Cocaine addiction: psychology and neurophysiology

The "Vicious Circle of addictive Social Media Use and Mental Health" Model

Social media use (SMU) is a significant part of many people's everyday life. Research around the globe describes an increase of addictive SMU tendencies since the COVID-19 outbreak. The present work combines available findings in the "Vicious Circle of addictive Social Media Use and Mental Health" model to explain how social media (SM) activity can contribute to the development of addictive tendencies, which consequences they have for mental health, and how to prevent them. Following the model, the interplay between the risk factors negative experiences caused by daily hassles and by unexpected global and traumatic events, SMU (dimension "quality"), and SM flow can directly contribute to addictive SMU through the "vicious circle". Time spent on SMU (dimension "quantity"), symptoms of depression and anxiety, and the personality trait narcissism contribute to the circle as moderators. Symptoms of stress, insomnia, and suicide-related outcomes are described as potential consequences of addictive SMU. Based on longitudinal intervention studies, a conscious reduction of SMU time and an increase of physical activity, as well as positive mental health and mindfulness are identified as protective factors that reduce the risk of addictive tendencies. The model contributes to a better understanding of addictive SMU. Implications of the model for future research and praxis, specifically for mental health programs and therapeutic treatment are discussed.

Exploring the association between suicidal thoughts, self-injury, and GLP-1 receptor agonists in weight loss treatments: Insights from pharmacovigilance measures and unmasking analysis

INTRODUCTION

The study addresses concerns about potential psychiatric side effects of Glucagon-like peptide-1 receptor agonists (GLP-1 RA).

AIM

The aim of this work was to analyse adverse drug reports (ADRs) from the Food and Drug Administration Adverse Events Reporting System (FAERS) using metformin and orlistat as comparators.

METHODS

Descriptive and pharmacovigilance disproportionality analyses was performed.

RESULTS

A total of 209,354 ADRs were reported, including 59,300 serious cases. Of those, a total of 5378 psychiatric disorder cases, including 383 'serious' cases related to selected ADRs were registered during 2005-2023. After unmasking, 271 cases where individual GLP-1 RA were implicated showing liraglutide (n = 90; Reported Odds Ratio (ROR) = 1.64), exenatide (n = 67; ROR = 0.80), semaglutide (n = 61; ROR = 2.03), dulaglutide (n = 45; ROR = 0.84), tirzepatide (n = 5; ROR = 1.76) and albiglutide (n = 2; ROR = 0.04). A greater association between these ADRs with metformin was observed, but not orlistat. With regards to selected preferred terms (PTs), 42 deaths including 13 completed suicides were recorded. Suicidal ideation was recorded in n = 236 cases for 6/7 GLP-1 RA (excluding lixisenatide).

DISCUSSION

Suicide/self-injury reports pertaining to semaglutide; tirzepatide; and liraglutide were characterised, although lower than metformin. It is postulated that rapid weight loss achieved with GLP-1 RA can trigger significant emotional, biological, and psychological responses, hence possibly impacting on suicidal and self-injurious ideations.

CONCLUSIONS

With the current pharmacovigilance approach, no causality link between suicidal ideation and use of any GLP-1 RA can be inferred. There is a need for further research and vigilance in GLP-1 RA prescribing, particularly in patients with co-existing psychiatric disorders.

Role of the gut-brain axis in HIV and drug abuse-mediated neuroinflammation

Drug abuse and related disorders are a global public health crisis affecting millions, but to date, limited treatment options are available. Abused drugs include but are not limited to opioids, cocaine, nicotine, methamphetamine, and alcohol. Drug abuse and human immunodeficiency virus-1/acquired immune deficiency syndrome (HIV-1/AIDS) are inextricably linked. Extensive research has been done to understand the effect of prolonged drug use on neuronal signaling networks and gut microbiota. Recently, there has been rising interest in exploring the interactions between the central nervous system and the gut microbiome. This review summarizes the existing research that points toward the potential role of the gut microbiome in the pathogenesis of HIV-1-linked drug abuse and subsequent neuroinflammation and neurodegenerative disorders. Preclinical data about gut dysbiosis as a consequence of drug abuse in the context of HIV-1 has been discussed in detail, along with its implications in various neurodegenerative disorders. Understanding this interplay will help elucidate the etiology and progression of drug abuse-induced neurodegenerative disorders. This will consequently be beneficial in developing possible interventions and therapeutic options for these drug abuse-related disorders.

Molecular pattern of a decrease in the rewarding effect of cocaine after an escalating-dose drug regimen

BACKGROUND

Long-term cocaine exposure leads to dysregulation of the reward system and initiates processes that ultimately weaken its rewarding effects. Here, we studied the influence of an escalating-dose cocaine regimen on drug-associated appetitive behavior after a withdrawal period, along with corresponding molecular changes in plasma and the prefrontal cortex (PFC).

METHODS

We applied a 5 day escalating-dose cocaine regimen in rats. We assessed anxiety-like behavior at the beginning of the withdrawal period in the elevated plus maze (EPM) test. The reinforcement properties of cocaine were evaluated in the Conditioned Place Preference (CPP) test along with ultrasonic vocalization (USV) in the appetitive range in a drug-associated context. We assessed corticosterone, proopiomelanocortin (POMC), β-endorphin, CART 55-102 levels in plasma (by ELISA), along with mRNA levels for D2 dopaminergic receptor (D2R), κ-receptor (KOR), orexin 1 receptor (OX1R), CART 55-102, and potential markers of cocaine abuse: miRNA-124 and miRNA-137 levels in the PFC (by PCR).

RESULTS

Rats subjected to the escalating-dose cocaine binge regimen spent less time in the cocaine-paired compartment, and presented a lower number of appetitive USV episodes. These changes were accompanied by a decrease in corticosterone and CART levels, an increase in POMC and β-endorphin levels in plasma, and an increase in the mRNA for D2R and miRNA-124 levels, but a decrease in the mRNA levels for KOR, OX1R, and CART 55-102 in the PFC.

CONCLUSIONS

The presented data reflect a part of a bigger picture of a multilevel interplay between neurotransmitter systems and neuromodulators underlying processes associated with cocaine abuse.

Are Borderline Personality Disorder Features Differentially Related to Pre-Incarceration Alcohol, Cannabis, Cocaine, and Opioid Dependence Among People Recently Incarcerated in Jail?

Borderline personality disorder (BPD) and substance use disorders (SUDs) commonly co-occur across various settings. However, little research has examined how BPD features relate to specific types of SUDs. This study examined whether BPD features assessed shortly after incarceration were differentially related to symptoms of dependence on alcohol, cannabis, cocaine, and opioids experienced in the 12 months prior to incarceration among 510 people recently incarcerated in jail. Follow-up multigroup analyses evaluated whether gender or race moderated the relation of BPD features to the four SUDs. Using structural equational modeling, the relationships of BPD features were compared to each of the four preincarceration dependence symptoms. BPD features were significantly related to dependence on each of the four substances, but the link between BPD features and cocaine dependence was stronger than BPD's association with alcohol, cannabis, or opioid dependence. These findings generalized across men and women and across White and Black people.

Disrupting reconsolidation by PKA inhibitor in BLA reduces heroin-seeking behavior

Drug abuse is considered a maladaptive pathology of emotional memory and is associated with craving and relapse induced by drug-associated stimuli or drugs. Reconsolidation is an independent memory process with a strict time window followed by the reactivation of drug-associated stimulus depending on the basolateral amygdala (BLA). Pharmacology or behavior treatment that disrupts the reconsolidation can effectively attenuate drug-seeking in addicts. Here, we hypothesized that heroin-memory reconsolidation requires cAMP-dependent protein kinase A (PKA) of BLA based on the fundamental effect of PKA in synaptic plasticity and memory process. After 10 days of acquisition, the rats underwent 11 days of extinction training and then received the intra-BLA infusions of the PKA inhibitor Rp-cAMPS at different time windows with/without a reactivation session. The results show that PKA inhibitor treatment in the reconsolidation time window disrupts the reconsolidation and consequently reduces cue-induced reinstatement, heroin-induced reinstatement, and spontaneous recovery of heroin-seeking behavior in the rats. In contrast, there was no effect on cue-induced reinstatement in the intra-BLA infusion of PKA inhibitor 6 h after reactivation or without reactivation. These data suggest that PKA inhibition disrupts the reconsolidation of heroin-associated memory, reduces subsequent drug seeking, and prevents relapse, which is retrieval-dependent, time-limited, and BLA-dependent.

Emotion recognition in individuals with cocaine use disorder: the role of abstinence length and the social brain network

RATIONALE

Emotion recognition is impaired in drug addiction. However, research examining the effects of cocaine use on emotion recognition yield mixed evidence with contradictory results potentially reflecting varying abstinence durations.

OBJECTIVES

Therefore, we investigated emotion recognition and its neural correlates in individuals with cocaine use disorder (CUD) parsed according to abstinence duration.

METHODS

Emotion recognition performance was compared between current cocaine users (CUD + , n = 28; cocaine-positive urine), short-term abstainers (CUD-ST, n = 23; abstinence < 6 months), long-term abstainers (CUD-LT, n = 20; abstinence ≥ 6 months), and controls (n = 45). A sample subset (n = 73) underwent structural magnetic resonance imaging to quantify regional gray matter volume (GMV) using voxel-based morphometry.

RESULTS

CUD + demonstrated greater difficulty recognizing happiness than CUD-ST and controls, and sadness and fear compared to controls (p < 0.01). For fear, CUD-ST also performed worse than controls (p < 0.01), while no differences emerged between CUD-LT and controls. Whole-brain analysis revealed lower GMV in the bilateral cerebellum in CUD + compared to CUD-LT and controls; a similar pattern was observed in the amygdala (CUD +  < CUD-LT) (p_FWE < 0.01). Collapsed across all participants, poorer recognition for happiness was associated with lower right cerebellar GMV (p_FWE < 0.05).

CONCLUSIONS

Emotion recognition is impaired with current cocaine use, and selective deficits (in fear) may persist with up to 6 months of abstinence. Lower cerebellar GMV may underlie deficits in positive emotion recognition. Interventions targeting emotional-social-cognitive deficits, especially among active users, may enhance treatment success for individuals with CUD.

Responsivity of serotonin transporter knockout rats to short and long access to cocaine: modulation of the glutamate signaling in the nucleus accumbens shell

Background and Purpose

It has been well established that glutamate in the nucleus accumbens (NAc) plays a critical role in the motivation to take drugs of abuse. We have previously demonstrated that rats with ablation of the serotonin transporter (SERT^−/− rats) show increased cocaine intake reminiscent of compulsivity.

Experimental Approach

By comparing SERT^−/− to SERT^+/+ rats, we investigated whether SERT deletion influences glutamate homeostasis under control conditions as well as after short access (ShA: 1 h per session) or long access (LgA: 6 h per session) to cocaine self‐administration. Rats were killed at 24 h after the last self‐administration session for ex vivo molecular analyses of the main determinants of the glutamate system, including transporters (vesicular and glial), receptors (main post‐synaptic subunits of NMDA and AMPA receptors together with the metabotropic subunit mGLUR5), and scaffolding proteins (SAP102, SAP97, and GRIP) in the NAc shell (sNAc)

Key Results

In cocaine‐naive animals, SERT deletion was associated with changes indicative for a reduction in glutamate signalling. ShA and LgA exposure led to a further dysregulation of the glutamatergic synapse.

Conclusion

SERT deletion may render the glutamatergic synapses of the NAc shell more responsive to both ShA and LgA intake of cocaine.

Driving under the influence of drugs: Correlation between blood psychoactive drug concentrations and cognitive impairment. A narrative review taking into account forensic issues

Driving under the influence of alcohol has been shown to increase the risk of involvement in road traffic collisions (RTCs) however, less is known about the effects of illicit drugs, and a clear correlation between drug concentrations and RTC risk is still debated. The goal of this narrative review is to assess the current literature regarding the most detected psychoactive drugs in RTC (ethanol, amphetamines, cannabis, opioids and cocaine), in relation to driving performance. Evidence on impaired driving due to psychoactive substances, forensic issues relating to the assessment of the impact of drugs, blood cut-off values proposed to date as well as scientific basis for proposed legislative limits are discussed. At present there is no unequivocal evidence demonstrating a clear dose/concentration dependent impairment in many substances. Per se and zero tolerance approaches seem to have negative effect on drugged driving fatalities. However, the weight of these approaches needs further investigation.

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Driving under the influence of psychotropic substances has become a widespread phenomenon.

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Only a few substances have been reported to have a clear dose/concentration dependent impairment.

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Statistically significant differences should not be considered as clinically significant per se

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There is wide variability in legislative cut-offs.

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Detection limits seems to be the most public safety-oriented legislative approach.

Psychostimulant Use Disorder, an Unmet Therapeutic Goal: Can Modafinil Narrow the Gap?

The number of individuals affected by psychostimulant use disorder (PSUD) has increased rapidly over the last few decades resulting in economic, emotional, and physical burdens on our society. Further compounding this issue is the current lack of clinically approved medications to treat this disorder. The dopamine transporter (DAT) is a common target of psychostimulant actions related to their use and dependence, and the recent availability of atypical DAT inhibitors as a potential therapeutic option has garnered popularity in this research field. Modafinil (MOD), which is approved for clinical use for the treatment of narcolepsy and sleep disorders, blocks DAT just like commonly abused psychostimulants. However, preclinical and clinical studies have shown that it lacks the addictive properties (in both behavioral and neurochemical studies) associated with other abused DAT inhibitors. Clinical availability of MOD has facilitated its off-label use for several psychiatric disorders related to alteration of brain dopamine (DA) systems, including PSUD. In this review, we highlight clinical and preclinical research on MOD and its R-enantiomer, R-MOD, as potential medications for PSUD. Given the complexity of PSUD, we have also reported the effects of MOD on psychostimulant-induced appearance of several symptoms that could intensify the severity of the disease (i.e., sleep disorders and impairment of cognitive functions), besides the potential therapeutic effects of MOD on PSUD.

The effects of cocaine exposure in adolescence: Behavioural effects and neuroplastic mechanisms in experimental models

Drug addiction is a devastating disorder with a huge economic and social burden for modern society. Although an individual may slip into drug abuse throughout his/her life, adolescents are at higher risk, but, so far, only a few studies have attempted to elucidate the underlying cellular and molecular bases of such vulnerability. Indeed, preclinical evidence indicates that psychostimulants and adolescence interact and contribute to promoting a dysfunctional brain. In this review, we have focused our attention primarily on changes in neuroplasticity brought about by cocaine, taking into account that there is much less evidence from exposure to cocaine in adolescence, compared with that from adults. This review clearly shows that exposure to cocaine during adolescence, acute or chronic, as well as contingent or non‐contingent, confers a vulnerable endophenotype, primarily, by causing changes in neuroplasticity. Given the close relationship between drug abuse and psychiatric disorders, we also discuss the translational implications providing an interpretative framework for clinical studies involving addictive as well as affective or psychotic behaviours.

Interaction between cocaine use and sleep behavior: A comprehensive review of cocaine's disrupting influence on sleep behavior and sleep disruptions influence on reward seeking

Dopamine, orexin (hypocretin), and adenosine systems have dual roles in reward and sleep/arousal suggesting possible mechanisms whereby drugs of abuse may influence both reward and sleep/arousal. While considerable variability exists across studies, drugs of abuse such as cocaine induce an acute sleep loss followed by an immediate recovery pattern that is consistent with a normal response to loss of sleep. Under more chronic cocaine exposure conditions, an abnormal recovery pattern is expressed that includes a retention of sleep disturbance under withdrawal and into abstinence conditions. Conversely, experimentally induced sleep disturbance can increase cocaine seeking. Thus, complementary, sleep-related therapeutic approaches may deserve further consideration along with development of non-human models to better characterize sleep disturbance-reward seeking interactions across drug experience.

Long access to cocaine self-administration dysregulates the glutamate synapse in the nucleus accumbens core of serotonin transporter knockout rats

Background and Purpose

It is well established that the nucleus accumbens and glutamate play a critical role in the motivation to take drugs of abuse. We have previously demonstrated that rats with ablation of the serotonin (5‐HT) transporter (SERT^−/− rats) show increased cocaine intake reminiscent of compulsivity.

Experimental Approach

By comparing SERT^−/− to SERT^+/+ rats, we set out to explore whether SERT deletion influences glutamate neurotransmission under control conditions as well as after short access (1 h/session) or long access (6 h/session) to cocaine self‐administration.

Key Results

Rats were killed at 24 h after the final self‐administration session for ex vivo molecular analyses of the glutamate system (vesicular and glial transporters, post‐synaptic subunits of NMDA and AMPA receptors and their related scaffolding proteins). Such analyses were undertaken in the nucleus accumbens core. In cocaine‐naïve animals, SERT deletion evoked widespread abnormalities in markers of glutamatergic neurotransmission that, overall, indicate a reduction of glutamate signalling. These results suggest that 5‐HT is pivotal for the maintenance of accumbal glutamate homeostasis. We also found that SERT deletion altered glutamate homeostasis mainly after long access, but not short access, to cocaine.

Conclusion and Implications

Our findings reveal that SERT deletion may sensitize the glutamatergic synapses of the nucleus accumbens core to the long access but not short access, intake of cocaine.

LINKED ARTICLES

This article is part of a themed issue on New discoveries and perspectives in mental and pain disorders. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.17/issuetoc

Deconstructing the 'cheque effect': short-term changes in injection drug use after receiving income assistance and associated factors

BACKGROUND AND AIMS

Disbursement of income assistance has been temporally associated with intensified drug use and related harms (coined the 'cheque effect'). However, relationships to injection drug use (IDU) remain understudied. We examined short-term 'cheque effects' and associated factors among people who inject drugs (PWID).

DESIGN

Cross-sectional analysis nested within a cohort study.

SETTING

Montreal, Quebec, Canada.

PARTICIPANTS

PWID receiving income assistance, with no employment income. A total of 613 PWID (median age 41, 83% male) contributed 3269 observations from 2011 to 2017.

MEASUREMENTS AND METHODS

At each cohort visit, an interviewer-administered questionnaire captured retrospective reports of injection-related behaviour during the 2-day periods (i) before and (ii) including/after receiving last month's income assistance payment (number of injections; drugs injected; any receptive syringe-sharing). The relative likelihood (odds) and magnitude (rate) of an increase in injection frequency ('cheque effect') were estimated in relation to social and behavioural factors using logistic and negative binomial regression in a covariate-adjusted two-part model.

FINDINGS

Prevalence of IDU and syringe-sharing were, respectively, 1.80 and 2.50 times higher in the days following versus preceding cheque receipt (P < 0.001). Among people with past-month IDU, most observations showed increased injection frequency (52%) or no change in injection frequency (44%). The likelihood of a 'cheque effect' was positively associated with cocaine injection [versus injection of other substances, odds ratio (OR) = 2.639, 95% confidence interval (CI) = 2.04-3.41], unstable housing (OR = 1.272, 95% CI = 1.03-1.57) and receiving opioid agonist therapy (OR =1.597, 95% CI = 1.27-2.00) during the same month. Magnitude of the 'cheque effect' was positively associated with cocaine injection [rate ratio (RR) = 1.795, 95% CI = 1.43-2.16], unstable housing (RR = 1.198, 95% CI = 1.02-1.38) and frequent injection (RR = 2.938, 95% CI = 2.43-3.44), but inversely associated with opioid agonist therapy (RR = 0.817, 95% CI = 0.68-0.95) and prescription opioid injection (RR = 0.794, 95% CI = 0.66-0.93).

CONCLUSION

Among people who inject drugs in Montreal, Canada, injection drug use and receptive syringe-sharing appear to be more prevalent in the 2 days after versus before receiving income assistance. The odds and rate of individual-level increases in injection frequency appear to be positively associated with cocaine injection (versus injection of other substances) and unstable housing.

Behavioral economics of cocaine self-administration in male and female rats

There are sex differences in the development of cocaine addiction. For example, the time that it takes for women from initial use to addiction is significantly shorter than for men. Thus, understanding why females are more vulnerable to cocaine addiction will provide insights into sex differences in the mechanisms underlying cocaine addiction. This study aimed to determine how cocaine demand intensity and elasticity might differ between sexes. In addition, the impact of estrous cycle and cocaine intake on demand was investigated. Male and female rats were trained to self-administer 0.125 mg of cocaine intravenously under a chained schedule in daily 2-h sessions for 2 weeks, and then, the cocaine demand function was determined with a modified within-session threshold procedure. Following the test, the rats began to self-administer a higher dose of cocaine (0.25 mg) to increase the cocaine intake. The demand function was then similarly determined in the same rats after 2 weeks of cocaine self-administration of the higher dose. No sex differences were found in either demand intensity or elasticity. Neither did the level of cocaine intake have an impact on demand. The demand elasticity, but not intensity, was significantly lower during proestrus/estrus compared with diestrus. These data suggest that the faster transition to cocaine addiction in women cannot be explained by sex differences in the demand for cocaine and such a demand may change during different phases of estrus cycle.

Cocaine Rituals in Club Culture: Intensifying and Controlling Alcohol Intoxication

Clubbing is an important part of the nighttime economy, and cocaine use is, for some young people, an essential part of this clubbing culture. However, the interaction rituals around the use of powder cocaine in this context remain understudied. This study is based on qualitative interviews with young adult recreational cocaine users ( n = 28) and explores how they use cocaine in club settings, in relation to rituals and drinking culture. The analysis identified three main explanations for using cocaine: (a) unity with friends because of shared transgression, (b) the high as a “collective effervescence,” and (c) the possibility to control, extend, and intensify drinking to intoxication. These three explanations illustrate how cocaine rituals were deeply integrated in drinking-to-intoxication rituals, and how the illegality of cocaine use reinforced feelings of unity with friends. In the nighttime economy, cocaine use and its related rituals are used to intensify and control alcohol-fuelled partying.

Sleep time differs among people who co-use cocaine and cannabis compared to people who only use cocaine

OBJECTIVE

People who use cocaine experience numerous sleep problems and often use cannabis to mitigate these problems. However, co-using cocaine and cannabis may result in worse sleep outcomes when compared to using cocaine only. The current study examined group differences in subjective sleep outcomes among people who use cocaine and people who co-use cocaine and cannabis.

METHODS

Participants were 82 individuals with cocaine use disorder who were enrolled in a randomized clinical trial for cocaine treatment. Sleep outcomes, assessed at baseline prior to treatment, were measured with the Saint Mary's Hospital Sleep Questionnaire and included total sleep time, perceived sleep quality, difficulty falling asleep, and daytime alertness. Analysis of covariance and Kruskal-Wallis tests were used to compare sleep outcomes between participants with urine samples that tested positive for both cocaine and cannabis at baseline, those who tested positive for cocaine only, and those who tested negative for all drugs.

RESULTS

Total reported sleep time was highest among those with a drug negative urine, followed by those with a cocaine positive urine and those who tested positive for cocaine and cannabis. There were no differences in perceived sleep quality, difficulty falling asleep, or daytime alertness between groups.

CONCLUSIONS

People who co-use cocaine and cannabis may report reduced sleep time relative to those who only use cocaine. Co-use of cannabis may exacerbate sleep difficulties in people who use cocaine by decreasing total sleep time, although it is important to note that the groups each reported similar sleep quality. Implications for treatment and directions for future research are discussed.

Problematic mobile phone use: Validity and reliability of the Problematic Use of Mobile Phone (PUMP) Scale in a German sample

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The German PUMP scale demonstrated very good reliability and validity and a high test-retest reliability.

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Reasonable stability of the construct “problematic mobile phone use” was shown.

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Problematic mobile phone use is a relevant issue in Germany.

Background

Mobile phones are ubiquitous in everyday life. Scientific studies on the problematic use of mobile phones have given initial indications of negative consequences, such as increased depression and anxiety rates and reduced sleep quality. The Problematic Use of Mobile Phone (PUMP) scale is a well evaluated, 20-item questionnaire, but a German version of the scale is still lacking.

Method

An online sample (n = 723, age 27.8 ± 11.2 years, 25.2% men) completed a German translation of the PUMP scale (PUMP-D). We conducted standard item analyses and calculated internal consistency and retest reliability. An exploratory (EFA) and a confirmatory factor analysis (CFA) were conducted using a random split of the sample, and correlations with the self-estimated time of mobile phone usage and a global self-rating of patterns of problematic use were computed. Additionally, a second sample (n = 256, age 25.0 ± 8.8 years, 34.0% men) completed the paper version of the PUMP-D scale twice to determine the 14-day retest reliability.

Results

The item-total correlations ranged from r = 0.35 (p < 0.001) to r = 0.75 (p < .001). The internal consistency was α = 0.90. The self-estimated time of usage correlated with the total value of the PUMP-D scale at r = 0.50 (p < .001). The EFA resulted in a single factor, which explained 36% of the variance. The CFA of the showed a moderate fit. The two-week retest reliability in the second sample was r_tt = 0.87 (p < .001).

Discussion

The German translation of the PUMP-D demonstrated a single factor structure, good psychometric properties and can be used in further research.

How Resilience Promotes Mental Health of Patients With DSM-5 Substance Use Disorder? The Mediation Roles of Positive Affect, Self-Esteem, and Perceived Social Support

Objectives: The existing studies found that resilience is a salient trait that can significantly affect people's psychological well-being with substance use disorders (SUDs). However, few studies examined how the mechanisms are connected between resilience and mental health among patients with Diagnostic and Statistical Manual of Mental Disorders-fifth edition SUD. This study investigated the mediation effects of positive affect, perceived social support, and self-esteem on the effect of resilience on perceived stress and life satisfaction in SUD patients. Design: A total of 415 patients diagnosed with Diagnostic and Statistical Manual of Mental Disorders-fifth edition SUD from the south of China joined the research. Outcome Measures: The study applied Connor-Davidson Resilience Scale, Positive and Negative Affect Scale, Multidimensional Scale of Perceived Social Support, Rosenberg Self-Esteem Scale, and Satisfaction with Life Scale to measure patients' resilience, positive affect, self-esteem, perceived social support, perceived stress, and life satisfaction. Results: Structural equation model analysis revealed that positive affect and self-esteem partially mediate the relationship between resilience and perceived stress. In contrast, positive affect and perceived social support partially mediate the relationship between resilience and life satisfaction. Conclusion: The findings provide insights for evidence-based substance abuse intervention that positive affect, self-esteem, and perceived social support can conditional the effects of resilience on promoting the mental health of SUD patients.

Taking Rapid and Intermittent Cocaine Infusions Enhances Both Incentive Motivation for the Drug and Cocaine-induced Gene Regulation in Corticostriatal Regions

A goal in addiction research is to distinguish forms of neuroplasticity that are involved in the transition to addiction from those involved in mere drug taking. Animal models of drug self-administration are essential in this context. Here, we compared in male rats two cocaine self-administration procedures that differ in the extent to which they evoke addiction-like behaviours. We measured both incentive motivation for cocaine using progressive ratio procedures, and cocaine-induced c-fos mRNA expression, a marker of neuronal activity. Rats self-administered intravenous cocaine (0.25 mg/kg/infusion) for seven daily 6-hour sessions. One group had intermittent access (IntA; 6 minutes ON, 26 min OFF × 12) to rapid infusions (delivered over 5 s). This models the temporal kinetics of human cocaine use and produces robust addiction-like behaviour. The other group had Long access (LgA) to slower infusions (90 s). This produces high levels of intake without promoting robust addiction-like behaviour. LgA-90 s rats took twice as much cocaine as IntA-5 s rats did, but IntA-5 s rats showed greater incentive motivation for the drug. Following a final self-administration session, we quantified c-fos mRNA expression in corticostriatal regions. Compared to LgA-90 s rats, IntA-5 s rats had more cocaine-induced c-fos mRNA in the orbitofrontal and prelimbic cortices and the caudate-putamen. Thus, a cocaine self-administration procedure (intermittent intake of rapid infusions) that promotes increased incentive motivation for the drug also enhances cocaine-induced gene regulation in corticostriatal regions. This suggests that increased drug-induced recruitment of these regions could contribute to the neural and behavioural plasticity underlying the transition to addiction.

Sex differences in the effect of the FKBP5 inhibitor SAFit2 on anxiety and stress-induced reinstatement following cocaine self-administration

Cocaine use and withdrawal prompt stress system responses. Stress and the negative affective state produced by cocaine withdrawal are major triggers for relapse. FKBP5 is a co-chaperone of the glucocorticoid receptor and regulates HPA axis negative feedback. The role of FKBP5 in cocaine-related behaviors has not been studied. The FKBP5 inhibitor SAFit2 was used to examine the role of FKBP5 in anxiety-like behavior during early cocaine withdrawal and in stress-induced reinstatement following cocaine self-administration in male and female rats. Withdrawal from cocaine self-administration resulted in heightened anxiety-like behavior in female rats, which was significantly attenuated by SAFit2 administration. SAFit2 pretreatment prior to stress-induced reinstatement to cocaine seeking significantly reduced active lever presses of males. In female rats, SAFit2 administration prevented stress-induced reinstatement for rats in metestrus or diestrus, but not proestrus or estrus phases at the time of reinstatement. These data suggest an important role for FKBP5 in stress-related behaviors following cocaine self-administration, particularly in females.

Drug instrumentalization

Psychoactive drugs with addiction potential are widely used by people of virtually all cultures in a non-addictive way. In order to understand this behaviour, its population penetrance, and its persistence, drug instrumentalization was suggested as a driving force for this consumption. Drug instrumentalization theory holds that psychoactive drugs are consumed in a very systematic way in order to make other, non-drug-related behaviours more efficient. Here, we review the evolutionary origin of this behaviour and its psychological mechanisms and explore the neurobiological and neuropharmacological mechanisms underlying them. Instrumentalization goals are discussed, for which an environmentally selective and mental state-dependent consumption of psychoactive drugs can be learned and maintained in a non-addictive way. A small percentage of people who regularly instrumentalize psychoactive drugs make a transition to addiction, which often starts with qualitative and quantitative changes in the instrumentalization goals. As such, addiction is proposed to develop from previously established long-term drug instrumentalization. Thus, preventing and treating drug addiction in an individualized medicine approach may essentially require understanding and supporting personal instrumentalization goals.

Cocaine use is declining among emerging adults in the United States: Trends by college enrollment

BACKGROUND

The difference in cocaine use between student and non-student emerging adults is not well understood, despite the longstanding assumption that college is protective against use.

OBJECTIVE

To describe trends in cocaine use among emerging adults by college enrollment.

METHODS

Using cross-sectional, nationally-representative data from the National Survey on Drug Use and Health (2002-2016), we estimated the prevalence of four cocaine use indicators by year among emerging adults (ages 18-22) and stratified by college enrollment. We tested for linear and quadratic trends over time.

RESULTS

From 2002 to 2016, 11.7% reported lifetime cocaine use, 5.8% reported past 12-month use, 1.7% reported past 30-day use, and 1% had a use disorder in the past 12-months. We observed significant linear decreases in all four use indicators over time (Lifetime: β = -0.20, Past 12-months: β = -0.17, Past 30-days: β = -0.22, Past 12-months disorder: β = -0.37). Students had lower rates of cocaine use than non-students, although prevalence estimates were more similar between groups for past 12-month (Students:5.3%, 95% CI:5.0-5.5; Non-students:6.3%, 95% CI:6.1-6.5) and past 30-day use (Students:1.6%, 95% CI:1.4-1.7; Non-students:1.8%, 95% CI:1.7-1.9) than for lifetime use (Students:9.4%, 95% CI:9.1-9.7; Non-students:13.8%, 95% CI:13.5-14.1).

CONCLUSIONS

Cocaine use has declined among emerging adults since the early 2000s. The college environment appears compensate for early life differences in cocaine use risk between students and non-students, closing the gap between groups for recent indicators of cocaine use. Given the severe health consequences associated with cocaine use, more public health attention to this issue is needed.

Activation of GSK3β induced by recall of cocaine reward memories is dependent on GluN2A/B NMDA receptor signaling

Glycogen synthase kinase-3β (GSK3β) is a critical regulator of the balance between long-term depression and long-term potentiation which is essential for learning and memory. Our previous study demonstrated that GSK3β activity is highly induced during cocaine memory reactivation, and that reconsolidation of cocaine reward memory is attenuated by inhibition of GSK3β. NMDA receptors and protein phosphatase 1 (PP1) are activators of GSK3β. Thus, this study investigated the roles of NMDA receptor subtypes and PP1in the reconsolidation of cocaine contextual reward memory. Cocaine contextual memories were established and evaluated using cocaine conditioned place preference methods. The regulation of GSK3β activity in specific brain areas was assessed by measuring its phosphorylation state using immunoblot assays. Mice underwent cocaine place conditioning for 8 days and were tested for place preference on day 9. Twenty-four hours later, mice were briefly confined to the compartment previous paired with cocaine to reactivate cocaine-associated memories. Administration of the GluN2A- and GluN2B-NMDA receptor antagonists, NVP-AAM077 and ifenprodil, respectively, immediately following recall abrogated an established cocaine place preference, while preventing the activation of GSK3β in the amygdala, nucleus accumbens, and hippocampus during cocaine memory reactivation. PP1 inhibition with okadaic acid also blocked the activation of GSK3β and attenuated a previously established cocaine place preference. These findings suggest that the dephosphorylation of GSK3β that occurred upon activation of cocaine-associated reward memories may be initiated by the activation of PP1 during the induction of NMDA receptor-dependent reconsolidation of cocaine mnemonic traces. Moreover, the importance of NMDA receptors and PP1 in reconsolidation of cocaine memory makes them potential therapeutic targets in treatment of cocaine use disorder and prevention of relapse.

Cholinergic Receptor Blockade in the VTA Attenuates Cue-Induced Cocaine-Seeking and Reverses the Anxiogenic Effects of Forced Abstinence

Drug relapse after periods of abstinence is a common feature of substance abuse. Moreover, anxiety and other mood disorders are often co-morbid with substance abuse. Cholinergic receptors in the ventral tegmental area (VTA) are known to mediate drug-seeking and anxiety-related behavior in rodent models. However, it is unclear if overlapping VTA cholinergic mechanisms mediate drug relapse and anxiety-related behaviors associated with drug abstinence. We examined the effects of VTA cholinergic receptor blockade on cue-induced cocaine seeking and anxiety during cocaine abstinence. Male Sprague-Dawley rats were trained to self-administer intravenous cocaine (~0.5 mg/kg/infusion, FR1 schedule) for 10 days, followed by 14 days of forced abstinence. VTA infusion of the non-selective nicotinic acetylcholine receptor antagonist mecamylamine (0, 10, and 30 μg/side) or the non-selective muscarinic receptor antagonist scopolamine (0, 2.4 and 24 μg /side) significantly decreased cue-induced cocaine seeking. In cocaine naïve rats, VTA mecamylamine or scopolamine also led to dose-dependent increases in open arm time in the elevated plus maze (EPM). In contrast, rats that received I.V. cocaine, compared to received I.V. saline rats, displayed an anxiogenic response on day 14 of abstinence as reflected by decreased open arm time in the EPM. Furthermore, low doses of VTA mecamylamine (10 μg /side) or scopolamine (2.4 μg /side), that did not alter EPM behavior in cocaine naive rats, were sufficient to reverse the anxiogenic effects of cocaine abstinence. Together, these data point to an overlapping role of VTA cholinergic mechanisms to regulate relapse and mood disorder-related responses during cocaine abstinence.

Drug-induced dysphoria is enhanced following prolonged cocaine abstinence and dynamically tracked by nucleus accumbens neurons

Negative reinforcement models postulate that addicts use drugs to alleviate negative affective states (e.g. dysphoria) associated with withdrawal. In a pre-clinical model, rats exhibit negative affect to a normally rewarding tastant when it predicts impending, but delayed cocaine, and nucleus accumbens (NAc) neurons dynamically track this state. Here, we examined the effects of short versus prolonged experimenter-imposed cocaine abstinence on negative affect, cocaine seeking and self-administration. Rats were given 14 saccharin-cocaine sessions; NAc activity and affective responses to the taste (i.e. taste reactivity) were measured during sessions 1 and 14. Next, following 1 or 30 days of abstinence, taste reactivity and cell firing were recorded in a three-phase test session: (1) intraoral saccharin infusions, (2) extinction and (3) cocaine self-administration. Results showed that 30 days of abstinence led to a significant enhancement of aversive responses to the cocaine-paired tastant, accompanied by a dramatic decline in NAc phasic activity during tastant infusion. While extinction behavior did not differ across groups, NAc phasic firing reemerged during drug seeking. Further, when drug was again readily available, greater aversion to the drug-paired tastant before and after abstinence was associated with increased self-administration following prolonged (30-day) abstinence in rats classified as high (not low) aversive. Collectively, these findings show that drug-induced dysphoria is enhanced following prolonged cocaine abstinence and that NAc neural signaling is dynamic, dampening when negative affect is at its highest (phase 1), but transitioning back 'online' during subsequent drug seeking and taking (phases 2 and 3).

Revisiting long-access versus short-access cocaine self-administration in rats: intermittent intake promotes addiction symptoms independent of session length

In rats, continuous cocaine access during long self-administration sessions (6 versus 1-2 hours) promotes the development of behavioral symptoms of addiction. This has led to the assumption that taking large amounts of drug during extended daily bouts is necessary to develop an addiction phenotype. Recent work shows that within-session intermittent access (IntA) to cocaine produces much less drug intake than continuous-access procedures (i.e. long-access sessions) but evokes addiction symptoms more effectively. IntA-sessions are also long, typically lasting 6 hours. It is not known whether IntA-sessions must be extended to promote addiction-relevant changes in drug use over time. Here, we determined the influence of IntA-session length on patterns of cocaine use relevant to addiction. Two groups of male Wistar rats self-administered cocaine (0.25 mg/kg/injection, injected over 5 seconds) during 18 daily IntA-sessions. One group had long 6-hour sessions (Long-IntA), the other group had shorter, 2-hour sessions (Short-IntA). Only Long-IntA rats escalated their cocaine intake over sessions, but both groups developed a burst-like pattern of drug use over time and similar levels of psychomotor sensitization. The two groups also showed robust and similar levels of both responding for cocaine under a progressive ratio schedule of reinforcement and cocaine-induced reinstatement of extinguished drug-seeking behavior. In summary, long IntA-sessions lead to greater cocaine intake than shorter IntA-sessions, but the two conditions are equally effective in evoking the patterns of drug-taking and drug-seeking that define addiction. This suggests that chronic intermittent cocaine use, even during short daily bouts, is sufficient to promote addiction symptoms.

Individual Vulnerability to Stress Is Associated With Increased Demand for Intravenous Heroin Self-administration in Rats

Opioid use is a widespread epidemic, and traumatic stress exposure is a critical risk factor in opioid use and relapse. There is a significant gap in our understanding of how stress contributes to heroin use, and there are limited studies investigating individual differences underlying stress reactivity and subsequent stress-induced heroin self-administration. We hypothesized that greater individual vulnerability to stress would predict higher demand for heroin self-administration in a within-subjects rodent model of stress and heroin use comorbidity. Male rats were exposed to inescapable intermittent swim stress (ISS) and individual biological (corticosterone) or behavioral [open field, social exploration, and forced swim tests (FSTs)] measures were assessed before and after the stress episode. Individual demand for self-administered heroin (0.05 mg/kg/infusion; 12-h sessions) was assessed using a behavioral economics approach followed by extinction and reinstatement tests triggered by stress re-exposure, non-contingent cue presentations, and yohimbine (0, 1.0, or 2.5 mg/kg). We found that behavioral, biological, and a combination of behavioral and biological markers sampled prior to and after the stress episode that occurred weeks before the access to heroin self-administration predicted the magnitude of individual demand for heroin. Non-contingent presentation of cues, that were previously associated with heroin, reinstated heroin seeking in extinction. For the first time, we show that individual biological response to an ecologically relevant stressor in combination with associated behavioral markers can be used to predict subsequent economic demand for heroin.

Increased Cocaine Motivation Is Associated with Degraded Spatial and Temporal Representations in IL-NAc Neurons

Craving for cocaine progressively increases in cocaine users during drug-free periods, contributing to relapse. The projection from the infralimbic cortex to the nucleus accumbens shell (IL-NAc) is thought to inhibit cocaine seeking. However, it is not known whether and how IL-NAc neurons contribute to the increased motivation associated with a drug-free period. We first performed cellular resolution imaging of IL-NAc neurons in rats during a drug-seeking test. This revealed neurons with spatial selectivity within the cocaine-associated context, a decrease in activity around the time of cocaine seeking, and an inverse relationship between cocaine-seeking activity and subsequent cocaine motivation. All these properties were reduced by a drug-free period. Next, we transiently activated this projection, which resulted in reduced drug seeking, regardless of the drug-free period. Taken together, this suggests that altered IL-NAc activity after a drug-free period may enhance cocaine motivation without fundamentally altering the projection's ability to inhibit drug seeking.

Mirtazapine attenuates anxiety- and depression-like behaviors in rats during cocaine withdrawal

BACKGROUND

Anxiety and depression, key symptoms of the cocaine withdrawal syndrome in human addicts, are considered the main factors that precipitate relapse in chronic cocaine addiction. Preclinical studies have found that rodents exposed to different withdrawal periods show an increase in anxiety and depressive-like behavior. Mirtazapine - a tetracyclic medication - is used primarily to treat depression and, sometimes, anxiety. It has also successfully improved withdrawal symptoms in drug-dependent patients.

AIM

This study sought to determine whether chronic dosing of mirtazapine during cocaine withdrawal reduced depression- and anxiety-like behaviors that characterize cocaine withdrawal in animals.

METHODS

Cocaine pre-treated Wistar rats were subjected to a 60-day cocaine withdrawal period during which depression- and anxiety-like behaviors were evaluated in open field tests (OFT), the elevated plus-maze (EPM), the light-dark box test (LDT), the forced swimming test (FST) and spontaneous locomotor activity (SLA).

RESULTS

We found that chronic dosing with different doses of mirtazapine (30 and 60 mg/kg) decreased depression- and anxiety-like behaviors induced by different doses of cocaine (10, 20 and 40 mg/kg) during the 60-day cocaine withdrawal.

INTERPRETATION

Our results suggest that the pharmacological effect of mirtazapine on its target sites of action (α₂-adrenergic and 5-HT_2A and 5-HT₃ receptors) within the brain may improve depression- and anxiety-like behaviors for long periods.

CONCLUSION

Therefore, the findings support the use of mirtazapine as a potentially effective therapy to reduce anxiety and depressive-like behavior during cocaine withdrawal.

Consideration of substance use in compensation and pension examinations of veterans filing PTSD claims

Veterans filing claims that service-induced PTSD impairs them worry that claims examiners may attribute their difficulties to conditions other than PTSD, such as substance use. Substance use commonly co-occurs with PTSD and complicates establishing a PTSD diagnosis because symptoms may be explained by PTSD alone, PTSD-induced substance use, or by a substance use condition independent of PTSD. These alternative explanations of symptoms lead to different conclusions about whether a PTSD diagnosis can be made. How substance use impacts an examiner’s diagnosis of PTSD in a Veteran’s service-connection claim has not been previously studied. In this study, we tested the hypothesis that mention of risky substance use in the Compensation & Pension (C&P) examination would result in a lower likelihood of service-connection award, presumably because substance use reflected an alternative explanation for symptoms. Data were analyzed from 208 Veterans’ C&P examinations, medical records, and confidentially-collected research assessments. In this sample, 165/208 (79%) Veterans’ claims were approved for a mental health condition; 70/83 (84%) with risky substance use mentioned and 95/125 (76%) without risky use mentioned (p = .02). Contrary to the a priori hypothesis, Veterans with risky substance use were more likely to get a service-connection award, even after controlling for baseline PTSD severity and other potential confounds. They had almost twice the odds of receiving any mental health award and 2.4 times greater odds of receiving an award for PTSD specifically. These data contradict assertions of bias against Veterans with risky substance use when their claims are reviewed. The data are more consistent with substance use often being judged as a symptom of PTSD. The more liberal granting of awards is consistent with literature concerning comorbid PTSD and substance use, and with claims procedures that make it more likely that substance use will be attributed to trauma exposure than to other causes.

Activation of 5-HT1B receptors in the Lateral Habenula attenuates the anxiogenic effects of cocaine

Recent work has implicated the Lateral Habenula (LHb) in the production of anxiogenic and aversive states. It is innervated by all the major monoamine neurotransmitter systems and has projections that have been shown to modulate the activity of both dopaminergic and serotonergic brain regions. Cocaine is a stimulant drug of abuse that potentiates neurotransmission in these monoamine systems and recent research suggests that the drug's behavioral effects may be related in part to its actions within the LHb. The present research was therefore devised to test the hypothesis that alterations in serotonin (5-HT) function within the LHb can affect the behavioral response to cocaine. Male rats were fitted with intracranial guide cannula and trained to traverse a straight alleyway once a day for a 1 mg/kg i.v. injection of cocaine. Intra-LHb pretreatment with the 5-HT1B agonist CP 94,253 (0, 0.1, or 0.25 μg/side) attenuated the development of approach/avoidance "retreat" behaviors known to be a consequence of cocaine's dual rewarding (approach) and anxiogenic (avoidance) properties. This effect was reversed by co-administration of a selective 5-HT1B antagonist, NAS-181 (0.1 μg/side), demonstrating drug specificity at the 5-HT1B receptor. These data suggest that 5-HT1B signaling within the LHb contributes to the anxiogenic effects of cocaine.

Trying to make sense of rodents' drug choice behavior

Since the first experimental hint for the existence of "an actual desire or striving for the drug" in nonhuman animals by Sidney Spragg in the late 1930s, much effort has been expended by lab researchers to try to model in a valid manner the key behavioral aspects and signs of addiction in animals, typically in rodents (i.e., mainly rats and, to a lesser extent, mice). Despite much advances, there still remains a lingering doubt about the disordered status of drug use in rodents. This is mainly because drug use occurs in a particular setting where animals have access to a drug for self-administration but without access to other valuable behavioral options that could compete with and divert from drug use. Here I review evidence showing that enriching the drug setting with other behavioral options can dramatically influence the pattern of drug choices in rodents. Overall, access to other options during drug access can divert the vast majority of rats from continued drug use. Only few individuals continue to engage in drug use despite access to and at the expense of other options. However, there exist certain high-risk settings in which virtually all animals are vulnerable to develop a harmful pattern of exclusive drug use that can even become fatal in the long run if not discontinued by an outside intervention. Paradoxically, it appears that the behavioral trait that is hypothesized to uniquely render rodents vulnerable to the latter settings (i.e., a narrow focus on the local, current choice, with no consideration of the global pattern of choice) would also protect most of them from using drugs in other choice settings. I conclude with an attempt to make sense of this peculiar setting-specific behavior and with some general propositions for future research.

Food addiction: a valid concept?

Can food be addictive? What does it mean to be a food addict? Do common underlying neurobiological mechanisms contribute to drug and food addiction? These vexing questions have been the subject of considerable interest and debate in recent years, driven in large part by the major health concerns associated with dramatically increasing body weights and rates of obesity in the United States, Europe, and other regions with developed economies. No clear consensus has yet emerged on the validity of the concept of food addiction and whether some individuals who struggle to control their food intake can be considered food addicts. Some, including Fletcher, have argued that the concept of food addiction is unsupported, as many of the defining features of drug addiction are not seen in the context of feeding behaviors. Others, Kenny included, have argued that food and drug addiction share similar features that may reflect common underlying neural mechanisms. Here, Fletcher and Kenny argue the merits of these opposing positions on the concept of food addiction.

Compulsive sucrose- and cocaine-seeking behaviors in male and female Wistar rats

RATIONALE

Compulsive cocaine use is a key feature of cocaine addiction and understanding the factors that promote the development of such a behavior will provide important insights into the mechanism of cocaine addiction and is essential for the clinical management of the disorder.

OBJECTIVES

This study aimed to determine how the preexisting compulsive reward-seeking behavior is related to the development of compulsive cocaine-seeking behavior in male and female rats and the potential impact of the reward value and estrous cycle on such behaviors.

METHODS

Adult male and female Wistar rats were first trained to self-administer sucrose pellets under a chained schedule, and then, the intensity-response effects of footshock punishment on sucrose SA reinforced by different values of sucrose were measured. Subsequently, the same rats went on to self-administer intravenous cocaine and the punishment intensity-response effects on cocaine SA reinforced by different doses of cocaine were similarly determined. For the female rats, the measurements were made during different phases of the estrous cycle.

RESULTS

The rats showed a wide range of levels of the compulsive behaviors despite the similar training history. Surprisingly, the compulsive sucrose-seeking behavior did not predict the compulsive cocaine-seeking behavior in either sex. Increasing cocaine dose significantly increased the compulsive cocaine-seeking behavior in the female but not male rats. Estrous cycle did not have impact on the compulsive behaviors.

CONCLUSION

Preexisting differences in compulsive sucrose-seeking behavior do not predict compulsive cocaine-seeking behavior. Compulsive cocaine-seeking behavior is influenced by cocaine dose but not estrous cycle in the female rats.

Substance use outcomes for mindfulness based relapse prevention are partially mediated by reductions in stress: Results from a randomized trial

OBJECTIVE

Mindfulness based relapse prevention (MBRP) has demonstrated efficacy in alleviating substance use, stress, and craving but how MBRP works for marginalized young adults has not been investigated. The current study used a novel rolling group format for MBRP as an additional intervention for young adults in residential treatment. We tested the hypothesis that MBRP (plus Treatment as usual (TAU)) would reduce stress, craving, and substance use among young adults in residential treatment relative to treatment-as-usual plus 12-step/self-help meetings (TAU only). Further, we examined whether reduced stress during treatment was a potential mechanism of change operating in MBRP.

METHOD

Seventy-nine young adults (M_age = 25.3,SD = 2.7;35 % female) were randomly assigned to MBRP (n = 44) or TAU (n = 35). Follow-up assessments were conducted bi-monthly for self-reported measures of stress, craving, and substance use.

RESULTS

At treatment completion young adults receiving MBRP had lower substance use (d = -0.58, [-0.91, -0.26]), craving (d = -0.58, [-1.0, -0.14]), and stress (d = -0.77 [-1.2, -0.30]) relative to TAU condition. Reduced stress during treatment partially mediated observed outcome differences between MBRP and TAU for substance use (β_indirect = -0.45 [-0.79, -0.11]).

CONCLUSIONS

Results suggest that MBRP is a useful and appropriate intervention for marginalized young adults. Further, our results suggest that the effects of MBRP on long-term substance use outcomes may be partially explained by reduced stress.

Incubation of Accumbal Neuronal Reactivity to Cocaine Cues During Abstinence Predicts Individual Vulnerability to Relapse

An important goal for the treatment of cocaine addiction is to identify neuromarkers that can predict individual vulnerability to relapse after abstinence. There is some evidence that individual reactivity to cue-induced craving may predict subsequent relapse after a period of abstinence. Here we sought to identify the neuronal correlates of this predictive relationship in rats. Rats were trained to self-administer cocaine (6 h) for 16 days to induce escalation of cocaine intake. Then rats underwent a 1-month period of forced abstinence after which they were re-exposed to cocaine self-administration (6 h) for 8 additional days to induce re-escalation of cocaine intake. We recorded nucleus accumbens (NAc) neuronal responses to drug conditioned stimuli (CS) 1 day before and after 1 month of abstinence from cocaine intake escalation. Rats were ranked according to their individual percentage of CS responsive neurons recorded during the last day of abstinence and split by the median into two groups. We found evidence for a robust, incubation-like increase in NAc reactivity to cocaine cues after abstinence only in a subset of individuals (High CS rats). Importantly, compared with other rats that did not present an incubation of NAc reactivity to cocaine cues (Low CS rats), High CS rats were faster to re-escalate their intake of cocaine after abstinence. In addition, after re-escalation, they worked harder and were less sensitive to risk of punishment than Low CS rats, indicating a strengthened motivation to seek and/or take the drug in that group of rats. Overall, these findings indicate that incubation of NAc neuronal reactivity to cocaine cues during abstinence may constitute a predictive neuromarker for individual vulnerability to relapse.

Past 15-year trends in lifetime cocaine use among US high school students

BACKGROUND

Most recent research on adolescent drug use has focused on alcohol, tobacco, and marijuana. Less is known about the recent epidemiology of adolescent cocaine use, which has serious health consequences.

PURPOSE

To describe recent trends in cocaine use by U.S. high school students, and identify differences in lifetime and repeated use across sex and racial/ethnic groups.

METHODS

We used data from the national Youth Risk Behavior Surveys (YRBS) from 1999 to 2015. We estimated the prevalence of lifetime cocaine use (LCU) and repeated lifetime cocaine use (RLCU) across years by race/ethnicity and sex and tested for linear and quadratic trends.

RESULTS

The prevalence of LCU decreased from 1999 to 2015 (9.54%-5.19%). RLCU also decreased (5.13%-2.84%). Despite the overall decline, LCU and RLCU both rose between 2009-2015 (LCU:2.78%-5.19%, RLCU:1.58%-2.84%). Boys had higher rates of LCU and RLCU than girls (LCU:6.42% vs 4.65%; RLCU:3.69% vs 2.18%). American Indian/Alaskan Native, Native Hawaiian/Pacific Islander, and Hispanic adolescents had the highest overall prevalence of LCU. Black adolescents' LCU patterns differed from other racial/ethnic groups. The prevalence of LCU among Black boys increased over time, while the prevalence for Black girls remained consistently low.

CONCLUSIONS

Adolescent cocaine use is less common today than in the 1990s. However, rates of adolescent cocaine use have risen across all racial/ethnic groups in the past few years. Public health efforts should address at risk groups with particularly high or rising rates of cocaine use.

Correlation between Blood and Oral Fluid Psychoactive Drug Concentrations and Cognitive Impairment in Driving under the Influence of Drugs

BACKGROUND

The effects of drugs on driving performance should be checked with drug concentration in the brain and at the same time with the evaluation of both the behavioural and neurophysiological effects. The best accessible indicator of this information is the concentration of the drug and/or metabolites in blood and, to a certain extent, oral fluid. We sought to review international studies on correlation between blood and oral fluid drug concentrations, neurological correlates and cognitive impairment in driving under the influence of drugs.

METHODS

Relevant scientific articles were identified from PubMed, Cochrane Central, Scopus, Web of Science, Science Direct, EMBASE up to April 2017.

RESULTS

Up to 2010, no epidemiological studies were available on this matter and International scientists suggested that even minimal amounts of parent drugs in blood and oral fluid could affect driving impairment. More recently, epidemiological data, systematic reviews and meta-analysis on drugged drivers allowed the suggestion of impairment concentration limits for the most common illicit drugs. These values were obtained comparing driving disability induced by psychotropic drugs with that of established blood alcohol limits. Differently from ethyl alcohol where both detection methods and concentration limits have been well established even with inhomogeneity of ranges within different countries, in case of drugs of abuse no official cut-offs have yet been established, nor any standardized analytical protocols.

CONCLUSION

Multiple aspects of driving performance can be differently affected by illicit drugs, and even if for few of them some dose/concentration dependent impairment has been reported, a wider knowledge on concentration/impairment relationship is still missing.

Cocaine Self-Administration Produces Long-Lasting Alterations in Dopamine Transporter Responses to Cocaine

Cocaine addiction is a debilitating neuropsychiatric disorder characterized by uncontrolled cocaine intake, which is thought to be driven, at least in part, by cocaine-induced deficits in dopamine system function. A decreased ability of cocaine to elevate dopamine levels has been repeatedly observed as a consequence of cocaine use in humans, and preclinical work has highlighted tolerance to cocaine's effects as a primary determinant in the development of aberrant cocaine taking behaviors. Here we determined that cocaine self-administration in rats produced tolerance to the dopamine transporter-inhibiting effects of cocaine in the nucleus accumbens core, which was normalized following a 14 or 60 d abstinence period; however, although these rats appeared to be similar to controls, a single self-administered infusion of cocaine at the end of abstinence, even after 60 d, fully reinstated tolerance to cocaine's effects. A single cocaine infusion in a naive rat had no effect on cocaine potency, demonstrating that cocaine self-administration leaves the dopamine transporter in a "primed" state, which allows for cocaine-induced plasticity to be reinstated by a subthreshold cocaine exposure. Further, reinstatement of cocaine tolerance was accompanied by decreased cocaine-induced locomotion and escalated cocaine intake despite extended abstinence from cocaine. These data demonstrate that cocaine leaves a long-lasting imprint on the dopamine system that is activated by re-exposure to cocaine. Further, these results provide a potential mechanism for severe cocaine binge episodes, which occur even after sustained abstinence from cocaine, and suggest that treatments aimed at transporter sites may be efficacious in promoting binge termination following relapse.

SIGNIFICANCE STATEMENT

Tolerance is a DSM-V criterion for substance abuse disorders. Abusers consistently show reduced subjective effects of cocaine concomitant with reduced effects of cocaine at its main site of action, the dopamine transporter (DAT). Preclinical literature has shown that reduced cocaine potency at the DAT increases cocaine taking, highlighting the key role of tolerance in addiction. Addiction is characterized by cycles of abstinence, often for many months, followed by relapse, making it important to determine possible interactions between abstinence and subsequent drug re-exposure. Using a rodent model of cocaine abuse, we found long-lasting, possibly permanent, cocaine-induced alterations to the DAT, whereby cocaine tolerance is reinstated by minimal drug exposure, even after recovery of DAT function over prolonged abstinence periods.

Attenuation of the anxiogenic effects of cocaine by 5-HT1B autoreceptor stimulation in the bed nucleus of the stria terminalis of rats

RATIONALE

Cocaine produces significant aversive/anxiogenic actions whose underlying neurobiology remains unclear. A possible substrate contributing to these actions is the serotonergic (5-HT) pathway projecting from the dorsal raphé (DRN) to regions of the extended amygdala, including the bed nucleus of the stria terminalis (BNST) which have been implicated in the production of anxiogenic states.

OBJECTIVES

The present study examined the contribution of 5-HT signaling within the BNST to the anxiogenic effects of cocaine as measured in a runway model of drug self-administration.

METHODS

Male Sprague-Dawley rats were fitted with bilateral infusion cannula aimed at the BNST and then trained to traverse a straight alley once a day for a single 1 mg/kg i.v. cocaine infusion delivered upon goal-box entry on each of 16 consecutive days/trials. Intracranial infusions of CP 94,253 (0, 0.25, 0.5, or 1.0 μg/side) were administered to inhibit local 5-HT release via activation of 5-HT_1B autoreceptors. To confirm receptor specificity, the effects of this treatment were then challenged by co-administration of the selective 5-HT_1B antagonist NAS-181.

RESULTS

Intra-BNST infusions of the 5-HT_1B autoreceptor agonist attenuated the anxiogenic effects of cocaine as reflected by a decrease in runway approach-avoidance conflict behavior. This effect was reversed by the 5-HT_1B antagonist. Neither start latencies (a measure of the subject's motivation to seek cocaine) nor spontaneous locomotor activity (an index of motoric capacity) were altered by either treatment.

CONCLUSIONS

Inhibition of 5-HT_1B signaling within the BNST selectively attenuated the anxiogenic effects of cocaine, while leaving unaffected the positive incentive properties of the drug.

CRF1 receptor-deficiency increases cocaine reward

Stimulant drugs produce reward but also activate stress-responsive systems. The corticotropin-releasing factor (CRF) and the related hypothalamus-pituitary-adrenal (HPA) axis stress-responsive systems are activated by stimulant drugs. However, their role in stimulant drug-induced reward remains poorly understood. Herein, we report that CRF₁ receptor-deficient (CRF₁-/-), but not wild-type, mice show conditioned place preference (CPP) responses to a relatively low cocaine dose (5 mg/kg, i.p.). Conversely, wild-type, but not CRF₁-/-, mice display CPP responses to a relatively high cocaine dose (20 mg/kg, i.p.), indicating that CRF₁ receptor-deficiency alters the rewarding effects of cocaine. Acute pharmacological antagonism of the CRF₁ receptor by antalarmin also eliminates cocaine reward. Nevertheless, CRF₁-/- mice display higher stereotypy responses to cocaine than wild-type mice. Despite the very low plasma corticosterone concentration, CRF₁-/- mice show higher nuclear glucocorticoid receptor (GR) levels in the brain region of the hippocampus than wild-type mice. Full rescue of wild-type-like corticosterone and GR circadian rhythm and level in CRF₁-/- mice by exogenous corticosterone does not affect CRF₁ receptor-dependent cocaine reward but induces stereotypy responses to cocaine. These results indicate a critical role for the CRF₁ receptor in cocaine reward, independently of the closely related HPA axis activity.

Ibudilast attenuates expression of behavioral sensitization to cocaine in male and female rats

There are no FDA-approved pharmacotherapies for cocaine use disorder, indicating a need to identify novel reagents with therapeutic potential. Ibudilast is an anti-inflammatory glial attenuator and non-selective phosphodiesterase inhibitor currently undergoing clinical evaluations for methamphetamine, opiate, and alcohol abuse disorders. We previously showed that twice daily (b.i.d.) ibudilast reduces the development of methamphetamine sensitization in male mice. However, nothing is known about the ability of ibudilast to modulate the expression of sensitization that occurs after drug re-exposure during abstinence, effects on cocaine-mediated behaviors, or potentially sexually dimorphic effects. Male and female rats were administered cocaine for 7 days and expression of sensitization was assessed by cocaine challenge after 21 days abstinence. On test days, 15 mg/kg i. p. cocaine was evaluated, whereas 30 mg/kg was administered on intervening days. Lower test doses avoid competition of non-motor behaviors with locomotion. In all measures where sensitization was expressed, ibudilast (7.5 and 10 mg/kg, i. p., b. i.d. for 3 days and once on test day) reversed this behavior to levels seen after acute exposure, but not below. There were some intriguing sexually dimorphic effects that were not a function of estrous cycle. Specifically, distance travelled in the center of the test arena and rearing only sensitized in male rats, and ibudilast reversed these behaviors to levels seen after acute cocaine exposure. In females, center distance travelled was reduced below acute cocaine levels by 7.5 mg/kg ibudilast. Increased distance travelled in the center versus periphery is thought to model anxiolytic-like behavior due to increased predation risk. Taken together, these data suggest that the clinical evaluation of ibudilast could be extended to cocaine use disorder.

One month of cocaine abstinence potentiates rapid dopamine signaling in the nucleus accumbens core

Cocaine addiction is a chronic relapsing disorder that is difficult to treat in part because addicts relapse even after extended periods of abstinence. Given the importance of the mesolimbic dopamine (DA) system in drug addiction, we sought to characterize cocaine abstinence induced changes in rapid DA signaling in the nucleus accumbens (NAc). Here, rats were trained to self-administer cocaine for 14 consecutive days, then divided into two groups. Day 1 rats (D1; n = 7) underwent 24 h of abstinence; Day 30 rats (D30; n = 7) underwent one month of abstinence. After abstinence, all rats underwent a single extinction session. Immediately after, rats were deeply anesthetized and fast scan cyclic voltammetry (FSCV) was used to measure DA release and uptake dynamics in the NAc core before and following a single cocaine injection. We show that one month of cocaine abstinence potentiates the peak concentration of electrically evoked DA in the NAc core following an acute injection of cocaine. This potentiation is not related to alterations in DA uptake parameters, which are unchanged following abstinence, but may reflect alterations in release. These results further support the abundance of literature showing that cocaine abstinence induces neuroplasticity in brain areas implicated in drug reward and relapse. The present findings also demonstrate critical differences between abstinence-induced neuroadaptations in DA signaling and those caused by drug exposure itself.

Cocaine-Mediated Autophagy in Astrocytes Involves Sigma 1 Receptor, PI3K, mTOR, Atg5/7, Beclin-1 and Induces Type II Programed Cell Death

Cocaine, a commonly used drug of abuse, has been shown to cause neuropathological dysfunction and damage in the human brain. However, the role of autophagy in this process is not defined. Autophagy, generally protective in nature, can also be destructive leading to autophagic cell death. This study was designed to investigate whether cocaine induces autophagy in the cells of CNS origin. We employed astrocyte, the most abundant cell in the CNS, to define the effects of cocaine on autophagy. We measured levels of the autophagic marker protein LC3II in SVGA astrocytes after exposure with cocaine. The results showed that cocaine caused an increase in LC3II level in a dose- and time-dependent manner, with the peak observed at 1 mM cocaine after 6-h exposure. This result was also confirmed by detecting LC3II in SVGA astrocytes using confocal microscopy and transmission electron microscopy. Next, we sought to explore the mechanism by which cocaine induces the autophagic response. We found that cocaine-induced autophagy was mediated by sigma 1 receptor, and autophagy signaling proteins p-mTOR, Atg5, Atg7, and p-Bcl-2/Beclin-1 were also involved, and this was confirmed by using selective inhibitors and small interfering RNAs (siRNAs). In addition, we found that chronic treatment with cocaine resulted in cell death, which is caspase-3 independent and can be ameliorated by autophagy inhibitor. Therefore, this study demonstrated that cocaine induces autophagy in astrocytes and is associated with autophagic cell death.

The effects of social contact on cocaine intake under extended-access conditions in male rats

Social learning theories of drug use propose that drug use is influenced by the behavior of peers. We previously reported that cocaine self-administration under limited-access conditions can be either facilitated or inhibited by social contact, depending on the behavior of a peer. The purpose of this study was to determine whether social contact influences cocaine self-administration under conditions that are more representative of problematic patterns of drug use. Male rats were assigned to either isolated or pair-housed conditions in which a social partner either had access to cocaine or did not have access to cocaine. Pair-housed rats were tested in custom-built operant conditioning chambers that allowed both rats to be tested simultaneously in the same chamber. In Experiment 1, rats were tested for 14 consecutive days during daily 6-hr test sessions. In Experiment 2, different doses of cocaine were tested in 23-hr test sessions conducted every 3 days. All groups of rats escalated their cocaine intake in Experiment 1; however, pair-housed rats with a partner without access to cocaine had lower levels of intake throughout the 14 days of testing. In Experiment 2, pair-housed rats with a partner without access to cocaine had lower levels of cocaine intake than did rats with a partner with access to cocaine, and this effect was observed at all doses of cocaine tested. These data indicate that the behavior of a social partner (i.e., whether or not that partner is also self-administering cocaine) influences cocaine self-administration under conditions that model problematic patterns of drug use. (PsycINFO Database Record

Attenuated neural response to emotional cues in cocaine-dependence: a preliminary analysis of gender differences

BACKGROUND

Cocaine users often report a loss of arousal for nondrug-related stimuli, which may contribute to their response to drug-related rewards. However, little is known about users' neural reactivity to emotional nondrug-related stimuli and the potential influence of gender.

OBJECTIVES

Test the hypotheses that cocaine-dependent individuals have an attenuated neural response to arousing stimuli relative to controls and that this difference is amplified in women.

METHODS

The brain response to typically arousing positive and negative images as well as neutral images from the International Affective Picture System was measured in 40 individuals (20 non-treatment seeking cocaine-dependent and 20 age- and gender-matched control participants; 50% of whom were women). Images were displayed for 4 s each in blocks of five across two 270-second runs. General linear models assessed within and between group activation differences for the emotional images.

RESULTS

Cocaine-dependent individuals had a significantly lower response to typically arousing positive and negative images than controls, with attenuated neural activity present in the medial prefrontal cortex (mPFC) and anterior cingulate cortex (ACC). Analyses by gender revealed less mPFC/ACC activation among female users, but not males, for both positive and negative images.

CONCLUSION

The dampened neural response to typically arousing stimuli among cocaine-dependent polydrug users suggests decreased salience processing for nondrug stimuli, particularly among female users. This decreased responding is consistent with data from other substance using populations and suggests that this may be a general feature of addiction. Amplifying the neural response to naturally arousing nondrug-related reinforcers may present an opportunity for unique behavioral and brain stimulation therapies.