PubMed Health⌕ Search

Biomedical subjects

R Ehrman

Publications and source records attributed to R Ehrman.

At least 19 recordsLinked to original sources
PubMed2001

Three decision-making tasks in cocaine-dependent patients: do they measure the same construct?

AIMS: Substance-abusing populations perform poorly on decision-making tasks related to delay and risk. These tasks include: (1) the Delay Discounting Procedure (DDP), in which choices are made between smaller-sooner and later-larger rewards, (2) the Gambling Task (GT), in which choices are made between alternatives varying in pay-off and punishment, and (3) the Rogers Decision-Making Task (RDMT) in which subjects choose between higher or lower probability gambles. We examine the interrelationship among these tasks. DESIGN: A test battery was created which included the DDP, GT and RDMT, as well as measures of impulsivity, intellectual functioning and drug use. SETTING: Subjects completed the test battery at an outpatient center, prior to beginning 12 weeks of treatment. PARTICIPANTS: Thirty-two treatment-seeking cocaine dependent individuals (primarily African-American males) participated. FINDINGS: Performance on the GT was significantly correlated with performance on the DDP (r = 0.37; p = 0.04). Reaction times on the RDMT correlated with performance on the GT (r = 0.36, p = 0.04) and DDP (r = 0.33, p = 0.07), but actual choices on the RDMT did not (p > 0.9 for both). While no significant relationships were observed between task performance and impulsivity, IQ estimate was positively correlated with both the GT (r = 0.44, p = 0.01) and RDMT (r = 0.41, p = 0.021). Split half reliability data indicated higher reliability when using only data from the latter half of the GT (r = 0.92 vs. r = 0.80). CONCLUSIONS: These data offer preliminary evidence of overlap in the decision-making functioning tapped by these tasks. Possible implications for drug-taking behavior are discussed.

Adult↗
PubMed1998

Conditioning factors in drug abuse: can they explain compulsion?

There is a good deal of clinical evidence suggesting that compulsion to resume drug taking is an important part of the addiction syndrome. The symptoms comprising motivation to resume drug use, namely craving and compulsion, have been studied experimentally in human subjects. While much work remains to be done, there is evidence showing that these symptoms are influenced by learning. The research has been guided by animal studies demonstrating that drug effects can be conditioned. Much attention has been directed toward demonstrating the existence of drug conditioning in human addicts and exploring the neurological structures that may underlie such learned responses. We do not yet know the relative importance of learning in the overall phenomenon of relapse, and treatments based on conditioning principles are still under investigation.

Alcohols↗
PubMed1993

Developing treatments that address classical conditioning.

Repetitive use of psychoactive drugs produces a variety of learned behaviors. These can be classified in the laboratory according to an operant/classical paradigm, but in vivo the two types of learning overlap. The classical CRs produced by drugs are complex and bidirectional. There has been progress in classifying and predicting the types of CRs, but little is known of mechanisms. New techniques for understanding brain function, such as microdialysis probes in animals and advanced imaging techniques (positron emission tomography and single photon emission computerized tomography) in human subjects, may be utilized in conditioning paradigms to "open the black box." Because the existence of CRs in drug users is now well established, clinical studies have been instituted to determine whether modification of CRs can influence clinical outcome. A recently completed study in cocaine addicts has produced evidence that outcome can be improved by a passive extinction technique over an 8-week outpatient treatment program.

Animals↗
PubMed1992

Classical conditioning in drug-dependent humans.

Repetitive use of psychoactive drugs produces a variety of learned behaviors. These can be classified in the laboratory according to an operant/classical paradigm, but in vivo the two types of learning overlap. The classically conditioned responses produced by drugs are complex and bi-directional. There has been progress in classifying and predicting the types of conditioned responses, but little is known of mechanisms. New techniques for understanding brain function such as micro-dialysis probes in animals and advanced imaging techniques (PET and SPECT) in human subjects may be utilized in conditioning paradigms to "open the black box." Because the existence of conditioned responses in drug users is now well established, clinical studies have been instituted to determine whether modification of conditioned responses can influence clinical outcome. A recently completed study in cocaine addicts has produced evidence that outcome can be improved by a passive extinction technique over an 8-week outpatient treatment program.

Animals↗
PubMed1992

Conditioned tolerance in human opiate addicts.

Repeated administration of opioid drugs results in tolerance, a lessening of the drug's effect. There is pre-clinical evidence suggesting a conditioning component to drug tolerance. In the present study, six former opiate dependent subjects received i.v. opiate either by un-signalled infusion or by signalled self-injection and the effects were compared with those of saline under double-blind conditions. The subjects' pre-injection rituals constitute a signal which reliably predict the appearance of the opiate. These rituals produced drug-opposite physiological responses which resulted in an attenuation of the effects of the drug. Thus, tolerance was observed when the subjects injected the opiate, but not when the same dose was received by un-signaled intravenous infusion. These results are consistent with a conditioning explanation for the observed drug tolerance.

Adult↗
PubMed1992

A learning model of addiction.

Repetitive use of psychoactive drugs produces a variety of learned behaviors. These can be classified in the laboratory according to an operant/classical paradigm, but in vivo the two types of learning overlap. The classically conditioned responses produced by drugs are complex and bi-directional. There has been progress in classifying and predicting the types of conditioned responses, but little is known of mechanisms. New techniques for understanding brain function such as micro-dialysis probes in animals and advanced imaging techniques (PET and SPECT) in human subjects may be utilized in conditioning paradigms to "open the black box." Because the existence of conditioned responses in drug users is now well-established, clinical studies have been instituted to determine whether modification of conditioned responses can influence clinical outcome. A recently completed study in cocaine addicts has produced evidence that outcome can be improved by a passive extinction technique over an 8 week outpatient treatment program.

Affect↗
PubMed1990

Integrating systemic cue exposure with standard treatment in recovering drug dependent patients.

Repeated drug administration readily produces classically conditioned responses in animal and human experimental studies. The majority of patients applying for treatment of drug dependence show both autonomic and subjective responses when exposed to drug-related stimuli. These responses are presumed to have been conditioned during a period of active drug use, persist after traditional treatment for drug dependence, and may constitute one of several factors which predispose to relapse. Preliminary data are presented from a novel treatment approach which is designed to test whether drug-conditioned responses can be reduced or extinguished by systematic exposure to drug-related cues and whether such extinction improves the overall results of treatment.

Adult↗
PubMed1988

Conditioned craving and arousal in cocaine addiction: a preliminary report.

Though data collection is still in progress, several significant findings are already apparent from our study of cocaine 'reminders': 1) In the laboratory, detoxified cocaine abusers show a differential responsivity to drug-related cocaine 'reminders', responding with strong signs of physiological arousal (peripheral skin temperature reductions and decreases in skin resistance) and subjective cocaine craving. 2) In extinction sessions, repeated, non-reinforced exposure to cocaine 'reminders' led to a complete reduction in craving to these stimuli by the fifteenth hour-long session. High and 'crash' responses were virtually eliminated by the sixth hour of extinction. 3) Physiological arousal to cocaine 'reminders' was often still in evidence even after fifteen hours of extinction. 4) Even after completing the current extinction protocol cocaine abusers may crave--and use--cocaine when experiencing drug 'reminders' in the natural environment. Clearly, detoxified cocaine abusers can experience conditioned craving and arousal to cocaine 'reminder' stimuli. These responses can be both intense and persistent, meaning that the abstinent cocaine abuser may be vulnerable long after detoxification is complete. Though the program of extinction described here is effective in reducing craving to cocaine-related stimuli presented in the context of the laboratory or clinic, this effect may not generalize well to the natural environment. We are currently considering two approaches to this problem: 1) One approach would attempt to increase the generalization of extinction by the use of even more realistic stimuli (e.g., the sight of real cocaine) and stimulus contexts (e.g., in vivo repeated exposures).(ABSTRACT TRUNCATED AT 250 WORDS)

Cocaine↗
PubMed1988

Classically conditioned responses in opioid and cocaine dependence: a role in relapse?

We have shown that conditioned phenomena occur in a number of drug-related settings and that they can be reliably elicited and studied. Our recent work suggests that conditioned craving is an extremely prevalent, if poorly understood, response to drug-related stimuli and that it can occur independent of conditioned withdrawal responses. Our current extinction protocols are effective in reducing the conditioned responses to both opioid and cocaine-related test stimuli. How well this extinction training generalizes to the "real world," is, of course, the crucial clinical question. We are trying to maximize the generalization of extinction through use of realistic, individualized drug "reminders." The final clinical impact of these extinction procedures awaits completion of our ongoing treatment/outcome studies in abstinent opioid and cocaine abusers.

Cocaine↗
PubMed1988

Update on behavioral treatments for substance abuse.

In the past five years there has been an encouraging increase in the amount and quality of research on behavioral treatments for substance abuse. Some of the most promising approaches combine behavioral treatments with each other (e.g., relapse prevention and cue exposure) or with other forms of treatment (e.g., psychotherapy), attempting to maximize impact on the multiple determinants of drug use. We are fast approaching the time when a patient may be systematically evaluated to develop a profile of vulnerabilities (cue responsivity, psychiatric symptoms, etc.) to rationally determine the treatment or combination of treatments of greatest potential benefit.

Behavior Therapy↗
PubMed1986

Extinguishing conditioned responses during opiate dependence treatment turning laboratory findings into clinical procedures.

Former opiate addicts (even those who have remained drug-free for several months) often report symptoms of opiate withdrawal (eg. nausea, gooseflesh, etc.) and/or intense drug craving when exposed to stimuli previously associated with the act of drug injection. This phenomenon of learned or "conditioned" withdrawal/craving is widely reported and is potentially important in explaining relapse to drug use. However, no effective, clinically applicable intervention had been available to "extinguish" these conditioned phenomena. An ongoing project to develop such an intervention has revealed: Conditioned withdrawal and craving are pervasive among both methadone maintained patients (even though actual physical withdrawal is blocked) and drug-free patients even after 30 days of inpatient Therapeutic Community rehabilitation. Conditioned withdrawal and craving can be effectively extinguished in an intensive, three-week, inpatient procedure. Emotional states such as anger, depression and anxiety can elicit and exacerbate conditioned withdrawal and craving. They may also act as an integral part of a conditioned stimulus complex. The authors discuss the problems associated with turning a laboratory-based procedure into a clinical intervention. Encouraging preliminary results from an integrated treatment "package" are presented.

Behavior Therapy↗
PubMed1983

Cynomolgus monkeys do not develop tolerance to opioids.

In order to examine the development of tolerance to opioids, eight cynomolgus and two rhesus monkeys were trained to press a lever for food reinforcement and then were catheterized so that drugs could be infused. Three doses of hydromorphone and six different interdose intervals were studied. Hydromorphone infusions initially suppressed lever pressing for food in both species. The rhesus monkeys acquired tolerance to these sedative effects after 14 exposures to the opioid. However, the cynomolgus monkeys failed to acquire tolerance after more than 100 exposures. Naloxone challenge elicited withdrawal symptoms from the rhesus monkeys but not from the cynomolgus monkeys. This differential response to sustained opioid administration in these closely related species suggests that a genetic mechanism may underlie tolerance to and physical dependence on opioids.

Animals↗