Efficacy of disulfiram and cognitive behavior therapy in cocaine-dependent outpatients: a randomized placebo-controlled trial

Disulfiram enhances subjective effects of dextroamphetamine in humans

Disulfiram has shown promise in several clinical trials for cocaine addiction, but its potential utility in the treatment of amphetamine addiction has not been examined. The goal of this study was to determine the effects of disulfiram on acute physiological and subjective responses to dextroamphetamine in healthy volunteers. Five male and 5 female subjects participated in an outpatient double-blind, placebo-controlled, crossover study. Subjects were randomly assigned to a sequence of disulfiram (250 mg/day) or placebo treatments each lasting for 4 days. Day four of each treatment period was the experimental session, in which subjects orally ingested a single dose of dextroamphetamine (20 mg/70 kg). Outcome measures included heart rate, blood pressure, plasma cortisol and prolactin, subjective and performance on the Sustained Attention to Response Test (SART). Disulfiram did not affect dextroamphetamine-induced increases in heart rate, blood pressure, cortisol, or prolactin. Disulfiram did enhance some of the subjective effects of dextroamphetamine including ratings of "high," "anxious," "bad drug effects," "want more drug" and "drug liking" and was also associated with decreased performance in the SART test. How these enhanced subjective amphetamine responses affect cocaine use behavior remains to be determined in future clinical trials.

The search for medications to treat stimulant dependence

Progress in understanding the neurobiology of stimulant dependence has enabled researchers to identify medications whose pharmacological effects suggest that they might help patients initiate abstinence or avoid relapse. Several of these medications and a vaccine have shown encouraging results in controlled clinical trials with cocaine-dependent patients. The search for a medical treatment for methamphetamine dependence started more recently, due to the later emergence of this epidemic, but at least one candidate medication has shown promise in early clinical testing. Treatment approaches that combine efficacious medications and empirically proven behavioral interventions, such as voucher-based reinforcement therapy, will almost certainly produce the best results.

Computer-assisted delivery of cognitive-behavioral therapy for addiction: a randomized trial of CBT4CBT

OBJECTIVES

This study evaluated the efficacy of a computer-based version of cognitive-behavioral therapy (CBT) for substance dependence.

METHOD

This was a randomized clinical trial in which 77 individuals seeking treatment for substance dependence at an outpatient community setting were randomly assigned to standard treatment or standard treatment with biweekly access to computer-based training in CBT (CBT4CBT) skills.

RESULTS

Treatment retention and data availability were comparable across the treatment conditions. Participants assigned to the CBT4CBT condition submitted significantly more urine specimens that were negative for any type of drugs and tended to have longer continuous periods of abstinence during treatment. The CBT4CBT program was positively evaluated by participants. In the CBT4CBT condition, outcome was more strongly associated with treatment engagement than in treatment as usual; furthermore, completion of homework assignments in CBT4CBT was significantly correlated with outcome and a significant predictor of treatment involvement.

CONCLUSIONS

These data suggest that CBT4CBT is an effective adjunct to standard outpatient treatment for substance dependence and may provide an important means of making CBT, an empirically validated treatment, more broadly available.

Gender differences with high-dose naltrexone in patients with co-occurring cocaine and alcohol dependence

This is a randomized, double-blind, placebo-controlled clinical trial that evaluated the efficacy of a higher-than-typical daily dose of naltrexone (150 mg/day), taken for 12 weeks, in 164 patients (n = 116 men and n = 48 women) with co-occurring cocaine and alcohol dependence. Patients were stratified by gender and then randomly assigned to either naltrexone or placebo, and to either cognitive-behavioral therapy or a type of medical management. The two primary outcomes were cocaine use and alcohol use. Significant Gender x Medication interactions were found for cocaine use via urine drug screens (three way, with time) and self-reports (two way) for drug severity (two way) and alcohol use (two way). The type of psychosocial treatment did not affect outcomes. Thus, 150 mg/day naltrexone added to a psychosocial treatment resulted in reductions in cocaine and alcohol use and drug severity in men, compared to higher rates of cocaine and alcohol use and drug severity in women.

Pilot study of interpersonal psychotherapy versus supportive psychotherapy for dysthymic patients with secondary alcohol abuse or dependence

Interpersonal psychotherapy (IPT) has demonstrated efficacy for depression but yielded negative results for substance disorders. Alcohol abuse frequently complicates mood disorders. This pilot study compared IPT with brief supportive psychotherapy (BSP) for dysthymic disorder and alcohol abuse. We hypothesized that effect sizes would suggest greater IPT efficacy for both diagnoses, despite limited statistical power. Subjects with primary DSM-IV dysthymic disorder and secondary alcohol abuse/dependence were randomly assigned 16 weeks of IPT (N = 14) or BSP (N = 12). Patients in both treatments reported improved depressive symptoms and alcohol abstinence. IPT had a large and BSP a moderate effect size in depression, whereas BSP had a moderate and IPT a small effect size in percentage of days abstinent. This pilot study offers initial data on IPT and BSP for comorbid chronic depression and alcohol abuse/dependence. Results suggest IPT may have specific antidepressant benefits for dysthymic alcoholic patients but not in treating alcoholism.

Norepinephrine signaling through beta-adrenergic receptors is critical for expression of cocaine-induced anxiety

BACKGROUND

Cocaine is a widely abused psychostimulant that has both rewarding and aversive properties. While the mechanisms underlying cocaine's rewarding effects have been studied extensively, less attention has been paid to the unpleasant behavioral states induced by cocaine, such as anxiety.

METHODS

In this study, we evaluated the performance of dopamine beta-hydroxylase knockout (Dbh -/-) mice, which lack norepinephrine (NE), in the elevated plus maze (EPM) to examine the contribution of noradrenergic signaling to cocaine-induced anxiety.

RESULTS

We found that cocaine dose-dependently increased anxiety-like behavior in control (Dbh +/-) mice, as measured by a decrease in open arm exploration. The Dbh -/- mice had normal baseline performance in the EPM but were completely resistant to the anxiogenic effects of cocaine. Cocaine-induced anxiety was also attenuated in Dbh +/- mice following administration of disulfiram, a dopamine beta-hydroxylase (DBH) inhibitor. In experiments using specific adrenergic antagonists, we found that pretreatment with the beta-adrenergic receptor antagonist propranolol blocked cocaine-induced anxiety-like behavior in Dbh +/- and wild-type C57BL6/J mice, while the alpha(1) antagonist prazosin and the alpha(2) antagonist yohimbine had no effect.

CONCLUSIONS

These results indicate that noradrenergic signaling via beta-adrenergic receptors is required for cocaine-induced anxiety in mice.

New treatments for cocaine dependence: a focused review

Cocaine, already a significant drug problem in North and South America, has become a more prominent part of the European drug scene. Cocaine dependence has major somatic, psychological, psychiatric, socio-economic, and legal implications. No specific effective pharmacological treatment exists for cocaine dependence. Recent advances in neurobiology have identified various neuronal mechanisms implicated in cocaine addiction and suggested several promising pharmacological approaches. Data were obtained from Medline, EMBASE, and PsycINFO searches of English-language articles published between 1985 and June 2007 using the key words: cocaine, addiction, cocaine dependence, clinical trials, pharmacotherapy(ies) singly and in combination. Large well-controlled studies with appropriate statistical methods were preferred. Pharmacological agents such as GABA agents (topiramate, tiagabine, baclofen and vigabatrin) and agonist replacement agents (modafinil, disulfiram, methylphenidate) seem to be the most promising in treatment of cocaine dependence. The results from trials of first- and second-generation neuroleptics are largely negative. Aripiprazole, a partial dopaminergic agonist that may modulate the serotonergic system, shows some promise. Preliminary results of human studies with anti-cocaine vaccine, N-acetylcysteine, and ondansetron, are promising, as are several compounds in preclinical development. While no medication has received regulatory approval for the treatment of cocaine dependence, several medications marketed for other indications have shown efficacy in clinical trials. An anti-cocaine vaccine and several compounds in preclinical development have also shown promise. Findings from early clinical trials must be confirmed in larger, less selective patient populations.

A double blind, placebo-controlled trial that combines disulfiram and naltrexone for treating co-occurring cocaine and alcohol dependence

BACKGROUND

This is a double blind, placebo-controlled trial that evaluated the efficacy of disulfiram, naltrexone and their combination in patients with co-occurring cocaine and alcohol dependence.

METHODS

208 patients were randomized to disulfiram (250 mg/day), naltrexone (100 mg/day), the combination, or placebo for 11 weeks. Outcomes were in-trial abstinence from cocaine and/or alcohol.

RESULTS

Few safety concerns were reported, although medication adherence was low in a number of patients for both medications, alone or in combination. In the primary analyses (GEE modeling), abstinence from cocaine as measured by cocaine-negative urines and days of self-reported abstinence from cocaine or alcohol did not differ between placebo and any of the medication groups. However, patients taking disulfiram (alone or in combination) were most likely to achieve combined abstinence from cocaine and alcohol. Secondary analyses revealed that patients taking the disulfiram-naltrexone combination were most likely to achieve 3 consecutive weeks of abstinence from cocaine and alcohol.

CONCLUSION

There was an association between disulfiram treatment and abstinence from cocaine and alcohol. More patients taking the disulfiram-naltrexone combination achieved 3 consecutive weeks of abstinence in treatment than placebo-treated patients.

Therapeutic options and challenges for substances of abuse

Addiction to substances continues to be a significant public health concern in the United States. The following review of current pharmacological treatments discusses a range of substances: nicotine, alcohol, cocaine, and opioids. The goal is to provide an overview of currently available and new pharmacological treatments for substance use disorders, while also addressing the pharmacothera-peutic challenges remaining. The significant advances in pharmacotherapy have had limited utilization, however. For example, naltrexone for alcoholism is infrequently prescribed, buprenorphine for opiates still has relatively few qualified prescribers, and stimulants have no Food and Drug Administration-approved pharmacotherapy. These pharmacotherapies are needed, with the rate of even the relatively uncommon abuse of opiates now rising sharply.

Levodopa pharmacotherapy for cocaine dependence: choosing the optimal behavioral therapy platform

BACKGROUND

The dopamine precursor levodopa has shown some, albeit relatively weak, promise in treating cocaine dependence. This study sought to identify the most appropriate behavioral therapy platform for levodopa pharmacotherapy by evaluating its effect when administered in combination with behavioral platforms of varying intensities.

METHOD

A total of 161 treatment-seeking cocaine dependent subjects received sustained release levodopa/carbidopa (400/100mg bid, Sinemet) or placebo delivered in combination with Clinical Management (ClinMan); ClinMan+cognitive behavioral therapy (CBT); or ClinMan+CBT+voucher-based reinforcement therapy (VBRT) in a 12-week randomized, placebo-controlled, double-blind (for medication condition) trial. Medication compliance was monitored with riboflavin (100mg/capsule) and the Medication Event Monitoring System. Protocol compliance was addressed in weekly, 10-min nurse-delivered ClinMan sessions. Weekly, 1-h CBT sessions focused on coping skills training. VBRT (with escalating reinforcer value) provided cash-valued vouchers contingent on cocaine-negative urine toxicology results. Urine benzoylecgonine assays collected thrice-weekly were analyzed by intention-to-treat criteria using generalized linear mixed models.

RESULTS

Levodopa main effects were found on all outcome measures of cocaine use. Contrasts testing the levodopa-placebo difference within each behavioral platform found reliable effects, favoring levodopa, only in the VBRT platform. Levodopa treatment with vouchers produced higher proportions of cocaine-negative urines and longer periods of consecutive abstinence compared to other treatment combinations.

CONCLUSION

This is the first study to find a significant treatment effect for levodopa and, in doing so, to demonstrate that the magnitude of this effect is dependent upon conditions of the behavioral therapy platform. The data support use of levodopa with abstinence-based reinforcement therapy as one efficacious combination in cocaine dependence disorder treatment.

Lessons learned from psychotherapy research

BACKGROUND

In addictions treatment research, there has been a relative paucity of work on mechanisms of action that account for observed treatment effects. In studies that have been done, there is little evidence that the purported active ingredients of behavioral interventions such as cognitive-behavioral treatment or motivational interviewing actually mediate treatment effects. This suggests that new approaches are needed to study the process of change in behavioral treatments for addiction.

METHOD

This article reviews several approaches that have been taken by psychotherapy researchers to identify mechanisms of change, including studies of critical sessions, change across sessions, and the relative importance of general vs. specific therapeutic factors.

RESULTS

These approaches all involve careful assessment of both therapist and patient behaviors during treatment sessions and study the relation of these factors to improvements or deteriorations in symptoms over the following weeks.

CONCLUSIONS

Suggestions are offered for how these methods could be used in addiction treatment research to generate hypotheses regarding mechanisms of change that could subsequently be tested in controlled studies.

Update on neuropharmacological treatments for alcoholism: scientific basis and clinical findings

The past decade has seen an expansion of research and knowledge on pharmacotherapy for the treatment of alcohol dependence. The Food and Drug Administration (FDA)-approved medications naltrexone and acamprosate have shown mixed results in clinical trials. Oral naltrexone and naltrexone depot formulations have generally demonstrated efficacy at treating alcohol dependence, but their treatment effect size is small, and more research is needed to compare the effects of different doses on drinking outcome. Acamprosate has demonstrated efficacy for treating alcohol dependence in European trials, but with a small effect size. In U.S. trials, acamprosate has not proved to be efficacious. Research continues to explore which types of alcohol-dependent individual would benefit the most from treatment with naltrexone or acamprosate. The combination of the two medications demonstrated efficacy for treating alcohol dependence in one European study but not in a multi-site U.S. study. Another FDA-approved medication, disulfiram, is an aversive agent that does not diminish craving for alcohol. Disulfiram is most effective when given to those who are highly compliant or who are receiving their medication under supervision. Of the non-approved medications, topiramate is among the most promising, with a medium effect size in clinical trials. Another promising medication, baclofen, has shown efficacy in small trials. Serotonergic agents such as selective serotonin reuptake inhibitors and the serotonin-3 receptor antagonist, ondansetron, appear to be efficacious only among certain genetic subtypes of alcoholic. As neuroscientific research progresses, other promising medications, as well as medication combinations, for treating alcohol dependence continue to be explored.

Severity of childhood trauma is predictive of cocaine relapse outcomes in women but not men

We prospectively examined the gender-specific effects of childhood trauma on cocaine relapse outcomes in an inpatient sample of treatment engaged cocaine dependent adults. Cocaine dependent men (n=70) and women (n=54) participating in inpatient treatment for cocaine dependence were assessed on severity of childhood trauma and followed for 90 days after discharge from treatment. Greater severity of childhood emotional abuse was associated with an increased risk of relapse in women. Severity of emotional abuse, sexual abuse, and overall childhood trauma was associated with the number of days cocaine was used during follow-up in women, as was the association of severity of physical abuse and overall childhood trauma with the average amount of cocaine used per occasion. No associations between childhood trauma and cocaine relapse outcomes were found in men. These findings demonstrate that childhood trauma increases the likelihood of cocaine relapse and drug use escalation after initial relapse in women but not in men. Comprehensive assessments of childhood trauma and specialized treatments that address trauma-related pathophysiology could be of benefit in improving cocaine treatment outcomes in women.

Treatment of co-occurring alcohol and other drug use disorders

Drug use disorders (DUDs) frequently co-occur with alcohol use disorders, affecting approximately 1.1 percent of the U.S. population. Compared with alcohol use disorders or DUDs alone, co-occurring disorders are associated with a greater severity of substance dependence; co-occurring psychiatric disorders also are common in this patient population. Many effective medications and behavioral treatments are available to treat alcohol dependence and drug dependence when these occur independent of one another. There is a paucity of research, however, specifically focused on the treatment of persons with co-occurring alcohol and other DUDs (AODUDs). The evidence to date on treating this patient population suggests that combining some of the behavioral and pharmacologic treatments that are effective in treating either drug or alcohol use disorders alone may be useful in the AODUD population as well.

Making consent more informed: preliminary results from a multiple-choice test among probation-referred marijuana users entering a randomized clinical trial

Although individuals who use illicit drugs are a potentially vulnerable population, there have been no objective evaluations of the effectiveness of standard informed consent procedures in assuring that prospective participants entering drug abuse treatment trials fully understand the nature of the research and treatments in which they have agreed to participate. Young, marijuana-dependent adults referred by the criminal justice system who were enrolling in a randomized treatment trial were asked to complete a multiple-choice quiz concerning basic elements of the trial before providing written informed consent. Participants were assigned to standard drug counseling or motivational interviewing/skills-building therapy, delivered alone or with incentives for attending sessions and submitting marijuana-free urine specimens. Only 55 percent of the 130 participants correctly answered all four questions, and 20 percent incorrectly answered a question concerning their right to refuse to participate. An unexpected finding was that quiz scores were modestly associated with marijuana use outcome measures. These preliminary findings highlight the importance of systematically evaluating the understanding of research participants, particularly those in vulnerable populations, of their rights and key aspects of the trials in which they agree to participate.

Enhancing brief cognitive-behavioral therapy with motivational enhancement techniques in cocaine users

BACKGROUND

We investigated the impact of enhancing brief cognitive-behavioral therapy with motivational interviewing techniques for cocaine abuse or dependence, using a focused intervention paradigm.

METHODS

Participants (n=74) who met current criteria for cocaine abuse or dependence were randomized to three-session cognitive-behavioral therapy (CBT) or three-session enhanced CBT (MET+CBT), which included an initial session of motivational enhancement therapy (MET). Outcome measures included treatment retention, process measures (e.g., commitment to abstinence, satisfaction with treatment), and cocaine use.

RESULTS

Participants who received the MET+CBT intervention attended more drug treatment sessions following the study interventions, reported significantly greater desire for abstinence and expectation of success, and they expected greater difficulty in maintaining abstinence compared to the CBT condition. There were no differences across treatment conditions on cocaine use.

CONCLUSIONS

These findings offer mixed support for the addition of MET as an adjunctive approach to CBT for cocaine users. In addition, the study provides evidence for the feasibility of using short-term studies to test the effects of specific treatment components or refinements on measures of therapy process and outcome.

Rethinking the paradigms that inform behavioral treatment research for substance use disorders

AIMS

Over the last three decades, the randomized controlled trial or 'psychotherapy technology' approach has been the dominant model of inquiry in research on addiction treatment. This period has yielded impressive discoveries, but recent failures to confirm core research hypotheses such as occurred in Project MATCH and the Cocaine Collaborative Treatment Study have raised questions about future research directions. The paper identifies several testable assumptions of the psychotherapy technology model.

METHODS

A review is conducted on four substance use disorder behavioral interventions--motivational interviewing, cognitive-behavioral treatment, behavioral couples treatment and 12-Step-oriented treatment--to determine whether these assumptions are supported by research findings.

RESULTS

Overall, the review suggests weak support for the technology model of psychotherapy research. Lack of support is interpreted as indicating flaws in several model assumptions about how to conceptualize and measure patient responsivity and the interaction of non-specific and specific therapeutic factors. The paper offers alternative strategies for addressing these issues drawn from the general psychotherapy process literature and provides illustrative examples of how these could be used to spur innovation in addiction treatment research.

CONCLUSIONS

The addiction treatment research field is coming up against the limitations of the psychotherapy technology model as the dominant paradigm guiding treatment research. It is important for addiction treatment researchers to explore alternative conceptualizations and methodologies in order to understand more clearly how treatment works.

Monoamine transporters and psychostimulant addiction

Psychostimulants are a broadly defined class of drugs that stimulate the central and peripheral nervous systems as their primary pharmacological effect. The abuse liability of psychostimulants is well established and represents a significant public health concern. An extensive literature documents the critical importance of monoamines (dopamine, serotonin and norepinephrine) in the behavioral pharmacology and addictive properties of psychostimulants. In particular, the dopamine transporter plays a primary role in the reinforcing and behavioral-stimulant effects of psychostimulants in animals and humans. Moreover, both serotonin and norepinephrine systems can reliably modulate the neurochemical and behavioral effects of psychostimulants. However, there is a growing body of evidence that highlights complex interactions among additional neurotransmitter systems. Cortical glutamatergic systems provide important regulation of dopamine function, and inhibitory amino acid gamma-aminobutyric acid (GABA) systems can modulate basal dopamine and glutamate release. Repeated exposure to psychostimulants can lead to robust and enduring changes in neurobiological substrates, including monoamines, and corresponding changes in sensitivity to acute drug effects on neurochemistry and behavior. Significant advances in the understanding of neurobiological mechanisms underlying psychostimulant abuse and dependence have guided pharmacological treatment strategies to improve clinical outcome. In particular, functional agonist treatments may be used effectively to stabilize monoamine neurochemistry, influence behavior and lead to long-term abstinence. However, additional clinical studies are required in order to identify safe and efficacious pharmacotherapies.

Site matters: multisite randomized trial of motivational enhancement therapy in community drug abuse clinics

The effectiveness of motivational enhancement therapy (MET) in comparison with counseling as usual (CAU) for increasing retention and reducing substance use was evaluated in a multisite randomized clinical trial. Participants were 461 outpatients treated by 31 therapists within 1 of 5 outpatient substance abuse programs. There were no retention differences between the 2 brief intervention conditions. Although both 3-session interventions resulted in reductions in substance use during the 4-week therapy phase, MET resulted in sustained reductions during the subsequent 12 weeks whereas CAU was associated with significant increases in substance use over this follow-up period. This finding was complicated by program site main effects and higher level interactions. MET resulted in more sustained substance use reductions than CAU among primary alcohol users, but no difference was found for primary drug users. An independent evaluation of session audiotapes indicated that MET and CAU were highly and comparably discriminable across sites.

Neurobiology of addiction. An integrative review

Evidence that psychoactive substance use disorders, bulimia nervosa, pathological gambling, and sexual addiction share an underlying biopsychological process is summarized. Definitions are offered for addiction and addictive process, the latter being the proposed designation for the underlying biopsychological process that addictive disorders are hypothesized to share. The addictive process is introduced as an interaction of impairments in three functional systems: motivation-reward, affect regulation, and behavioral inhibition. An integrative review of the literature that addresses the neurobiology of addiction is then presented, organized according to the three functional systems that constitute the addictive process. The review is directed toward identifying candidate neurochemical substrates for the impairments in motivation-reward, affect regulation, and behavioral inhibition that could contribute to an addictive process.

There and back again: a tale of norepinephrine and drug addiction

Fueled by anatomical, electrophysiological, and pharmacological analyses of endogenous brain reward systems, norepinephrine (NE) was identified as a key mediator of both natural and drug-induced reward in the late 1960s and early 1970s. However, reward experiments from the mid-1970s that could distinguish between the noradrenergic and dopaminergic systems resulted in the prevailing view that dopamine (DA) was the primary 'reward transmitter' (a belief holding some sway still today), thereby pushing NE into the background. Most damaging to the NE hypothesis of reward were studies demonstrating that NE receptor antagonists and NE reuptake inhibitors failed to impact drug self-administration. In recent years new tools, such as genetically engineered mice, and new experimental paradigms, such as reinstatement of drug seeking following withdrawal, have propelled NE back into the awareness of addiction researchers. Of particular interest is disulfiram, an inhibitor of the NE biosynthetic enzyme dopamine beta-hydroxylase, which has demonstrated promising efficacy in the treatment of cocaine dependence in preliminary clinical trials. The purpose of this review is to synthesize the new data linking NE to critical aspects of DA signaling and drug addiction, with a focus on psychostimulants (eg, cocaine), opiates (eg, morphine), and alcohol.

New developments in the pharmacotherapy of cocaine abuse

Despite huge advances in the neuroscience of substance abuse and dependence in the past 20 years, no approved pharmacological treatment exists for cocaine abuse. The available drugs for the treatment of cocaine abuse are poorly effective, hence the need for new compounds to be screened and tested for efficacy: targeting symptoms might improve the effectiveness of the treatment of cocaine abuse and dependence. On the basis of the known neurochemistry of cocaine, some target compounds have been studied: among others, BP-897, a D3 partial agonist; vanoxerine, a highly selective inhibitor of dopamine uptake; aripiprazole, a partial mixed-action agonist approved for the treatment of schizophrenia. Recently modafinil, approved for the treatment of narcolepsy, proved effective in favouring cocaine abstinence in cocaine-abusing people. Some placebo-controlled studies also reported the effectiveness of topiramate, a licensed antiepileptic drug, and of tiagabine, a gamma-aminobutyric acid (GABA) re-uptake inhibitor also approved as an anticonvulsant; both compounds increased cocaine abstinence with no serious adverse events. Promising results came from two more compounds acting on the GABA circuits, baclofen and valproic acid. Finally disulfiram, prescribed with active psychosocial therapy, was found to favour higher retention rates and longer abstinence periods from both alcohol and cocaine in polydrug-abusing patients. An alternative approach rests on the use of vaccines, to date in the experimental stage still. Psychosocial treatments are a useful companion in the pharmacotherapy of cocaine abuse, with group therapy and contingency management therapies improving motivation and social functioning, particularly in patients abusing alcohol as well.

Dopamine beta-hydroxylase gene (DbetaH) -1021C-->T influences self-reported paranoia during cocaine self-administration

BACKGROUND

Variation in the gene for dopamine beta-hydroxylase (DbetaH) has been reported to associate with cocaine-induced paranoia as assessed by retrospective self-report. This association has yet to be tested prospectively.

METHODS

Visual analog scale (VAS) ratings of paranoia were obtained in 31 cocaine users during three cocaine self-administration sessions (8, 16, and 32 mg/70 kg). Pharmacogenetic interactions between cocaine and a putative functional polymorphism in DbetaH (-1021C-->T) were assessed.

RESULTS

VAS self-ratings showed significant or trend-level interactions of genotype and time during each session (p = .004, .09 and .003, respectively) with TT homozygotes endorsing greater paranoia over time than either CT or CC individuals. Interactions were significant at all doses in African Americans (n = 19; p = .02, .04 and .05). No other demographic or experimental variable distinguished genotypic groups.

CONCLUSIONS

Results indicate that individuals homozygous for the 'very low-activity' T allele at DbetaH -1021C-->T show an increased propensity to paranoia over time during cocaine self-administration.

Safety, tolerability and efficacy of levodopa-carbidopa treatment for cocaine dependence: two double-blind, randomized, clinical trials

RATIONALE

The role of dopamine in cocaine abuse has been long recognized. Cocaine use can profoundly alter dopaminergic functioning through depletion of this monoamine and changes in receptor functioning. Based on these facts, levodopa (L-dopa) pharmacotherapy may be helpful in reducing or abolishing cocaine use.

OBJECTIVE

The current studies sought to evaluate the safety, tolerability and efficacy of L-dopa as a treatment for cocaine dependence.

METHODS

In Study 1, 67 cocaine-dependent subjects were randomized in a 5-week, double-blind, placebo-controlled safety trial. Subjects received either placebo, or 400 mg L-dopa plus 100 mg of the peripheral decarboxylase inhibitor, carbidopa, in a sustained-release preparation (Sinemet CR). In Study 2, 122 cocaine-dependent subjects were enrolled in a 9-week, randomized, double-blind, placebo-controlled trial to compare placebo to 400/100 mg and 800/200 mg L-dopa/carbidopa treatments. Placebo or L-dopa were administered twice daily in both studies.

RESULTS

L-dopa was well tolerated with similar retention and medication adherence rates compared to placebo. Only two side effects occurred more often in L-dopa-treated patients: nausea and dizziness. L-dopa lowered diastolic blood pressure in a dose-dependent fashion. In these trials, L-dopa had no effect on cocaine use, cocaine craving, or mood.

CONCLUSION

These two studies demonstrate the safety and tolerability of L-dopa pharmacotherapy in cocaine-dependent patients. No evidence for greater efficacy of L-dopa compared to placebo was observed. The possibility of enhancing treatment effects by combining L-dopa with other behavioral or pharmacological interventions is discussed.

Pharmacotherapy of dual substance abuse and dependence

The US FDA has approved a limited number of treatments for alcohol, nicotine and opioid dependence; however, no treatments for other abused drugs such as marijuana, cocaine or methamphetamine are approved. This review focuses on research into drug pharmacotherapies, particularly single-drug therapies, for substance abuse and dependence contributing to the most important dual substance use disorders (SUDs). Given the implications of poly-substance abuse, it is essential that clinicians and researchers be aware of potential pharmacotherapies for the treatment of dual SUDs.A substantial number of patients abuse more than one drug concurrently, complicating the treatment of SUD and leaving clinicians with few FDA-approved drug options for their patients. In this era of evidence-based medicine, such patients are typically treated with therapeutically proven medications, but in ways that are outside the scope of a drug's original indication by the FDA. Such 'off-label' prescribing has become an important therapeutic strategy for practitioners seeking treatments for other diseases in subpopulations such as paediatrics and gerontology or for medical conditions such as oncology or mental illness. Similarly, the information that most clinicians use to make their decisions for treating patients abusing multiple drugs stems from trials treating a single SUD, anecdotal experiences from their own practice or that of their colleagues, or single-case studies reported in the literature. The existing evidence suggests there are few treatments for SUDs that confer significant reductions in substance use across a broad patient population. Moreover, even fewer clinical efficacy trials have been conducted that provide evidence of therapeutic benefit for these drugs. Recognising the difficulty in making the proper drug choice for facilitating maximum treatment success, this review highlights the single drugs or drug combinations that show some potential for treating dual SUDs. This review finds strongest support for the use of disulfiram for treatment of alcohol and cocaine dependence (with or without concomitant methadone maintenance), baclofen for alcohol and cocaine dependence (but not opioid-dependent cocaine users), tiagabine for cocaine dependence in methadone-maintained patients, and topiramate for alcohol, nicotine and cocaine dependence. While ondansetron and olanzapine show some efficacy in treating alcohol and cocaine dependence, more research is needed to better delineate the subpopulation in which these drugs may provide their maximum effect.

Disulfiram effects on responses to intravenous cocaine administration

Disulfiram has been studied as a treatment for cocaine dependence. We report results of a randomized, double-blind, placebo-controlled, within-subject study to examine the interaction of disulfiram with intravenous cocaine.

METHODS

Non-treatment-seeking, cocaine-dependent, volunteers participated in serial experiments in which they received disulfiram placebo, 62.5 or 250 mg/day on days 1-6. On days 4-6, participants received a morning disulfiram dose 2 h prior to a scheduled session in which they were administered intravenous cocaine placebo, 0.25 mg/kg (n=9) or 0.5 mg/kg (n=3) over 1 min. Blood, cardiovascular and subjective measures were collected. Seven days of washout occurred between disulfiram conditions.

RESULTS

Following active disulfiram treatments and cocaine 0.25 mg/kg administration, plasma cocaine AUC (0-480 min) was increased (p=0.003 and 0.001) and cocaine clearance decreased (p<0.001). Disulfiram treatments also decreased cocaine clearance for the 0.5 mg/kg cocaine dose (p=0.002 and<0.001). Neither disulfiram dose with cocaine altered cardiovascular responses relative to cocaine alone. Following cocaine 0.25 mg/kg, 'any high' (p=0.021 and 0.019), 'cocaine high' (p=0.017 and 0.018) and 'rush' (p=0.013 and 0.047) significantly decreased with either disulfiram dose.

CONCLUSIONS

Disulfiram decreased cocaine clearance without toxicity. Cocaine 'high' and 'rush' were diminished. Disulfiram may be a promising pharmacotherapy in selected cocaine dependent individuals.

Clinical care of the HIV-infected drug user

HIV/AIDS and chemical dependency, the latter often intertwined with mental illness, are complex, overlapping spheres that adversely influence each other and the overall clinical outcomes of the affected individual. Each disorder individually impact tens of millions of people adversely, with explosive epidemics described worldwide. This article addresses the adverse consequences of HIV/AIDS, drug injection, the secondary comorbidities of both, and the impact of immunosuppression on presentation of disease as well as approaches to managing the HIV-infected drug user.

Direct care workers in the National Drug Abuse Treatment Clinical Trials Network: characteristics, opinions, and beliefs

OBJECTIVE

Individuals with direct care responsibilities in 348 drug abuse treatment units were surveyed to obtain a description of the workforce and to assess support for evidence-based therapies.

METHODS

Surveys were distributed to 112 programs participating in the National Drug Abuse Treatment Clinical Trials Network (CTN). Descriptive analyses characterized the workforce. Analyses of covariance tested the effects of job category on opinions about evidence-based practices and controlled for the effects of education, modality (outpatient or residential), race, and gender.

RESULTS

Women made up two-thirds of the CTN workforce. One-third of the workforce had a master's or doctoral degree. Responses from 1,757 counselors, 908 support staff, 522 managers-supervisors, and 511 medical staff (71% of eligible participants) suggested that the variables that most were most consistently associated with responses were job category (19 of 22 items) and education (20 of 22 items). Managers-supervisors were the most supportive of evidence-based therapies, and support staff were the least supportive. Generally, individuals with graduate degrees had more positive opinions about evidence-based therapies. Support for using medications and contingency management was modest across job categories.

CONCLUSIONS

The relatively traditional beliefs of support staff could inhibit the introduction of evidence-based practices. Programs initiating changes in therapeutic approaches may benefit from including all employees in change efforts.

Therapeutic options and challenges for substances of abuse

Addiction to substances continues to be a significant public health concern in the United States. The following review of current pharmacological treatments discusses a range of substances: nicotine, alcohol, cocaine, and opioids. The goal is to provide an overview of currently available and new pharmacological treatments for substance use disorders, while also addressing the pharmacotherapeutic challenges remaining. The significant advances in pharmacotherapy have had limited utilization, however. For example, naltrexone for alcoholism is infrequently prescribed, buprenorphine for opiates still has relatively few qualified prescribers, and stimulants have no Food and Drug Administration-approved pharmacotherapy. These pharmacotherapies are needed, with the rate of even the relatively uncommon abuse of opiates now rising sharply.

Psychosocial approaches to psychostimulant dependence: A systematic review

This review examines the nature and evidence for the effectiveness of psychosocial interventions for psychostimulant dependence. Psychostimulant dependence and related harms continue to increase in many parts of the world, while treatment responses are predominantly limited to psychosocial interventions. The effectiveness of psychosocial interventions is compromised by poor rates of treatment induction and retention. As with other substance use disorders, increasing the diversity of treatment options is likely to improve treatment coverage and outcomes across a broader range of users. Identifying medications that might enhance treatment induction and retention would also enhance the effectiveness of psychosocial programs. It is concluded that psychosocial interventions are moderately effective in reducing psychostimulant use and related harms among psychostimulant-dependent persons.

A breath test to assess compliance with disulfiram

AIMS

To evaluate the ability of a hand-held breath analyser, the Zenalyser((R)) (Zenics Medical), to identify alcohol-dependent patients receiving disulfiram therapy and to assess the sensitivity and specificity of the instrument at different time intervals post-disulfiram dosing.

DESIGN

Breath samples were taken from two groups of alcohol-dependent patients, one group on a daily disulfiram regimen and one group receiving no disulfiram. The breath samples were analysed for the combined concentration of carbon disulphide and acetone produced from the metabolism of disulfiram. From these data, two reference ranges were prepared and used for sensitivity and specificity assessments.

SETTING

Breath samples for the reference ranges were obtained from patients at Shelton Hospital, Shrewsbury. Breath samples used to assess the sensitivity and specificity of the instrument were obtained from patients at the Edinburgh Alcohol Problems Clinic.

PARTICIPANTS

Twenty in-patients from Shelton Hospital receiving a daily 200 mg disulfiram regimen and 20 in-patients receiving no disulfiram. At the Edinburgh Clinic, 54 patients taking a thrice-weekly disulfiram regimen and 22 patients not on disulfiram.

MEASUREMENTS

A total of 489 breath samples from Shelton Hospital and 391 breath samples from the Edinburgh Clinic were analysed for the combined concentrations of carbon disulphide and acetone.

FINDINGS

The breath analyser produced results that distinguished between the disulfiram-treated and untreated groups (P < 0.001). At 1 day post-dose, the sensitivity was 100% and the specificity was 100%. At 2 and 3 days post-dose, the sensitivities and specificities were 84.6% and 100% and 88.2% and 100%, respectively.

CONCLUSION

The breath analyser can improve the assessment of the compliance status of patients receiving a daily dose regimen of disulfiram, but is less useful for this purpose if disulfiram is taken on a thrice-weekly regimen.

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.

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.

Dopamine beta-hydroxylase knockout mice have alterations in dopamine signaling and are hypersensitive to cocaine

Multiple lines of evidence demonstrate that the noradrenergic system provides both direct and indirect excitatory drive onto midbrain dopamine (DA) neurons. We used DA beta-hydroxylase (DBH) knockout (Dbh-/-) mice that lack norepinephrine (NE) to determine the consequences of chronic NE deficiency on midbrain DA neuron function in vivo. Basal extracellular DA levels were significantly attenuated in the nucleus accumbens (NAc) and caudate putamen (CP), but not prefrontal cortex (PFC), of Dbh-/- mice, while amphetamine-induced DA release was absent in the NAc and attenuated in the CP and PFC. The decrease in dopaminergic tone was associated with a profound increase in the density of high-affinity state D1 and D2 DA receptors in the NAc and CP, while DA receptors in the PFC were relatively unaffected. As a behavioral consequence of these neurochemical changes, Dbh-/- mice were hypersensitive to the psychomotor, rewarding, and aversive effects of cocaine, as measured by locomotor activity and conditioned place preference. Antagonists of DA, but not 5-HT, receptors attenuated the locomotor hypersensitivity to cocaine in Dbh-/- mice. As DBH activity in humans is genetically controlled and the DBH inhibitor disulfiram has shown promise as a pharmacotherapy for cocaine dependence, these results have implications for the influence of genetic and pharmacological DBH inhibition on DA system function and drug addiction.

[New developments in the pharmacotherapy of cocaine dependence]

New possibilities with medications for the treatment of cocaine dependence have begun to emerge. For example, in a randomised controlled study, disulfiram succeeded for the first time in significantly reducing cocaine consumption. In October 2003, a phase IIb study was started in the USA testing active immunisation against cocaine dependence. There is also an ongoing study in Switzerland testing methylphenidate treatment in combination with cognitive behavioural therapy. Pilot studies indicate that vigabatrin, selegiline, and topiramate are promising candidates for further clinical substance testing.

Needs and scientific opportunities for research on substance abuse treatment among Hispanic adults

The results of a focused search of the literature on empirical studies of substance abuse treatment outcomes with Hispanic adults are reviewed. Also provided are key research opportunities and recommendations on substance abuse treatment for Hispanics. The paper is divided into two major sections: the first focuses on behavioral drug treatment studies on Hispanic adults, and the second identifies published original articles in pharmacotherapy, namely that more empirical research is needed to determine which treatments are efficacious with Hispanic populations. For treatment modalities not associated with promising effect sizes with Hispanic samples, cultural modifications may be needed to improve the compatibility of the treatment with Hispanic culture. For those treatments found to have promising effect sizes with various Hispanic subgroups, with Hispanics at different levels of acculturation, and with Hispanics from various socioeconomic backgrounds. The authors stress the need for theory-driven interventions to be developed specifically for well-characterized Hispanic subgroups (e.g., suburban middle-income Puerto Ricans living in the Northeast).

Kokainmissbrauch in Wien und in europäischen Metropolen – eine multizentrische Studie

INTRODUCTION

As cocaine consumption seems to have increased over the last decades, the EU has funded this multi-center, cross-sectional survey to investigate cocaine consumption in three different target groups. The study was conducted by the Addiction Clinic, Department of Psychiatry, Medical University Vienna and other nine European cities.

METHODS

Data were collected by structured face-to-face interviews. The sample was composed of 211 cocaine abusers out of three target groups: (1) treatment group undergoing opioid maintenance therapy, (2) marginalized scene group and (3) integrated party group. Sociodemographic data such as age, education, employment, monthly expenses on cocaine/crack, data on consumption patterns, physical and mental health and personal needs regarding cocaine consumption were evaluated. Urine toxicology results for cocaine in the treatment group completed the analysis.

RESULTS

The marginalized scene group was the oldest with a mean age of 29.35 years, with the highest unemployment rate (mean 25.11 days) and the longest duration of cocaine consumption (mean 5.80 years). They had the highest cocaine consumption pattern with a mean of 22.32 days within the last month. On average 1969 Euros/months was spent for their addiction. The treatment group had the lowest school education with a mean of 10.36 years, but showed a sufficient insight in their cocaine problem. However, the party group (with the lowest mean age, 25.64 years) highly underestimated their drug problem, the mean amount of money they spent for their addiction was 588.99 Euro/months. Structured urine toxicology between 1996 and 2002 in patients undergoing opioid maintenance therapy ("treatment group") revealed a significant increase of concomitant cocaine consumption (1996: 33.1%; 2002: 40.2%; p = 0.044).

DISCUSSION

The European trend of increased cocaine use could also be observed in Vienna. One of the greatest barriers for establishing adequate treatment settings for this target group is the difficulty to reach this population. In addition, multiple substance abuse seems to be one of the predominating patterns of cocaine consumption and this aspect should be integrated within treatment (in the treatment and scene groups additional heroin and benzodiapzepines abuse is observed, in the party group intensive alcohol consumption). The Viennese results are in line with those of the other European cities; however, it could not be confirmed that consumption of crack cocaine and binge play a similarly significant role as in cities such as Hamburg or London.

Effects of baclofen on cocaine self-administration: opioid- and nonopioid-dependent volunteers

Preclinical and clinical studies suggest that GABAB receptor agonists selectively decrease cocaine use. The behavioral mechanism for the interaction between baclofen and cocaine in humans is not known, nor have its effects been characterized in individuals dependent on both cocaine and methadone. The objective of this study is to determine how maintenance on baclofen influences smoked cocaine's reinforcing and subjective effects, mood and cocaine craving prior to and after the initiation of cocaine use in cocaine-dependent volunteers with and without concurrent opioid dependence. Nontreatment-seeking volunteers (10 nonopioid dependent; seven methadone maintained), residing on an in-patient research unit for 21 days, were maintained on each baclofen dose (0, 30, 60 mg po) for 7 days. A smoked cocaine dose-response curve (0, 12, 25, 50 mg) was determined twice: on days 3-4 and days 6-7 of each baclofen maintenance condition. Cocaine sessions began with a sample trial, when participants smoked the cocaine dose available that session, and five choice trials, when participants chose between smoking the available cocaine dose or receiving one 5 dollars merchandise voucher. The results show that in the nonmethadone group, baclofen (60 mg) decreased self-administration of a low cocaine dose (12 mg). In the methadone group, baclofen decreased craving for cocaine. In both groups, baclofen decreased cocaine's effects on heart rate. Baclofen did not alter cocaine's robust subjective effects (eg 'High,' 'Stimulated') for either group. The results from this laboratory study appear consistent with clinical evidence showing that baclofen decreases cocaine use in nonopioid-dependent patients seeking treatment for cocaine dependence. The distinct pattern of effects in methadone-maintained participants suggests baclofen may not be effective in opioid-dependent cocaine users.

The status of disulfiram: a half of a century later

For more than 55 years, disulfiram has been approved by the Food and Drug Administration for the treatment of alcohol dependence. It is a unique medication that relies on "psychological threat" to avoid disulfiram-ethanol reactions. This paper reviews the history of disulfiram treatment, the current status of disulfiram treatment, the ensuing developments in disulfiram use in treating various addictions, and future directions. Clinical trials using disulfiram for the treatment of alcohol, cocaine, or co-occurring alcohol + cocaine dependence were included in this review. Disulfiram efficacy studies focusing on supervised, implant, and combination pharmacotherapies were also examined. In clinical trials, disulfiram has demonstrated inconsistent results in helping patients to abstain from alcohol, and patients poorly adhere to a disulfiram-treatment regimen. This has raised questions about disulfiram's practicality in the treatment of alcohol dependence. Recently, however, disulfiram has gained attention as a complementary agent to newer pharmacological medications, such as an opiate antagonist that specifically reduces alcohol craving. One hypothesis is that disulfiram would assist patients in gaining psychological control over drinking when given in conjunction with an opiate antagonist that would act directly on reducing alcohol craving. Preliminary evidence also suggests that disulfiram treatment could be a viable treatment for cocaine dependence because it was shown to reduce cocaine use among nonalcoholic, cocaine-dependent patients.

ADH4 gene variation is associated with alcohol dependence and drug dependence in European Americans: results from HWD tests and case-control association studies

The alcohol dehydrogenase (ADH) family constitutes one of the key sets of enzymes responsible for the oxidation of alcohol. The ADH4 gene, an important member of this family, is a functional and positional candidate for alcohol dependence. The present study aimed to investigate the relationship between ADH4 gene variation and alcohol dependence and drug dependence in European-Americans (EAs) and African-Americans (AAs). Seven single nucleotide polymorphisms (SNPs) spanning the ADH4 gene were genotyped in 365 healthy controls (317 EAs and 48 AAs) and 561 subjects (400 EAs and 161 AAs) affected with alcohol dependence and/or drug dependence (436 with alcohol dependence; 356 with drug dependence). Hardy-Weinberg equilibrium (HWE) for the genotype frequency distributions of these markers was tested in all phenotype groups to evaluate association between ADH4 gene variation and phenotypes and to fine-map the disease risk locus. The allele, genotype, and haplotype frequency distributions of these markers were compared between cases and controls to confirm the associations. The genotype frequency distributions of ADH4 markers were in HWE in EA controls, but were in Hardy-Weinberg disequilibrium (HWD) (ie, deviation from HWE) in EA cases. Among all markers, SNP2 (rs1042363) at exon 9 or SNP6 (rs1800759) at the promoter showed the greatest degree of HWD, among patients with either alcohol dependence or drug dependence. Significant differences between EA cases and controls were seen for genotype (10(-6)<global p<0.044), but not any allele or haplotype, frequency distributions for all seven ADH4 markers. These findings suggest that ADH4 genotypes predispose to alcohol dependence and drug dependence in a recessive manner, a predisposition that is population specific. SNP2 or SNP6 was the marker genetically closest to the functional risk loci for both alcohol dependence and drug dependence.

Gender differences in cardiovascular and corticoadrenal response to stress and drug cues in cocaine dependent individuals

RATIONALE

Extensive research suggests that gender may affect neuroendocrine and cardiovascular arousal mechanisms underlying biological responses to stress.

OBJECTIVE

To examine the impact of gender on response to stress and to drug-cue exposure in treatment-seeking cocaine abusers.

METHODS

Fifty recently abstinent cocaine dependent individuals (25F/25M), who were matched on cocaine use history, were exposed to a brief guided-imagery procedure that involved imagining a recent personal stressful situation, a personal drug-related situation and neutral-relaxing situation, one imagery per session, presented in random order. Subjective craving and anxiety, cardiovascular measures and plasma adrenocorticotrophic hormone (ACTH), cortisol and prolactin were assessed.

RESULTS

Males showed significantly higher levels of ACTH, cortisol, and SBP, both at baseline and following all three imagery conditions. Females showed significantly higher basal heart rate and prolactin, although no gender differences were observed following imagery. No gender differences were seen in subjective anxiety or cocaine craving.

CONCLUSIONS

Results indicate significant gender differences in baseline sensitivity and subsequent variations in hypothalamus-pituitary-adrenal (HPA) and cardiovascular response to imagery challenge. Such gender-specific responses could have implications for the development of pharmacological treatments that address stress and drug-cue-related relapse in cocaine-abusing individuals.

Self-reported paranoia during laboratory "binge" cocaine self-administration in humans

Cocaine-induced paranoia (CIP) has been extensively studied by retrospective interviews; however, only limited efforts have been made to further characterize CIP by human laboratory methods. We examined CIP in 28 healthy cocaine-dependent volunteers, who participated in 2-h, intravenous cocaine self-administration sessions at 8, 16, and 32 mg/70 kg doses, including 18 in a placebo-controlled design. Self-reports of paranoia showed significant main effects of cocaine dose (p=0.0002) and time (p=0.0003), and were statistically distinguishable from placebo at the two highest doses (16 and 32 mg). These effects were accounted for by a subgroup of vulnerable subjects in whom self-reports were consistent across dose and test-retest sessions. Subjects with CIP did not differ from those without CIP with respect to demographic, cocaine use, or cocaine self-administration variables. In conclusion, self-reports of CIP in the human lab are frequently endorsed, dose-dependent, and though variable between subjects, reproducible within subjects. Such methods may facilitate our understanding of the vulnerability to CIP in humans.

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.

Bromocriptine treatment for cocaine addiction: association with plasma prolactin levels

Bromocriptine is a dopamine receptor agonist used with mixed success in the treatment of cocaine addiction. Variations in dopamine receptor sensitivity may help account for these differences. We evaluated this question in a 24-week outpatient controlled clinical trial in 70 cocaine-abusing (DSM-III) men (86% African-American, mean age 34 years, mean 39 months of regular cocaine use [predominantly smoked]). Subjects received 4 weeks of inpatient treatment. During the last 2 weeks they were inducted onto bromocriptine (maximum dose 2.5mg po tid) (n=35) or placebo (n=35). Plasma prolactin concentrations were assayed before and after the first bromocriptine dose (1.25mg po) as a measure of dopamine receptor sensitivity. After discharge, subjects continued on medication with weekly group counseling. Bromocriptine significantly suppressed prolactin concentrations (4.4 ng/ml decrease), while placebo did not (0.1 ng/ml decrease). Both groups decreased their cocaine use, with no significant group differences in retention in treatment or proportion of cocaine-positive urine samples. There was no significant association between basal plasma prolactin concentrations or prolactin response to first bromocriptine dose and either outcome measure. These data do not support the efficacy of bromocriptine treatment nor a role for prolactin concentration in predicting treatment response.