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Biomedical subjects

Thomas R Kosten

Publications and source records attributed to Thomas R Kosten.

At least 19 recordsLinked to original sources
PubMed2007

Nicotine dependence, symptoms and oxidative stress in male patients with schizophrenia.

The high rate of smoking in schizophrenia may reflect patients' attempts to reduce the side effects of antipsychotic medications, and one mechanism for this reduction may be a reduction in oxidative stress and free radical-mediated brain damage that may contribute to schizophrenic symptoms and to complications of its treatment. Symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS), side effects were assessed with the Simpson and Angus Rating Scale (SAS), and malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) activities were measured in plasma. All of these measures were compared in 130 male inpatients with DSM-IV schizophrenia: 104 smokers and 26 non-smokers. The results showed that the positive PANSS symptoms were lower in smokers than non-smokers (14.5 vs 17.5), while the negative symptoms were lower in those who smoked more cigarettes (r=-0.23). The SAS showed no differences. The CAT activity was correlated with both GSH-Px and SOD activities. Of the three enzymes only the CAT activity was significantly higher in smokers than non-smokers (2.9 vs 1.6 U/ml), but greater SOD activity correlated more cigarettes smoked (r=0.24). Consistent with some protection against oxidative stress, MDA also was significantly lower in smokers than non-smokers (9.2 vs 14.4 nmol/ml). The fewer positive symptoms in smokers and fewer negative symptoms in those who smoked more cigarettes may be a selection bias, but appears to be associated with decreased oxidative stress and lipid peroxidation in schizophrenics who smoke tobacco.

Adult↗
PubMed2007

Systematic review: opioid treatment for chronic back pain: prevalence, efficacy, and association with addiction.

BACKGROUND: The prevalence, efficacy, and risk for addiction for persons receiving opioids for chronic back pain are unclear. PURPOSE: To determine the prevalence of opioid treatment, whether opioid medications are effective, and the prevalence of substance use disorders among patients receiving opioid medications for chronic back pain. DATA SOURCES: English-language studies from MEDLINE (1966-March 2005), EMBASE (1966-March 2005), Cochrane Central Register of Controlled Clinical Trials (to 4th quarter 2004), PsychInfo (1966-March 2005), and retrieved references. STUDY SELECTION: Articles that studied an adult, nonobstetric sample; used oral, topical, or transdermal opioids; and focused on treatment for chronic back pain. DATA EXTRACTION: Two investigators independently extracted data and determined study quality. DATA SYNTHESIS: Opioid prescribing varied by treatment setting (range, 3% to 66%). Meta-analysis of the 4 studies assessing the efficacy of opioids compared with placebo or a nonopioid control did not show reduced pain with opioids (g, -0.199 composite standardized mean difference [95% CI, -0.49 to 0.11]; P = 0.136). Meta-analysis of the 5 studies directly comparing the efficacy of different opioids demonstrated a nonsignificant reduction in pain from baseline (g, -0.93 composite standardized mean difference [CI, -1.89 to -0.03]; P = 0.055). The prevalence of lifetime substance use disorders ranged from 36% to 56%, and the estimates of the prevalence of current substance use disorders were as high as 43%. Aberrant medication-taking behaviors ranged from 5% to 24%. LIMITATIONS: Retrieval and publication biases and poor study quality. No trial evaluating the efficacy of opioids was longer than 16 weeks. CONCLUSIONS: Opioids are commonly prescribed for chronic back pain and may be efficacious for short-term pain relief. Long-term efficacy (> or =16 weeks) is unclear. Substance use disorders are common in patients taking opioids for back pain, and aberrant medication-taking behaviors occur in up to 24% of cases.

Analgesics, Opioid↗
PubMed2007

Association of functional catechol O-methyl transferase (COMT) Val108Met polymorphism with smoking severity and age of smoking initiation in Chinese male smokers.

RATIONALE: Catechol-O-methyltransferase (COMT) is an enzyme involved in the degradation and inactivation of the neurotransmitter dopamine, which is important in mediating drug reward such as nicotine in tobacco smoke. Different COMT alleles encode enzyme whose activity varies from three- to fourfold that may affect dopamine levels and alter subjective effects of nicotine. Recent evidence also suggests that a COMT polymorphism may be especially important in determining an individual's predisposition to developing nicotine dependence. SUBJECTS AND METHODS: We studied the COMT Val108Met polymorphism in a male population of 203 current smokers, 66 former smokers, and 102 non-smokers. The age-adjusted odds ratios were estimated by multiple logistic regression models. RESULTS: The results showed no significant association of the COMT Val108Met with initiation, persistent smoking, or smoking cessation. However, current smokers with the Met allele had significantly higher Fagerstrom Test for Nicotine Dependence scores (7.5 +/- 2.1 vs 6.8 +/- 1.8, p = 0.018) and started smoking significantly earlier (18.4 +/- 4.9 vs 20.1 +/- 5.9 years, p = 0.036). CONCLUSIONS: These results suggest that the COMT Val108Met polymorphism may not influence smoking status in a Chinese male population but may influence the age at which smoking started and smoking severity among smokers. However, the findings must be regarded as preliminary because of the relatively small sample size and marginal associations and should be replicated in a larger cohort.

Adult↗
PubMed2006

Effects of lofexidine on stress-induced and cue-induced opioid craving and opioid abstinence rates: preliminary findings.

OBJECTIVE: A preliminary study examined whether lofexidine decreases stress-induced and cue-induced opioid craving and improves opioid abstinence in naltrexone-treated opioid-dependent individuals. MATERIALS AND METHODS: Eighteen opioid-dependent patients were stabilized for 4 weeks with naltrexone (50 mg daily) and lofexidine (2.4 mg bid) before entering a 4-week randomized, double-blind placebo-controlled discontinuation study where one group continued on lofexidine for an additional 4 weeks, while the second was tapered to placebo (Lofexidine-naltrexone vs Placebo-naltrexone). Ten patients also participated in guided imagery exposure to stress, drug cue, and neutral scenarios in a single laboratory session. RESULTS: Lofexidine-naltrexone patients had higher opioid abstinence rates and improved relapse outcomes as compared to the Placebo-naltrexone group. Furthermore, Lofexidine-naltrexone patients had significantly lower heart rates and an attenuated stress and drug cue-induced opioid craving response in the laboratory as compared to the Placebo-naltrexone group. CONCLUSIONS: Although preliminary, these findings are the first to document lofexidine's potential in addressing stress-related opioid craving and relapse outcomes in humans. The results also suggest that combination therapies that target both drug-related reinforcement (naltrexone) and stress- and cue-related aspects of drug seeking could be beneficial in addiction relapse prevention. Further development of lofexidine to address stress-related opioid craving and relapse is warranted.

Adult↗
PubMed2006

Serum BDNF levels and weight gain in schizophrenic patients on long-term treatment with antipsychotics.

Several lines of evidence suggest that central brain-derived neurotrophic factor (BDNF) modulates food intake, metabolism, and increases in body weight. Reports have also shown that serum BDNF is altered in schizophrenic patients treated with antipsychotics. This study aimed to determine if there was a relationship between BDNF and antipsychotic-induced weight gain in patients with chronic schizophrenia. Serum BDNF was measured in 124 schizophrenia patients chronically treated with clozapine (n=57), risperidone (n=23) or typical antipsychotics (n=44) and 50 healthy control subjects. To further assess group differences in serum BDNF, additional analyses were performed in a subset of patients and controls individually matched for body mass index (BMI). BDNF levels were lower in patients with schizophrenia than normal controls. However, this difference was not present when controlling for current BMI. In the individually BMI-matched sample, no differences in serum BDNF levels were observed in schizophrenic patients compared to BMI-matched healthy controls. BDNF levels negatively correlated with BMI gain in female but not in male patients when gender was considered. Antipsychotic class exerted differential effects over BDNF levels and BMI gain. Our findings suggest that decreased BDNF levels may be associated with weight gain in female schizophrenic patients on long-term antipsychotic treatment.

Antipsychotic Agents↗
PubMed2006

Genetics of dopamine and its contribution to cocaine addiction.

Cocaine addiction is a major health and social problem for which there are presently no effective pharmacotherapies. Many of the most promising medications target dopamine based on the large literature that supports its role in addiction. Recent studies show that genetic factors are also important. Rodent models and gene knock-out technology have helped elucidate the involvement of specific genes in the function of the dopamine reward system and intracellular cascades that lead to neuronal changes in this system. Human epidemiological, linkage, and association studies have identified allelic variants (polymorphisms) that give rise to altered metabolism of dopamine and its functional consequences. Individuals with these polymorphisms respond differently to psychostimulants and possibly to pharmacotherapies. Here we review the literature on genetic variations that affect dopamine neurotransmission, responses to psychostimulants and potential treatments for cocaine addiction. Behavioral responses to psychostimulants in animals with different or modified genetics in dopamine signaling are discussed. We also review polymorphisms in humans that affect dopaminergic neurotransmission and alter the subjective effects of psychostimulants. Pharmacotherapies may have increased efficacy when targeted to individuals possessing specific genetic polymophisms in dopamine's metabolic and intracellular messenger systems.

Animals↗
PubMed2006

Clinical efficacy of gabapentin versus tiagabine for reducing cocaine use among cocaine dependent methadone-treated patients.

BACKGROUND: GABAergic medications appear to reduce the reinforcing effects of cocaine by attenuating cocaine-induced dopamine release. This study evaluated gabapentin and tiagabine compared to placebo in reducing cocaine taking behavior. METHODS: A total of 76 treatment seeking, cocaine dependent, methadone-treated, predominately Caucasian male subjects were randomly assigned to tiagabine 24 mg/day (N=25), gabapentin 2400 mg/day (N=26) or placebo (N=25) in a 10-week double-blind placebo-controlled trial. Study medications were slowly increased to their full dosages by the end of week 5 and maintained through week 10. The primary outcome measure was thrice-weekly drug free urine samples. RESULTS: Treatment retention was significantly less for the gabapentin group relative to the other groups (log rank=5.29, d.f.=1, p=0.02). The proportion of cocaine-free urine samples during weeks 6-10 was significantly larger in the tiagabine treated group (p<0.05). The longitudinal data showed significant change in thrice-weekly cocaine free urines that reached a greater abstinent rate for the tiagabine treated group (22%) compared to gabapentin (5%) or placebo (13%) treated groups. Mixed-effects ordinal regression models showed a significant tiagabine by time interaction compared to gabapentin (Z=2.48, d.f.=1, p=0.01) and placebo (Z=3.90, d.f.=1, p=0.0001). The gabapentin group did not differ from placebo. CONCLUSION: Gabapentin showed poor treatment retention and ineffectiveness in reducing cocaine use. Tiagabine significantly reduced cocaine taking behavior compared to placebo or gabapentin among methadone-stabilized cocaine abusers.

Adult↗
PubMed2006

Antisocial personality and stress-induced brain activation in cocaine-dependent patients.

We explore the neural correlates underlying distress processing in antisocial personality in cocaine-dependent individuals. Twenty-seven abstinent cocaine-dependent individuals took part in script-guided stress imagery in a functional magnetic resonance imaging study. Regional brain activation during stress imagery was compared with a baseline period, for male and female participants separately. Their California Psychological Inventory socialization scores were then correlated in region of interest analysis with corticolimbic brain regions that showed significant activation during stress. The effect size of activity change in the medial prefrontal cortex is associated with lower socialization score (i.e. greater sociopathy) and with the change in heart rate, but only among female participants. These results highlight important sex differences in the association between antisocial personality and distress processing in cocaine-dependent individuals.

Adult↗
PubMed2006

Six-month trial of bupropion with contingency management for cocaine dependence in a methadone-maintained population.

CONTEXT: No effective pharmacotherapies exist for cocaine dependence, although contingency management (CM) has demonstrated efficacy. OBJECTIVE: To compare the efficacy of bupropion hydrochloride and CM for reducing cocaine use in methadone hydrochloride-maintained individuals. DESIGN: This 25-week, placebo-controlled, double-blind trial randomly assigned participants to 1 of 4 treatment conditions: CM and placebo (CMP), CM and 300 mg/d of bupropion hydrochloride (CMB), voucher control and placebo (VCP), or voucher control and bupropion (VCB). SETTING: Outpatient clinic at the Veterans Affairs Connecticut Healthcare System. PARTICIPANTS: A total of 106 opiate-dependent, cocaine-abusing individuals. INTERVENTIONS: All study participants received methadone hydrochloride (range, 60-120 mg). Participants receiving bupropion hydrochloride were given 300 mg/d beginning at week 3. In the CM conditions, each urine sample negative for both opioids and cocaine resulted in a monetary-based voucher that increased for consecutively drug-free urine samples during weeks 1 to 13. Completion of abstinence-related activities also resulted in a voucher. During weeks 14 to 25, only completion of activities was reinforced in the CM group, regardless of sample results. The voucher control groups received vouchers for submitting urine samples, regardless of results, throughout the study. MAIN OUTCOME MEASURE: Thrice-weekly urine toxicologic test results for cocaine and heroin. RESULTS: Groups did not differ in baseline characteristics or retention rates. Opiate use decreased significantly, with all treatment groups attaining equivalent amounts of opiate use at the end of the study. In the CMB group, the proportion of cocaine-positive samples significantly decreased during weeks 3 to 13 (P<.001) relative to week 3 and remained low during weeks 14 to 25. In the CMP group, cocaine use significantly increased during weeks 3 to 13 (P<.001) relative to week 3, but then cocaine use significantly decreased relative to the initial slope during weeks 14 to 25 (P<.001). In contrast, by treatment end, the VCB and VCP groups showed no significant improvement in cocaine use. CONCLUSION: These findings suggest that combining CM with bupropion for the treatment of cocaine addiction may significantly improve outcomes relative to bupropion alone.

Adult↗
PubMed2006

Cue-induced brain activity changes and relapse in cocaine-dependent patients.

This study used functional magnetic resonance imaging (fMRI) to examine the association between brain activation during exposure to cocaine-related cues and relapse to drug use in cocaine-dependent (CD) patients. We imaged 17 CD subjects during a 2-week in-patient stay. The subjects then entered a 10-week outpatient placebo-controlled, double-blind randomized clinical trial where urine toxicologies were assessed three times weekly to calculate the treatment effectiveness score (TES). Worse TES correlated with BOLD activation in the left precentral, superior temporal, and posterior cingulate cortices (PCC), and right middle temporal and lingual cortices (R>0.65; P<0.005). The left PCC activation also distinguished eight nonrelapsers (TES above mean and completed treatment) from nine relapsers. Cocaine-free urines were significantly greater in the nonrelapsers (92%) than in the relapsers (66%), who also remained in treatment for an average of only 3.2 weeks. Self-reports of craving during fMRI did not differ between nonrelapsers and relapsers and did not correlate with TES. Relapse to cocaine abuse was associated with increased activation in the sensory association cortex, the motor cortex, and PCC while viewing images of cocaine-related cues. These results suggest that relapse to cocaine abuse is associated with increased brain activation to cocaine cues in sensory, motor, and cognitive-emotional processing areas. This physiological activation was a better predictor of relapse than subjective reports of craving, and may be a useful target for treatment development.

Adult↗
PubMed2006

Emerging pharmacological strategies in the fight against cocaine addiction.

Cocaine addiction continues to be an important public health problem worldwide. At present, there are no proven pharmacotherapies for cocaine addiction. The studies reviewed here revealed a number of emerging targets for cocaine pharmacotherapy. First, disulfiram, a medication with dopaminergic effects, reduced cocaine use in a number of clinical trials. Second, GABA medications, tiagabine and topiramate, were found promising in clinical trials. Third, a beta-adrenergic blocker, propranolol, may be effective especially among cocaine-addicted individuals with high withdrawal severity. Fourth, treatment with a stimulant medication, modafinil, has reduced cocaine use. Last, a cocaine vaccine that slows entry of cocaine into the brain holds promise. These promising findings need to be further tested in controlled clinical trials.

Adrenergic beta-Antagonists↗
PubMed2005

Tiagabine affects the subjective responses to cocaine in humans.

In preclinical studies, medications which increase the synaptic GABA levels have been shown to block cocaine reinforcement. In this study, we examined the interaction between a GABA enhancing medication, tiagabine, and cocaine in cocaine users. A total of 7 subjects, 5 male and 2 female cocaine users had 2 experimental sessions. Before each session, subjects received either two oral doses of 4 mg of tiagabine or placebo. Starting 2 h after the second dose of medication treatment, subjects received an injection of saline followed by 2 escalating cocaine doses (0.15 and 0.3 mg/kg) intravenously. Tiagabine treatment did not affect the cocaine-induced blood pressure and heart rate changes. Tiagabine treatment attenuated the subjective ratings of "stimulated" and "crave cocaine" in response to cocaine administration. These results suggest that tiagabine treatment attenuates some of the subjective effects of cocaine without affecting its cardiovascular effects. GABA medications, including tiagabine, are currently being evaluated in controlled clinical trials for the treatment of cocaine dependence.

Blood Pressure↗
PubMed2005

Neural activity associated with stress-induced cocaine craving: a functional magnetic resonance imaging study.

OBJECTIVE: Stress is known to increase cocaine craving and relapse risk in cocaine dependence. Identifying neural activity associated with stress and stress-induced cocaine craving is important in understanding the neurobiology of cocaine craving and relapse. METHOD: Blood oxygenation level dependent (BOLD) signal changes were assessed in a functional magnetic resonance imaging (fMRI) session with healthy controls and treatment-engaged, abstinent, cocaine-dependent individuals (patients) as they participated in brief guided imagery and recall of three personal stress and three personal neutral situations. RESULTS: During stress, patients showed significantly less BOLD activation than controls in specific frontal and para-limbic regions, such as the anterior cingulate (AC) region, left hippocampal/parahippocampal region, right fusiform gyrus, and the right postcentral gyrus. On the other hand, patients had increased activity in the caudate and dorsal striatum region during stress, activation that was significantly associated with stress-induced cocaine craving ratings. CONCLUSIONS: Patients failed to activate AC and related circuits during stress, regions associated with control, and regulation of emotion and distress states. Instead, they exhibited greater craving-related activation in the dorsal striatum, a region related to reward pathways and part of the obsessive-compulsive circuitry. Such functional alterations in stress processing may underlie the stress-related vulnerability to cocaine relapse often observed in cocaine-dependent individuals in early recovery.

Adult↗
PubMed2005

Efficacy of dose and contingency management procedures in LAAM-maintained cocaine-dependent patients.

Opioid- and cocaine-dependent participants (N=140) were randomly assigned to one of the following in a 12-week clinical trial: LAAM (30, 30, 39 mg/MWF) with contingency management (CM) procedures (LC); LAAM (30, 30, 39 mg/MWF) without CM (LY); LAAM (100, 100, 130 mg/MWF) with CM (HC); LAAM (100, 100, 130 mg/MWF) without CM (HY). Urine samples were collected thrice-weekly. In CM, each urine negative for both opioids and cocaine resulted in a voucher worth a certain monetary value that increased for consecutively drug-free urines. Subjects not assigned to CM received vouchers according to a yoked schedule. Vouchers were exchanged for mutually agreed upon goods and services. Groups generally did not differ on retention and baseline characteristics. Overall opioid use was least in the HC and HY groups; opioid use decreased most rapidly over time in the HC group relative to the HY, LC and LY groups. Overall cocaine use was least in the HC group relative to the HY, LC, and LY groups; cocaine use decreased over time most rapidly in the HC and LY groups. Abstinence from both was greatest in the HC group. Opioid withdrawal symptoms decreased most rapidly in the high-dose groups relative to the low-dose groups. These results suggest that an efficacious maintenance dose is necessary for contingencies to be effective in facilitating both opioid and cocaine abstinence.

Adult↗
PubMed2005

Vaccine pharmacotherapy for the treatment of cocaine dependence.

BACKGROUND: Cocaine abuse has no established pharmacotherapy, but active immunotherapy with a cocaine vaccine shows promise as a therapeutic intervention. METHODS: An open label, fourteen week, dose-escalation study evaluated the safety, immunogenicity, and clinical efficacy of a novel human cocaine vaccine (TA-CD) in eighteen cocaine dependent subjects. Ten subjects (400 microg total dose group) received four-100 microg injections over the course of eight weeks. Subsequently, eight subjects (2000 microg total dose group) received five-400 microg vaccinations over twelve weeks. Intent to treat analysis of thrice weekly urine toxicologies and cocaine antibody titers were compared. RESULTS: Sixteen of 18 subjects completed the study. There were no serious adverse reactions and the vaccine was well tolerated. The 2000 microg total dose group had a significantly higher mean antibody titer response (2000 units) as compared to the 400 microg total dose group (1000 units) (p = .05). The 2000 microg group was more likely to maintain cocaine free urines than those in the 400 microg group (Z = -3.12, p = .002). Despite relapse in both groups, most reported an attenuation of cocaine's usual euphoric effects at the six month follow-up time points (63% in the 400 microg and 100% in the 2000 microg groups). CONCLUSIONS: The conjugated cocaine vaccine was well tolerated and cocaine specific antibodies persisted at least six months. The likelihood of using cocaine decreased in subjects who received the more intense vaccination schedule.

Adult↗
PubMed2005

Sex differences in brain activation during stress imagery in abstinent cocaine users: a functional magnetic resonance imaging study.

BACKGROUND: Because stress mediates drug seeking and relapse, and sex differences have been observed in stress and in the development of cocaine addiction, in this study we used functional neuroimaging to examine the effect of sex on stress responses in abstinent cocaine users. METHODS: In a functional magnetic resonance imaging session, 17 male and 10 female cocaine-dependent subjects participated in script-guided imagery of neutral or stress situations. Subjects rated imagery vividness, anxiety, and cocaine craving for each trial. Brain activation during the stress and neutral imagery periods relative to their own baseline was examined in individual subjects. Sex contrast was obtained in second-level group analysis. RESULTS: Female subjects demonstrated more activation, compared with male subjects, in left middle frontal, anterior cingulate, and inferior frontal cortices and insula, and right cingulate cortex during stress imagery. Region of interest analysis showed that the change of activity in left anterior cingulate and right posterior cingulate cortices both correlated inversely with the change of craving rating during stress imagery. CONCLUSIONS: The greater left frontolimbic activity in women suggests that women might use more verbal coping strategies than do men while experiencing stress. The results also suggest a distinct role of the cingulate cortices in modulating stress-induced cocaine craving.

Adult↗
PubMed2005

Cortical excitability in cocaine-dependent patients: a replication and extension of TMS findings.

Cortical excitability can be assessed by transcranial magnetic stimulation (TMS). Previously we observed that TMS motor threshold (MT) was elevated in abstinent cocaine-dependent subjects. In the current study we aimed at replicating our initial finding, exploring other TMS-based measures of excitability, and examining association with personality characteristics. Nineteen cocaine-dependent and 12 healthy control subjects were examined. Resting and activated motor thresholds (RMT and AMT) and duration of the cortical silent period (CSP) were examined. The Cocaine Experience Questionnaire (CEQ) was administered to assess cocaine-induced psychotic symptoms. The relationship between Minnesota Multiphasic Personality Inventory (MMPI) scales and cortical excitability measures was also examined. AMT was significantly elevated in cocaine-dependent subjects on both hemispheres. RMT was also significantly elevated on the right hemisphere. No CSP changes were noted. Patients with cocaine-induced paranoia had longer CSPs on the right hemisphere compared to subjects reporting no paranoid experiences. The patients displayed significantly elevated scores on several MMPI scales, though the scale scores did not correlate with cortical excitability measures. These data support our initial finding of decreased cortical excitability in abstinent cocaine-dependent subjects. We interpret this finding as a compensatory mechanism against the stimulating and epileptogenic effects of cocaine.

Adult↗