Craving predicts use during treatment for methamphetamine dependence: a prospective, repeated-measures, within-subject analysis

Addiction and treatment experiences among active methamphetamine users recruited from a township community in Cape Town, South Africa: A mixed-methods study

BACKGROUND

Since 2000, there has been a dramatic increase in methamphetamine use in South Africa, but little is known about the experiences of out-of-treatment users. This mixed-methods study describes the substance use histories, addiction symptoms, and treatment experiences of a community-recruited sample of methamphetamine users in Cape Town.

METHODS

Using respondent driven sampling, 360 methamphetamine users (44% female) completed structured clinical interviews to assess substance abuse and treatment history and computerized surveys to assess drug-related risks. A sub-sample of 30 participants completed in-depth interviews to qualitatively explore experiences with methamphetamine use and drug treatment.

RESULTS

Participants had used methamphetamine for an average of 7.06 years (SD=3.64). They reported using methamphetamine on an average of 23.49 of the past 30 days (SD=8.90); 60% used daily. The majority (90%) met ICD-10 criteria for dependence, and many reported severe social, financial, and legal consequences. While only 10% had ever received drug treatment, 90% reported that they wanted treatment. In the qualitative interviews, participants reported multiple barriers to treatment, including beliefs that treatment is ineffective and relapse is inevitable in their social context. They also identified important motivators, including desires to be drug free and improve family functioning.

CONCLUSION

This study yields valuable information to more effectively respond to emerging methamphetamine epidemics in South Africa and other low- and middle-income countries. Interventions to increase uptake of evidence-based services must actively seek out drug users and build motivation for treatment, and offer continuing care services to prevent relapse. Community education campaigns are also needed.

Assessing craving and its relationship to subsequent prescription opioid use among treatment-seeking prescription opioid dependent patients

BACKGROUND

Craving is viewed as a core feature of substance use disorders and has been shown to predict future drug use, particularly over the short term. Accordingly, craving is often assessed in treatment settings as a marker of risk for subsequent drug use. The identification of the briefest measure that maintains predictive validity is of particular value for both clinical and research settings to minimize assessment burden while maintaining utility for the prediction of use.

METHODS

Data from a multi-site clinical trial of treatment for prescription opioid dependence were examined to evaluate whether a brief, 3-item craving scale administered each week predicted urine-confirmed self report of prescription opioid use in the subsequent week. Logistic regression models examining the association between craving and presence or absence of opioid use in the following week were conducted, controlling for opioid use in the previous week, treatment condition, and lifetime history of heroin use.

RESULTS

Greater craving was associated with a higher odds of prescription opioid use in the following week. For each one-unit increase on this 10-point scale, the odds of using opioids in the subsequent week was 17% higher. In addition to an item assessing urges, items assessing cue-induced craving and perceived likelihood of relapse in an environment where drugs were previously used contributed uniquely to this association.

CONCLUSIONS

A brief measure of prescription opioid craving predicted prescription opioid use among individuals in treatment. This measure offers an efficient strategy to inform the assessment of risk for use in this population.

Methamphetamine: an update on epidemiology, pharmacology, clinical phenomenology, and treatment literature

BACKGROUND

Despite initial reports of a decline in use in the early 2000s, methamphetamine remains a significant public health concern with known neurotoxic and neurocognitive effects to the user. The goal of this review is to update the literature on methamphetamine use and addiction since its assent to peak popularity in 1990s.

METHODS

We first review recent epidemiological reports with a focus on methamphetamine accessibility, changes in use and disorder prevalence rates over time, and accurate estimates of the associated burden of care to the individual and society. Second, we review methamphetamine pharmacology literature with emphasis on the structural and functional neurotoxic effects associated with repeated use of the drug. Third, we briefly outline the findings on methamphetamine-related neurocognitive deficits as assessed via behavioral and neuroimaging paradigms. Lastly, we review the clinical presentation of methamphetamine addiction and the evidence supporting the available psychosocial and pharmacological treatments within the context of an addiction biology framework.

CONCLUSION

Taken together, this review provides a broad-based update of the available literature covering methamphetamine research over the past two decades and concludes with recommendations for future research.

Retrieval-induced NMDA receptor-dependent Arc expression in two models of cocaine-cue memory

The association of environmental cues with drugs of abuse results in persistent drug-cue memories. These memories contribute significantly to relapse among addicts. While conditioned place preference (CPP) is a well-established paradigm frequently used to examine the modulation of drug-cue memories, very few studies have used the non-preference-based model conditioned activity (CA) for this purpose. Here, we used both experimental approaches to investigate the neural substrates of cocaine-cue memories. First, we directly compared, in a consistent setting, the involvement of cortical and subcortical brain regions in cocaine-cue memory retrieval by quantifying activity-regulated cytoskeletal-associated (Arc) protein expression in both the CPP and CA models. Second, because NMDA receptor activation is required for Arc expression, we investigated the NMDA receptor dependency of memory persistence using the CA model. In both the CPP and CA models, drug-paired animals showed significant increases in Arc immunoreactivity in regions of the frontal cortex and amygdala compared to unpaired controls. Additionally, administration of a NMDA receptor antagonist (MK-801 or memantine) immediately after cocaine-CA memory reactivation impaired the subsequent conditioned locomotion associated with the cocaine-paired environment. The enhanced Arc expression evident in a subset of corticolimbic regions after retrieval of a cocaine-context memory, observed in both the CPP and CA paradigms, likely signifies that these regions: (i) are activated during retrieval of these memories irrespective of preference-based decisions, and (ii) undergo neuroplasticity in order to update information about cues previously associated with cocaine. This study also establishes the involvement of NMDA receptors in maintaining memories established using the CA model, a characteristic previously demonstrated using CPP. Overall, these results demonstrate the utility of the CA model for studies of cocaine-context memory and suggest the involvement of an NMDA receptor-dependent Arc induction pathway in drug-cue memory interference.

Are mindfulness-based interventions effective for substance use disorders? A systematic review of the evidence

Mindfulness-based interventions (MBIs) are increasingly suggested as therapeutic approaches for effecting substance use and misuse (SUM). The aim of this article is to review current evidence on the therapeutic efficacy of MBIs for SUM. A literature search was undertaken using four electronic databases and references of retrieved articles. The search included articles written in English published up to December 2011. Quality of included trials was assessed. In total, 24 studies were included, three of which were based on secondary analyses of previously investigated samples. Current evidence suggests that MBIs can reduce the consumption of several substances including alcohol, cocaine, amphetamines, marijuana, cigarettes, and opiates to a significantly greater extent than waitlist controls, non-specific educational support groups, and some specific control groups. Some preliminary evidence also suggests that MBIs are associated with a reduction in craving as well as increased mindfulness. The limited generalizability of the reviewed findings is noted (i.e., small sample size, lack of methodological details, and the lack of consistently replicated findings). More rigorous and larger randomized controlled studies are warranted.

Dopamine transporter dysfunction in Han Chinese people with chronic methamphetamine dependence after a short-term abstinence

Single-photon emission-computed tomography (SPECT) after the administration of (99m)Tc-TRODAT-1 was performed on healthy subjects and subjects with methamphetamine (METH)dependence at time 1 (T1) after 24-48 h of abstinence, time 2 (T2) after 2 weeks of abstinence, and time 3 (T3) after 4 weeks of abstinence. In contrast to values in controls, the values of the striatal DAT specific uptake ratios (SURs) in subjects with METH dependence were significantly lower at T1 (n=25), T2 (n=9), and T3 (n=8); a mild increase in SURs was observed at T2 and T3, but values were still significantly lower than those in controls. In subjects with METH dependence, there was a trend for a negative correlation of striatal DAT SURs and craving for METH at T1. METH craving, anxiety and depression scores significantly decreased from T1 to T2 to T3. We conclude that Han Chinese people with METH dependence experience significant striatal DAT dysfunction, and that these changes may be mildly reversible after 4 weeks of abstinence, but that DAT levels still remain significantly lower than those in healthy subjects. The mild recovery of striatal DAT may parallel improvements in craving, anxiety and depression.

A cognitive behavioral therapy-based text messaging intervention for methamphetamine dependence

Psychosocial treatments for methamphetamine dependence are of limited effectiveness. Thus, a significant need exists for add-on therapy for this substance user disorder. The aim of this study was to develop and test a novel text messaging intervention for use as an adjunct to cognitive behavioral group therapy for methamphetamine users. Text messaging has the potential to support patients in real-time, around the clock. We convened two meetings of an expert panel, held three focus groups in current and former users, and conducted 15 semi-structured interviews with in-treatment users in order to develop a fully automated, cognitive behavioral therapy-based text messaging intervention. We then conducted a randomized, crossover pre-test in five users seeking treatment. Participants' ratings of ease of use and functionality of the system were high. During the pre-test, we performed real-time assessments via text messaging on daily methamphetamine use, craving levels, and the perceived usefulness of messages; 79% of scheduled assessments were collected. The odds of messages being rated as "very" or "extremely" useful were 6.6 times (95% CI: 2.2, 19.4) higher in the active vs. placebo periods. The intervention is now ready for testing in randomized clinical trials.

Efficacy of psychostimulant drugs for amphetamine abuse or dependence

BACKGROUND

Amphetamine dependence is a public health problem with medical, psychiatric, cognitive, legal and socioeconomic consequences. To date, no pharmacological treatment has been approved for this disorder, and psychotherapy remains the mainstay of treatment. In recent years, psychostimulants have been investigated as a possible replacement therapy.

OBJECTIVES

To evaluate the efficacy and safety of psychostimulant medications for amphetamine abuse or dependence. The influences of type of drug, type of dependence, comorbid disorders, clinical trial risk of bias and publication of data were also studied.

SEARCH METHODS

Relevant trials were searched in the following sources: PubMed (January 1966 to 6 June 2012), EMBASE (January 1988 to 6 June 2012), CENTRAL (The Cochrane Library, Issue 5 of 12, May 2012), PsycINFO (January 1985 to 6 June 2012) and the Specialised Register of the Cochrane Drug and Alcohol Group (June 2012). We also searched the reference lists of retrieved trials, the list of studies citing the included trials and the main electronic registers of ongoing trials (ClinicalTrials.gov, International Clinical Trials Registry Platform and EU Clinical Trials Register). Finally, we contacted investigators to request information about unpublished trials. Searches included non-English language literature.

SELECTION CRITERIA

All randomised, placebo-controlled, parallel-group clinical trials investigating the efficacy or safety of psychostimulants for amphetamine dependence or abuse conducted in an outpatient setting.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

Eleven studies were included in the review (791 participants). Studied psychostimulants included dexamphetamine, bupropion, methylphenidate and modafinil. No significant differences were found between psychostimulants and placebo for any of the studied efficacy outcomes. Overall retention in studies was low (50.4%). Psychostimulants did not reduce amphetamine use (mean difference (MD) -0.26, 95% confidence interval (CI) -0.85 to 0.33) or amphetamine craving (MD 0.07, 95% CI -0.44 to 0.59) and did not increase sustained abstinence (relative risk (RR) 1.12, 95% CI 0.84 to 1.49). The proportion of adverse events inducing dropout was similar for psychostimulants and placebo (risk difference (RD) 0.01, 95% CI -0.03 to 0.04). The main findings did not change in any subgroup analysis.

AUTHORS' CONCLUSIONS

Results of this review do not support the use of psychostimulant medications at the tested doses as a replacement therapy for amphetamine abuse or dependence. Future research could change this conclusion, as the numbers of included studies and participants are limited and information on relevant outcomes, such as efficacy according to the severity of dependence or craving, is still missing.

mGluR5 is necessary for maintenance of methamphetamine-induced associative learning

Conditioned place preference (CPP) reflects the significance of contextual cues that are associated with rewarding effects of abused drugs such as methamphetamine (Meth). Glutamate neurotransmission is augmented following exposure to stimulants and associated cues. Activation of group I metabotropic glutamate receptors (mGluR) is critical for the acquisition and expression of stimulant-induced CPP. We hypothesized that the maintenance of Meth-induced CPP would also require activated mGluR, and that the role of mGluR1 vs. mGluR5 group I subtypes may differ. To test this hypothesis, negative allosteric modulators (NAMs) of these receptors were administered following the development of Meth-induced CPP. NAMs exert their functional effects by displacing agonist from agonist-occupied receptors, thus NAMs selectively target brain regions with glutamate release. Conditioning with Meth every other day for six days resulted in significant preference for the Meth-paired compartment. Two once-daily injections of the mGluR1 NAM, JNJ16259685 (0.3mg/kg, i.p.) or its vehicle on days 13 and 14 after Meth-conditioning did not influence the maintenance of Meth-induced CPP; however, administration of the mGluR5 NAMs MTEP (3mg/kg, i.p.) and MPEP (30 mg/kg, i.p.) inhibited maintenance processes necessary for CPP to be expressed. These findings suggest a subtype-specific role of mGluR5 receptors in the maintenance of place preference memory and potential of mGluR5 NAMs as a useful target for Meth addiction therapy.

Fine-grain analysis of the treatment effect of topiramate on methamphetamine addiction with latent variable analysis

BACKGROUND

As reported previously, 140 methamphetamine-dependent participants at eight medical centers in the U.S. were assigned randomly to receive topiramate (N=69) or placebo (N=71) in a 13-week clinical trial. The study found that topiramate did not appear to reduce methamphetamine use significantly for the primary outcome (i.e., weekly abstinence from methamphetamine in weeks 6-12). Given that the treatment responses varied considerably among subjects, the objective of this study was to identify the heterogeneous treatment effect of topiramate and determine whether topiramate could reduce methamphetamine use effectively in a subgroup of subjects.

METHODS

Latent variable analysis was used for the primary and secondary outcomes during weeks 6-12 and 1-12, adjusting for age, sex, and ethnicity.

RESULTS

Our analysis of the primary outcome identified 30 subjects as responders, who either reduced methamphetamine use consistently over time or achieved abstinence. Moreover, topiramate recipients had a significantly steeper slope in methamphetamine reduction and accelerated to abstinence faster than placebo recipients. For the secondary outcomes in weeks 6-12, we identified 40 subjects as responders (who had significant reductions in methamphetamine use) and 65 as non-responders; topiramate recipients were more than twice as likely as placebo recipients to be responders (odds ratio=2.67; p=0.019). Separate analyses of the outcomes during weeks 1-12 yielded similar results.

CONCLUSIONS

Methamphetamine users appear to respond to topiramate treatment differentially. Our findings show an effect of topiramate on the increasing trend of abstinence from methamphetamine, suggesting that a tailored intervention strategy is needed for treating methamphetamine addiction.

Retraining the addicted brain: a review of hypothesized neurobiological mechanisms of mindfulness-based relapse prevention

Addiction has generally been characterized as a chronic relapsing condition (Leshner, 1999). Several laboratory, preclinical, and clinical studies have provided evidence that craving and negative affect are strong predictors of the relapse process. These states, as well as the desire to avoid them, have been described as primary motives for substance use. A recently developed behavioral treatment, mindfulness-based relapse prevention (MBRP), was designed to target experiences of craving and negative affect and their roles in the relapse process. MBRP offers skills in cognitive-behavioral relapse prevention integrated with mindfulness meditation. The mindfulness practices in MBRP are intended to increase discriminative awareness, with a specific focus on acceptance of uncomfortable states or challenging situations without reacting "automatically." A recent efficacy trial found that those randomized to MBRP, as compared with those in a control group, demonstrated significantly lower rates of substance use and greater decreases in craving following treatment. Furthermore, individuals in MBRP did not report increased craving or substance use in response to negative affect. It is important to note, areas of the brain that have been associated with craving, negative affect, and relapse have also been shown to be affected by mindfulness training. Drawing from the neuroimaging literature, we review several plausible mechanisms by which MBRP might be changing neural responses to the experiences of craving and negative affect, which subsequently may reduce risk for relapse. We hypothesize that MBRP may affect numerous brain systems and may reverse, repair, or compensate for the neuroadaptive changes associated with addiction and addictive-behavior relapse.

A double blind, placebo-controlled study of the effects of post-retrieval propranolol on reconsolidation of memory for craving and cue reactivity in cocaine dependent humans

RATIONALE/OBJECTIVES

This study examined the effects of propranolol vs. placebo, administered immediately after a "retrieval" session of cocaine cue exposure (CCE), on craving and physiological responses occurring 24 h later during a subsequent "test" session of CCE. It was hypothesized that compared to placebo-treated cocaine-dependent (CD) individuals, propranolol-treated CD individuals would evidence attenuated craving and physiological reactivity during the test session. Secondarily, it was expected that group differences identified in the test session would be evident at a 1-week follow-up CCE session. Exploratory analyses of treatment effects on cocaine use were also performed at follow-up.

METHODS

CD participants received either 40 mg propranolol or placebo immediately following a "retrieval" CCE session. The next day, participants received a "test" session of CCE that was identical to the "retrieval" session except no medication was administered. Participants underwent a "follow-up" CCE session 1 week later. Craving and other reactivity measures were obtained at multiple time points during the CCE sessions.

RESULTS

Propranolol- vs. placebo-treated participants evidenced significantly greater attenuation of craving and cardiovascular reactivity during the test session. Analysis of the follow-up CCE session data did not reveal any group differences. Although there was no evidence of treatment effects on cocaine use during follow-up, this study was insufficiently powered to rigorously evaluate differential cocaine use.

CONCLUSIONS

This double-blind, placebo-controlled laboratory study provides the first evidence that propranolol administration following CCE may modulate memories for learning processes that subserve cocaine craving/cue reactivity in CD humans. Alternative interpretations of the findings were considered, and implications of the results for treatment were noted.

Craving for cannabis in patients with psychotic disorder, their non-affected siblings and healthy controls: psychometric analysis of the obsessive compulsive drug use scale

Cannabis use is more common in individuals with non-affective psychotic disorder and their siblings compared to healthy controls. As cannabis use is associated with a greater risk to develop psychotic disorder and an adverse outcome in those who already developed psychosis, it is important to know the role of craving in continued cannabis use and relapse in these vulnerable subjects. Therefore, we examined the validity of the Obsessive Compulsive Drug Use Scale for cannabis (OCDUS-CAN) in patients with non-affective psychotic disorder, their siblings, and healthy controls who all used cannabis in the past year. Simultaneous component analysis (SCA) was used to determine component weights that optimally explained the (co)variance of the OCDUS-CAN variables in these different populations simultaneously. A three-component SCA solution explained 74.2 % of the total variance, and consisted of well-interpretable subscales that could be best described as craving/urge, resistance, and impact. Reliability of the subscales was good. The three subscales significantly discriminated between frequent and infrequent cannabis users. Patients scored higher on the craving/urge and impact scale than siblings and controls, which could be related to primary and secondary symptoms of their disorder. The OCDUS-CAN is well suitable for people with or without vulnerability for psychotic disorder.

Evaluating the impact of community-based treatment options on methamphetamine use: findings from the Methamphetamine Treatment Evaluation Study (MATES)

AIMS

To evaluate the impact of community-based drug treatment on methamphetamine use using inverse probability of treatment-weighted (IPTW) estimators to derive treatment effects.

DESIGN

A longitudinal prospective cohort study with follow-ups at 3 months, 1 year and 3 years. Treatment effects were derived by comparing groups at follow-up. IPTW estimators were used to adjust for pre-treatment differences between groups.

SETTING

Sydney and Brisbane, Australia.

PARTICIPANTS

Participants were methamphetamine users entering community-based detoxification (n = 112) or residential rehabilitation (n = 248) services and a quasi-control group of methamphetamine users (n = 101) recruited from the community.

MEASUREMENTS

Frequency of methamphetamine use between interviews (no use, less than weekly, 1-2 days per week, 3+ days per week), continuous abstinence from methamphetamine use, past month methamphetamine use and methamphetamine dependence.

FINDINGS

Detoxification did not reduce methamphetamine use at any follow-up relative to the quasi-control group. Relative to quasi-control and detoxification groups combined, residential rehabilitation produced large reductions in the frequency of methamphetamine use at 3 months [odds ratio (OR) = 0.23, 95% confidence interval (CI) 0.15-0.36, P < 0.001), with a marked attenuation of this effect at 1 year (OR 0.62, 95% CI 0.40-0.97, P = 0.038) and 3 years (OR = 0.71, 95% CI 0.42-1.19, P = 0.189). The greatest impact was for abstinence: for every 100 residential rehabilitation clients there was a gain of 33 being continuously abstinent at 3 months, with this falling to 14 at 1 year and 6 at 3 years.

CONCLUSIONS

Community-based residential rehabilitation may produce a time-limited decrease in methamphetamine use, while detoxification alone does not appear to do so.

Does alexithymia explain variation in cue-elicited craving reported by methamphetamine-dependent individuals?

Drug craving is an important motivational phenomenon among addicted individuals, and successful management of craving is essential to both the initiation and maintenance of abstinence. Although craving in response to drug cues is common in drug-dependent individuals, it is not universal. At the present time, it is not known why approximately 20-30% of all addicted persons fail to report appreciable craving in laboratory-based cue reactivity studies. This study examined the possibility that alexithymia, a personality attribute characterized by a difficulty identifying and describing emotions, may contribute to the impoverished cue-elicited craving experienced by some addicts. Specifically, we tested the hypothesis that alexithymia, as measured by the Toronto Alexithymia Scale (TAS), would be inversely related to the magnitude of cue-elicited craving obtained in a cue reactivity protocol. Forty methamphetamine-dependent individuals completed the TAS and provided craving ratings for methamphetamine after presentation of methamphetamine-associated cues. Thirteen participants (32%) reported no methamphetamine cue-elicited craving. Contrary to expectation, TAS factor 1 (a measure of difficulty identifying feelings) scores were positively associated with cue-elicited craving. Thus, the results suggest that increasing difficulty-identifying feelings may be associated with higher cue-elicited craving. Clinical implications for this finding are discussed.

Attenuation of methamphetamine seeking by the mGluR2/3 agonist LY379268 in rats with histories of restricted and escalated self-administration

Recent findings implicate group II metabotropic glutamate receptors (mGluR(2/3)) in the reinforcing effects of psychostimulants and have identified these receptors as potential treatment targets for drug addiction. Here, we investigated the effects of mGluR(2/3) stimulation on cue- and drug-primed reinstatement in rats with different histories of methamphetamine (METH) self-administration training, under two conditions: 16 daily sessions of short access (90 min/day, ShA), or 8 daily sessions of short access followed by 8 sessions of long access (6 h/day, LgA). Following self-administration and subsequent extinction training, rats were pretreated with the selective mGluR(2/3) agonist LY379268 (variable dose, 0-3 mg/kg), exposed to METH-paired cues or a priming injection of METH (1 mg/kg), and tested for reinstatement of METH-seeking behavior. LgA rats self-administered greater amounts of METH during the second half of training, but when pretreated with vehicle, ShA and LgA rats showed cue- and drug-primed reinstatement at equivalent response rates. However, LgA rats demonstrated greater sensitivity to mGluR(2/3) stimulation with attenuated responding during cue-induced reinstatement after 0.3 mg/kg and higher doses of LY379268, whereas ShA rats decreased cue-induced reinstatement behavior following 1.0 mg/kg and 3.0 mg/kg LY379268. Additionally, both LgA and ShA rats exhibited decreased METH-primed reinstatement behavior following 0.3 mg/kg and higher doses of LY379268. A separate group of control rats was trained to self-administer sucrose pellets, and demonstrated attenuated cue-induced sucrose-seeking behavior following 1.0 and 3.0 mg/kg LY379268. Together, the results indicate that LY379268 has differential attenuating effects on cue-induced reinstatement behavior in rats with different histories of METH intake. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.

A pilot randomised controlled trial of modafinil during acute methamphetamine withdrawal: feasibility, tolerability and clinical outcomes

INTRODUCTION AND AIMS

There are no medications approved for the treatment of methamphetamine withdrawal. Wake-promoting agent modafinil has recently been proposed as a viable option. This paper reports on the results of a pilot study that tested the feasibility of modafinil in an inpatient withdrawal setting during acute methamphetamine withdrawal.

DESIGN AND METHODS

In a double-blind, randomised, placebo-controlled study, 19 methamphetamine dependent participants received modafinil (n = 9) or placebo (n = 10) daily for 7 days (200 mg for the first 5 days and 100 mg on days 6 and 7). Primary outcomes were retention in treatment and severity of withdrawal symptoms. Secondary outcomes were methamphetamine craving, sleep and physiological outcomes.

RESULTS

There were no significant differences between groups on retention in treatment, withdrawal severity, craving, sleep or physiological outcomes. There were no adverse events or side-effects reported.

CONCLUSIONS

Modafinil was found to be tolerable and well accepted by methamphetamine users and feasible for short-term inpatient withdrawal, but the sample was too small to detect treatment effects. Larger trials are needed to establish efficacy.

Cue-induced craving and physiological reactions in recently and long-abstinent heroin-dependent patients

OBJECTIVE

To understand the different patterns of cue-induced craving and physiological reactions among recently abstinent and long-abstinent heroin-dependent patients.

METHOD

26 healthy adult controls (HC), 29 long-abstinent (more than 1 year, LA), and 26 recently abstinent (less than 1 month, RA) heroin-dependent individuals were exposed to heroin-related and neutral video cues, one video per session, on different days in random order. Self-reported heroin craving by a 10-point visual analog scale (VAS), physiological reactions [skin conductance (SC), muscle electromyography (MEG), skin temperature (TEMP)] and cardiovascular arousal [heart rates (HR), systolic blood pressure (HBP) and diastolic blood pressure (LBP)] were assessed at baseline and after exposure.

RESULTS

Both heroin-abstinent groups showed increased heroin craving, SC, MEG, HR, SBP and LBP after exposure to heroin-related video, compared to the control group and compared to exposure to the neutral video. Except the RA group showed more HR changes, changes of heroin craving, SC, MEG, HR, SBP and LBP after exposure to the heroin cue video were not different between the LA and RA groups.

CONCLUSIONS

Abstinent heroin-dependent patients had elevated craving and physiological reactions after exposure to videos containing heroin-related cues and the cue induced responses still occurred in long-abstinent patients. This phenomenon should be addressed in treatment and recovery services for heroin dependence.

Baclofen facilitates the extinction of methamphetamine-induced conditioned place preference in rats

The powerful, long-lasting association between the rewarding effects of a drug and contextual cues associated with drug administration can be studied using conditioned place preference (CPP). The GABA(B) receptor agonist baclofen facilitates the extinction of morphine-induced CPP in mice. The current study extended this work by determining if baclofen could enhance the extinction of methamphetamine (Meth) CPP. CPP was established using a six-day conditioning protocol wherein Meth-pairings were alternated with saline-pairings. Rats were subsequently administered baclofen (2 mg/kg i.p. or vehicle) immediately after each daily forced extinction session, which consisted of a saline injection immediately prior to being placed into the previously Meth- or saline-paired chamber. One extinction training cycle, consisted of six once-daily forced extinction sessions, mimicking the alternating procedure established during conditioning, followed by a test for preference (Ext test). CPP persisted for at least four extinction cycles in vehicle-treated rats. In contrast, CPP was inhibited following a single extinction training cycle. These data indicate that Meth-induced CPP was resistant to extinction, but extinction training was rendered effective when the training was combined with baclofen. These findings converge with the prior demonstration of baclofen facilitating the extinction of morphine-induced CPP indicating that GABA(B) receptor actions are independent of the primary (unconditioned) stimulus (i.e., the opiate or the stimulant) and likely reflect mechanisms engaged by extinction learning processes per se. Thus, baclofen administered in conjunction with extinction training may be of value for addiction therapy regardless of the class of drug being abused.

The clinical significance of drug craving

Although drug craving has received considerable research attention over the past several decades, to date there has been no systematic review of the general clinical significance of craving. This paper presents an overview of measurement issues of particular relevance to a consideration of use of craving in clinical settings. The paper then considers the relevance of craving across a broad array of clinical domains, including diagnosis, prognostic utility, craving as an outcome measure, and the potential value of craving as a direct target of intervention. The paper is both descriptive and prescriptive, informed by the current state of the science on craving with recommendations for the definition of craving, assessment practices, future research, and clinical applications. We conclude that craving has considerable utility for diagnosis and as a clinical outcome, and that findings from future research will likely expand the clinical potential of the craving construct in the domains of prognosis and craving as a treatment target.

Context-dependent effects of a single administration of mirtazapine on the expression of methamphetamine-induced conditioned place preference

Re-exposure to cues repeatedly associated with methamphetamine (Meth) can trigger Meth-seeking and relapse in the abstinent abuser. Weakening the conditioned Meth-associated memory during cue re-exposure may provide a means for relapse-reduction pharmacotherapy. Accordingly, we sought to determine if the atypical antidepressant mirtazapine disrupted the persistence of Meth-induced conditioned place preference (CPP) when administered in conjunction with re-exposure to contextual conditioning cues, and if this effect was altered by Meth being present during cue re-exposure. First, we evaluated the effect of mirtazapine on the maintenance of Meth-induced CPP during re-exposure to either the saline- or Meth-paired chamber 12 days after conditioning. Meth-conditioned rats subsequently administered mirtazapine expressed CPP independent of re-exposure to the saline- or Meth-paired chamber; but the magnitude of CPP was significantly less for mirtazapine-treated rats re-exposed to the Meth-paired chamber. Next, we evaluated the effect of mirtazapine on a "reinforced re-exposure" to the Meth-paired context. Administration of mirtazapine vehicle and Meth, prior to re-exposure to the Meth-paired chamber did not disrupt the ability of rats to demonstrate CPP 15 days after conditioning; however, CPP was disrupted when rats were administered mirtazapine and Meth prior to re-exposure to the Meth-paired chamber. These results indicate that the capacity of mirtazapine to diminish Meth-induced CPP is promoted if mirtazapine treatment is coupled with Meth administration in the Meth-associated context and thus appears to be the consequence of disrupting processes necessary to reconsolidate CPP following activation of drug-associated memories.

Poor response to sertraline in methamphetamine dependence is associated with sustained craving for methamphetamine

BACKGROUND

Depression is common among individuals with methamphetamine (MA) use disorders. As agents that enhance serotonergic function are frequently used to treat depression, one might predict that they would be useful medications for MA dependence. However, clinical trials of serotonergic agents for MA addiction have been unsuccessful.

OBJECTIVE

To identify factors that distinguish MA-dependent research participants who increased MA self-administration while receiving treatment with the selective serotonin reuptake inhibitor (SSRI) sertraline from other groups of participants.

METHOD

Using a dataset from a 12-week randomized, placebo-controlled trial of sertraline (100mg daily) for MA addiction, we identified participants who had completed at least 8 weeks of the trial (n=61 sertraline, n=68 placebo). We compared the proportions of MA-positive urine tests for weeks 8-12 of the trial for these subjects to their pre-randomization baseline, and identified those subjects who increased MA use during treatment. Using classification trees, we then assessed all data collected during the study to identify factors associated with increasing MA use during treatment with sertraline, compared to placebo.

RESULTS

More subjects in the sertraline condition increased MA use during treatment (n=13) than in the placebo condition (n=5; p=0.03). Classification trees identified multiple factors from both pre-treatment and in-treatment data that were associated with increased MA use during treatment. Only elevated in-treatment craving for MA specifically characterized subjects in the sertraline group who increased their MA use.

CONCLUSIONS

Some MA-abusing individuals treated with SSRIs have sustained craving with an increased propensity to relapse during treatment despite psychosocial treatment interventions.

Brain region-selective cellular redistribution of mGlu5 but not GABA(B) receptors following methamphetamine-induced associative learning

Alterations in receptor expression and distribution between cell surface and cytoplasm are means by which psychostimulants regulate neurotransmission. Metabotropic glutamate receptor group I, subtype 5 (mGluR5) and GABA(B) receptors (GABA(B) R) are critically involved in the development and expression of stimulant-induced behaviors, including conditioned place preference (CPP), an index of drug-seeking. However, it is not known if psychostimulant-induced CPP alters the trafficking of these receptors. To fill this gap, this study used methamphetamine (Meth)-induced CPP in rats to ascertain if receptor changes occur in limbic brain regions that regulate drug-seeking, the medial prefrontal cortex (mPFC), nucleus accumbens (NAc), and ventral pallidum (VP). To do so, ex vivo tissue was assessed for changes in expression and surface vs. intracellular distribution of mGluR5 and GABA(B) Rs. There was a decrease in the surface to intracellular ratio of mGluR5 in the mPFC in Meth-conditioned rats, commensurate with an increase in intracellular levels. mGluR5 levels in the NAc or the VP were unaltered. There were no changes for GABA(B) R in any brain region assayed. This ex vivo snapshot of metabotropic glutamate and GABA receptor cellular distribution following induction of Meth-induced CPP is the first report to determine if these receptors are differentially altered after Meth-induced CPP. The results suggest that this Meth treatment paradigm likely induced a compensatory change in mGluR5 surface to intracellular ratio such that the surface remains unaltered while an increase in intracellular protein occurred.

Role of dopamine D1- and D2-like receptor mechanisms in drug-seeking following methamphetamine self-administration in rats

It has been suggested that dopaminergic mechanisms mediate relapse to drug-seeking behavior and both D1- and D2-like receptor mechanisms have been implicated. In contrast to self-administration of other drugs, there is a relative paucity of studies that has examined the pharmacological basis of methamphetamine (MA) seeking. Accordingly, the present study used an animal model of drug-seeking to determine the role of D1- and D2-like receptor mechanisms in relapse to MA abuse. Rats were trained to self-administer MA, and then responding was extinguished by replacing the MA solution with vehicle. Experimenter-administered injections of MA or the dopamine uptake inhibitor, GBR 12909, reinstated extinguished responding in a dose-dependent manner. The D1-like antagonist, SCH 23390 attenuated drug-seeking but the D2-like antagonist, eticlopride, was ineffective. The results suggest that MA-seeking is predominantly mediated by DA D1-like receptor mechanisms. These findings are in contrast to the literature on drug-seeking following self-administration of other drugs, and suggest that relapse to different drugs of abuse may rely upon different DA receptor mechanisms.

A controlled trial of flumazenil and gabapentin for initial treatment of methylamphetamine dependence

Drug use has been associated with craving, which may be described as a powerful and sometimes overwhelming urge to use the drug. Patients seeking treatment for methylamphetamine dependence must cope with drug cravings as they engage in psychosocial treatments. Changes in brain GABA(A) receptors during substance use and withdrawal provide a neurobiological basis for craving and associated anxiety. Flumazenil (a benzodiazepine antagonist) plus gabapentin (an antiepileptic) were compared with placebo in a randomized, double-blind study to assess the effects on craving during initial treatment for methylamphetamine dependence. Evaluation was conducted over a 30-day period. Craving and drug use were found to be highly correlated. Craving was reduced significantly in the flumazenil plus gabapentin group compared with placebo following the initial treatment period and throughout the 30 days. Decreased methylamphetamine use was also observed, as measured by urine drug screens and self-reports.

A randomized, placebo-controlled trial of sustained-release dextroamphetamine for treatment of methamphetamine addiction

Sixty treatment-seeking individuals with methamphetamine (MA) dependence entered a randomized, placebo-controlled, double-blind clinical trial of oral dextroamphetamine (d-AMP) as a replacement therapy for MA dependence. The subjects took 60 mg sustained-release d-AMP for 8 weeks, during which time they received eight 50-min sessions of individual psychotherapy. Adverse events and urine toxicology for MA were assessed two times a week. There were no serious adverse events. Urine samples containing <1,000 ng/ml of MA were classified as negative for MA. The MA-negative scores in the d-AMP group (3.1 ± SD 4.6) were no higher than those in the placebo group (3.3 ± SD 5.3; P > 0.05). However, withdrawal and craving scores were significantly lower in the d-AMP group (P < 0.05 for both). Although subjects taking d-AMP did not reduce their use of MA, the significant reductions observed in withdrawal and craving scores in this group support the need for further exploration of d-AMP as a pharmacologic intervention for MA dependence, possibly at higher doses.

Withdrawal symptoms in abstinent methamphetamine-dependent subjects

AIMS

Withdrawal symptoms have been linked to a propensity for relapse to drug abuse. Inasmuch as this association applies to methamphetamine (MA) abuse, an understanding of the course of MA withdrawal symptoms may help to direct treatment for MA dependence. Previous studies of symptoms manifested during abstinence from MA have been limited in size and scope. We asked (i) whether debilitating psychological and/or physical symptoms appear during the first several weeks of MA abstinence, (ii) how craving for MA evolves and (iii) whether psychiatric symptoms (e.g. depression, psychosis) persist beyond a month of abstinence.

DESIGN

A study of MA-dependent participants, who initiated and maintained abstinence from the drug for up to 5 weeks, compared to a matched healthy comparison group.

SETTING

In-patient research hospital ward (MA-dependent subjects) and out-patient (comparison subjects).

PARTICIPANTS

Fifty-six MA-dependent and eighty-nine comparison subjects.

MEASUREMENTS

Rater-assessed MA withdrawal questionnaire and self-report assessment of craving (MA-dependent subjects) and self-report assessment of psychiatric symptoms (both groups).

FINDINGS

At study entry, MA-dependent subjects exhibited a wide range in severity of depressive symptoms, with the average score at a mild-moderate level of severity. Symptoms of psychosis were also prevalent. While depressive and psychotic symptoms largely resolved within a week of abstinence, craving did not decrease significantly from the time of initiating abstinence until the second week, and then continued at a reduced level to the fifth week.

CONCLUSIONS

Depressive and psychotic symptoms accompany acute withdrawal from methamphetamine but resolve within 1 week. Craving is also present and lasts at least 5 weeks.

Depression, craving, and substance use following a randomized trial of mindfulness-based relapse prevention

OBJECTIVE

A strong relation between negative affect and craving has been demonstrated in laboratory and clinical studies, with depressive symptomatology showing particularly strong links to craving and substance abuse relapse. Mindfulness-based relapse prevention (MBRP), shown to be efficacious for reduction of substance use, uses mindfulness-based practices to teach alternative responses to emotional discomfort and lessen the conditioned response of craving in the presence of depressive symptoms. The goal in the current study was to examine the relation between measures of depressive symptoms, craving, and substance use following MBRP.

METHOD

Individuals with substance use disorders (N = 168; mean age 40.45 years, SD = 10.28; 36.3% female; 46.4% non-White) were recruited after intensive stabilization, then randomly assigned to either 8 weekly sessions of MBRP or a treatment-as-usual control group. Approximately 73% of the sample was retained at the final 4-month follow-up assessment.

RESULTS

Results confirmed a moderated-mediation effect, whereby craving mediated the relation between depressive symptoms (Beck Depression Inventory) and substance use (Timeline Follow-Back) among the treatment-as-usual group but not among MBRP participants. MBRP attenuated the relation between postintervention depressive symptoms and craving (Penn Alcohol Craving Scale) 2 months following the intervention (f(2) = .21). This moderation effect predicted substance use 4 months following the intervention (f(2) = .18).

CONCLUSION

MBRP appears to influence cognitive and behavioral responses to depressive symptoms, partially explaining reductions in postintervention substance use among the MBRP group. Although results are preliminary, the current study provides evidence for the value of incorporating mindfulness practice into substance abuse treatment and identifies a potential mechanism of change following MBRP.

An examination of drug craving over time in abstinent methamphetamine users

Craving for addictive drugs may predict relapse in abstinent addicts. To assess relationships between craving and use, we examined changes in craving for methamphetamine (MA) in a sample of 865 outpatients in a multisite 16-week MA-treatment study. Craving was assessed on a 0-100 scale, and MA use was assessed by self-report and confirmed by urinalysis. We hypothesized that the magnitude of craving would decline (decay) with increased time of abstinence, and that decay would be greater for more frequent MA users, and greater for intravenous (IV) users and smokers as compared to those who used MA intranasally. Craving declined significantly as the number of weeks of consecutive abstinence increased. Rate of decay was greater for IV users and smokers as compared to both intranasal users and oral users, but not for more frequent users of MA. Rate of decay was independent of age, gender, and race/ethnicity. The trajectory to 0 (no) craving was 1 week shorter for females than males because females had significantly lower pretreatment craving scores compared to males. This study confirms that the sooner MA-dependent people are able to quit using and the longer that they are able to stay abstinent, the more likely it is that their craving for MA will decrease over time. 

Methamphetamine craving induced in an online virtual reality environment

The main aim of this study was to assess self-reported craving and physiological reactivity in a methamphetamine virtual reality (METH-VR) cue model created using Second Life, a freely available online gaming platform. Seventeen, non-treatment seeking, individuals that abuse methamphetamine (METH) completed this 1-day, outpatient, within-subjects study. Participants completed four test sessions: 1) METH-VR, 2) neutral-VR, 3) METH-video, and 4) neutral-video in a counterbalanced (Latin square) fashion. The participants provided subjective ratings of urges to use METH, mood, and physical state throughout each cue presentation. Measures of physiological reactivity (heart rate variability) were also collected during each cue presentation and at rest. The METH-VR condition elicited the greatest change in subjective reports of "crave METH", "desire METH", and "want METH" at all time points. The "high craving" participants displayed more high frequency cardiovascular activity while the "low craving" participants displayed more low frequency cardiovascular activity during the cue conditions, with the greatest difference seen during the METH-VR and METH-video cues. These findings reveal a physiological divergence between high and low craving METH abusers using heart rate variability, and demonstrate the usefulness of VR cues for eliciting subjective craving in METH abusers, as well as the effectiveness of a novel VR drug cue model created within an online virtual world.

Written emotional expression during recovery from cocaine dependence: group and individual differences in craving intensity

We conducted a prospective, single-blind, parallel group, controlled trial to evaluate effects of written emotional expression in patients receiving intensive treatment for cocaine dependence in a residential-unit setting. Randomization to the emotional expression treatment produced changes in blood pressure and mood during writing sessions, possibly because of its ability to stimulate active coping behavior. At an initial follow-up visit, patients that had received written emotional expression reported lower values for craving intensity and were less likely to self-report use of cocaine. These results may indicate a therapeutic effect of written emotional expression during recovery from cocaine dependence.

Extinction of drug cue reactivity in methamphetamine-dependent individuals

Conditioned responses to drug-related environmental cues (such as craving) play a critical role in relapse to drug use. Animal models demonstrate that repeated exposure to drug-associated cues in the absence of drug administration leads to the extinction of conditioned responses, but the few existing clinical trials focused on extinction of conditioned responses to drug-related cues in drug-dependent individuals show equivocal results. The current study examined drug-related cue reactivity and response extinction in a laboratory setting in methamphetamine-dependent individuals. Methamphetamine cue-elicited craving was extinguished during two sessions of repeated (3) within-session exposures to multi-modal (picture, video, and in-vivo) cues, with no evidence of spontaneous recovery between sessions. A trend was noted for a greater attenuation of response in participants with longer (4-7 day) inter-session intervals. These results indicate that extinction of drug cue conditioned responding occurs in methamphetamine-dependent individuals, offering promise for the development of extinction- based treatment strategies.

Imagery Scripts and a Computerized Subtraction Stress Task Both Induce Stress in Methamphetamine Users: A Controlled Laboratory Study

Patients treated for methamphetamine (MA) dependence have a high rate of relapse, and stress is thought to play a key role. We sought to develop a computerized procedure for experimentally inducing stress in MA users. In a within-subjects design, we compared a computerized subtraction stress task (SST) to personalized stress-imagery scripts and a control condition (neutral imagery) in 9 former MA users, recruited in San Francisco in 2006–2007. We assessed blood hormone levels, anxiety and craving for MA on visual analog scales, and the Positive and Negative Affect Schedule and made linear mixed-effects models to analyze the results. Both the SST and stress scripts were effective in inducing self-report markers of stress in MA users. Because the SST is easily reproducible and requires less time of staff and participants, it may be a useful alternative for measuring stress reactivity in drug users.

Cocaine craving and use during daily life

RATIONALE

Craving is often assumed to cause ongoing drug use and relapse and is a major focus of addiction research. However, its relationship to drug use has not been adequately documented.

OBJECTIVES

The aim of this study was to investigate the relationship between craving and drug use in real time and in the daily living environments of drug users.

METHODS

In a prospective, longitudinal, cohort design (ecological momentary assessment), 112 cocaine-abusing individuals in methadone maintenance treatment rated their craving and mood at random times (two to five times daily, prompted by electronic diaries) as they went about their everyday activities. They also initiated an electronic diary entry each time they used cocaine. Drug use was monitored by thrice-weekly urine testing.

RESULTS

During periods of urine-verified cocaine use, ratings of cocaine craving increased across the day and were higher than during periods of urine-verified abstinence. During the 5 h prior to cocaine use, ratings of craving significantly increased. These patterns were not seen in ratings of heroin craving or mood (e.g., feeling happy or bored).

CONCLUSIONS

Cocaine craving is tightly coupled to cocaine use in users' normal environments. Our findings provide previously unavailable support for a relationship that has been seriously questioned in some theoretical accounts. We discuss what steps will be needed to determine whether craving causes use.

Predicting adherence to treatment for methamphetamine dependence from neuropsychological and drug use variables

Although some individuals who abuse methamphetamine have considerable cognitive deficits, no prior studies have examined whether neurocognitive functioning is associated with outcome of treatment for methamphetamine dependence. In an outpatient clinical trial of bupropion combined with cognitive behavioral therapy and contingency management (Shoptaw, S., Heinzerling, K.G., Rotheram-Fuller, E., Steward, T., Wang, J., Swanson, A.N., De La Garza, R., Newton, T., Ling, W., 2008. Randomized, placebo-controlled trial of bupropion for the treatment of methamphetamine dependence. Drug Alcohol Depend 96, 222-232.), 60 methamphetamine-dependent adults completed three tests of reaction time and working memory at baseline. Other variables that were collected at baseline included measures of drug use, mood/psychiatric functioning, employment, social context, legal status, and medical status. We evaluated the relative predictive value of all baseline measures for treatment outcome using Classification and Regression Trees (CART; Breiman, L., Friedman, J.H., Olshen, R.A., Stone, C.J., 1984. Classification and Regression Trees. Wadsworth, Belmont, CA.), a nonparametric statistical technique that produces easily interpretable decision rules for classifying subjects that are particularly useful in clinical settings. Outcome measures were whether or not a participant completed the trial and whether or not most urine tests showed abstinence from methamphetamine abuse. Urine-verified methamphetamine abuse at the beginning of the study was the strongest predictor of treatment outcome; two psychosocial measures (e.g., nicotine dependence and Global Assessment of Functioning) also offered some predictive value. A few reaction time and working memory variables were related to treatment outcome, but these cognitive measures did not significantly aid prediction after adjusting for methamphetamine usage at the beginning of the study. On the basis of these findings, we recommend that research groups seeking to identify new predictors of treatment outcome compare the predictors to methamphetamine usage variables to assure that unique predictive power is attained.

Theories of addiction: methamphetamine users' explanations for continuing drug use and relapse

A variety of preclinical models have been constructed to emphasize unique aspects of addiction-like behavior. These include Negative Reinforcement ("Pain Avoidance"), Positive Reinforcement ("Pleasure Seeking"), Incentive Salience ("Craving"), Stimulus Response Learning ("Habits"), and Inhibitory Control Dysfunction ("Impulsivity"). We used a survey to better understand why methamphetamine-dependent research volunteers (N = 73) continue to use methamphetamine, or relapse to methamphetamine use after a period of cessation of use. All participants met DSM-IV criteria for methamphetamine abuse or dependence, and did not meet criteria for other current Axis I psychiatric disorders or dependence on other drugs of abuse, other than nicotine. The questionnaire consisted of a series of face-valid questions regarding drug use, which in this case referred to methamphetamine use. Examples of questions include: "Do you use drugs mostly to make bad feelings like boredom, loneliness, or apathy go away?", "Do you use drugs mostly because you want to get high?", "Do you use drugs mostly because of cravings?", "Do you find yourself getting ready to take drugs without thinking about it?", and "Do you impulsively take drugs?". The scale was anchored at 1 (not at all) and 7 (very much). For each question, the numbers of participants rating each question negatively (1 or 2), neither negatively or affirmatively (3-5), and affirmatively (6 or 7) were tabulated. The greatest number of respondents (56%) affirmed that they used drugs due to "pleasure seeking." The next highest categories selected were "impulsivity" (27%) and "habits"(25%). Surprisingly, many participants reported that "pain avoidance" (30%) and "craving" (30%) were not important for their drug use. Results from this study support the contention that methamphetamine users (and probably other drug users as well) are more heterogeneous than is often appreciated, and imply that treatment development might be more successful if treatments targeted subtypes of patients, though a range of limitations to the approach used are acknowledged.

Clinical and laboratory assessment of the subjective experience of drug craving

Measures of subjective drug craving - often defined as the experience of an intense or compelling urge or desire - may be used to predict relapse, evaluate psychological and pharmacological treatments, and test theories of addiction and craving. This review summarizes both direct self-report questionnaires and indirect behavioral, physiological and reaction time measures designed to assess craving for alcohol, amphetamines, cocaine, heroin, marijuana, and tobacco. Multi-item questionnaires have typically been based on one of four underlying conceptualizations of addiction or craving (obsessive-compulsive, approach-avoidance, multi-dimensional, intensity-frequency-duration). Most multi-item self-report questionnaires have high internal consistency, correlate significantly with single-item craving ratings, and demonstrate several aspects of construct validity. Proposed indirect or proxy measures of craving include drug dreams, speed of drug consumption, willingness to work for drug access, selection of monetary rewards over drug access, psychophysiological reactivity, and attentional bias to drug cues. These proxy measures of craving are presumed to obviate self-report biases, to be less subject to conscious self-control, and to reflect craving which the person may not be able to articulate; however, there have been too few demonstrations of their validity and they have too many practical limitations to supplant self-report measures of craving at this time.

A review of psychosocial interventions for amphetamine use

There are clear signs that amphetamine use is increasing in Australia and internationally, yet there are few services that offer amphetamine-specific interventions. This review examines the evidence for the use of psychosocial interventions for amphetamine users. The literature is very limited in the number of well-conducted, controlled studies, but the evidence available suggests that cognitive-behavioural therapy appears to be current best practice. Motivational interviewing has been recommended as a strategy to assist those ambivalent for treatment. There is also some evidence that contingency management is effective while clients are in treatment. The effectiveness of other types of intervention is not well supported. The literature is particularly hindered by a paucity of well-conducted studies among primary amphetamine users. Recommendations about appropriate interventions for use in clinical settings are offered and directions for future research are considered.

Association between psychiatric symptoms and craving in methamphetamine users

This study examined the differences in psychiatric symptoms between adult methamphetamine users (n = 46) and control subjects (n = 31), the relationship between psychiatric symptoms and the intensity of methamphetamine craving, and whether psychiatric symptoms were correlated to methamphetamine drug-usage variables (ie, length of abstinence, frequency, duration, and lifetime grams). We found that depressive symptoms on the Center for Epidemiology Studies-Depression (CES-D) and many other psychiatric symptoms on the Symptom Checklist-90 (SCL-90) significantly correlated with craving methamphetamine on the visual analog scale (VAS) for craving. Methamphetamine users had significantly more depressive symptoms (on CES-D) and psychotic symptoms (on SCL-90) compared to controls. There were no significant correlations between psychiatric symptoms and methamphetamine-usage variables. This study provides the first evidence to suggest that depressive symptoms (on CES-D) and psychiatric symptoms (on SCL-90) are strongly associated with the intensity of craving (on VAS) for the drug in methamphetamine users. However, the methamphetamine usage variables had no relationship with psychiatric symptoms. Therefore, methamphetamine users, regardless of their usage patterns, may benefit from treatment of their psychiatric symptoms in order to minimize craving and subsequent relapse to drug use.

Predicting treatment outcome in stimulant dependence

The purpose of this review is to highlight some of the issues that need to be addressed to optimally use functional neuroimaging as a clinical tool to predict outcomes in substance use disorders. First, the importance of recognizing the clinical heterogeneity of the substance use disorders population is highlighted. We also emphasize that empirical and theoretical analyses support the idea that the courses of substance use disorders are relatively independent of the types of substance being used. Second, various approaches to the measurement and characterization of the longitudinal courses of substance use disorders are summarized. Third, predictors of outcomes are reviewed and their limitations are discussed. Within this context, we describe aspects of our work that focus on using functional magnetic resonance imaging to predict outcomes. Fourth, we discuss future directions, critical experiments, and the utility of functional neuroimaging as a clinical tool.

Evaluation of the cardiovascular and subjective effects of rivastigmine in combination with methamphetamine in methamphetamine-dependent human volunteers

Acetylcholine (ACh) has been implicated in the reinforcing and locomotor-activating effects produced by methamphetamine (Meth). Of interest, recent data suggest that acetylcholinesterase (AChE) inhibitors attenuate Meth-seeking behaviour in rats. We conducted this study in order to determine the safety (adverse events, mood changes, cardiovascular effects) and preliminary efficacy (subjective effects) of the AChE inhibitor rivastigmine (Riv) when tested in combination with Meth. Twenty-three non-treatment-seeking Meth-dependent participants resided in an in-patient unit at UCLA for 2mg i.v.) and Meth (day 5, 30mg, n=7) or Riv (1.5mg, n=9). On day 11, the subjects received saline and Meth infusions again (randomized to either 11:30 or 14:30 hours), under double-blind conditions. The data analyses compared across-study measures of adverse events and mood, and a post-randomization analysis of cardiovascular and subjective effects (on day 11). The data reveal that rivastigmine was not associated with increased adverse events or alterations in mood. As expected, acute Meth exposure (30mg, significantly attenuated Meth-induced increases in diastolic blood pressure, and self-reports of and (p<0.05). Taken together, the findings in the current report suggest that pharmacological manipulations that enhance brain ACh warrant continued investigation as potential treatments for Meth addiction.

Neural basis of reward and craving--a homeostatic point of view

Here, it is argued that the interoceptive system, which provides information about the subject's internal state and is integrated in the insular cortex, and not the subcortical ventral striatum, is the critical neural substrate for reward-related processes. Understanding the internal state of the individual, which is processed via this system, makes it possible to develop new interventions that are aimed at treating reward-dysfunction disorders, ie, substance and alcohol dependence. Although the ventral striatum is important for signaling the degree to which rewarding stimuli are predicted to occur, this system alone cannot account for the complex affective, cognitive, and behavioral phenomena that occur when individuals come into contact with potentially rewarding stimuli. On the other hand, the interoceptive system is able to make connections between all cortical, subcortical, and limbic systems to orchestrate a complex set of responses. Craving and urges are among the most notable responses, and may have important functions to preserve homeostasis.

How Long Does Craving Predict Use of Methamphetamine? Assessment of Use One to Seven Weeks after the Assessment of Craving

Aims

This study lays the foundation for a clinical prediction model based on methamphetamine craving intensity and its ability to predict the presence or absence of within-treatment methamphetamine use.

Design

We used a random effects logistic approach for estimating repeated-measures, generalized linear mixed models (GLMM) using craving as the sole predictor of methamphetamine. A multivariate GLMM included craving, length of treatment, treatment assignment, and methamphetamine use the previous week as covariates to control for potential confounds. We performed receiver operating characteristic (ROC) analyses to evaluate predictive accuracy. We investigated further whether methamphetamine craving predicted subsequent use more accurately at intervals more proximal to versus those more distal to assessment, examining one-week periods ending one to seven weeks after assessment of craving.

Setting

The study was part of the Center for Substance Abuse Treatment (CSAT) Methamphetamine Treatment Project (MTP).

Subjects

Analyses were based on data from 691 methamphetamine dependent outpatients enrolled in the MTP.

Measurements

Craving was assessed by self-report on a 0–100 scale. Self-reported methamphetamine use was toxicologically verified. Craving and drug use were assessed weekly for 8 weeks.

Findings

In the univariate analysis craving predicted methamphetamine use in the week immediately following the craving report (p < 0.0001), with subject-specific use increasing 0.38% for each one-point increase in craving on a 0–100 scale. In the multivariate analysis the probability of use decreased by 2.45% for each week in treatment increased by 33.11% for previous methamphetamine use, and the probability of methamphetamine use still increased with craving, rising 0.28% for each one-point increase in craving score (all p < 0.0001). Predictive accuracy was strongest at the one-week time-lag and declined in magnitude the more distal the assessment period.

Conclusions

Craving is a predictor of within-treatment methamphetamine use. Intensity of craving is appropriate for use as a surrogate marker in methamphetamine dependence.

Predicting in-treatment performance and post-treatment outcomes in methamphetamine users

AIMS

This study examines the utility of individual drug use and treatment characteristics for predicting in-treatment performance and post-treatment outcomes over a 1-year period.

DESIGN, SETTING AND PARTICIPANTS

Data were collected from 420 adults who participated in the Methamphetamine Treatment Project (MTP), a multi-site study of randomly assigned treatment for methamphetamine dependence. Interviews were conducted at baseline, during treatment and during three follow-up time-points: treatment discharge and at 6 and 12 months following admission.

MEASUREMENTS

The Addiction Severity Index (ASI); the Craving, Frequency, Intensity and Duration Estimate (CFIDE); and laboratory urinalysis results were used in the current study.

FINDINGS

Analyses addressed both in-treatment performance and post-treatment outcomes. The most consistent finding is that pre-treatment methamphetamine use predicts in-treatment performance and post-treatment outcomes. No one variable predicted all in-treatment performance measures; however, gender, route of administration and pre-treatment methamphetamine use were significant predictors. Similarly, post-treatment outcomes were predicted by a range of variables, although pre-treatment methamphetamine use was significantly associated with each post-treatment outcome.

CONCLUSIONS

These findings provide useful empirical information about treatment outcomes for methamphetamine abusers, and highlight the utility of assessing individual and in-treatment characteristics in the development of appropriate treatment plans.

Location, location: using functional magnetic resonance imaging to pinpoint brain differences relevant to stimulant use

AIMS

The purpose of this review is to summarize the neural substrate dysfunctions and disrupted cognitive, affective and experiential processes observed in methamphetamine and cocaine-dependent individuals.

METHODS

We reviewed all publications in PubMed that conducted comparison studies between healthy volunteers and cocaine-, amphetamine- or methamphetamine-dependent individuals using functional magnetic resonance imaging.

RESULTS

Stimulant dependence is characterized by a distributed alteration of functional activation to a number of experimental paradigms. Attenuated anterior and posterior cingulate activation, reduced inferior frontal and dorsolateral prefrontal cortex activation and altered posterior parietal activation point towards an inadequate demand-specific processing of information. Processes reported most consistently to be deficient in these functional neuroimaging studies include inhibitory control, executive functioning and decision-making.

CONCLUSION

One emerging theme is that stimulant-dependent individuals show specific, rather than generic, brain activation differences, i.e. instead of showing more or less brain activation regardless of task, they exhibit process-related brain activation differences that are consistent with a shift from context-specific, effortful processing to more stereotyped, habitual response generation.