Bromocriptine-desipramine protocol in treatment of cocaine addiction

Integrative Pharmacology in the Treatment of Substance Use Disorders

The detrimental physical, mental, and socioeconomic effects of substance use disorders (SUDs) have been apparent to the medical community for decades. However, it has become increasingly urgent in recent years to develop novel pharmacotherapies to treat SUDs. Currently, practitioners typically rely on monotherapy. Monotherapy has been shown to be superior to no treatment at all for most substance classes. However, many randomized controlled trials (RCTs) have revealed that monotherapy leads to poorer outcomes when compared with combination treatment in all specialties of medicine. The results of RCTs suggest that monotherapy frequently fails since multiple dysregulated pathways, enzymes, neurotransmitters, and receptors are involved in the pathophysiology of SUDs. As such, research is urgently needed to determine how various neurobiological mechanisms can be targeted by novel combination treatments to create increasingly specific yet exceedingly comprehensive approaches to SUD treatment. This article aims to review the neurobiology that integrates many pathophysiologic mechanisms and discuss integrative pharmacology developments that may ultimately improve clinical outcomes for patients with SUDs. Many neurobiological mechanisms are known to be involved in SUDs including dopaminergic, nicotinic, N-methyl-D-aspartate (NMDA), and kynurenic acid (KYNA) mechanisms. Emerging evidence indicates that KYNA, a tryptophan metabolite, modulates all these major pathophysiologic mechanisms. Therefore, achieving KYNA homeostasis by harmonizing integrative pathophysiology and pharmacology could prove to be a better therapeutic approach for SUDs. We propose KYNA-NMDA-α7nAChRcentric pathophysiology, the "conductor of the orchestra," as a novel approach to treat many SUDs concurrently. KYNA-NMDA-α7nAChR pathophysiology may be the "command center" of neuropsychiatry. To date, extant RCTs have shown equivocal findings across comparison conditions, possibly because investigators targeted single pathophysiologic mechanisms, hit wrong targets in underlying pathophysiologic mechanisms, and tested inadequate monotherapy treatment. We provide examples of potential combination treatments that simultaneously target multiple pathophysiologic mechanisms in addition to KYNA. Kynurenine pathway metabolism demonstrates the greatest potential as a target for neuropsychiatric diseases. The investigational medications with the most evidence include memantine, galantamine, and N-acetylcysteine. Future RCTs are warranted with novel combination treatments for SUDs. Multicenter RCTs with integrative pharmacology offer a promising, potentially fruitful avenue to develop novel therapeutics for the treatment of SUDs.

Combination pharmacotherapies for stimulant use disorder: a review of clinical findings and recommendations for future research

Despite concerted efforts to identify a pharmacotherapy for managing stimulant use disorders, no widely effective medications have been approved. Innovative strategies are necessary to develop successful pharmacotherapies for stimulant use disorders. This manuscript reviews human laboratory studies and clinical trials to determine whether one such strategy, use of combination pharmacotherapies, holds promise. The extant literature shows that combination pharmacotherapy produced results that were better than placebo treatment, especially with medications shown to have efficacy as monotherapies. However, many studies did not compare individual constituents to the combination treatment, making it impossible to determine whether combination treatment is more effective than monotherapy. Future research should systematically compare combined treatments with individual agents using medications showing some efficacy when tested alone.

Antidepressants for cocaine dependence and problematic cocaine use

BACKGROUND

Cocaine dependence is a disorder for which no pharmacological treatment of proven efficacy exists, advances in the neurobiology could guide future medication development.

OBJECTIVES

To investigate the efficacy and acceptability of antidepressants alone or in combination with any psychosocial intervention for the treatment of cocaine dependence and problematic cocaine use.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, EMBASE and CINAHL in July 2011 and researchers for unpublished trials.

SELECTION CRITERIA

Randomised clinical trials comparing antidepressants alone or associated with psychosocial intervention with placebo, no treatment, other pharmacological or psychosocial interventions.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data.

MAIN RESULTS

37 studies were included in the review (3551 participants).Antidepressants versus placebo: results for dropouts did not show evidence of difference, 31 studies, 2819 participants, RR 1.03 (Cl 95% 0.93 to 1.14). Looking at Abstinence from cocaine use, even though not statistically significant, the difference shown by the analysis in the three-weeks abstinence rate was in favour of antidepressants (eight studies, 942 participants, RR 1.22 (Cl 95% 0.99 to 1.51)). Considering only studies involving tricyclics, five studies, 367 participants, or only desipramine, four studies, 254 participants, the evidence was in favour of antidepressants. However, selecting only studies with operationally defined diagnostic criteria, statistical significance favouring antidepressants, as well as the trend for significance shown by the full sample, disappeared. Looking at safety issues, the results did not show evidence of differences (number of patients withdrawn for medical reasons, thirteen studies, 1396 participants, RR 1.39 (Cl 95% 0.91 to 2.12)). Subgroup analysis considering length of the trial, associated opioid dependence or associated psychosocial interventions as confounding factors, failed in showing consistent and statistically significant differences in favour of antidepressants.Antidepressants versus other drugs: Comparing antidepressants with dopamine agonists or with anticonvulsants, no evidence of differences was shown on dropouts and on other outcomes (abstinence from cocaine use, adverse events).

AUTHORS' CONCLUSIONS

At the current stage of evidence data do not support the efficacy of antidepressants in the treatment of cocaine abuse/dependence. Partially positive results obtained on secondary outcome measures, such as depression severity, do not seem to be associated with an effect on direct indicators of cocaine abuse/dependence. Antidepressants cannot be considered a mainstay of treatment for unselected cocaine abusers/dependents.

WITHDRAWN: Dopamine agonists for cocaine dependence

BACKGROUND

Cocaine dependence is a common and serious condition, which has become a substantial public health problem. There is a wide and well documented range of consequences associated to chronic use of cocaine, such as medical, psychological and social problems.. Therapeutic management of the cocaine addicts includes an initial period of abstinence from the drug. During this phase the subjects may experience, besides the intense craving for cocaine, symptoms such as depression, fatigue, irritability, anorexia, and sleep disturbances. It was demonstrated that the acute use of cocaine may enhance dopamine transmission and chronically it decreases dopamine concentrations in the brain. Pharmacological treatment that affects dopamine could theoretically reduce these symptoms and contribute to a more successful therapeutic approach.

OBJECTIVES

To evaluate the efficacy and acceptability of dopamine agonists for treating cocaine dependence.

SEARCH STRATEGY

Electronic searches of Cochrane Library, EMBASE, MEDLINE, PsycLIT, Biological Abstracts and LILACS; reference searching; personal communication; conference abstracts; unpublished trials from pharmaceutical industry; book chapters on treatment of cocaine dependence, was performed for the primary version of this review in 2001. Another search of the electronic databases was done in December of 2002 for this update. The specialised register of trials of the Cochrane Group on Drugs and Alcohol was searched until February 2003.

SELECTION CRITERIA

The inclusion criteria for all randomised controlled trials were that they should focus on the use of dopamine agonists on the treatment of cocaine dependence.

DATA COLLECTION AND ANALYSIS

The reviewers extracted the data independently and Relative Risks, weighted mean difference and number needed to treat were estimated. The reviewers assumed that people who died or dropped out had no improvement and tested the sensitivity of the final results to this assumption.

MAIN RESULTS

Seventeen studies were included, with 1224 participants randomised. Amantadine, bromocriptine, and pergolide were the drugs evaluated. The main outcomes evaluated were positive urine sample for cocaine metabolites, for efficacy, and retention in treatment, as an acceptability measure. There were no significant differences between interventions, and in trials where participants had primary cocaine dependence or had additional diagnosis of opioid dependence and/or were in methadone maintenance treatment.

AUTHORS' CONCLUSIONS

Current evidence does not support the clinical use of dopamine agonists in the treatment of cocaine dependence. Given the high rate of dropouts in this population, clinicians may consider adding other supportive measures aiming to keep patients in treatment.

Neural substrates of psychostimulant withdrawal-induced anhedonia

Psychostimulant drugs have powerful reinforcing and hedonic properties and are frequently abused. Cessation of psychostimulant administration results in a withdrawal syndrome characterized by anhedonia (i.e., an inability to experience pleasure). In humans, psychostimulant withdrawal-induced anhedonia can be debilitating and has been hypothesized to play an important role in relapse to drug use. Hence, understanding the neural substrates involved in psychostimulant withdrawal-induced anhedonia is essential. In this review, we first summarize the theoretical perspectives of psychostimulant withdrawal-induced anhedonia. Experimental procedures and measures used to assess anhedonia in experimental animals are also discussed. The review then focuses on neural substrates hypothesized to play an important role in anhedonia experienced after termination of psychostimulant administration, such as with cocaine, amphetamine-like drugs, and nicotine. Both neural substrates that have been extensively investigated and some that need further evaluation with respect to psychostimulant withdrawal-induced anhedonia are reviewed. In the context of reviewing the various neurosubstrates of psychostimulant withdrawal, we also discuss pharmacological medications that have been used to treat psychostimulant withdrawal in humans. This literature review indicates that great progress has been made in understanding the neural substrates of anhedonia associated with psychostimulant withdrawal. These advances in our understanding of the neurobiology of anhedonia may also shed light on the neurobiology of nondrug-induced anhedonia, such as that seen as a core symptom of depression and a negative symptom of schizophrenia.

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.

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.

Desipramine treatment of cocaine-dependent patients with depression: a placebo-controlled trial

OBJECTIVE

The aim of this study was to test the hypothesis that desipramine would be an effective treatment in cocaine abusers with current depressive disorders.

METHOD

This was a randomized, 12-week, double-blind, 'placebo-controlled trial of outpatients (N = 111) meeting DSM-III-R criteria for cocaine dependence and major depression or dysthymia (by SCID interview). Participants were treated with desipramine, up to 300 mg per day, or matching placebo. All patients received weekly individual manual-guided relapse prevention therapy. Weekly outcome measures included the Clinical Global Impression Scale, self-reported cocaine use and craving, urine toxicology, and the Hamilton Depression Scale (biweekly). Summary measures of mood and cocaine use outcome were compared between treatment groups with chi2- or t-tests. Dichotomous summary measures of depression response and cocaine response were the primary outcomes. Mixed effect models were also fit to explore the relationship of cocaine use to mood improvement and treatment over weeks in the trial.

RESULTS

Desipramine was associated with a higher rate of depression response (51%, 28/55) than placebo (32%, 18/56) (p < 0.05), but treatment groups did not differ in rate of cocaine response. Depression improvement was associated with improvement in cocaine use. Desipramine was associated with more dropouts due to side effects and medical adverse events, while placebo was associated with more dropouts due to psychiatric worsening.

CONCLUSIONS

Desipramine was an effective treatment for depression among cocaine-dependent patients. Improvement in mood was associated with improvement in cocaine abuse, but a direct effect of medication on cocaine outcome was not clearly established and rates of sustained abstinence were low. Future research should examine newer antidepressant medications with more benign side effect profiles and combinations of behavioral and pharmacological treatments to maximize effects on cocaine use.

Psychostimulant withdrawal as an inducing condition in animal models of depression

A large body of evidence indicates that the withdrawal from high doses of psychostimulant drugs in humans induces a transient syndrome, with symptoms that appear isomorphic to those of major depressive disorder. Pharmacological treatment strategies for psychostimulant withdrawal in humans have focused mainly on compounds with antidepressant properties. Animal models of psychostimulant withdrawal have been shown to demonstrate a wide range of deficits, including changes in homeostatic, affective and cognitive behaviors, as well as numerous physiological changes. Many of these behavioral and physiological sequelae parallel specific symptoms of major depressive disorder, and have been reversed by treatment with antidepressant drugs. These combined findings provide strong support for the use of psychostimulant withdrawal as an inducing condition in animal models of depression. In the current review we propound that the psychostimulant withdrawal model displays high levels of predictive and construct validity. Recent progress and limitations in the development of this model, as well as future directions for research, are evaluated and discussed.

Cocaine pharmacology and current pharmacotherapies for its abuse

Cocaine abuse continues to be prevalent and effective therapies for cocaine craving and addiction remain elusive. In the last decade immunopharmacotherapy has been proposed as a promising means to alleviate this illness. By using the organism's natural immune response, an anti-cocaine vaccine promotes the production of cocaine-specific antibodies that sequester the drug before their passage into the brain, where it exerts its reinforcing and thus addictive effects. A series of studies demonstrating the cocaine-blocking properties of various immunogenic conjugates will be reviewed in the context of the neuropsychopharmacological profile of the drug.

Dopamine agonists for cocaine dependence

BACKGROUND

Cocaine dependence is a common and serious condition, which has become nowadays a substantial public health problem. There is a wide and well documented range of consequences associated to chronic use of this drug, such as medical, psychological and social problems, including the spread of infectious diseases (e.g. AIDS, hepatitis and tuberculosis), crime, violence and neonatal drug exposure. Therapeutic management of the cocaine addicts includes an initial period of abstinence from the drug. During this phase the subjects may experience, besides the intense craving for cocaine, symptoms such as depression, fatigue, irritability, anorexia, and sleep disturbances. It was demonstrated that the acute use of cocaine may enhance dopamine transmission and chronically it decreases dopamine concentrations in the brain. Pharmacological treatment that affects dopamine could theoretically reduce these symptoms and contribute to a more successful therapeutic approach.

OBJECTIVES

To evaluate the efficacy and acceptability of dopamine agonists for treating cocaine dependence.

SEARCH STRATEGY

Electronic searches of Cochrane Library, EMBASE, MEDLINE, PsycLIT, Biological Abstracts and LILACS; reference searching; personal communication; conference abstracts; unpublished trials from pharmaceutical industry; book chapters on treatment of cocaine dependence, was performed for the primary version of this review in 2001. Another search of the electronic databases was done in December of 2002 for this update. The specialised register of trials of the Cochrane Group on Drugs and Alcohol was searched until February 2003.

SELECTION CRITERIA

The inclusion criteria for all randomised controlled trials were that they should focus on the use of dopamine agonists on the treatment of cocaine dependence.

DATA COLLECTION AND ANALYSIS

The reviewers extracted the data independently and Relative Risks, weighted mean difference and number needed to treat were estimated. The reviewers assumed that people who died or dropped out had no improvement and tested the sensitivity of the final results to this assumption.

MAIN RESULTS

Seventeen studies were included, with 1224 participants randomised. Amantadine, bromocriptine, and pergolide were the drugs evaluated. The main outcomes evaluated were positive urine sample for cocaine metabolites, for efficacy, and retention in treatment, as an acceptability measure. There were no significant differences between interventions, and in trials where participants had primary cocaine dependence or had additional diagnosis of opioid dependence and/or were in methadone maintenance treatment.

REVIEWER'S CONCLUSIONS

Current evidence does not support the clinical use of dopamine agonists in the treatment of cocaine dependence. Given the high rate of dropouts in this population, clinicians may consider adding other supportive measures aiming to keep patients in treatment.

The effects of acute haloperidol or risperidone on subjective responses to methamphetamine in healthy volunteers

Despite extensive evidence that selective dopamine antagonists attenuate the reinforcing effects of stimulants in laboratory animals, there is little evidence that dopamine antagonists block the positive subjective effects of stimulants in humans. However, recent evidence suggests that the subjective effects of stimulants in humans may depend in part on serotonin. The goal of this study was to examine the effects of haloperidol, a drug that primarily blocks dopamine receptors, and risperidone, a drug that blocks both dopamine and serotonin receptors, on the physiological and subjective effects of methamphetamine in healthy volunteers. Two groups of subjects participated in a placebo-controlled, within-subject, 2 x 2 repeated measures design. One group was tested with haloperidol (3 mg; N = 18), the other with risperidone (0.75 mg; N = 18). Each subject participated in four sessions receiving all combinations of antagonist or placebo and methamphetamine (20 mg) or placebo. Dependent measures included vital signs and standardized questionnaires of subjective effects. At these doses, both haloperidol and risperidone produced mild sedative-like effects compared to placebo. However, neither drug consistently reduced the stimulant-like effects of methamphetamine. These results add to the growing body of literature suggesting that D(2) dopamine receptor antagonists do not block the euphorigenic subjective effects of stimulant drugs in humans, and also do not support the idea that serotonin contributes significantly to these effects.

Pharmacological treatment of cocaine dependence: a systematic review

AIMS

Cocaine dependence is a common and serious condition, associated with severe medical, psychological and social problems, including the spread of infectious diseases. This systematic review assesses critically the efficacy of pharmacotherapy for treating cocaine dependence.

METHODS

The literature search strategy included: electronic searches of Cochrane Library holdings, EMBASE, MEDLINE, PsycLIT, Biological Abstracts and LILACS; scans of reference lists of relevant articles, personal communications, conference abstracts, unpublished trials from the pharmaceutical industry and book chapters on the treatment of cocaine dependence. Randomized controlled trials (RCTs) focusing on the use of antidepressants (ADs), carbamazepine (CBZ), dopamine agonists (DAs) and other drugs used in the treatment of cocaine dependence were included. The reviewers extracted data independently, and relative risks (RR) with 95% confidence interval (CI) were estimated. Qualitative assessments were carried out using a Cochrane validated checklist. Where possible, analysis was carried out according to 'intention-to-treat' principles.

FINDINGS

The search strategy generated 45 different trials. Most studied drugs were ADs (20 studies), DAs and CBZ. Data were very heterogeneous, with dropout rates within the studies between 0 and 84%. A non-significant trend favoring CBZ was found in terms of dropouts (RR 0.88; 95% CI 0.75-1.03) and results from one trial suggest that fluoxetine patients are less likely to drop out. The main efficacy outcome reported in the studies was the presence of cocaine metabolites in the urine. No significant results were found, regardless the type of drug or dose used for all relevant outcomes assessed.

CONCLUSIONS

There is no current evidence supporting the clinical use of CBZ, antidepressants, dopamine agonists, disulfiram, mazindol, phenytoin, nimodipine, lithium and NeuRecover-SA in the treatment of cocaine dependence. Larger randomized investigation must be considered, while taking into account that these time-consuming efforts should be reserved for medications showing more relevant and promising evidence. Given the high dropout rate among the test population, clinicians may wish to consider adding psychotherapeutic supportive measures aimed at keeping patients in treatment programs.

Effects of antidepressant drugs on rats bred for low activity in the swim test

To determine responsivity to antidepressant medication of Sprague-Dawley rats bred for low activity in the swim test [Swim Low-Active (SwLo) rats], these animals were given different antidepressant drugs via subcutaneously implanted minipumps for 1, 12, or 26 days, and then were tested for activity in the swim test and 2 days later in the open field. Antidepressant drugs given were amitriptyline, imipramine, desipramine (tricyclics), phenelzine (monoamine oxidase inhibitor (MAOI)], fluoxetine [selective serotonin reuptake inhibitor (SSRI)], venlafaxine, and bupropion (atypical). To assess specificity of response, the nonantidepressant drugs amphetamine, caffeine, and haloperidol were also tested. For comparison, several drugs were also tested in rats bred for high activity in the swim test [Swim High-Active (SwHi) rats]. When administered for 14 and/or 28 days (but not for 1 day), imipramine, desipramine, venlafaxine, phenelzine, and bupropion significantly increased struggling behavior of SwLo rats in swim test. No nonantidepressant drug significantly elevated struggling activity. Long-term administration of phenelzine and bupropion also significantly decreased floating behavior in the swim test, although amphetamine also had this effect at all times of administration. No significant effects of antidepressants were seen in SwHi rats. Amitriptyline and fluoxetine were ineffective in altering either struggling or floating in SwLo rats; however, a high dose of an SSRI (sertraline) did reduce floating, but this type of effect is probably not indicative of antidepressant action. Behavior in the open field was not consistently affected by any drug type. It is concluded that, based on pharmacological response profile in the swim test, SwLo rats represent depression that is responsive to potent norepinephrine reuptake-blocking antidepressants and also MAOIs; atypical depression may fit this profile.

Pretreatment status variables and treatment implementation for cocaine misuse: a latent variable structural model pilot study

This study was designed to test the utility of a latent variable structural equation covariance model for cocaine misuser treatment outcome research. Three structural models were tested for goodness-of-fit of data obtained from a sample of subjects (N = 206) receiving drug misuser treatment in four treatment settings in a treatment program in Nevada. Fourteen variables were entered into the structural equations. An adequately fitting model was found (CFK = .956), [chi 2(6, N = 205) = 15.77, p > .01]. The subjects' discharge rates did not differ significantly by the severity of cocaine misuse at admission.

Pharmacotherapy for opioid and cocaine abuse

The need for continued development of medications to address opioid and cocaine addiction is unequivocal. Methadone maintenance, despite its limitations, remains the best-established pharmacologic treatment for opioid dependence. Continued participation in methadone programs is associated with decreased risk of acquiring HIV infection. Clonidine alone or combined with naltrexone may be used for opioid detoxification in the office practice. At the present time, no proven pharmacologic therapy for cocaine addiction exists.

The management of treatment resistance in depressed patients with substance use disorders

General principles for treatment-resistant psychiatric disorders include reevaluation of diagnosis, search for hidden comorbidity, and systematic trials of alternative treatments and treatment combinations. For the combination of refractory depression and substance abuse, alternative approaches to both problems need to be tried, as suggested in the decision tree in Figure 1. Recognition of a previously unappreciated substance abuse problem or institution of more effective substance abuse treatment (see Table 2) can improve the outcome of depression. Hospitalization is often useful to enforce abstinence and to clarify the diagnosis of depression, and is particularly indicated if substance abuse is severe. If hospitalization is not possible then features of the history, such as relative onsets of depression and substance abuse, can be considered to support the diagnosis. TCAs and SSRIs have been studied in depressed substance abusers and should be the first lines of treatment. If these fail, other medications, medication combinations, or ECT should be considered, extrapolating from the general literature on treatment of refractory depression. In general, single agents should be preferred to combinations, as this reduces the odds of drug-drug interactions in patients who may abuse a variety of substances. Impairment by antidepressant agents of hepatic metabolism of other drugs should be considered, and sertraline, for example, might be preferred over fluoxetine for this reason. For each case, the known side effects and risks of a given antidepressant medication must be considered in the context of a patient's substance abuse pattern and medical problems. Such risk:benefit analyses are often difficult, as illustrated in the cases presented. Finally, although it is a rare occurrence, antidepressant medications that are anticholinergic or amphetamine-like may be abused, and this needs to be monitored. Alcohol or drug abuse history is a likely risk factor for benzodiazepine abuse, and benzodiazepines should, therefore, be avoided or used with caution. These recommendations for management of treatment-resistant depression with substance abuse are based upon clinical experience and extrapolation from the literature on treatment-resistant depression, treatment of substance abuse, and initial treatment of depression in substance abusers with TCAs and SSRIs. More treatment research is needed, particularly on Type IV patients where both depression and substance use are treatment resistant.

Imipramine treatment of cocaine abuse: possible boundaries of efficacy

A 12-week placebo-controlled, randomized clinical trial was undertaken to evaluate imipramine as a treatment for cocaine abuse, and to examine whether its effect may be limited to subgroups defined by route of use or by diagnosis of depression. One-hundred thirteen patients were randomized, stratified by route of use and depression. All patients received weekly individual counseling. Compared to placebo the imipramine group showed greater reductions in cocaine craving, cocaine euphoria, and depression, but the effect of imipramine on cocaine use was less clear. A favorable response, defined as at least 3 consecutive, urine-confirmed, cocaine-free weeks was achieved by 19% (11/59) of patients on imipramine compared to 7% (4/54) on placebo (P < 0.09). The imipramine effect was greater among nasal users--33% (9/27) response on imipramine vs. 5% (1/22) on placebo (P < 0.02). Response was also more frequent, but not significantly so, among depressed users on imipramine (26%, 10/38) than on placebo (13%, 4/31) (P < 0.19). Response rates were low in intravenous and freebase users and those without depression. Considered together with the literature on desipramine, these data suggest tricyclic antidepressants are not promising as a mainstay of treatment for unselected cocaine abusers. However, tricyclics may be useful for selected cocaine abusers with comorbid depression or intranasal use, or in conjunction with a more potent psychosocial intervention.

Treatment of crack-cocaine-induced compulsive behavior with trazodone

Foraging is a compulsive behavior of searching for pieces of crack cocaine that the individual believes might have been accidentally misplaced. Three clinical cases of compulsive foraging behavior associated with crack cocaine are described. Due to the development of side effects secondary to the antidepressant desipramine, the patients were switched to the antidepressant trazodone. The use of trazodone led to remission of the foraging behavior. The authors hypothesize this remission was due to trazodone serotonin reuptake inhibitory action. In all three cases, the patients did not relapse into abusing crack cocaine.

Continuous or intermittent cocaine administration: effects of flupenthixol treatment during withdrawal

Research indicates that chronic daily cocaine injections produce sensitization to, while the chronic continuous infusion of cocaine produces tolerance to, its behavioral and neurochemical effects. The present experiments examined whether flupenthixol administration during withdrawal would attenuate/eliminate the behavioral effects produced by these administration regimens. The rats were pretreated for 14 days with either continuous or intermittent daily injections of cocaine, and were then withdrawn from the pretreatment regimen for 7 days. On days 1-5 of the withdrawal period, subjects received a daily 0.125-2.0 mg/kg IP injection of flupenthixol. Then on day 7 of withdrawal from the cocaine pretreatment, all rats were given a 15.0 mg/kg IP injection of cocaine. Their behavior was rated according to a modified version of the Ellinwood and Balster (6) scale for 60 min. The results indicated that flupenthixol treatment during withdrawal eliminated the tolerance normally associated with the continuous infusion of cocaine. However, this effect of flupenthixol was not dose dependent: the lowest dose had the same effect as the highest dose of flupenthixol. In the cocaine-injection subjects, flupenthixol had a slight but statistically significant reduction in the behavioral effects of cocaine. The same was true in the saline-control rats, except for the highest dose of flupenthixol, which had a significant enhancing effect on the behavioral response to cocaine. The present results suggest that the current procedures may represent an effective screening methodology for potential cocaine pharmacotherapies.

Dopamine receptor agonists, partial agonists and psychostimulant addiction

Despite the epidemic growth of psychostimulant addiction over the past years, few pharmacological means of intervention are available to date for clinical treatment. This is of importance since the withdrawal syndrome that follows abstinence from drugs such as cocaine and the amphetamines is characterized, among other symptoms, by intense craving for the abused drug, and this is considered a critical factor leading into relapse of drug use. In this article, Luigi Pulvirenti and George Koob focus on the modulatory role shown by drugs acting at the dopamine receptor on the various phases of psychostimulant dependence in preclinical models and in human studies, and suggest that a class of compounds with partial agonist properties at the dopamine receptor may have therapeutic potential.

Continuous or intermittent cocaine administration: effects of amantadine treatment during withdrawal

Research indicates that daily cocaine injections produce sensitization to, while the continuous infusion of cocaine produces tolerance to, its behavioral and neurochemical effects. The effects of the continuous infusion of cocaine are consistent with the withdrawal syndrome reported by human cocaine abusers. The present experiment examined whether amantadine administrations during withdrawal from continuous or intermittent cocaine attenuate and/or eliminate the behavioral effects produced by these administration regimens. The rats were pretreated for 14 days with either continuous or intermittent daily injections of cocaine, and were then withdrawn from the pretreatment regimen for 7 days. On days 1-5 of the withdrawal period, half the subjects received a 5.0 mg/kg IP injection of amantadine, and the other half received a 20.0 mg/kg IP injection of amantadine. On day 7 of withdrawal from the cocaine pretreatment, all rats were given a 15.0 mg/kg IP injection of cocaine. Their behavior was rated according to the modified Ellinwood and Balster (6) scale for 60 min. The results indicated that amantadine treatment during withdrawal eliminated the tolerance normally associated with the continuous infusion of cocaine. In contrast, in both the saline control and daily injection subjects amantadine treatment during withdrawal resulted in a slight, but statistically significant, reduction in the behavioral effects of cocaine. The present results therefore indicate that low doses of amantadine should be considered as a potential pharmacotherapy for the early stages of cocaine withdrawal. Furthermore, the present experimental procedures may represent an effective screening methodology for potential cocaine pharmacotherapies.

Cocaine abuse in North America: a milestone in history

The euphoric effects of coca leaves have been known to mankind for thousands of years. Yet the first epidemic of cocaine use in America occurred during the late 19th century. Initially, there were no laws restricting the consumption or sale of cocaine. In fact, cocaine was freely available in drug stores, saloons, from mail-order vendors, and even in grocery stores. It is reported that one drug manufacturer, in 1885, was selling cocaine in 15 different forms, including cigarettes, cheroots, inhalants, cordials, crystals, and solutions. Many famous imported wines, such as "Vin Mariani," contained a mixture of wine and coca. For consumers on budgets, the wonder drug was available as Coca-Cola and dozens of other soda pops and pick-me-up drinks. One of them even had a simple and direct name, Dope. Soon enough, the ill effects of cocaine became apparent, and by the 1920s cocaine was the most feared of all illicit drugs. Most states began enacting laws against cocaine use. President William Taft proclaimed cocaine as Public Enemy No. 1, and in 1914 the Congress passed the Harrison act, which tightly regulated the distribution and sale of cocaine. By the late 1950s, cocaine use in the United States was simply considered a problem in the past. Unfortunately, the people who were aware of the nation's first cocaine epidemic gradually passed away, and America once again was ready for its fling with cocaine in the 1960s. Today, it is estimated that upwards of 50 million Americans, that is one in four, have used cocaine. In addition, another fifty thousand people use this substance for the first time each day. More than 6 million Americans use cocaine on a regular basis. Little wonder, then, that America as well as the other countries have declared a "War on Drugs." In this review, pharmacology of cocaine, major complications arising from its use, and efforts to curb its abuse are discussed.

Treatment of khat addiction

The authors present two cases of khat addiction that were successfully treated with bromocriptine. Khat is a bush cultivated in the Mid East because of its highly stimulant effects. Its leaves contain a variety of sympathomimetics. While khat is rarely found in the U.S., American soldiers stationed in the Arabian peninsula may be exposed to it. Because of an alcohol interdiction during the current Persian Gulf crisis, these troops may be tempted to use this plant as an alternative recreational drug.

A randomized trial of bromocriptine for cocaine users presenting to the emergency department

OBJECTIVE

To determine the practicality of treating heavy cocaine users with bromocriptine in an outpatient setting to reduce cocaine use and increase entry into drug treatment.

DESIGN

Double-blind, randomized, placebo-controlled trial.

SETTING

VA Medical Center emergency department.

PARTICIPANTS

Twenty-nine men presenting for minor medical complaints who used cocaine at least four times per week for the previous month.

INTERVENTION

Subjects received either bromocriptine, 1.25 mg, or placebo three times per day for two weeks.

MEASUREMENTS AND MAIN RESULTS

On three follow-up visits, subjects were tested for cocaine metabolites and surveyed about their drug use and symptoms. Eight of 14 subjects randomized to the bromocriptine group appeared for follow-up evaluation and seven enrolled in drug treatment. Three of these patients tested negative for cocaine at all three visits. Ten of 15 control patients appeared for follow-up visits and five enrolled in drug treatment. None of the control patients tested negative for cocaine for all three visits. There was no major side effect.

CONCLUSION

Bromocriptine can be administered safely to heavy cocaine users in an emergency department setting. The question of whether bromocriptine will reduce the use of cocaine or promote entry into drug treatment deserves further research.

Bromocriptine and cocaine cue reactivity in cocaine-dependent patients

Based on previous reports that bromocriptine, a postsynaptic dopamine agonist, reduced cocaine craving and prevented relapse in cocaine-dependent subjects, effects of the drug were evaluated in 20 cocaine-dependent males in an inpatient drug rehabilitation programme. The subjective and physiologic effects of exposure to both cocaine-associated and neutral stimuli, presented using videotapes, were measured at one-week intervals. Between laboratory sessions subjects received either bromocriptine (1.25 mg bid) or a matched placebo, administered in double-blind fashion. Compared with the neutral videotape, the cocaine videotape elicited both a greater desire to use cocaine and more symptoms associated with cocaine self-administration. These results support an appetitive conditioning model of cocaine effects. Bromocriptine, however, had no effect on the cocaine-cue-associated reactivity, which declined over the 1-week interval in both treatment groups. Methodological differences among studies that have examined the effects of bromocriptine in cocaine-dependent subjects may explain the variable findings observed.

One-year follow-up after multimodal inpatient treatment for cocaine and methamphetamine dependencies

Of a randomly selected sample of 214 patients treated with aversion therapy for cocaine dependence in four chemical dependency units operated by Schick Shadel Hospitals, 156 were followed up 12 to 20 months posttreatment (average 15.2 months). Significant other validation was obtained in 33%. Total abstinence from cocaine for the group overall was 53% at one year post treatment, and current abstinence of at least 6 months at follow-up was 68.6%. Those treating with aversion for cocaine alone had a one-year abstinence of 39% and a current abstinence of 62.4%. Those treating with aversion for alcohol and cocaine had a one-year total abstinence from cocaine of 69% and a current abstinence of 76%. Those treating with aversion for cocaine and marijuana had a one-year total abstinence from cocaine of 50% and a current abstinence of 65%. Those treating with aversion for alcohol, cocaine, and marijuana had a one-year total abstinence from cocaine of 73% and a current abstinence of 73%. One-year total abstinence from alcohol was 54% for those receiving aversion for both alcohol and cocaine and 77% for those receiving aversion for alcohol, cocaine, and marijuana. Current abstinence from alcohol at follow-up was 68% and 81%, respectively. One-year total abstinence from marijuana was 42% for those treating with aversion for cocaine and marijuana and 64% for those treating with aversion for alcohol, cocaine, and marijuana. Current abstinence at follow-up from marijuana was 61% and 81%, respectively. The use of aversion therapy for both alcohol and cocaine in alcoholics who were also using cocaine was associated with higher total abstinence rates (88% vs. 55%) from cocaine when compared with alcoholics who used cocaine but received no aversion as part of their program. The conclusion is tentative since the follow-up rate in this study was lower than that of the previous study (64% vs. 84%). Being around other users accounted for 49% of relapse situations. Family/Work stress was associated with relapse in 33% of cases and unpleasant feelings in 24% of cases. The use of both reinforcement treatments and the use of support following treatment were associated with improved abstinence rates from cocaine. Those patients who reported losing all urges for cocaine after treatment had a total abstinence from cocaine of 90%, those who reported losing all the uncontrollable urges had a total abstinence of 64%, and those who reported still having the urge reported only 33% total abstinence from cocaine.

Molecular Mechanisms Associated with Cocaine Effects

Cocaine has been shown to be a highly addictive and toxic drug. It produces these effects and a variety of other physiological and behavioral effects through its interactions with several distinct central nervous system receptor sites. We present the results of a series of studies that utilized multiple site analyses to elucidate which cocaine binding sites influence the reinforcing and toxic effects of cocaine and with what proportion of influence. The nature of cocaine interactions with monoamine transporters is also discussed, especially with the dopamine transporter, which has been shown to be the cocaine binding site that is primarily associated with the reinforcing effects of cocaine. We also provide evidence that vulnerability to both the toxic and addictive effects of cocaine may be significantly influenced by genetic differences in both humans and animals. In view of the fact that cocaine is commonly abused in a polydrug situation, we present the results of both behavioral and biochemical experiments which suggest that common biochemical pathways may mediate the reinforcing or addictive properties of drugs of abuse. Finally, we discuss research on the biochemical mechanisms associated with effects of ethanol, particularly those which may also influence cocaine self-administration and speculate on pharmacotherapeutic strategies for concurrent abuse of cocaine and ethanol.

Acute treatment of alcohol and cocaine emergencies

This chapter addresses the acute treatment of alcohol and cocaine. Because of the widespread use of both these drugs, health professionals must recognize the medical complications of alcohol and cocaine abuse and addiction. The biochemistry will be briefly reviewed as an avenue to understand the different treatment targets and modalities.

Desmethylimipramine attenuates cocaine withdrawal in rats

Depression and anhedonia are two major symptoms of cocaine withdrawal in humans. Hence, pharmacological treatments effective in depression might also alleviate the symptoms of cocaine withdrawal. In the present study, the effects of acute and repeated administration of a tricyclic antidepressant, desmethylimipramine (DMI), were investigated in naive and cocaine-withdrawing rats. An animal model of cocaine withdrawal was used that employs the elevation in intracranial self-stimulation (ICSS) thresholds following the termination of prolonged periods of cocaine self-administration as a measure of an animal's "anhedonic" state. The influence of chronic DMI treatment on beta-adrenergic receptor binding and affinity was also correlated with the behavioral signs of cocaine withdrawal. Neither acute nor repeated DMI treatment influenced reward functions in rats that were not undergoing cocaine withdrawal. However, repeated DMI treatment significantly down-regulated beta-adrenergic receptors, and shortened the duration of the post-cocaine "anhedonia" (elevation in thresholds). Furthermore, the magnitude of the beta-adrenergic receptor down-regulation correlated significantly with the degree of effectiveness of DMI treatment in reversing the post-cocaine "anhedonia". However, chronic DMI treatment did reduce the amount of cocaine self-administered by the animals. The reversal of the post-cocaine anhedonia in this animal model of cocaine withdrawal by chronic DMI treatment demonstrates the potential usefulness of the model in identifying new pharmacotherapies for cocaine withdrawal. In addition, the results indicate that tricyclic antidepressants may be able to ameliorate some of the symptoms of cocaine withdrawal.

Substance abuse and schizophrenia: impediments to optimal care

With lifetime prevalence estimates of substance abuse among schizophrenics as high as 47.01%, there is an increasing awareness of the importance of this dual diagnosis and the global deficiencies in our knowledge about this comorbid condition. Patients with substance abuse disorders and schizophrenia are problematic from a clinical, economic, and health care systems perspective. The lack of systematic research into phenomenology, etiology, and treatment approaches (both psychotherapeutic and psychopharmacologic) has hindered the development of an adequate strategy to care for the needs of these patients. Thus, these patients place a significant burden on the mental health delivery system through chronic disability, social dysfunction, frequent rehospitalizations, and poor overall treatment compliance. The authors critically review the contemporary literature relevant to concurrent substance abuse and schizophrenia, highlight major deficiencies in our knowledge, and call for research to reduce the individual, economic, and social costs of this condition.

Drug misuse in alcoholics

Concurrent drug misuse is an increasing trend among alcoholics. It is occurring in an age-dependent manner so that the younger the age, the higher the incidence of concurrent misuse. Drugs concurrently misused by alcoholics, in decreasing order of frequency, are marijuana, cocaine and other sympathomimetics, phencyclidine, benzodiazepines, barbiturates, and psychedelics. Because of increasing prevalence of concurrent misuse, evaluation for alcohol detoxification should always include consideration of other drugs. Concurrent alcohol/drug addiction in alcoholics as well as increased incidence in alcoholism in families of drug addicts suggest a common genetic vulnerability to alcoholism and drug addiction.

Pharmacologic treatment of cocaine abuse

The recent surge in the use of cocaine has imposed increased financial burdens on society in terms of cocaine-related crimes, and funding for hospitalization/medical treatment and long-term rehabilitation programs. Unfortunately, healthcare costs secondary to chronic cocaine use are likely to increase in the future as drug research into cocaine abuse and effective treatment programs are severely lacking. This article reviews existing literature on treatment of cocaine abuse and is intended to serve as a practical guide to the general clinician involved in drug management of cocaine abuse. Antidepressant agents and the dopamine agonists are emphasized because most of the studies showing benefit have used these agents. Advantages and disadvantages of various interventions are objectively assessed. Additionally, specific implications for both acute and chronic management of cocaine abuse are given along with discussion and recommendations regarding comorbidity.

Comparison of amantadine and desipramine combined with psychotherapy for treatment of cocaine dependence

We conducted a single-blind, random assignment, placebo-controlled, 12-week comparison of desipramine hydrochloride and amantadine hydrochloride as adjunctive treatments to counseling for cocaine dependence. Subjects were 54 outpatients who met DSM III-R criteria for active cocaine dependence and who completed a minimum of 2 weeks of treatment. Subjects treated with fixed doses of 200 mg/day desipramine (N = 17), 400 mg/day amantadine-placebo (N = 16), and placebo (N = 21) did not differ for lifetime cocaine use, lifetime histories of psychopathology, admission scores on psychometric assessments, and sociodemographics. All treatment groups demonstrated dramatic and persistent decreases in cocaine use, craving for cocaine, and psychiatric symptoms consequent to treatment. Although there was a trend for more dropouts by subjects taking desipramine, there were no significant differences among treatment groups regarding retention in treatment, craving for cocaine, and decreased cocaine use confirmed by urine toxicology. There was a trend for subjects treated with desipramine to maintain longer periods of cocaine abstinence. Mean plasma concentration of desipramine in a subsample of our subjects was less than that recommended for treatment of depression, thus the dosage of desipramine may have been subtherapeutic.

A simple test of cocaine craving and related responses

This study evaluated a self-rated instrument for assessing perceived craving, mood, energy, and health levels in patients who are withdrawing from cocaine addiction. The instrument consisted of four 20-centimeter line scales. Twenty-five patients in a 28-day inpatient addictions treatment unit were chosen at random points in their treatment and given a chance to rate themselves on each scale by making a mark on a line that corresponded to their self-perception. Each patient performed two self-assessment, one day apart. The scores for each scale were correlated and found to be highly reliable. Surprisingly, none of the other three scale scores had a strong relationship with craving, and possible reasons for this result are discussed.

Effects of carbamazepine on self-administration of intravenously delivered cocaine in rats

Carbamazepine (Tegretol) is widely used therapeutically as an anticonvulsant. Based on an hypothesis that links electrical kindling in the limbic system (leading to seizures) to reverse tolerance or sensitivity to cocaine's effects, carbamazepine is being tested as a treatment for human cocaine users. The purpose of this experiment was to examine the effects of carbamazepine on intravenous cocaine self-administration in rats. Rats self-administered intravenously delivered cocaine (0.2 mg/kg) under a fixed-ratio 4 schedule. When cocaine injections reached stable levels, carbamazepine was mixed with the rats' food for 8 days. Three doses of carbamazepine were tested (80, 120, and 160 mg/kg) in different groups of 5 rats each. The rats were later separated into groups with a high (greater than 750 infusions) and a low (500-750 infusions) cocaine baseline. Two control groups of 5 rats each received carbamazepine treatments (120 or 160 mg/kg) and self-administered an orally delivered solution of glucose and saccharin (G + S). At the highest carbamazepine dose in the high cocaine baseline group, carbamazepine reduced cocaine infusions by at least 50 percent and food intake by approximately 25 percent during the 8 days of treatment. Cocaine infusions returned to baseline within 24 hr after the regular diet was restored. Carbamazepine had a minimal effect in groups of rats with lower cocaine baselines. Responding reinforced by the G + S solution was reduced by both the 120 and 160 mg/kg carbamazepine doses. Water intake was not systematically affected by the addition of carbamazepine to the food; however, activity measures were significantly lower in some groups at the higher carbamazepine doses.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of cocaine on food intake of baboons before, during, and after a period of repeated desipramine

Food intake of five adult male baboons (Papio c. anubis) was monitored during daily 22-hr experimental sessions. Food was available under a chain schedule with two components. Following completion of the "procurement" component, the first response requirement, access to food, i.e., a meal, became available under the second, "consumption" component, during which each response produced a 1 g food pellet. After a 10-min interval in which no response occurred, the consumption component was terminated. Complete dose-response functions for cocaine (0.50-4.0 mg/kg, IM) and desipramine (0.50-4.0 mg/kg, IM), were determined before, during, and after a period of repeated administration of desipramine. Cocaine produced dose-dependent increases in the latency to initiate feeding and decreases in food intake during the first eight hr of the session. Compensatory feeding occurred later in the session so that cocaine had no effect on total daily intake. There was no interaction between repeated desipramine and the acute effects of cocaine. Desipramine produced dose-dependent decreases in intake during the first two hr of the session, the size of the first meal and intake during the entire session. These measures, as well as number of meals and second meal size, remained below baseline during repeated desipramine. Thus, repeated desipramine, while having significant effects on feeding behavior itself, did not influence the effects of cocaine administration on food-maintained responding.

Combining pharmacological antagonists and behavioural psychotherapy in treating addictions. Why it is effective but unpopular

Supervised administration of disulfiram is one of the very few treatments that can significantly reduce alcohol consumption, yet it is rarely used, despite being simple and cheap. Disulfiram is not 'aversion therapy', but a technique for facilitating exposure and response prevention, and it fits comfortably into a behavioural, social-learning model of addiction (or dependence) and its treatment. The availability of other effective antagonists, notably to opiates, suggests that an approach that is demonstrably effective in alcohol dependence may be helpful in treating other addictions. The reasons for the unpopularity of this approach appear to be largely ideological.

Schedule-induced oral self-administration of cocaine and ethanol solutions: lack of effect of chronic desipramine

Groups of rats drinking either solutions of cocaine HCl (0.16 mg/ml), ethanol (2.5% v/v), or water, drank excessive, equivalent volumes in daily, 3-h sessions of food-pellet delivery under a fixed-time 1-min (FT 1-min) schedule. During single-session exposures to pellet-delivery schedules using longer inter-pellet values (FT 3- or 5-min probe sessions), the cocaine and ethanol groups, but not the water group, drank greater ml/pellet amounts, confirming previous research. Inasmuch as enhanced ml/pellet intake during the greater FT probes correlated with the abuse potential of the drinking solution in previous research, the effect of chronic desipramine HCl (2 mg/kg, i.p. daily) on this enhanced intake response was determined. For all groups, chronic desipramine treatment (2 mg/kg was judged to be the maximum dose free of non-specific, suppressive effects) affected neither FT 1-min schedule-induced polydipsia nor did it affect the enhanced ingestional response to the greater FT probes for the cocaine and ethanol groups. Chronic administration of desipramine may have therapeutic efficacy in treating cocaine abuse only in subjects attempting to refrain from cocaine who are aided in their passage through a withdrawal phase by desipramine.

Bromocriptine and amantadine in cocaine detoxification

The effects of bromocriptine and amantadine in treating cocaine withdrawal were compared. Withdrawal symptoms are thought to be due to central dopamine depletion. Both bromocriptine and amantadine are dopamine agonists previously reported to diminish withdrawal symptoms. Thirty subjects were withdrawn for 30 days with amantadine, bromocriptine, or placebo. Bromocriptine and amantadine were more effective than placebo for 15 days. Amantadine's effectiveness then declined so that it was no more effective than placebo by experiment's end. Bromocriptine was significantly more effective than both throughout the latter phase of the study. Amantadine's decline in effectiveness is hypothesized to be due to stimulation of dopamine release.

The relevance to clinical care of recent research in neurobiology

Progress continues to be made in clarifying neurobiological factors in alcoholism and other chemical dependencies. Research in animal behavioral genetics and human genetics has revealed substantial genetic predispositions for some cases of alcoholism. Studies of neurotransmitters suggest that some alcoholics may have antecedent deficiencies in one or more important neurochemical systems. Cocaine dependence is considered to be related to biphasic change in dopaminergic neurons and receptor systems. Condensation products such as salsolinol, tetrahydropapaveroline, and beta carbolines can alter alcoholic preference and motivate heavy ethanol consumption in animals. However, hypothesized theoretical mechanisms underlying such increased drinking with infusions of condensation products are unclear and may require revision. New pharmacological treatments stemming from advances in neurobiological research have been applied successfully to treatment of withdrawal states, but none have been demonstrated to be appropriate for long-term maintenance of abstinence.

Drug abuse and depression: possible models for geriatric anorexia

The central biochemical pathology of anorexia and the natural aging of the brain is similar. Biochemical models for drug withdrawal and depression may also assist in understanding geriatric anorexia. Norepinephrine, corticotropin releasing factor and beta-endorphin may key neurotransmitters in all of these conditions.