Correlates of outpatient drug treatment drop-out among methamphetamine users

The role of aggression in substance use: The prison case

OBJECTIVES

Substance use and aggressive behaviour pattern is considered as a serious criminal behaviour threat. This analytical cross-sectional study was designed to determine the level of aggression of convicts with substance use and to determine the variables predicting the substance use characteristics of convicts.

METHODS

The study was carried out with 255 male convicts in 2 different closed penal execution institutions in Izmir province. In order to measure demographic variables, data were collected using the Information Form, Buss Perry Aggression Questionnaire and Addiction Profile Index.

RESULTS

When convicts were examined according to demographic variables, it was found that there was a significant difference between the groups in terms of variables such as age, marital status, domestic violence, history of psychological treatment and self-harm behaviour. The results showed that 85.5% of convicts had used cannabis more than three times in their lifetime. Also there was a significant difference between the total score obtained from the aggression scale and the number of substance types used.

CONCLUSIONS

Multidisciplinary approach in the field of addiction can go a long way in solving the problem and will play an important role in the protection of society, individuals and victims.

Demonstration of an app-delivered digital therapeutic program for methamphetamine use disorder

This study assessed the feasibility and utility of a digital, all-virtual program designed for treatment of methamphetamine use disorder (MUD). Forty-nine adults with moderate- to severe-level MUD (per DSM-5 criteria) commenced the 8-week intervention. All aspects of the program were delivered via smartphone-based app. Intervention components included counseling (cognitive behavioral therapy in group and individual sessions), app-based therapeutic tasks, remote biological drug testing, medical oversight by psychiatrists/nurse practitioners, and contingency management procedures (including rewards for methamphetamine-free saliva drug tests, accomplishing tasks, and engaging in assigned activities). Of the 49 participants who commenced treatment, 27 participants (55%) completed the program. Repeated-measures mixed-model analyses show that participants were more likely to test negative for meth use from week 1 to week 8 (OR = 1.57, 95% CI [1.28, 1.97]; p = 0.034). Well-being and social functioning improved among the majority of participants. These results demonstrate the utility of the all-virtual, digital therapeutic program and its ability to help individuals with MUD to reduce or cease methamphetamine use. The program was efficiently implemented and was well received by participants and clinical personnel, indicating its ability to deliver comprehensive, effective care and to retain the difficult-to-engage population of persons with MUD. Of the 27 completers, 16 responded to a 1-month follow-up survey and reported no meth use in the month since completing the program.

Exploring psilocybin-assisted psychotherapy in the treatment of methamphetamine use disorder

Methamphetamine use disorder is a chronic relapsing condition associated with substantial mental, physical, and social harms and increasing rates of mortality. Contingency management and psychotherapy interventions are the mainstays of treatment but are modestly effective with high relapse rates, while pharmacological treatments have shown little to no efficacy. Psilocybin-assisted psychotherapy is emerging as a promising treatment for a range of difficult-to-treat conditions, including substance use disorders; however, no studies have yet been published looking at psilocybin-assisted psychotherapy in the treatment of methamphetamine use disorder. Here we review the rationale for psilocybin-assisted psychotherapy as a potential treatment for this indication, and describe practical considerations based on our early experience designing and implementing four separate clinical trials of psilocybin-assisted psychotherapy for methamphetamine use disorder.

Correlates of treatment engagement and client outcomes: results of a randomised controlled trial of nabiximols for the treatment of cannabis use disorder

INTRODUCTION AND AIMS

There is increasing interest and evidence for the use of cannabinoid medications in the treatment of cannabis use disorder, but little examination of the correlates of successful treatment. This paper is a secondary analysis of a randomised placebo-controlled trial of nabiximols for the treatment of cannabis use disorder (CUD), aiming to identify which client and treatment characteristics impact treatment engagement and outcomes.

METHOD

Bayesian multiple regression models were used to examine the impact of age, gender, duration of regular cannabis use, daily quantity of cannabis, cannabis use problems, self-efficacy for quitting, sleep, mental health, pain measures, and treatment group upon treatment engagement (retention, medication dose, and counselling participation) and treatment outcomes (achieving end-of-study abstinence, and a 50% or greater reduction in cannabis use days) among the 128 clients participating in the 12-week trial.

RESULTS

Among the treatment factors, greater counselling attendance was associated with greater odds of abstinence and ≥ 50% reduction in cannabis use; nabiximols with greater odds of ≥ 50% reduction and attending counselling, and reduced hazard of treatment dropout; and higher dose with lower odds of ≥ 50% reduction. Among the client factors, longer duration of regular use was associated with higher odds of abstinence and 50% reduction, and lower hazard of treatment dropout; greater quantity of cannabis use with reduced hazard of dropout, greater odds of attending counselling, and higher average dose; greater pain at baseline with greater odds of ≥ 50% reduction and higher average dose; and more severe sleep issues with lower odds of ≥ 50% reduction. Males had lower odds of attending counselling.

DISCUSSIONS AND CONCLUSIONS

These findings suggest that counselling combined with agonist pharmacotherapy may provide the optimal treatment for cannabis use disorder. Younger clients, male clients, and clients with sleep issues could benefit from extra support from treatment services to improve engagement and outcomes.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ACTRN12616000103460) https://www.anzctr.org.au.

A specific cognitive behavioral group therapy program for stimulant use disorder

INTRODUCTION

Stimulant use is an important health issue. In the US in 2018, 2.8% of males and 1.5% of females older than 18 had used cocaine in the preceding 12 months.

OBJECTIVE

To intervene in a specific targeted group of Stimulant Use Disorder (SUD) patients according to CBT and relapse prevention theories, and to determine the program's feasibility and attendance.

METHOD

Stimulant Use Disorder patients in addiction care were evaluated for addictive, psychological and psychiatric dimensions at baseline and conclusion in a 9-session CBT group program with several themes: define SUD, enhance motivation, involve close companions, cope with craving, decline a proposal, solve problems, invite expert patients, invest time and money, and review content.

RESULTS

In total, 41 patients attended at least one session. They were mainly poly dependent, primarily cocaine users. Sixty percent of the population also suffered from another psychiatric comorbidity. Median attendance for participants was 7/9 sessions.

CONCLUSION

A specific targeted CBT group for stimulant dependent highly comorbid patients is feasible. These findings suggest that peers should be included in addiction care services.

Oxytocin increases physiological linkage during group therapy for methamphetamine use disorder: a randomized clinical trial

Patients and psychotherapists often exhibit behavioral, psychological, and physiological similarity. Here, we test whether oxytocin—a neuropeptide that can enhance expressivity and social perception—influences time-lagged “linkage” of autonomic nervous system responses among participants and facilitators during group therapy. Physiological linkage estimates (n = 949) were created from ten cohorts, each with two facilitators (n = 5) and four to six participants (n = 48), over six weekly sessions of group therapy for methamphetamine use disorder. All participants of a cohort received oxytocin or placebo intranasally in a randomized double-blind procedure before each session. Cardiac interbeat intervals (IBI) were measured continuously during sessions to estimate physiological linkage, operationalized as one cohort-mate’s IBI reactivity during one minute predicting another cohort-mate’s IBI reactivity during the following minute. In oxytocin cohorts, participants and facilitators experienced significant physiological linkage to their cohort-mates (i.e., their physiological responses were predicted by the prior responses of their cohort-mates) and significantly more linkage than people in placebo cohorts. Both effects occurred during the first and second sessions but not later sessions. Results suggest that oxytocin may enhance psychosocial processes often associated with linkage—such as social engagement—in groups and highlight oxytocin’s potential to improve group cohesion during group therapy.

Clinical Trials Registration: NCT02881177, First published on 26/08/2016.

Predictors of length of treatment, discharge reason, and re-admission to Aboriginal alcohol and other drug residential rehabilitation services in New South Wales, Australia

INTRODUCTION

Aboriginal clients accessing Aboriginal community-controlled residential alcohol and other drug rehabilitation services in New South Wales, Australia believe they have better outcomes due to culturally appropriate care. However, there is a paucity of published treatment outcome data. This study aims to identify predictors of treatment outcomes based on client characteristics at intake.

METHODS

A cross-sectional, retrospective, observational study of 2326 admissions to six services between January 2011 and December 2016. The outcomes were: (i) leaving treatment early; (ii) self-discharge or house discharge (by staff); and (iii) re-admission within two years. The predictors examined were Aboriginal status, age, justice system referral and primary substance of concern. Competing risk and Poisson regression analyses were used to identify trends in the data.

RESULTS

The mean age of clients was 33 years, and the majority (56%) stayed at least 6 weeks. Aboriginal clients whose primary substance of concern was stimulants were almost eight times more likely to re-admitted within 2 years than other clients (risk ratio 7.91; P < 0.001). Aboriginal clients who were also referred from justice were more likely to self-discharge (risk ratio 1.87; P < 0.001). Furthermore, Aboriginal clients who were aged older than 30 were less likely to have a re-admission (risk ratio 0.32; P ≤ 0.001).

DISCUSSION AND CONCLUSIONS

This study showed client characteristics that are predictive of harmful outcomes include age under 30, justice client, primary substance of use and their interactions. Future research could build on these results to aid ongoing development of residential rehabilitation programs for Aboriginal peoples.

Factors Associated with Substance Use Disorder Treatment Completion, Rhode Island, USA, 2018

INTRODUCTION

The successful retention of individuals with substance use disorders in treatment remains a challenge but is an important indicator of positive post-treatment outcomes. The aim of this study is to advance understanding of pre-admission factors associated with substance use treatment completion in Rhode Island.

METHODS

Data for this longitudinal analysis are from the RI Behavioral Health On-Line Database (RI-BHOLD). The primary outcome of interest was substance use treatment completion defined as any planned discharge from treatment, including transfers to other facilities. Associations were assessed using generalized estimating equations (GEE) to account for the potential of repeated measures for the same individuals.

RESULTS

Among the 7,351 clients discharged from a substance use treatment program in RI in 2018, the treatment completion rate was 58.1%. There was a positive relationship between the frequency of attendance of voluntary self-help groups and odds of treatment completion. Treatment completion rates were lower among those who reported use of opioids (AOR: 0.59; 95% CI: 0.52-0.66) and other drugs (AOR: 0.52; 95% CI: 0.44-0.62), compared to alcohol and for those with co-occurring mental health conditions (AOR: 0.85; 95% CI: 0.76-0.94).

CONCLUSIONS

This study highlights the importance of social connectedness in substance use disorder treatment completion. Future research is needed to identify the characteristics of persons who are most likely to benefit from self-help groups and the optimal combination of treatment participation and attendance of self-help groups across a spectrum of disorder severity and community resources.

Integrated Care for Pregnant Women and Parents With Methamphetamine-Related Mental Disorders

Background: Methamphetamine use is a rapidly increasing cause of morbidity and mortality. Pregnant women and new parents who consume methamphetamine are at high risk since they seldom seek health services despite having multiple needs. We addressed this care gap by implementing an easily accessible program that pools resources from psychiatric, obstetric, and pediatric departments as well as community and government agencies. Method: This real-life observational study evaluated an integrated care program in 27 expecting parents and 57 parents of minors. The outcome criteria were treatment retention, psychosocial functioning, and abstinence. We compared participant demographics according to outcome and applied ordinal logistic regression to predict treatment success. Results: Patients received integrated care for almost 7 months on average. Nearly half achieved stable abstinence and functional recovery. Only one pregnant woman dropped out before a care plan could be implemented, and all women who gave birth during treatment completed it successfully. Three-fourths of patients had psychiatric comorbidities. Patients with depressive disorders were almost 5 times less likely to succeed with treatment. Attention-deficit hyperactivity disorder (ADHD) was diagnosed in nearly 30% of patients who dropped out of a care plan, which was about 4 times more often than in the successful outcome group. Conclusion: Our program engaged pregnant women and parents in treatment and helped them recover from methamphetamine-related mental disorders. Management of comorbid ADHD and depression should be an integral part of care initiatives to counter the methamphetamine crisis that affects parents and children across the globe.

Cognitive impairment in chronic ketamine abusers

BACKGROUND

The treatment of ketamine users is substantially challenged by high dropout rates, raising questions regarding contributing factors. A number of studies have highlighted the potential of greater focus on the clinical significance of cognitive impairments in ketamine users. The present study hypothesized that cognitive deficits would play a role in greater risk for treatment dropout in chronic ketamine users.

METHODS

Our study examined cognitive performance in the form of working memory, verbal memory, visual memory and executive function among chronic ketamine users who completed three-month treatment in residential detoxification centres (N = 165), those who dropped out prematurely (N = 121) and drug-free healthy controls (N = 111). The data collection was completed in Hong Kong among the East Asia population.

RESULTS

Compared to healthy controls, cognitive impairments were found in ketamine users, including in verbal/visual memory and executive function. Executive dysfunction was significantly associated with dropout in ketamine users within three months.

CONCLUSION

Our findings suggest that executive dysfunction may have clinical benefits in ketamine users admitted to residential treatment programmes.

Oxytocin-enhanced group therapy for methamphetamine use disorder: Randomized controlled trial

BACKGROUND

Methamphetamine (METH) use is a public health crisis that disproportionately affects men who have sex with men (MSM). There are currently no FDA-approved pharmacological interventions to treat methamphetamine use disorder (MUD). MUD is associated with social impairments and extremely high treatment attrition rates. Administration of oxytocin, a neuropeptide involved in social attachment, may be a novel approach to addressing these issues. Moreover, oxytocin administration has shown promise for reducing METH-related addictive behavior in animal models, but has not yet been investigated in clinical trials for MUD. Last, oxytocin is known to modulate stress responsivity via regulation of the autonomic nervous system, which is dysregulated in METH users. We hypothesize that oxytocin, in combination with group psychotherapy, will increase treatment engagement, reduce addiction behavior, and mitigate stress hyperreactivity.

METHODS

This is a randomized, double blind trial of oxytocin 40-IU (n = 24) or placebo (n = 24) administered intranasally prior to each of six weekly motivational interviewing group therapy (MIGT) sessions for MUD in MSM.

PRIMARY OUTCOME

(a) session attendance.

SECONDARY OUTCOMES

(b) group cohesion, (c) anxiety, (d) METH craving, (e) METH use, and (f) in-session cardiac physiology.

RESULTS

Participants receiving oxytocin had significantly higher group therapy attendance than those receiving placebo, OR 3.26, 95% CI [1.27-8.41], p = .014. There was a small effect of oxytocin on group cohension, but not anxiety or craving. METH use did not change over the six-week MIGT course in either treatment arm. Participants receiving oxytocin had lower average heart rates during MIGT sessions and higher heart rate variability. There were positive main effects of MIGT over Time regardless of study drug.

CONCLUSIONS

This evidence, and the lack of any serious adverse events, suggests that oxytocin may safely increase treatment attendance. One possible mechanism by which it may do so is its modulation of the autonomic nervous system. Further investigation is warranted.

Initial treatment dropout in patients with substance use disorders attending a tertiary care de-addiction centre in north India

Background & objectives:

Dropout from substance use disorders treatment is associated with poor outcomes. Although many factors have been associated with an early dropout of patients, the reasons for dropping out of treatment prematurely remain poorly understood particularly in the Indian context. This study was aimed to study socio-demographic and clinical variables predicting initial dropout of patients attending a tertiary care de-addiction treatment centre in north India.

Methods:

Information was extracted from the records of consecutive newly registered patients from January 2011 to December 2014. The patients who did not come for follow up within 30 days of the first contact were defined as initial dropouts.

Results:

Data of 7991 patients could be retrieved. Majority of the sample consisted of male, married and employed individuals. Of them, 4907 patients (61.3%) were considered initial dropouts. Multivariate analysis revealed that after controlling for other factors, greater age, being employed, lower educational status, lesser duration of substance use, use of alcohol, opiate, tobacco, cannabis or sedative-hypnotic use but the absence of multi-substance use predicted initial drop out.

Interpretation & conclusions:

This study identified some socio-demographic and clinical variables which might predict treatment attrition in substance use disorders. Clinician's awareness towards these factors and tailor-made intervention might improve initial treatment retention. Future research could be directed to find the validity of this assumption.

Age differences in outcomes among patients in the "Stimulant Abuser Groups to Engage in 12-Step" (STAGE-12) intervention

Emerging adults (roughly 18-29years) with substance use disorders can benefit from participation in twelve-step mutual-help organizations (TSMHO), however their attendance and participation in such groups is relatively low. Twelve-step facilitation therapies, such as the Stimulant Abuser Groups to Engage in 12-Step (STAGE-12), may increase attendance and involvement, and lead to decreased substance use.

AIMS

Analyses examined whether age moderated the STAGE-12 effects on substance use and TSMHO meeting attendance and participation.

DESIGN

We utilized data from a multisite randomized controlled trial, with assessments at baseline, mid-treatment (week 4), end-of-treatment (week 8), and 3- and 6- months post-randomization.

PARTICIPANTS

Participants were adults with DSM-IV diagnosed stimulant abuse or dependence (N=450) enrolling in 10 intensive outpatient substance use treatment programs across the U.S.

ANALYSIS

A zero-inflated negative binomial random-effects regression model was utilized to examine age-by-treatment interactions on substance use and meeting attendance and involvement.

FINDINGS

Younger age was associated with larger treatment effects for stimulant use. Specifically, younger age was associated with greater odds of remaining abstinent from stimulants in STAGE-12 versus Treatment-as-Usual; however, among those who were not abstinent during treatment, younger age was related to greater rates of stimulant use at follow-up for those in STAGE-12 compared to TAU. There was no main effect of age on stimulant use. Younger age was also related to somewhat greater active involvement in different types of TSMHO activities among those in STAGE-12 versus TAU. There were no age-by-treatment interactions for other types of substance use or for treatment attendance, however, in contrast to stimulant use; younger age was associated with lower odds of abstinence from non-stimulant drugs at follow-up, regardless of treatment condition. These results suggest that STAGE-12 can be beneficial for some emerging adults with stimulant use disorder, and ongoing assessment of continued use is of particular importance.

Applying an ensemble classification tree approach to the prediction of completion of a 12-step facilitation intervention with stimulant abusers

The purpose of this study was to explore the selection of predictor variables in the evaluation of drug treatment completion using an ensemble approach with classification trees. The basic methodology is reviewed, and the subagging procedure of random subsampling is applied. Among 234 individuals with stimulant use disorders randomized to a 12-step facilitative intervention shown to increase stimulant use abstinence, 67.52% were classified as treatment completers. A total of 122 baseline variables were used to identify factors associated with completion. The number of types of self-help activity involvement prior to treatment was the predominant predictor. Other effective predictors included better coping self-efficacy for substance use in high-risk situations, more days of prior meeting attendance, greater acceptance of the Disease model, higher confidence for not resuming use following discharge, lower Addiction Severity Index (ASI) Drug and Alcohol composite scores, negative urine screens for cocaine or marijuana, and fewer employment problems. The application of an ensemble subsampling regression tree method utilizes the fact that classification trees are unstable but, on average, produce an improved prediction of the completion of drug abuse treatment. The results support the notion there are early indicators of treatment completion that may allow for modification of approaches more tailored to fitting the needs of individuals and potentially provide more successful treatment engagement and improved outcomes.

The Baltimore Buprenorphine Initiative: understanding the role of buprenorphine in addressing heroin addiction in an urban-based community

Adequate drug treatment for substance users continues to be a challenge for most U.S. cities. To address heroin addiction in Baltimore, the Baltimore Buprenorphine Initiative was implemented as a joint project to promote individualized, patient-centered buprenorphine therapy in conjunction with behavioral treatment to accelerate recovery from opioid addiction. The purpose of this analysis was to explore differences in recovery trajectories predicting length of stay and use this information to predict characteristics that influence an individual's ability to remain in the Baltimore Buprenorphine Initiative program. The sample consisted of 1,039 subjects enrolled in the program between January 2008 and June 2009. The regression modeling determined that age, income, employment, and higher level of treatment were significant predictors of length of stay in the recovery program. The findings of this study have practical implications for the design and implementation of heroin addiction programs. The research indicates that focusing on these specific predictive variables early in the program design phase could increase recovery success rates as measured by length of stay.

Older methadone patients achieve greater durations of cocaine abstinence with contingency management than younger patients

BACKGROUND AND OBJECTIVES

Contingency management (CM) interventions are efficacious in treating cocaine abusing methadone patients, but few studies have examined the effect of age on treatment outcomes in this population. This study evaluated the impact of age on treatment outcomes in cocaine abusing methadone patients.

METHODS

Data were analyzed from 189 patients enrolled in one of three randomized studies that evaluated the efficacy of CM versus standard care (SC) treatment.

RESULTS

Age was associated with some demographics and drug use characteristics including racial composition, education, and methadone dose. Primary drug abuse treatment outcomes did not vary across age groups, but CM had a greater benefit for engendering longer durations of abstinence in the middle/older and older age groups compared to the younger age groups. At the 6-month follow-up, submission of a cocaine positive urine sample was predicted by submission of a cocaine positive sample at intake, higher methadone doses, and assignment to SC rather than CM treatment.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

As substance abusers are living longer, examination of the efficacy of pharmacological and psychosocial treatments specifically within older age groups may lead to a better understanding of subpopulations for whom enhanced treatments such as CM are warranted.

Examining the interactive effect of posttraumatic stress disorder, distress tolerance, and gender on residential substance use disorder treatment retention

An extensive body of research has demonstrated that patients with a co-occurring posttraumatic stress disorder (PTSD) and substance use disorder (SUD) diagnosis are at high risk for a wide range of negative clinical outcomes, including treatment noncompletion. However, no studies to date have explored the effect of a PTSD-SUD diagnosis on residential SUD treatment completion, as well as potential moderators of this effect. Consequently, the goal of this study was to examine the interactive effect of a PTSD diagnosis, distress tolerance (DT), and gender on residential SUD treatment retention. Participants were 214 substance-dependent patients consecutively admitted to a residential SUD treatment facility. Participants were administered diagnostic interviews, completed a laboratory-based measure of DT, and were followed throughout the course of treatment. Although no significant main effects were found, results did reveal a significant PTSD × gender × DT interaction. Post hoc analyses indicated that, among men, those with a current diagnosis of PTSD and low DT completed a significantly lower proportion of residential SUD treatment compared to all other groups. The implications of the study's findings for identifying ways to improve residential SUD treatment retention among patients with a PTSD-SUD diagnosis are discussed.

Gender Differences in Psychiatric Symptoms among Methamphetamine Dependent Residents in Sober Living Houses

OBJECTIVES

Although psychiatric symptoms among methamphetamine (MA) dependent individuals have been studied in treatment programs, they have not been examined in services designed to support sustained recovery in the community (e.g. sober living houses). In addition, some disorders more common among women, such as somatoform and bulimia, have been understudied among MA dependent individuals. This study aimed to examine psychiatric symptom differences between MA dependent men and women who we entering sober living houses (SLHs).

METHODS

Two hundred forty five individuals were interviewed within one week of entering SLHs. Instruments included a DSM IV based measure for MA dependence, a psychiatric screen (the Psychiatric Diagnostic Screening Questionnaire), demographics, recent substance use and recent use of services.

RESULTS

Of the 245 participants, 103 men and 25 women met criteria for MA dependence. Womenwith MA dependence reported more psychiatric symptoms than men. They also trended toward reporting more psychiatric symptoms than non-MA dependent women. For men, psychiatric symptoms did not vary between those with and without MA dependence. Some understudied disorders (e.g., somatoform) had large proportions of women meeting the screening criteria.

CONCLUSIONS

Additional research is needed on understudied psychiatric disorders that are common among MA dependent women. SLH's should consider ways to address psychiatric symptoms among MA dependent individuals, especially women. Strategies could include increasing linkages with professional mental health services as well as developing peer oriented strategies for managing symptoms.

Two-Year Outcomes of Treatment for Methamphetamine Use

While evaluation research supports the general effectiveness of substance abuse treatment, there is not a comprehensive literature on treatment effectiveness for methamphetamine (MA) use. The authors consider three outcome measures--MA use, criminal activity, and employment--compared across three periods: 24-months pretreatment, during treatment, and 24-months post-treatment. Data are from an intensive natural history interview conducted two to three years after treatment for 349 randomly selected admissions to treatment for MA abuse in a large publicly-funded county treatment system. Through this naturalistic design, data provide a system-wide perspective on effectiveness of treatment as usual. Results showed reduction in MA use and crime during and following treatment and increased employment following treatment over pretreatment levels. Regression analyses showed higher levels of education and more time in treatment related to more positive post-treatment outcomes for all three measures. Lower percentage of post-treatment months with MA use also was related to more pretreatment MA-related problems, lower pretreatment MA use, and residential (compared to outpatient) treatment modality. Lower post-treatment criminal activity was also related to gender (being female), lower pretreatment criminal activity, and residential modality. Higher percentage of post-treatment months with employment also was related to gender (being male), ethnicity (not African-American), and higher pretreatment employment.

Where did all the pathological gamblers go? Gambling symptomatology and stage of change predict attrition in longitudinal research

Attrition can introduce a systematic bias that can negatively affect validity (Cook and Campbell, Quasi-experimentation: design and analysis issues for field settings. Rand McNally, Chicago, 1979). Current longitudinal research in gambling, however, has generally overlooked the reasons for attrition. The current research examined the relationship between pathological gambling symptomatology, stage of change and attrition. Three hundred and seventy-nine participants were contacted 12 months after initially participating in a study on gambling for a follow-up session. Logistic regression revealed those in the contemplation and preparation stages of change reported higher levels of pathological gambling symptomatology and were more likely to drop out of the study compared to those in the precontemplation stage. As predicted, gambling symptomatology mediated the relationship between stages of change and attrition. The implication for longitudinal research on gambling as well as extant findings that have used this methodological approach is discussed.

Interaction effects of age and contingency management treatments in cocaine-dependent outpatients

As the American population ages, older adults are accounting for a larger percentage of the drug-abusing population, but little attention has been given to this age group especially in regards to evaluating responsivity to different treatment modalities. Contingency management (CM) is a highly effective behavioral treatment that provides positive tangible reinforcers for objective evidence of behavior change. The purpose of this study was to examine main and interactive effects of age on outcomes in cocaine-dependent patients receiving CM with standard care (SC) or SC alone. Patients (N = 393) participating in 1 of 3 randomized trials of CM for cocaine dependence were divided into young, middle, and older age cohorts. Baseline characteristics and outcomes were compared across the age groups. The oldest age group had more medical problems than the youngest and middle age groups but had fewer legal difficulties and psychiatric symptoms. The oldest age group remained in treatment significantly longer than the other age groups, regardless of the type of treatment received. Although all age groups benefited from CM in terms of retention and longest duration of abstinence achieved, a significant age by treatment interaction effect emerged, with the older cohort improving relatively less from CM than the younger age groups. These findings demonstrate that age may play a role in moderating intervention outcomes, and tailoring CM to the needs of older and middle-aged substance abusers may be important for improving outcomes in this growing population.

Perceptions of discriminatory treatment by staff as predictors of drug treatment completion: utility of a mixed methods approach

INTRODUCTION AND AIMS

Staff interactions with their clients are an important factor in the quality of care that is provided to people in drug treatment. Yet there is very little research that addresses staff attitudes or clients' perceptions of discrimination and prejudice by staff with regard to treatment outcomes. This research aimed to assess whether perceptions of discrimination by staff predict drug treatment completion.

DESIGN AND METHODS

The study used a mixed methods approach. Ninety-two clients in residential rehabilitation facilities in Sydney were administered a series of quantitative measures assessing drug history, severity of drug use, treatment history, perceptions of staff discrimination and treatment motivation. Clients were followed up regularly until an outcome (dropout or completion) was obtained for the full sample.

RESULTS

Perceptions of discrimination were a significant predictor of treatment completion, with greater perceived discrimination associated with increased dropout. Qualitative interviews with 13 clients and eight health-care workers from these treatment services were then conducted to gain insight into how perceived discrimination may impact on treatment experiences. Clients and staff discussed how they would address the issue of perceived discrimination during the current treatment experience.

DISCUSSION AND CONCLUSIONS

Adopting a mixed methods approach facilitated exploration of the impact of perceived discrimination on treatment from both clients' and health-care workers' perspectives. This methodology may also enhance interpretation and utilisation of these findings in drug treatment.

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. 

Psychosocial treatment for methamphetamine use disorders: a preliminary randomized controlled trial of cognitive behavior therapy and Acceptance and Commitment Therapy

Acceptance and Commitment Therapy (ACT) incorporates developments in behavior therapy, holds promise but has not been evaluated for methamphetamine use disorders. The objective of this study was to test whether ACT would increase treatment attendance and reduce methamphetamine use and related harms compared to cognitive behavior therapy (CBT). One hundred and four treatment-seeking adults with methamphetamine abuse or dependence were randomly assigned to receive 12 weekly 60-minute individual sessions of ACT or CBT. Attrition was 70% at 12 weeks and 86% at 24 weeks postentry. Per intention-to-treat analysis, there were no significant differences between the treatment groups in treatment attendance (median 3 sessions), and methamphetamine-related outcomes; however, methamphetamine use (toxicology-assessed and self-reported), negative consequences, and dependence severity significantly improved over time in both groups. Although ACT did not improve treatment outcomes or attendance compared to CBT, it may be a viable alternative to CBT for methamphetamine use disorders. Future rigorous research in this area seems warranted.

Feasibility and acceptability of a phase II randomized pharmacologic intervention for methamphetamine dependence in high-risk men who have sex with men

OBJECTIVE

To determine whether actively using, methamphetamine (meth)-dependent men who have sex with men (msm) could be enrolled and retained in a pharmacologic intervention trial, and the degree to which participants would adhere to study procedures, including medication adherence. study design: phase ii randomized, double-blind trial of bupropion vs. placebo.

METHODS

Thirty meth-dependent, sexually active MSM were randomized to receive daily bupropion XL 300 mg or placebo for 12 weeks. Participants received weekly substance use counseling, provided weekly urine specimens, and completed monthly audio-computer assisted self-interview (ACASI) behavioral risk assessments. Adherence was measured by medication event monitoring systems (MEMS) caps (the number of distinct MEMS cap openings divided by the number of expected doses) and self-report.

RESULTS

Ninety percent completed the trial: 89% of monthly ACASIs were completed, 81% of study visits were attended, and 81% of urine samples were collected. Adherence by MEMS cap was 60% and by self-report was 81% and did not differ significantly by treatment assignment. The median number of positive urine samples was 5.5 out of a possible 11 (50%). Participants in both arms reported similar declines in the median number of sex partners (P = 0.52). No serious adverse events occurred and there were no significant differences in adverse events by treatment assignment (P = 0.11).

CONCLUSIONS

It is feasible to enroll and retain actively using, meth-dependent MSM in a pharmacologic intervention. Bupropion was well tolerated. Study participation and retention rates were high, however, study drug medication adherence was only moderate. Findings support a larger trial with improved adherence support to evaluate the efficacy of bupropion and other pharmacologic interventions for meth dependence in this population.

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.

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.

Substance user treatment dropout from client and clinician perspectives: a pilot study

Reasons for premature termination of outpatient substance user treatment were evaluated from client and clinician perspectives using qualitative (focus groups) and quantitative (survey) methods in a pilot study (N = 44). The sample consisted of clients (n = 22), the majority of whom were male (73%) and African American (50%) or Caucasian (41%). The sample of clinicians (n = 22) were predominantly female (64%), and Caucasian (52%) or African American (24%). The most frequently endorsed reasons for leaving treatment were related to individual rather than program characteristics with heavy drug or alcohol use, transportation or financial problems, and ambivalence about abstinence being highly rated by both clinicians and clients. Survey results indicated that clinicians more frequently attributed treatment dropout to individual- or client-level factors than did clients. Focus group ratings indicated that clinicians felt client motivation and staff connection issues were primary reasons for dropout, whereas clients indicated social support and staff connection issues. The findings suggest that the development of early therapeutic alliance and active problem solving of potential barriers to treatment attendance may influence treatment retention.

Early exit: estimating and explaining early exit from drug treatment

Background

Early exit (drop-out) from drug treatment can mean that drug users do not derive the full benefits that treatment potentially offers. Additionally, it may mean that scarce treatment resources are used inefficiently. Understanding the factors that lead to early exit from treatment should enable services to operate more effectively and better reduce drug related harm. To date, few studies have focused on drop-out during the initial, engagement phase of treatment. This paper describes a mixed method study of early exit from English drug treatment services.

Methods

Quantitative data (n = 2,624) was derived from three English drug action team areas; two metropolitan and one provincial. Hierarchical linear modelling (HLM) was used to investigate predictors of early-exit while controlling for differences between agencies. Qualitative interviews were conducted with 53 ex-clients and 16 members of staff from 10 agencies in these areas to explore their perspectives on early exit, its determinants and, how services could be improved.

Results

Almost a quarter of the quantitative sample (24.5%) dropped out between assessment and 30 days in treatment. Predictors of early exit were: being younger; being homeless; and not being a current injector. Age and injection status were both consistently associated with exit between assessment and treatment entry. Those who were not in substitution treatment were significantly more likely to leave treatment at this stage. There were substantial variations between agencies, which point to the importance of system factors. Qualitative analysis identified several potential ways to improve services. Perceived problems included: opening hours; the service setting; under-utilisation of motivational enhancement techniques; lack of clarity about expectations; lengthy, repetitive assessment procedures; constrained treatment choices; low initial dosing of opioid substitution treatment; and the routine requirement of supervised consumption of methadone.

Conclusion

Early exit diminishes the contribution that treatment may make to the reduction of drug related harm. This paper identifies characteristics of people most likely to drop out of treatment prematurely in English drug treatment services and highlights a range of possibilities for improving services.

A nine session manual of motivational enhancement therapy for methamphetamine dependence: adherence and efficacy

Motivational enhancement therapy (MET) is a brief therapy shown to be effective for problem drinkers. Because the response to MET for other addictive disorders is mixed, we assessed the utility of increasing the number of sessions in subjects with methamphetamine (MA) dependence. One therapist was trained in a nine-session manual of MET, which was tested over eight weeks in 30 MA-dependent outpatients. Adherence to the manual was assessed by two raters, who reviewed a random sample of 15 audiotaped therapy sessions. Interventions were rated on a seven-point Likert scale for frequency/extensiveness (1 = not at all to 7 = extensively) and skill level (1 = unacceptable to 7 = high level of mastery). Ratings of adherence were moderate for frequency/extensiveness (4.2 +/- 2.2 and 4.3 +/- 1.8; Mean +/- SD) and high for skill level (5.4 +/- 0.6 and 5.2 +/- 0.4). Subjects attended 7.0 +/- 2.5 (78%) of nine sessions. Self-reported days of methamphetamine use decreased from 841/1793 (47%) of the 60 days prior to study entry to 448/1458 (31%) during the study (p = 0.011). MA-positive urine samples decreased from 76/118 (64%) during screening to 93/210 (44%) during treatment (p = 0.015). The MET manual was readily learned, and subjects attended a high proportion of therapy sessions with marked reductions in methamphetamine use.

Criminal justice itreatment admissions for methamphetamine use in California: a focus on Proposition 36

Methamphetamine (MA) use is considered as one of the nation's most pressing drug problems. In California, MA use has outstripped all other drugs in epidemiological extent, law enforcement activities, and treatment services demand. An opportunity for further study of MA use and its treatment emerged from a change in offender sentencing options introduced by California's Substance Abuse and Crime Prevention Act of 2000 (SACPA). Results indicate that statewide admissions for MA rose from 8.4% in FY 1992/1993 to 34.6% in FY 2004/2005, a four-fold increase over the 13 years. From the year before SACPA implementation to the year after, the percentage of treatment admissions due to MA use increased from 18.8% to 25.6%, an increase largely due to the fact that SACPA admissions were over 50% MA users. With the exception of alcohol, MA users entering treatment through SACPA had higher completion rates (about one third) from community based treatment than users of other primary drugs. This result held true for demographic and other subgroups of MA users. Multivariate regression results illuminate the relative importance of the variables examined. Implication of the findings for policy, intervention services, and research are discussed.

Drug court treatment for methamphetamine dependence: Treatment response and posttreatment outcomes

Relatively little is known about the impact of drug court treatment programs for methamphetamine (MA) dependence. This article examines treatment performance among a subsample of 287 MA-dependent adults who participated in the Methamphetamine Treatment Project from 1999 to 2001. To gain a preliminary indication of MA users' response to drug court intervention, we compared a group of 57 MA-dependent participants treated in outpatient treatment within the context of a drug court to a group of comparable MA-dependent individuals treated in outpatient treatment but not supervised by a drug court (n = 230). Analyses reveal that drug court participation was associated with better rates of engagement, retention, completion, and abstinence, compared to outpatient treatment without drug court supervision. Six- and 12-month outcome analyses indicated that participants who were enrolled in drug court intervention used MA significantly less frequently. These findings suggest that drug court supervision coupled with treatment may improve the outcomes of MA-dependent offenders beyond that seen from treatment alone.

Open-label study of a proprietary treatment program targeting type A gamma-aminobutyric acid receptor dysregulation in methamphetamine dependence

OBJECTIVE

To evaluate the safety and efficacy of the pharmacological component of a proprietary medical treatment program targeting type A gamma-aminobutyric acid receptor dysregulation in adults who met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision criteria for methamphetamine dependence.

PARTICIPANTS AND METHODS

A prospective, open-label, single-group study of the medication portion of a proprietary treatment program for methamphetamine dependence was conducted from July 1, 2005, to May 10, 2006, at Research Across America, an outpatient private, for-profit, clinical research company in Dallas, TX. In the study, flumazenil, hydroxyzine, and gabapentin, all of which were approved by the US Food and Drug Administration for indications other than drug dependence, were used off-label for the treatment of methamphetamine dependence. Fifty persons who had used methamphetamine within 7 days of study entry were enrolled and received the treatment. Treatment lasted 4 weeks, followed by 8 weeks of weekly follow-up visits to monitor for methamphetamine use via urine drug tests and self-reporting.

RESULTS

Participant retention was higher than expected, with 85% of participants completing the program. Significant decrease in methamphetamine use (P<.001) was noted at 84 days after vs 90 days before treatment. If missing data are counted as days of methamphetamine use, a 47% reduction in use was observed for the entire sample (P<.001) and a 65% reduction for the 36 who completed the 8-week evaluation phase (P<.001). Urine test results and self-reported use were positively correlated (Pearson r=0.72, P<.001). The frequency of cravings was reduced on average by 66% (P<.001), with 30 of 31 (97%) of the 36 who completed the study reporting reduction in cravings.

CONCLUSION

Substantial reductions in methamphetamine cravings and use were observed in all phases of treatment, and the retention rate of participants was high. These findings suggest that the efficacy of the medications and of the entire program in treating methamphetamine dependence should be examined in controlled trials.

Psychosocial approaches to psychostimulant dependence: A systematic review

This review examines the nature and evidence for the effectiveness of psychosocial interventions for psychostimulant dependence. Psychostimulant dependence and related harms continue to increase in many parts of the world, while treatment responses are predominantly limited to psychosocial interventions. The effectiveness of psychosocial interventions is compromised by poor rates of treatment induction and retention. As with other substance use disorders, increasing the diversity of treatment options is likely to improve treatment coverage and outcomes across a broader range of users. Identifying medications that might enhance treatment induction and retention would also enhance the effectiveness of psychosocial programs. It is concluded that psychosocial interventions are moderately effective in reducing psychostimulant use and related harms among psychostimulant-dependent persons.

Social pressure, coercion, and client engagement at treatment entry: a self-determination theory perspective

Research on coercion in addiction treatment typically investigates objective sources of social pressure among legally mandated clients. Little research has examined the impact of clients' perceptions of social pressures in generalist addiction services. Clients seeking substance abuse treatment (N=300; 221 males and 79 females; M age=36.6 years) rated the extent to which treatment was being sought because of coercive social pressures (external motivation; alpha=.89), guilt about continued substance abuse (introjected motivation; alpha=.84), or a personal choice and commitment to the goals of the program (identified motivation; alpha=.85). External treatment motivation was positively correlated with legal referral, social network pressures to enter treatment, and was inversely related to problem severity. In contrast, identified treatment motivation was positively correlated with self-referral and problem severity, and was inversely related to perceived coercion (ps<.05). Hierarchical multiple regression analyses showed that referral source (i.e., mandated treatment status), legal history, and social network pressures did not predict any of 6 measures of client engagement at the time treatment was sought. However, treatment motivation variables accounted for unique variance in these outcomes when added to each model (DeltaR(2)s=.06-.23, ps<.05). Specifically, identified treatment motivation predicted perceived benefits of reducing substance use, attempts to reduce drinking and drug use, as well as self (and therapist) ratings of interest in the upcoming treatment episode (betas=.18-.31, ps<.05). Results suggest that the presence of legal referral and/or social network pressures to quit, cut down, and/or enter treatment does not affect client engagement at treatment entry.

Methamphetamine treatment: trends and predictors of retention and completion in a large state treatment system (1992-2002)

This report describes trends in treatment admissions for methamphetamine/amphetamine (MA) abuse from 1992 to 2002 in California and assesses predictors of treatment retention and completion. Results show such admissions increasing fivefold and representing a growing proportion of overall treatment admissions. Patients admitted for MA abuse were increasingly diverse in race/ethnicity, older in age, and more frequently under legal supervision status over time. There was a decrease in injection drug use. Several user characteristics played consistent roles as risk factors for noncompletion and shorter treatment retention for both residential and outpatient admissions: having lower than a high school education, being younger at treatment admission, having a disability, having greater severity of MA use, and using injection drugs. Consistently, those with legal supervision status at admission had higher completion rates and longer retention than those reporting no legal status. Overall, findings suggested that clients with greater socioeconomic disadvantage and more severe problems may require greater efforts (e.g., services) to be retained in treatment.

The methamphetamine epidemic: implications for HIV prevention and treatment

Methamphetamine and related amphetamine compounds are among the most commonly used illicit drugs, with over 35 million users worldwide. In the United States, admissions for methamphetamine treatment have increased dramatically over the past 10 years. Methamphetamine use is prevalent among persons with HIV infection and persons at risk for HIV, particularly among men who have sex with men. In addition to being associated with increased sexual risk behavior, methamphetamine causes significant medical morbidity, including neurologic deficits, cardiovascular compromise, dental decay, and skin infections, all of which may be worsened in the presence of HIV/AIDS. Methamphetamine use may also result in decreased medication adherence, particularly during "binging" episodes. Behavioral counseling remains the standard of treatment for methamphetamine dependence, although the effectiveness of most counseling interventions has not been rigorously tested. Pharmacologic and structural interventions may prove valuable additional interventions to reduce methamphetamine use.

Reasons for dropout from drug abuse treatment: symptoms, personality, and motivation

Previous research has identified risk factors for early attrition from substance abuse treatment, but has not assessed reasons for dropout from the client's perspective. Interview and self-report assessment data were collected from 24 clients who prematurely terminated outpatient treatment to evaluate their subjective reasons for dropping out and the association of these reasons with demographic and clinical variables. Items from scales indicating problems with client motivation or conflicts with program staff were the most commonly endorsed. The severity of participant's symptoms and logistical problems interfering with appointments were less commonly reported as reasons for dropping out. Demographic, substance abuse, and motivational stage indicators were infrequently associated with subjective reasons for dropout. In contrast, indicators of maladaptive personality functioning were strongly associated with many reasons for dropping out, especially concerns about privacy and boundary issues within the program. Results from this preliminary evaluation will guide the development of an instrument and intervention focused on dropout risk factors and treatment reengagement.

Social control and coercion in addiction treatment: towards evidence-based policy and practice

BACKGROUND

Social pressures are often an integral part of the process of seeking addiction treatment. However, scientists have not developed conclusive evidence on the processes, benefits and limitations of using legal, formal and informal social control tactics to inform policy makers, service providers and the public. This paper characterizes barriers to a robust interdisciplinary analysis of social control and coercion in addiction treatment and provides directions for future research.

APPROACH

Conceptual analysis and review of key studies and trends in the area are used to describe eight implicit assumptions underlying policy, practice and scholarship on this topic.

FINDINGS

Many policies, programmes and researchers are guided by a simplistic behaviourist and health-service perspective on social controls that (a) overemphasizes the use of criminal justice systems to compel individuals into treatment and (b) fails to take into account provider, patient and public views.

CONCLUSIONS

Policies and programmes that expand addiction treatment options deserve support. However, drawing a firm distinction between social controls (objective use of social pressure) and coercion (client perceptions and decision-making processes) supports a parallel position that rejects treatment policies, programmes, and associated practices that create client perceptions of coercion.

Depressive symptoms among amphetamine and cocaine users before and after substance abuse treatment

This study examined whether higher rates of depressive symptoms among amphetamine compared with cocaine users result from amphetamine use itself, polydrug use, or experiencing a major lifetime depressive episode and whether depressive symptoms among amphetamine users are more likely to persist 12 months after treatment. The association between amphetamine use and depressive symptoms disappears when controlling for polydrug use and lifetime major depressive episode. Polydrug use and lifetime depressive episode are significantly related to depressive symptoms in the year preceding treatment. Amphetamine use at intake does not predict depressive symptoms among individuals who are abstinent at follow-up, and amphetamine users are no more likely than cocaine users to report depression at a 12-month follow-up.

Persistent antagonism of methamphetamine-induced dopamine release in rats pretreated with GBR12909 decanoate

Methamphetamine abuse is a serious global health problem, and no effective treatments for methamphetamine dependence have been developed. In animals, the addictive properties of methamphetamine are mediated via release of dopamine (DA) from nerve terminals in mesolimbic reward circuits. At the molecular level, methamphetamine promotes DA release by a nonexocytotic diffusion-exchange process involving DA transporter (DAT) proteins. We have shown that blocking DAT activity with high-affinity DA uptake inhibitors, such as 1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-(3-phenylpropyl) piperazine (GBR12909), can substantially reduce amphetamine-induced DA release in vivo. In the present study, we examined the ability of a long-acting depot formulation of GBR12909 decanoate (GBR-decanoate) to influence neurochemical actions of methamphetamine in the nucleus accumbens of rats. Rats received single injections of GBR-decanoate (480 mg/kg i.m.) and were subjected to in vivo microdialysis testing 1 and 2 weeks later. Pretreatment with GBR-decanoate produced modest elevations in basal extracellular levels of DA, but not 5-hydroxytryptamine (5-HT), at both time points. GBR-decanoate nearly eliminated the DA-releasing ability of methamphetamine (0.3 and 1.0 mg/kg i.v.) for 2 weeks, whereas methamphetamine-induced 5-HT release was unaffected. Autoradiographic analysis revealed that GBR-decanoate caused long-term decreases in DAT binding in the brain. Our data suggest that GBR-decanoate, or similar agents, may be useful adjuncts in treating methamphetamine dependence. This therapeutic strategy would be especially useful for noncompliant patient populations.

Preclinical evaluation of GBR12909 decanoate as a long-acting medication for methamphetamine dependence

Methamphetamine (METH) abuse is a growing health problem, and no treatments for METH dependence have been identified. The powerful addictive properties of METH are mediated by release of dopamine (DA) from nerve terminals in mesolimbic reward pathways. METH stimulates DA release by acting as a substrate for DA transporter (DAT) proteins, thereby triggering efflux of DA from cells into the synapse. We have shown that blocking DAT activity with high-affinity DA uptake inhibitors, like GBR12909, can substantially reduce METH-evoked DA release in vitro, suggesting GBR12909 may have potential as a pharmacotherapy for METH dependence. The purpose of the present study was to examine the neurobiological effects of a long-acting oil-soluble preparation of GBR12909 (1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-(3-hydroxy-3-phenylpropyl) piperazinyl decanoate, or GBR-decanoate). Male rats received GBR-decanoate (480 mg/kg, i.m.) or its oil vehicle, and were tested using a variety of methods one and two weeks later. Ex vivo autoradiography showed that GBR-decanoate decreases DAT binding in DA-rich brain regions. In vivo microdialysis in the nucleus accumbens revealed that GBR-decanoate elevates baseline levels of extracellular DA and antagonizes the ability of METH to evoke DA release. The dopaminergic effects of GBR-decanoate were sustained, lasting for at least two weeks. Rats pretreated with GBR-decanoate displayed enhanced locomotor responses to novelty at one week, but not two weeks, postinjection. Administration of the D(2)/D(3) receptor agonist quinpirole (10 and 100 microg/kg, s.c.) decreased locomotor activity and suppressed plasma prolactin levels; quinpirole-induced responses were not altered by GBR-decanoate. Thus, GBR-decanoate is able to elevate basal synaptic DA levels and block METH-evoked DA release in a persistent manner, without significant perturbation of DA receptor function. The findings suggest that GBR-decanoate, or similar long-acting agents, should be evaluated further as potential treatment adjuncts in the management of METH addiction in humans.