Biomedical subjects

John Roll

Publications and source records attributed to John Roll.

6 recordsLinked to original sources

PubMed2006

Randomized, placebo-controlled trial of baclofen and gabapentin for the treatment of methamphetamine dependence.

OBJECTIVE: To conduct a 16-week, randomized, placebo-controlled, double-blind trial of two GABAergic medications, baclofen (20 mg tid) and gabapentin (800 mg tid), for the treatment of methamphetamine dependence. METHODS: Adults with methamphetamine dependence were randomized to one of three conditions for 16 weeks: baclofen (n = 25), gabapentin (n = 26) or placebo (n = 37). All participants attended clinic thrice weekly to receive study medication and psychosocial counseling, complete study assessments, and provide urine samples. RESULTS: No statistically significant main effects for baclofen or gabapentin in reducing methamphetamine use were observed using a generalized estimating equation (GEE). A significant treatment effect was found in post hoc analyses for baclofen, but not gabapentin, relative to placebo among participants who reported taking a higher percentage of study medication (significant treatment group and medication adherence interaction in GEE model of methamphetamine use). CONCLUSIONS: While gabapentin does not appear to be effective in treating methamphetamine dependence, baclofen may have a small treatment effect relative to placebo. Future studies evaluating the effectiveness of baclofen and other GABAergic agents for treatment of methamphetamine may be warranted.

Adult↗

PubMed2006

Randomized, placebo-controlled trial of sertraline and contingency management for the treatment of methamphetamine dependence.

BACKGROUND: Methamphetamine dependence and associated medical and psychiatric concerns are significant public health issues. This project evaluated the efficacy of sertraline (50mg bid) and contingency management (CM) for the treatment of methamphetamine dependence. METHOD: In this randomized, placebo-controlled, double-blind trial, participants completed a 2-week non-medication baseline and were randomized to one of four conditions for 12 weeks: sertraline plus CM (n=61), sertraline-only (n=59), matching placebo plus CM (n=54), or matching placebo-only (n=55). All participants attended clinic thrice-weekly for data collection, medication dispensing, and relapse prevention groups. Outcomes included methamphetamine use (urine drug screening and self-reported days of use), retention (length of stay), drug craving (visual analogue scale), and mood symptoms (Beck Depression Inventory). RESULTS: No statistically significant main or interaction effects for sertraline or CM in reducing methamphetamine use were observed using a generalized estimating equation (GEE), although post hoc analyses showed the sertraline-only condition had significantly poorer retention than other conditions (chi(2) (3)=8.40, p<0.05). Sertraline conditions produced significantly more adverse events than placebo conditions. A significantly higher proportion of participants in CM conditions achieved three consecutive weeks of methamphetamine abstinence than those in non-CM conditions. CONCLUSIONS: These data do not demonstrate improved outcomes for sertraline versus placebo for treatment of methamphetamine dependence; indeed, they suggest sertraline is contraindicated for methamphetamine dependence. Findings provide support for the use of contingency management for treatment of methamphetamine dependence.

Adult↗

PubMed2006

Cognitive function and nigrostriatal markers in abstinent methamphetamine abusers.

OBJECTIVE: Preclinical investigations have established that methamphetamine (MA) produces long-term changes in dopamine (DA) neurons in the striatum. Human studies have suggested similar effects and correlated motor and cognitive deficits. The present study was designed to further our understanding of changes in brain function in humans that might result from chronic high dose use of MA after at least 3 months of abstinence. METHOD: Brain function in abstinent users was compared to controls using neuroimaging of monoamine transporters and cognitive assessment. Striatal levels of DA transporter (DAT) and vesicular monoamine transporter type-2 (VMAT2) were determined using [11C]methylphenidate and [11C]dihydrotetrabenazine positron emission tomography, respectively. Cognitive function was evaluated using tests of motor function, memory, learning, attention, and executive function. RESULTS: Striatal DAT was approximately 15% lower and VMAT2 was 10% lower in MA abusers across striatal subregions. The MA abusers performed within the normal range but performed more poorly compared to controls on three of the 12 tasks. CONCLUSIONS: Failure to find more substantial changes in transporter levels and neurocognitive function may be attributed to the length of time that MA users were abstinent (ranging from 3 months to more than 10 years, mean 3 years), although there were no correlations with length of abstinence. Persistent VMAT2 reductions support the animal literature indicating a toxic effect of MA on nigrostriatal nerve terminals. However, the magnitude of the MA effects on nigrostriatal projection integrity is sufficiently small that it is questionable whether clinical signs of DA deficiency are likely to develop.

Adolescent↗

PubMed2006

Contingency management for treatment of substance use disorders: a meta-analysis.

AIMS: To examine the effectiveness of contingency management (CM) techniques in treating substance use disorders (i.e. illicit drugs, alcohol, tobacco). DESIGN: Meta-analysis was used to determine the average effect size and potential moderators in 47 comparisons of the effectiveness of CM from studies based on a treatment-control group design and published between 1970 and 2002. FINDINGS: The mean effect size (ES) of CM was positive, with a magnitude of d = 0.42 using a fixed effects model. The magnitude of the ES declined over time, following treatment. CM was more effective in treating opiate use (d = 0.65) and cocaine use (d = 0.66), compared with tobacco (d = 0.31) or multiple drugs (d = 0.42). Larger effect sizes were associated with higher researcher involvement, earlier studies and shorter treatment duration. CONCLUSIONS: Study findings suggest that CM is among the more effective approaches to promoting abstinence during the treatment of substance use disorders. CM improves the ability of clients to remain abstinent, thereby allowing them to take fuller advantage of other clinical treatment components.

Behavior Therapy↗

PubMed2003

Improving on-time counseling attendance in a methadone treatment program: a contingency management approach.

Two studies were conducted to investigate the effectiveness of contingency management techniques in promoting punctual counseling attendance among methadone maintenance patients. In Study 1, 50 participants were recruited from an inner-city methadone maintenance program. Study 1 used an A-B-A design with baseline, intervention, and return-to-baseline phases. On-time attendance was reinforced during the intervention phase with a voucher that was redeemable for a draw out of a box containing 100 tokens with values varying from 0.00 dollars to 100.00 dollars. Methadone maintenance patients who exhibited poor attendance during baseline showed a significant positive response during the contingency management intervention phase. Study 2 used the same design as Study 1 except that the 52 participants were randomized into reinforcement groups that received either the variable rate of reinforcement as in Study 1 or a fixed value reinforcer of 3.25 dollars. As in Study 1, Poor Attenders significantly improved counseling attendance during the intervention. There were no differences between the variable and fixed reinforcement groups. Overall, results suggest that targeting Poor Attenders with contingency management techniques may be a cost-effective method of improving counseling attendance. Targeting Poor Attenders early in treatment may be especially important for improving treatment outcomes.

Adult↗

PubMed2003

Vertebroplasty in focal Paget disease of the spine. Case report.

Paget disease is an idiopathic metabolic disease of bone that may involve the axial and appendicular skeleton. In up to one third of patients there may be pagetoid involvement of the spine, which can cause back pain and vertebral collapse, with instability or myeloradiculopathy. Although medical therapy is the mainstay of treatment, decompressive surgery or stabilization may be required. The authors report on a case of localized Paget disease of the spine treated successfully by performing percutaneous vertebroplasty. They propose this procedure as a useful intervention that can be undertaken safely in patients with spinal Paget disease, in whom acquisition of a transpedicular biopsy sample is required as part of diagnosis.

Humans↗