Biomedical subjects

Thomas R Kosten

Publications and source records attributed to Thomas R Kosten.

At least 19 recordsLinked to original sources

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↗

PubMed2005

Methadone versus buprenorphine with contingency management or performance feedback for cocaine and opioid dependence.

OBJECTIVE: Physicians may prescribe buprenorphine for opioid agonist maintenance treatment outside of narcotic treatment programs, but treatment guidelines for patients with co-occurring cocaine and opioid dependence are not available. This study compares effects of buprenorphine and methadone and evaluates the efficacy of combining contingency management with maintenance treatment for patients with co-occurring cocaine and opioid dependence. METHOD: Subjects with cocaine and opioid dependence (N=162) were provided manual-guided counseling and randomly assigned in a double-blind design to receive daily sublingual buprenorphine (12-16 mg) or methadone (65-85 mg p.o.) and to contingency management or performance feedback. Contingency management subjects received monetary vouchers for opioid- and cocaine-negative urine tests, which were conducted three times a week; voucher value escalated during the first 12 weeks for consecutive drug-free tests and was reduced to a nominal value in weeks 13-24. Performance feedback subjects received slips of paper indicating the urine test results. The primary outcome measures were the maximum number of consecutive weeks abstinent from illicit opioids and cocaine and the proportion of drug-free tests. Analytic models included two-by-two analysis of variance and mixed-model repeated-measures analysis of variance. RESULTS: Methadone-treated subjects remained in treatment significantly longer and achieved significantly longer periods of sustained abstinence and a greater proportion drug-free tests, compared with subjects who received buprenorphine. Subjects receiving contingency management achieved significantly longer periods of abstinence and a greater proportion drug-free tests during the period of escalating voucher value, compared with those who received performance feedback, but there were no significant differences between groups in these variables during the entire 24-week study. CONCLUSIONS: Methadone may be superior to buprenorphine for maintenance treatment of patients with co-occurring cocaine and opioid dependence. Combining methadone or buprenorphine with contingency management may improve treatment outcome.

Adult↗

PubMed2005

Novel approaches to the treatment of cocaine addiction.

Cocaine addiction continues to be an important public health problem with over 1.7 million users in the US alone. Although there are no approved pharmacotherapies for cocaine addiction, a number of medications have been tested with some promising results. In this review, we summarise some of the emerging targets for cocaine pharmacotherapy including dopaminergic and GABA medications, adrenoceptor antagonists, vasodilators and immunotherapies. The brain dopamine system plays a significant role in mediating the rewarding effects of cocaine. Among dopaminergic agents tested for cocaine pharmacotherapy, disulfiram has decreased cocaine use in a number of studies. Amantadine, another medication with dopaminergic effects, may also be effective in cocaine users with high withdrawal severity. GABA is the main inhibitory neurotransmitter in the brain, and accumulating evidence suggests that the GABA system modulates the dopaminergic system and cocaine effects. Two anticonvulsant medications with GABAergic effects, tiagabine and topiramate, have yielded positive findings in clinical trials. Baclofen, a GABA(B) receptor agonist, is also promising, especially in those with more severe cocaine use. Some of the physiological and behavioural effects of cocaine are mediated by activation of the adrenergic system. In cocaine users, propranolol, a beta-adrenoceptor antagonist, had promising effects in individuals with more severe cocaine withdrawal symptoms. Cerebral vasodilators are another potential target for cocaine pharmacotherapy. Cocaine users have reduced cerebral blood flow and cortical perfusion deficits. Treatment with the vasodilators amiloride or isradipine has reduced perfusion abnormalities found in cocaine users. The functional significance of these improvements needs to be further investigated. All these proposed pharmacotherapies for cocaine addiction act on neural pathways. In contrast, immunotherapies for cocaine addiction are based on the blockade of cocaine effects peripherally, and as a result, prevent or at least slow the entry of cocaine into the brain. A cocaine vaccine is another promising treatment for cocaine addiction. The efficacy of this vaccine for relapse prevention is under investigation. Many initial promising findings need to be replicated in larger, controlled clinical trials.

Adrenergic Agents↗

PubMed2005

Future of anti-addiction vaccines.

The medical rational for using anti-drug antibodies in the serum as a treatment is to reduce drug levels in the brain and to bind drug before it enters the brain. Drugs of abuse are small molecules that can readily cross the blood brain barrier, while antibodies are larger molecules that cannot get into the brain. Thus, any drug that is bound to antibody also cannot cross the blood brain barrier and cannot enter the brain. Active anti-drug vaccines stimulate the body to makes its own antibodies, but the small size of abused drugs prevents them from stimulating an immune response. Thus, individuals do not ordinarily produce antibodies to abused drugs, and vaccines to stimulate antibodies are made by chemically linking these abused drugs to toxins such as cholera toxin. Alternatively, passive immunotherapy uses monoclonal antibodies that are generated in a laboratory and then administered via intravenous injection. Antibodies can be used to treat drug overdose; to reduce drug use relapse; or to protect certain at risk populations who have not yet become drug dependent. The advantages of anti-addiction vaccines are that antibodies target the drug, not the drug's sites of action in the brain and antibody binding inactivates the drug. These vaccines can complement behavioral and other medical therapies with minimal side effects and are not addictive like some chemical agonists. Technology advances in manufacturing and delivery systems will improve future anti-addiction vaccines, but social acceptance of anti-addiction vaccines will depend on substance abuse program staff and the families of substance abusers, who have some values that oppose medical solutions to addictive diseases and view addictions as moral problems.

Drug Delivery Systems↗

PubMed2004

New medication strategies for comorbid substance use and bipolar affective disorders.

Comorbidity of substance abuse disorders (SUD) with bipolar disorders (BPD) is a serious treatment problem. Childhood BPD can be further complicated by comorbidity with attention-deficit/hyperactivity disorder (ADHD) and later SUD during adolescence. The aim of this article is to review the literature on pharmacotherapies for these patients. Developing the ideal pharmacotherapy for BPD and SUD can be informed by the role of gamma-aminobutyric acid (GABA) in the neurobiology of SUD. This ideal pharmacotherapy would have several key characteristics. These characteristics include treating the BPD, relieving withdrawal symptoms, and preventing relapse to SUD. The ideal medication should have low abuse liability, require infrequent dosing, be well tolerated, and have few side effects. A medication approaching this ideal is the GABA enhancer valproate. Adding atypical antipsychotic agents might not improve valproate's efficacy, but combining GABA medications with selective serotonin reuptake inhibitors holds promise for SUD with depression. Pemoline might be the best option for minimizing the risk of SUD complicating comorbid ADHD with BPD.

Adolescent↗

PubMed2004

Perfusion abnormalities and decision making in cocaine dependence.

BACKGROUND: Previous studies have shown that cocaine abusers have cerebral perfusion deficits that may diminish cognitive functioning. This study examined whether cocaine-dependent patients have perfusion abnormalities associated with poor decision-making ability as measured by the Iowa Gambling Task (IGT). METHODS: Seventeen abstinent cocaine-dependent patients were administered the IGT after completion of resting 99mTc-HMPAO single-photon emission computed tomography (SPECT). RESULTS: Better IGT performance was negatively correlated with perfusion within the anterior cingulate gyrus, middle frontal gyrus, medial frontal gyrus, and superior frontal gyrus. The time to complete card selections was positively correlated with the severity of impairment. CONCLUSIONS: Resting hyperperfusion in brain regions previously implicated in decision making and response inhibition was associated with worse IGT scores. Impaired performance was related to a greater amount of time taken for card selections, suggesting that reduced ability was due to cognitive factors other than an impulsive response pattern.

Adult↗

PubMed2004

Choosing a behavioral therapy platform for pharmacotherapy of substance users.

Behavioral therapy platforms have become virtual requirements in pharmacotherapy trials due to their utility in reducing noise variability, preventing differential medication adherence and protocol attrition, enhancing statistical power and addressing ethical issues in placebo-controlled trials. Selecting an appropriate behavioral platform for a particular trial requires study-specific tailoring, taking into account both the stage of development of the medication being evaluated, as well as the specific strengths and weaknesses of a broad array of available empirically supported behavioral therapies and the range of their possible targets (e.g., enhancing medication adherence, preventing attrition, addressing co-morbid problems, fostering abstinence, and targeting specific weaknesses of the pharmacologic agent). Choosing a suitable behavioral platform also requires consideration of the characteristics of the population to be treated, stage of scientific knowledge regarding the medication's effects, appropriate balance of internal and external validity, and consideration of potential ceiling effects. Available manualized behavioral treatments are reviewed, noting their strengths and limitations as behavioral therapy platforms for pharmacotherapy trials and as potential concomitant therapies in clinical practice.

Behavior Therapy↗

PubMed2004

Isradipine and dextromethorphan in methadone-maintained humans under a naloxone discrimination procedure.

In seven methadone-maintained human participants trained to distinguish between a low dose of naloxone (0.15 mg/70 kg, i.m.; i.e., Drug A) and placebo (i.e., Drug B) under an instructed novel-response drug discrimination procedure, the calcium channel blocker isradipine (0-10 mg/70 kg, p.o.; N=7) and the N-methyl-D-aspartic acid (NMDA) receptor antagonist dextromethorphan (0-60 mg/70 kg, p.o.; N=6) were tested each alone and in combination with the training dose of naloxone. Isradipine alone produced some naloxone- and novel-appropriate responding, minimal changes in self-reports and decreases in blood pressure. Dextromethorphan alone produced some novel-appropriate responding and minimal changes in self-reports and vital signs. When combined with naloxone, isradipine significantly attenuated naloxone-occasioned responding, without increasing novel-appropriate responding, and attenuated naloxone-induced increases in opioid receptor antagonist ratings and ratings measuring sedation. Dextromethorphan significantly attenuated naloxone-appropriate responding, increased novel-appropriate responding, and enhanced naloxone's effects on ratings of dysphoric effects. These results suggest that isradipine attenuates and dextromethorphan enhances some of the behavioral effects of naloxone in opioid-dependent humans.

Adult↗

PubMed2004

Gender-specific vulnerability for rCBF abnormalities among cocaine abusers.

Fifty abstinent cocaine-dependent patients and 20 healthy controls were evaluated with 99mTc-HMPAO SPECT to examine gender differences in perfusion. Group contrasts with statistical parametric mapping revealed male and female patients exhibited not only different regions, but different types of perfusion abnormality, including decreased perfusion in the anterior cingulate/frontal regions among cocaine-dependent men, and increased perfusion in the posterior cingulate of cocaine-dependent women. The findings suggested that cocaine-dependent men have perfusion deficits previously associated with cocaine withdrawal and impaired response inhibition, whereas, cocaine-dependent women demonstrated perfusion abnormalities consistent with heightened stress responsivity and worse treatment outcome. The possibility of different neural mechanisms underlying relapse in men and women, and the implications for utilizing specialized treatments are discussed.

Adult↗