserin decreases cannabis self-administration in daily cannabis smokers.

There are no FDA-approved treatments for cannabis use disorder (CUD). Preclinical research has shown that the 5HT-2C agonist lorcaserin attenuates cue-induced reinstatement of THC seeking and self-administration. The goal of this placebo-controlled, counterbalanced, within-subject human laboratory study was to examine lorcaserin's effects on cannabis intoxication and self-administration. Lorcaserin (10 mg BID) was administered during one of two 13-day inpatient phases and placebo during the other; each phase was separated by ≥7 days of washout. Inpatient phases comprised (1) standardized cannabis administration (7.0% THC) at no financial cost (intoxication), counterbalanced with (2) the option to self-administer cannabis following either 0 or 3 days of abstinence. Cognitive task performance, food intake, subjective ratings of drug effects, objective/subjective sleep measures, and tobacco cigarette use were also assessed. Fifteen normal-weight, daily cannabis users (4F, 11M) not seeking treatment for CUD completed the study. Lorcaserin significantly reduced cannabis self-administration following 0 and 3 days of cannabis abstinence and also reduced craving for cannabis during abstinence. Lorcaserin produced small but significant increases in positive cannabis ratings and body weight relative to placebo. Lorcaserin also reduced tobacco cigarette smoking on days of cannabis administration relative to placebo. During abstinence, subjective but not objective measures of sleep quality worsened during lorcaserin maintenance. Overall, lorcaserin's ability to decrease drug taking and cannabis craving in nontreatment-seeking cannabis users supports further investigation of 5HT-2C agonists as potential pharmacotherapies for CUD.

A role for the endocannabinoid enzymes monoacylglycerol and diacylglycerol lipases in cue-induced cocaine craving following prolonged abstinence.

Following exposure to drugs of abuse, long-term neuroadaptations underlie persistent risk to relapse. Endocannabinoid signaling has been associated with drug-induced neuroadaptations, but the role of lipases that mediate endocannabinoid biosynthesis and metabolism in regulating relapse behaviors following prolonged periods of drug abstinence has not been examined. Here, we investigated how pharmacological manipulation of lipases involved in regulating the expression of the endocannabinoid 2-AG in the nucleus accumbens (NAc) influence cocaine relapse via discrete neuroadaptations. At prolonged abstinence (30 days) from cocaine self-administration, there is an increase in the NAc levels of diacylglycerol lipase (DAGL), the enzyme responsible for the synthesis of the endocannabinoid 2-AG, along with decreased levels of monoacylglycerol lipase (MAGL), which hydrolyzes 2-AG. Since endocannabinoid-mediated behavioral plasticity involves phosphatase dysregulation, we examined the phosphatase calcineurin after 30 days of abstinence and found decreased expression in the NAc, which we demonstrate is regulated through the transcription factor EGR1. Intra-NAc pharmacological manipulation of DAGL and MAGL with inhibitors DO-34 and URB-602, respectively, bidirectionally regulated cue-induced cocaine seeking and altered the phosphostatus of translational initiation factor, eIF2α. Finally, we found that cocaine seeking 30 days after abstinence leads to decreased phosphorylation of eIF2α and reduced expression of its downstream target NPAS4, a protein involved in experience-dependent neuronal plasticity. Together, our findings demonstrate that lipases that regulate 2-AG expression influence transcriptional and translational changes in the NAc related to drug relapse vulnerability.