Stress enhances retrieval of drug-related memories in abstinent heroin addicts

A novel stress-based intervention reduces cigarette use in non-treatment seeking smokers

Tobacco use is the leading cause of preventable mortality worldwide. Since current smoking cessation aids show only modest efficacy, new interventions are needed. Given the evidence that stress is a potent trigger for smoking, the present randomized clinical trial tested whether stress could augment the effects of a memory updating (retrieval-extinction) intervention. Non-treatment seeking smokers (n = 76) were assigned to one of four conditions composed of either a stressful or non-stressful psychosocial challenge followed by either smoking or neutral cues. Ten minutes after this manipulation, all underwent a 60-minute extinction procedure during which they viewed smoking-related videos and images and manipulated smoking paraphernalia. Compared to participants who were not exposed to the laboratory stressor, the stressor-exposed groups exhibited greater psychophysiological responses during their intervention and greater decreases in cigarette use at two- and six-weeks follow-up independent of smoking cue exposure. Together, these findings suggest that the ability of stress to activate cigarette seeking processes can be exploited to decrease cigarette use. With replication, the stress-based intervention could become a novel strategy for decreasing cigarette use in non-treatment seeking smokers.Clinicaltrials.gov identifier: NCT04843969.

The Relationship between Coping and Expressed Emotion in Substance Users

The involvement of family is an integral part of the recovery process, and the use of adaptive coping strategies has an important implication for treatment outcomes. Little research to date has examined the relationship between coping and family dynamics in substance users, although this may help to unravel the mechanism underlining the increased risk of relapse for individuals from critical family environment. The aim of the present research was to assess the association between the level of expressed emotion (LEE) (i.e., criticism), coping style, and psychological distress (i.e., anxiety, depression) in people with substance use disorder (SUD). Compared to control subjects, persons with SUD reported less use of rational coping and detached coping, and perceived greater criticism and irritability from family. A higher degree of family criticism and lack of emotional support was associated with greater use of emotional and avoidance coping in persons with SUD, while psychological distress was more related to rational and detached coping. The present study reveals the unique connection between family relationships, coping and psychological distress, implicating the need to address the influence of family relationships and stress on persons’ coping in SUD treatment.

Consideration of sex as a biological variable in the translation of pharmacotherapy for stress-associated drug seeking

Stress is a frequent precipitant of relapse to drug use. Pharmacotherapies targeting a diverse array of neural systems have been assayed for efficacy in attenuating stress-induced drug-seeking in both rodents and in humans, but none have shown enough evidence of utility to warrant routine use in the clinic. We posit that a critical barrier in effective translation is inattention to sex as a biological variable at all phases of the research process. In this review, we detail the neurobiological systems implicated in stress-induced relapse to cocaine, opioids, methamphetamine, and cannabis, as well as the pharmacotherapies that have been used to target these systems in rodent models, the human laboratory, and in clinical trials. In each of these areas we additionally describe the potential influences of biological sex on outcomes, and how inattention to fundamental sex differences can lead to biases during drug development that contribute to the limited success of large clinical trials. Based on these observations, we determine that of the pharmacotherapies discussed only α₂-adrenergic receptor agonists and oxytocin have a body of research with sufficient consideration of biological sex to warrant further clinical evaluation. Pharmacotherapies that target β-adrenergic receptors, other neuroactive peptides, the hypothalamic-pituitary-adrenal axis, neuroactive steroids, and the endogenous opioid and cannabinoid systems require further assessment in females at the preclinical and human laboratory levels before progression to clinical trials can be recommended.

Associations Among Resilience, Stress, Depression, and Internet Gaming Disorder in Young Adults

Background and Aims: Using gaming to escape emotional difficulty has been suggested to be a candidate mechanism contributing to Internet gaming disorder (IGD). This study evaluated the associations among resilience, perceived stress, depression, and IGD. Methods: A total of 87 participants in an IGD group and 87 participants in a control group were recruited into this study. IGD was diagnosed using the Diagnostic and Statistical Manual of Mental Disorders. Stress levels, resilience, and depression were measured by a self-reported questionnaire. Results: The IGD group had a lower resilience, higher perceived stress, and depression than the control group. Hierarchical regression analysis demonstrated that resilience was associated with IGD when perceived stress was controlled. After depression was controlled, resilience and perceived stress were not associated with IGD. Among the IGD group, those with low resilience had higher depression. Furthermore, discipline was the resilience characteristic associated with IGD. Conclusions: Low resilience was associated with a higher risk of IGD. IGD individuals with low resilience had higher depression. Depression was more associated with IGD than resilience. Depression assessments and stress coping interventions should be provided for individuals with IGD who exhibit low resilience or high stress.

Paraventricular Thalamus Projection Neurons Integrate Cortical and Hypothalamic Signals for Cue-Reward Processing

The paraventricular thalamus (PVT) is an interface for brain reward circuits, with input signals arising from structures, such as prefrontal cortex and hypothalamus, that are broadcast to downstream limbic targets. However, the precise synaptic connectivity, activity, and function of PVT circuitry for reward processing are unclear. Here, using in vivo two-photon calcium imaging, we find that PVT neurons projecting to the nucleus accumbens (PVT-NAc) develop inhibitory responses to reward-predictive cues coding for both cue-reward associative information and behavior. The multiplexed activity in PVT-NAc neurons is directed by opposing activity patterns in prefrontal and lateral hypothalamic afferent axons. Further, we find that prefrontal cue encoding may maintain accurate cue-reward processing, as optogenetic disruption of this encoding induced long-lasting effects on downstream PVT-NAc cue responses and behavioral cue discrimination. Together, these data reveal that PVT-NAc neurons act as an interface for reward processing by integrating relevant inputs to accurately inform reward-seeking behavior.

Prefrontal Neuronal Excitability Maintains Cocaine-Associated Memory During Retrieval

Presentation of drug-associated cues provokes craving and drug seeking, and elimination of these associative memories would facilitate recovery from addiction. Emotionally salient memories are maintained during retrieval, as particular pharmacologic or optogenetic perturbations of memory circuits during retrieval, but not after, can induce long-lasting memory impairments. For example, in rats, inhibition of noradrenergic beta-receptors, which control intrinsic neuronal excitability, in the prelimbic medial prefrontal cortex (PL-mPFC) can cause long-term memory impairments that prevent subsequent cocaine-induced reinstatement. The physiologic mechanisms that allow noradrenergic signaling to maintain drug-associated memories during retrieval, however, are unclear. Here we combine patch-clamp electrophysiology ex vivo and behavioral neuropharmacology in vivo to evaluate the mechanisms that maintain drug-associated memory during retrieval in rats. Consistent with previous studies, we find that cocaine experience increases the intrinsic excitability of pyramidal neurons in PL-mPFC. In addition, we now find that this intrinsic plasticity positively predicts the retrieval of a cocaine-induced conditioned place preference (CPP) memory, suggesting that such plasticity may contribute to drug-associated memory retrieval. In further support of this, we find that pharmacological blockade of a cAMP-dependent signaling cascade, which allows noradrenergic signaling to elevate neuronal excitability, is required for memory maintenance during retrieval. Thus, inhibition of PL-mPFC neuronal excitability during memory retrieval not only leads to long-term deficits in the memory, but this memory deficit provides protection against subsequent cocaine-induced reinstatement. These data reveal that PL-mPFC intrinsic neuronal excitability maintains a cocaine-associated memory during retrieval and suggest a unique mechanism whereby drug-associated memories could be targeted for elimination.

Association between stress pathway gene (CRHR1⧹CRHBP) polymorphisms and heroin dependence

Stress could increase risk of heroin addiction and relapse. Genetic factors that associated with stress may be involved in this process. To explore the relationship between stress pathway gene (CRHR1⧹CRHBP) polymorphisms and heroin dependence, nine tag single nucleotide polymorphisms (CRHR1 rs12953076, rs4458044, rs242924, rs17689966; CRHBP rs1715751, rs3792738, rs32897, rs10062367, rs1875999) of stress related genes were genotyped by TaqMan SNP genotyping assay for 524 heroin-dependent patients who were abstinent and 489 normal controls. The patients were followed up for 5 years to determine whether relapse or not. Life stress was assessed by Perceived Stress Scale (PSS) at baseline and within 12 months just discharged. No differences were found in the frequencies of genotypes and alleles in nine loci of stress pathway genes between case and control groups (p > 0.05), but there were significant discrepancy in perceived stress scores in genotype distributions. Multivariate regression analysis revealed that CRHBP gene polymorphism rs3792738 had interactions with life stress during predicting the risk of heroin relapse. It was concluded that the predictive value of a genetic interaction with the stress axis for the risk of heroin relapse may be useful for future preventive and individualized therapeutic strategies.

Cocaine Seeking During Initial Abstinence Is Driven by Noradrenergic and Serotonergic Signaling in Hippocampus in a Sex-Dependent Manner

There is evidence for sex differences in cocaine addiction from both clinical and preclinical studies. In particular, preclinical studies indicate that females may be more sensitive than males to stress-induced drug seeking. The dorsal hippocampus (DH) is prominently involved in the stress response, as are the locus coeruleus norepinephrine (LC-NE) and dorsal raphe serotonin (DR 5-HT) systems. Moreover, DH receives strong inputs from LC-NE and DR 5-HT neurons. We hypothesized that the stress associated with non-reinforced drug seeking during early abstinence (on extinction day 1 (ED1)) may contribute to drug seeking via β-adrenergic and 5-HT neurotransmission in DH. We observed decreased drug-seeking behavior on ED1 following 10 mg/kg S-propranolol (β-adrenergic and 5-HT1A/1B receptor antagonist), R-propranolol (5-HT1A/1B receptor antagonist), or racemic propranolol in both male and female rats. ED1 increased Fos expression in DH, LC, and DR, and DH Fos was decreased by systemic S-propranolol. Based on these results, we investigated the effects of blocking 5-HT and β-adrenoceptor transmission in DH on drug seeking during ED1 by infusing a cocktail of WAY100635 plus GR127935 (5-HT1A/1B receptor antagonists), betaxolol plus ICI-118 551 (β1 and β2 antagonists), or S-propranolol alone. In males, WAY100635/GR127935 was most effective in reducing drug-seeking on ED1, whereas betaxolol/ICI-118 551 was ineffective. In contrast, S-propranolol was most effective in females in reducing drug seeking on ED1, and WAY100635/GR127935 and betaxolol/ICI-118 551 were each partially effective. Our results indicate that drug seeking during initial abstinence involves 5-HT and β-adrenergic signaling in female DH, but only 5-HT signaling in male DH.

Association of stress coping strategies with Internet addiction in college students: The moderating effect of depression

BACKGROUND

This study examined the association between stress-related coping strategies and Internet addiction and the moderating effect of depression in a sample of Taiwanese college students.

METHOD

A total of 500 college students (238 men and 262 women) participated in this study. Internet addiction was assessed using the Chen Internet Addiction Scale. Participants' stress coping strategies and depressive symptoms were measured using the Coping Orientation to Problems Experienced and the Beck Depression Inventory-II, respectively. We used t and chi-square tests to examine differences in demographic characteristics, depression, and stress coping strategies between participants with and without Internet addiction. Significant variables were used in a logistic regression model to examine the association between stress coping strategies and Internet addiction and the moderating effect of depression on the association.

RESULTS

Results indicated that use of restraint coping was negatively associated with Internet addiction (odds ratio [OR]=0.886, 95% confidence interval [CI]: 0.802-0.977), whereas denial (OR=1.177, 95% CI: 1.029-1.346) and mental disengagement (OR=2.673, 95% CI: 1.499-4.767) were positively associated with Internet addiction. Depression had a moderating effect on the association between denial and Internet addiction (OR=0.701, 95% CI: 0.530-0.927).

CONCLUSIONS

Stress coping strategies and depression are important factors to evaluate when developing intervention programs targeting college undergraduate students with Internet addiction.

Inhibition of hippocampal β-adrenergic receptors impairs retrieval but not reconsolidation of cocaine-associated memory and prevents subsequent reinstatement

Retrieval of drug-associated memories is critical for maintaining addictive behaviors, as presentation of drug-associated cues can elicit drug seeking and relapse. Recently, we and others have demonstrated that β-adrenergic receptor (β-AR) activation is necessary for retrieval using both rat and human memory models. Importantly, blocking retrieval with β-AR antagonists persistently impairs retrieval and provides protection against subsequent reinstatement. However, the neural locus at which β-ARs are required for maintaining retrieval and subsequent reinstatement is unclear. Here, we investigated the necessity of dorsal hippocampus (dHipp) β-ARs for drug-associated memory retrieval. Using a cocaine conditioned place preference (CPP) model, we demonstrate that local dHipp β-AR blockade before a CPP test prevents CPP expression shortly and long after treatment, indicating that dHipp β-AR blockade induces a memory retrieval disruption. Furthermore, this retrieval disruption provides long-lasting protection against cocaine-induced reinstatement. The effects of β-AR blockade were dependent on memory reactivation and were not attributable to reconsolidation disruption as blockade of β-ARs immediately after a CPP test had little effect on subsequent CPP expression. Thus, cocaine-associated memory retrieval is mediated by β-AR activity within the dHipp, and disruption of this activity could prevent cue-induced drug seeking and relapse long after treatment.

Effects of acute combined serotonin and dopamine depletion on cue-induced drinking intention/desire and cognitive function in patients with alcohol dependence

BACKGROUND

Alcohol cues can precipitate the desire to drink and cause relapse in recovering alcohol-dependent patients. Serotonin and dopamine may play a role in alcohol cue-induced craving. Acute combined tryptophan (Trp), tyrosine (Tyr), and phenylalanine (Phe) depletion (CMD) in the diet attenuates the synthesis of serotonin and dopamine in the human brain. However, no study of the effects of acute CMD has been previously conducted. Therefore, we investigated whether the attenuation of serotonin and dopamine synthesis changes cue-induced alcohol craving in recently abstinent alcoholics.

METHODS

In this double-blind, randomized, placebo-controlled, crossover design, 12 male patients who met the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, criteria for alcohol dependence were divided into two conditions: (1) monoamine depletion (i.e., consumption of a concentrated amino acid beverage that resulted in a rapid and significant decrease in plasma-free Tyr/Phe/Trp) and (2) balanced condition (i.e., consumption of a similar beverage that contained Tyr/Phe/Trp). The participants were scheduled for two experimental sessions, with an interval of ≥7 days. The cue-induced craving test session was conducted 6h after each amino acid beverage administration. Drinking urge, blood pressure, heart rate, working memory, and attention/psychomotor performance were assessed before and after administration.

RESULTS

Compared with the balanced condition, the monoamine depletion condition significantly increased drinking intention/desire and diastolic blood pressure. Cognitive performance was not different between the two conditions.

CONCLUSIONS

Acute combined serotonin and dopamine depletion may increase drinking intention/desire and diastolic blood pressure without influencing cognitive function.

Effects of β-adrenergic receptor blockade on drug-related memory reconsolidation in abstinent heroin addicts

RATIONALE AND OBJECTIVE

The reactivation of a consolidated memory can return it to a labile state, a process referred to as reconsolidation. A previous study showed that oral administration of the β-adrenergic receptor antagonist propranolol before memory reactivation in humans erased the behavioral expression of the fear memory 24h later. In this study, we investigated whether propranolol impairs the drug-related memory by disrupting the reconsolidation process in heroin addicts.

METHODS

Seventy abstinent heroin addicts learned a word list (including 10 heroin-related positive words, 10 heroin-related negative words, and 10 neutral words) on day 1. Participants orally administered the β-adrenergic receptor antagonist propranolol or placebo before retrieval of the word list on day 2. Free recall of the word list and other psychological and physical responses were assessed on day 3.

RESULTS

Oral administration of propranolol before reactivation of the word list impaired reconsolidation of drug-related positive and negative but not neutral words in abstinent heroin addicts, and these impairments critically depended on reactivation of the word list.

CONCLUSIONS

This study extends earlier reports that a β-adrenergic receptor antagonist affects the drug-related memory reconsolidation process. Our findings may have important implications for the understanding and treatment of persistent and abnormal drug-related memories in abstinent heroin addicts.

Stress- and cue-elicited craving and reactivity in marijuana-dependent individuals

RATIONALE

Cue-elicited craving and stress responses have been identified as predictors of relapse in drug dependence, but little research exists on the contribution of these factors to marijuana use specifically.

OBJECTIVES

The aims of the present study were to evaluate (1) responses to a psychological stressor, (2) responses to marijuana-related cues, and (3) if an exposure to a psychological stressor augmented craving subsequently elicited by marijuana-related cue exposure in marijuana-dependent individuals.

METHODS

Subjective (craving, stress), neuroendocrine (adrenocorticotropic hormone (ACTH), cortisol), and physiologic responses to the presentation of neutral and marijuana cues were assessed after randomization to a stress (Trier Social Stress Task (TSST)) or non-stress control condition in marijuana-dependent individuals. Outcome measures were assessed at baseline, post-stressor/pre-neutral cue, post-neutral cue, and post-marijuana cue.

RESULTS

Eighty-seven participants completed procedures (stress group, n = 45; non-stress group, n = 42). The stress group had a significant increase over the non-stress group in stress rating (p < 0.001), craving (p = 0.028), cortisol (p < 0.001), and ACTH (p < 0.001) after the completion of the TSST. An increased craving response for all participants was seen following the presentation of the marijuana cues (p = 0.005). Following the TSST or non-stress condition, the non-stress group had an increase in craving to marijuana cues as compared to neutral cues (p = 0.002); an increase in craving was not observed in the stress group (p = 0.404).

CONCLUSIONS

Marijuana cue exposure and a social stressor increased craving in marijuana-dependent individuals. Completion of the TSST did not increase craving response to subsequent marijuana cue exposure.

Inhibition of β-adrenergic receptors induces a persistent deficit in retrieval of a cocaine-associated memory providing protection against reinstatement

Drug-seeking behavior is maintained by encounters with drug-associated cues. Preventing retrieval of drug-associated memories that these cues provoke would therefore limit relapse susceptibility; however, little is known regarding the mechanisms of retrieval. Here, we show that β-adrenergic receptor activation is necessary for the retrieval of a cocaine-associated memory. Using a conditioned place preference (CPP) procedure, rats were conditioned to associate one chamber, but not another, with cocaine. When administered before a CPP trial, propranolol, but not saline, prevented retrieval of a cocaine-associated CPP. In subsequent drug-free trials, rats previously treated with propranolol continued to show a retrieval deficit, as no CPP was evident. This retrieval deficit was long lasting and robust, as the CPP did not re-emerge during a test for spontaneous recovery 14 days later or reinstate following a priming injection of cocaine. Moreover, the peripheral β-adrenergic receptor antagonist sotalol did not affect retrieval. Thus, retrieval of cocaine-associated memories is mediated by norepinephrine acting at central β-adrenergic receptors. Our findings support the use of propranolol, a commonly prescribed β-blocker, as an adjunct to exposure therapy for the treatment of addiction by preventing retrieval of drug-associated memories during and long after treatment, and by providing protection against relapse.