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Background and aims Individuals with methamphetamine dependence ( MD) exhibit dysfunction in brain regions involved in goal maintenance and reward processing when compared with healthy individuals. We examined whether these characteristics also reflect relapse vulnerability within a sample of MD patients. Design Longitudinal, with functional magnetic resonance imaging ( fMRI) and clinical interview data collected at baseline and relapse status collected at 1-year follow-up interview. Setting Keck Imaging Center, University of California San Diego, USA. Participants MD patients ( n = 60) enrolled into an in-patient drug treatment program at baseline. MD participants remaining abstinent at 1-year follow-up (abstinent MD group; n = 42) were compared with MD participants who relapsed within this period (relapsed MD group; n = 18). Measurements Behavioral and neural responses to a reinforcement learning (paper-scissors-rock) paradigm recorded during an fMRI session at time of treatment. Findings The relapsed MD group exhibited greater bilateral inferior frontal gyrus ( IFG) and right striatal activation than the abstinent MD group during the learning of reward contingencies ( Cohen's d range: 0.60-0.83). In contrast, the relapsed MD group displayed lower bilateral striatum, bilateral insula, left IFG and left anterior cingulate activation than the abstinent MD group ( Cohen's d range: 0.90-1.23) in response to winning, tying and losing feedback. Conclusions Methamphetamine-dependent individuals who achieve abstinence and then relapse show greater inferior frontal gyrus activation during learning, and relatively attenuated striatal, insular and frontal activation in response to feedback, compared with methamphetamine-dependent people who remain abstinent. [ABSTRACT FROM AUTHOR]

Aims In order to increase the number of investigative teams and sites conducting research on pharmacological treatments for methamphetamine use disorders, the National Institute on Drug Abuse (NIDA) established an infrastructure of clinical sites in areas where methamphetamine addiction is prevalent. This multi-site infrastructure would serve to run multiple Phases II and III protocols effectively and expeditiously. Methods NIDA collaborated with investigators from the University of California at Los Angeles (UCLA) to set up the Methamphetamine Clinical Trials Group (MCTG). This paper describes the development process, as well as data from a test trial to assess the capability of research-naive sites to recruit research participants and conduct study procedures according to research protocol. Subsequent trials are also described. Results A total of 151 candidates signed consent; 65 individuals were enrolled and 35 (53.8%) completed the 12 weeks' behavioral trial. Self-reported substance use report (SUR) showed comparable use of methamphetamine across sites with the individual site means ranging from 59% (site 5) to 80% (site 3). Drug use as measured by urinalysis was greatly reduced at week 13 compared to the baseline measure; the average rate of methamphetamine-free urine samples across all participants in sites at week 13 was 53%. The highest percentage of methamphetamine-free samples was 85% at site 5; the lowest was at site 1 (40%). Addiction severity index (ASI) composite scores at baseline and protocol completion for all participants demonstrated improvement in all categories over time, except for the medical composite score. The largest composite score reduction in baseline-protocol completion was in the drug domain (0.23 versus 0.15). The changes in the ASI scores from baseline to week 13 were consistent across all five sites. Conclusions Outcomes of the behavioral trial indicated that the MCTG recruited well; collected study data accurately and reliably; and created a vehicle that can assess promising pharmacotherapies for methamphetamine addiction treatment medications. The MCTG strategy appears to be a feasible approach to increase NIDA's capacity to conduct clinical trials to evaluate potential pharmacotherapies for methamphetamine addiction. [ABSTRACT FROM AUTHOR]

Aims To test aripiprazole for efficacy in decreasing use in methamphetamine-dependent adults, compared to placebo. Design Participants were randomized to receive 12 weeks of aripiprazole or placebo, with a 3-month follow-up and a platform of weekly 30-minute substance abuse counseling. Setting The trial was conducted from January 2009 to March 2012 at the San Francisco Department of Public Health. Participants Ninety actively using, methamphetamine-dependent, sexually active adults were recruited from community venues. Measurements The primary outcome was regression estimated reductions in weekly methamphetamine-positive urines. Secondary outcomes were study medication adherence [by self-report and medication event monitoring systems ( MEMS)], sexual risk behavior and abstinence from methamphetamine. Findings Participant mean age was 38.7 years, 87.8% were male, 50.0% white, 18.9% African American, and 16.7% Latino. Eighty-three per cent of follow-up visits and final visits were completed. By intent-to-treat, participants assigned to aripiprazole had similar reductions in methamphetamine-positive urines as participants assigned to placebo [risk ratio ( RR) 0.88, 95% confidence interval ( CI): 0.66-1.19, P = 0.41]. Urine positivity declined from 73% (33 of 45 participants) to 45% (18 of 40) in the placebo arm and from 77% (34 of 44) to 44% (20 of 35) in the aripiprazole arm. Adherence by MEMS and self-report was 42 and 74%, respectively, with no significant difference between arms ( MEMS P = 0.31; self-report P = 0.17). Most sexual risk behaviors declined similarly among participants in both arms (all P > 0.05). There were no serious adverse events related to study drug, although participants randomized to aripiprazole reported more akathisia, fatigue and drowsiness ( P < 0.05). Conclusion Compared with placebo, aripiprazole did not reduce methamphetamine use significantly among actively using, dependent adults. [ABSTRACT FROM AUTHOR]