Biomedical subjects

Gantt P Galloway

Publications and source records attributed to Gantt P Galloway.

12 recordsLinked to original sources

PubMed2006

Attentional control and brain metabolite levels in methamphetamine abusers.

BACKGROUND: Methamphetamine abuse is associated with neurotoxicity to frontostriatal brain regions with concomitant deleterious effects on cognitive processes. METHODS: By using a computerized measure of selective attention and single-voxel proton magnetic resonance spectroscopy, we examined the relationship between attentional control and brain metabolite levels in the anterior cingulate cortex (ACC) and primary visual cortex (PVC) in 36 currently abstinent methamphetamine abusers and 16 non-substance-using controls. RESULTS: The methamphetamine abusers exhibited reduced attentional control (i.e., increased Stroop interference) compared with the controls (p = .04). Bonferroni-adjusted comparisons revealed that ACC levels of N-acetyl aspartate (NAA)-creatine and phosphocreatine (Cr) were lower and that levels of choline (Cho)-NAA were higher in the methamphetamine abusers compared with the controls, at the adjusted p value of .0125. Levels of NAA-Cr, but not of Cho-NAA, within the ACC correlated with measures of attentional control in the methamphetamine abusers (r = -.41; p = .01) but not in controls (r = .22; p = .42). No significant correlations were observed in the PVC (methamphetamine abusers, r = .19; p = .28, controls, r = .38; p = .15). CONCLUSIONS: Changes in neurochemicals within frontostriatal brain regions including ACC may contribute to deficits in attentional control among chronic methamphetamine abusers.

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

A treatment model for craving identification and management.

This article presents an addiction treatment model based on craving identification and management (CIM). Craving is broadly defined as the desire to use alcohol or other drugs; it increases the likelihood of use of these substances. In the CIM Model treatment interventions are referenced to craving, i.e., helping clients to identify their craving level and equipping them with strategies to avoid use. Four causes of craving are identified: (1) environmental cues (triggers): exposure to people, places, and things associated with prior drug-using experiences may cause immediate and overwhelming craving; (2) stress: addicted persons experience stress as craving; (3) mental illness; and (4) drug withdrawal: symptoms of both mental illness and withdrawal lead to craving if clients associate use with relief of these symptoms. The CIM Model incorporates four service delivery elements: Relapse Prevention Workshop, individual counseling, medical/psychiatric services, and screening for ongoing drug use. At its core, the CIM Model asks clients to be aware of craving, analyze its causes, and, based on those causes, implement specific strategies to prevent and manage craving. The CIM Model combines several treatment components, including control of exposure to environmental cues, establishment of a daily schedule, the use of behaviors that dissipate craving (tools), and treatment (with medications when appropriate) of mental health and withdrawal symptoms. The CIM Model is a client-derived approach to achieving and maintaining sobriety based on a process of analyzing craving and managing it with an individualized program of recovery activities.

Behavior, Addictive↗

PubMed2006

Measuring confrontation during recovery from addiction.

The effect of confrontation on recovery from addiction continues to be a topic of considerable debate. Although many residential treatment programs view some form of confrontation as an integral part of recovery, a number of studies have found confrontation from professional treatment staff to be counterproductive. One of the problems inherent in the current debates about confrontation is the lack of a comprehensive measure of confrontation that assesses different dimensions. This study describes the development of the "Alcohol and Drug Confrontation Subscale" (ADCS), a 72-item instrument designed to measure the quantity and frequency of confrontation that individuals receive about drug or alcohol use-related problems. Confrontation is defined as an individual being told "bad things" might happen to them if they do not make changes to address a drug or alcohol use-related problem or make changes to maintain sobriety. The instrument also measures the respondents' perceptions about their relationships with confronters (three-item alpha = .79) and perceptions about the confrontational statements (three-item alpha = .63). The sample included 108 individuals entering three sober living housing organizations in Northern California between 2003 and 2005. They indicated that receiving confrontational statements about alcohol or drug use-related problems was common, especially from spouses/significant others (56% of those with significant others) and family members (60%). Participants who reported receiving more confrontation reported having more positive views about their relationships with confronters and about confrontational statements than those who received less confrontation. Additional studies are necessary to establish validity, generalize results to more diverse populations, and assess confrontation at different time points during recovery.

Adolescent↗

PubMed2005

Pharmacokinetics, safety, and tolerability of a depot formulation of naltrexone in alcoholics: an open-label trial.

BACKGROUND: Naltrexone is an effective medication for treatment of alcohol dependence, but its efficacy is limited by lack of adherence to the oral dosage form. A long-acting depot formulation of naltrexone may increase adherence. METHODS: A single site, 6-week open label study was conducted with 16 alcohol dependent subjects each receiving 300 mg of Naltrexone Depot by intramuscular injection. The main outcomes were safety and tolerability of the Naltrexone Depot formulation, blood levels of naltrexone and its main metabolite 6-beta naltrexol, and self-reported alcohol use. All subjects received weekly individual counseling sessions. RESULTS: The medication was well tolerated with 88% of subjects completing the 6-week trial. The most common side effect experienced was injection site complications. There were no serious adverse events. Subjects had naltrexone and 6-beta-naltrexol concentrations throughout the trial with mean values ranging from 0.58 ng/mL to 2.04 ng/mL and 1.51 ng/mL to 5.52 ng/mL, respectively, at each sampling time following administration. Compared to baseline, subjects had significantly reduced number of drinks per day, heavy drinking days and proportion of drinking days. CONCLUSION: Naltrexone Depot is safe and well tolerated in alcoholics and these findings support the further investigation of its utility in larger double-blind placebo controlled trials.

Adolescent↗

PubMed2005

A dissociation in attentional control: evidence from methamphetamine dependence.

BACKGROUND: Selective attention comprises multiple, dissociable component processes, including task shifting and selective inhibition. The goal of this study was to test whether task-shifting, selective inhibition, or both processes were impaired in long-term but currently abstinent methamphetamine-dependent individuals. METHODS: Participants were 34 methamphetamine-dependent subjects and 20 nonsubstance abusing controls who were tested on an alternating-runs switch task with conflict sequences that required subjects to switch tasks on every second trial (AABBAABB). RESULTS: Methamphetamine-dependent individuals committed more errors on trials that required inhibition of distracting information compared with controls (methamphetamine = 17%; controls = 13%; p = .02). By contrast, error rates did not differ between the groups on switch trials (methamphetamine = 7%; controls = 6%; p = .68). CONCLUSIONS: These results indicate that selective inhibition, but not task switching, is selectively compromised by methamphetamine.

Adult↗

PubMed2005

Methamphetamine users in sustained abstinence: a proton magnetic resonance spectroscopy study.

BACKGROUND: Abnormal patterns of metabolite levels have been detected by magnetic resonance spectroscopy in frontostriatal regions of individuals meeting DSM-IV criteria for methamphetamine dependence, but less is known about the effects of drug abstinence on metabolite levels. OBJECTIVE: To assess the effects of long-term methamphetamine use and drug abstinence on brain metabolite levels. DESIGN: To assess regional specific metabolite levels using magnetic resonance spectroscopy imaging techniques in 2 groups of currently abstinent methamphetamine users: methamphetamine users who recently initiated abstinence and methamphetamine users who had initiated abstinence more than 1 year prior to study. SETTING: Participants were recruited from outpatient substance abuse treatment centers. PARTICIPANTS: Eight methamphetamine users with sustained abstinence (1 year to 5 years) and 16 recently abstinent methamphetamine users (1 month to 6 months) were compared with 13 healthy, non-substance-using controls. MAIN OUTCOME MEASURES: Magnetic resonance spectroscopy measures of N-acetylaspartate-creatine and phosphocreatine (NAA/Cr), choline-creatine and phosphocreatine (Cho/Cr), and choline-N-acetylaspartate (Cho/NAA) ratios were obtained in the anterior cingulate cortex as well as in the primary visual cortex, which served as a control region. RESULTS: The absolute values of Cr did not differ between controls and methamphetamine users. Methamphetamine users had abnormally low NAA/Cr levels within the anterior cingulate cortex, regardless of the time spent abstinent (F(2,34) = 12.61; P<.001). No NAA/Cr group differences were observed in the primary visual cortex (F(2,33) = 0.29; P = .75). The Cho/NAA values for the anterior cingulate cortex were abnormally high in the methamphetamine users who recently initiated abstinence but followed a normal pattern in the methamphetamine users who had initiated abstinence more than 1 year prior to study (F(2,34) = 7.31; P = .002). CONCLUSIONS: The relative choline normalization across periods of abstinence suggests that following cessation of methamphetamine use, adaptive changes occur, which might contribute to some degree of normalization of neuronal structure and function in the anterior cingulum. More research is needed to elucidate the mechanisms underlying these adaptive changes.

Adult↗

PubMed2004

The case for high-dose motivational enhancement therapy.

Motivational Enhancement Therapy (MET) is a brief therapy for treating substance use-related problems that draws upon the stages of the change model of Prochaska et al. (1992) and the clinical techniques of Motivational Interviewing (MI) Miller et al. (1992). Studies have shown that MET is effective in improving motivation for change and decreasing substance use. However, comparison of MET with more intensive treatment is limited and no studies have compared the standard low dose of MET with higher doses of MET. This article makes the case for a higher dose model. The rationale for the more intensive dose draws upon several sources: 1) Descriptive studies documenting that length of treatment is a predictor of outcome, 2) Well-controlled, randomized psychotherapy trials for other disorders, such as depression, that show a dose-response relationship, and 3) Conceptual considerations about the nature and process of psychotherapy.

Counseling↗

PubMed2004

A multi-site comparison of psychosocial approaches for the treatment of methamphetamine dependence.

AIMS: The Center for Substance Abuse Treatment (CSAT) Methamphetamine Treatment Project (MTP) is the largest randomized clinical trial of treatments for methamphetamine (MA) dependence to date. The objective of the study was to compare the Matrix Model, a manualized treatment method, with treatment-as-usual (TAU) in eight community out-patient settings in the Western United States. DESIGN: Over an 18-month period between 1999 and 2001, 978 treatment-seeking, MA-dependent people were randomly assigned to receive either TAU at each site or a manualized 16-week treatment (Matrix Model). SETTING: The study was conducted as an eight-site out-patient trial, with six sites located in California and one each in Montana and Hawaii. FINDINGS: In the overall sample, and in the majority of sites, those who were assigned to Matrix treatment attended more clinical sessions, stayed in treatment longer, provided more MA-free urine samples during the treatment period and had longer periods of MA abstinence than those assigned to receive TAU. Measures of drug use and functioning collected at treatment discharge and 6 months post-admission indicate significant improvement by participants in all sites and conditions when compared to baseline levels, but the superiority of the Matrix approach did not persist at these two timepoints. CONCLUSIONS: Study results demonstrate a significant initial step in documenting the efficacy of the Matrix approach. Although the superiority of the Matrix approach over TAU was not maintained at the post-treatment timepoints, the in-treatment benefit is an important demonstration of empirical support for this psychosocial treatment approach.

Adolescent↗

PubMed2002

Low N-acetyl-aspartate and high choline in the anterior cingulum of recently abstinent methamphetamine-dependent subjects: a preliminary proton MRS study. Magnetic resonance spectroscopy.

Studies based on animal models report that methamphetamine (MA) abuse diminishes dopamine (DA) and serotonin innervation in frontal brain regions. In this in vivo human study, we used proton magnetic resonance spectroscopy (MRS), which yields measures of N-acetyl-aspartate (NAA), a marker of living neurons, to examine frontal brain regions possibly affected by methamphetamine dependence (MD). We tested the hypothesis that MD subjects would exhibit abnormally low levels of NAA, referenced to creatine (Cr), in anterior cingulate gray matter. We further hypothesized that the primary visual cortex, which receives relatively less DA innervation than the frontal brain regions, would show normal NAA/Cr ratios in MD subjects. Subjects included nine MD men (mean+/-standard deviation (S.D.)=32.5+/-6.4 years) and nine age-matched control men (mean+/-S.D.=32.7+/-6.8 years). The MD subjects were MA-free for 4-13 weeks. Proton MRS metabolites were expressed as ratios of creatine; the absolute values of which did not distinguish controls and MD subjects. With regard to metabolite ratios, the MD men had significantly lower NAA/Cr in the cingulum (mean+/-standard error (S.E.): control=1.46+/-0.03; MD=1.30+/-0.03; Mann-Whitney P=0.01) but not in the visual cortex (mean+/-S.E.: control=1.64+/-0.06; MD=1.69+/-11; Mann-Whitney P=0.52) relative to controls. These results provide evidence for NAA/Cr deficit that is selective to the anterior cingulum, at least with respect to visual cortex, in MD subjects. The neuronal compromise that these changes reflect may contribute to the attentional deficits and dampened reward system in MD.

Adult↗

PubMed2002

Preliminary evidence of reduced cognitive inhibition in methamphetamine-dependent individuals.

Chronic methamphetamine abuse is associated with disruption of frontostriatal function involving serotonin and dopamine circuitry. Clinically, methamphetamine-dependent (MD) individuals are highly distractible and have difficulty focussing. Here, we used a computerized single-trial version of the Stroop Test to examine selective attention and priming in MD. Subject groups comprised eight MD men (31.7+/-7.2 years of age), who had used methamphetamine for 15.75+/-8.4 years but were currently abstinent for 2-4 months, and 12 controls (35.7+9.7 years of age). Compared with the control group, the MD group exhibited significantly greater interference (P<0.05) despite intact priming. Error rates did not differ between the groups. This preliminary finding of reduced cognitive inhibition in MD individuals is consistent with the distractibility they show clinically. Furthermore, the dissociation between explicit attentional performance and priming effects suggests that some attentional functions are not as affected by long-term methamphetamine use as others.

Adult↗

PubMedDate not supplied

Psychiatric symptoms in methamphetamine users.

The Methamphetamine Treatment Project (MTP) offers the opportunity to examine co-occurring psychiatric conditions in a sample of 1016 methamphetamine users participating in a multisite outpatient treatment study between 1999-2001. Participants reported high levels of psychiatric symptoms, particularly depression and attempted suicide, but also anxiety and psychotic symptoms. They also reported high levels of problems controlling anger and violent behavior, with a correspondingly high frequency of assault and weapons charges. Findings continue to support the value of integrated treatment for co-occurring conditions, especially the importance of training counseling staff to handle psychotic symptoms when needed.

Adult↗