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Biomedical subjects

C P O'Brien

Publications and source records attributed to C P O'Brien.

At least 19 recordsLinked to original sources
PubMed2002

Brain activity during simulated deception: an event-related functional magnetic resonance study.

TheGuilty Knowledge Test (GKT) has been used extensively to model deception. An association between the brain evoked response potentials and lying on the GKT suggests that deception may be associated with changes in other measures of brain activity such as regional blood flow that could be anatomically localized with event-related functional magnetic resonance imaging (fMRI). Blood oxygenation level-dependent fMRI contrasts between deceptive and truthful responses were measured with a 4 Tesla scanner in 18 participants performing the GKT and analyzed using statistical parametric mapping. Increased activity in the anterior cingulate cortex (ACC), the superior frontal gyrus (SFG), and the left premotor, motor, and anterior parietal cortex was specifically associated with deceptive responses. The results indicate that: (a) cognitive differences between deception and truth have neural correlates detectable by fMRI, (b) inhibition of the truthful response may be a basic component of intentional deception, and (c) ACC and SFG are components of the basic neural circuitry for deception.

Adult↗
PubMed2002

Caffeine: behavioral effects of withdrawal and related issues.

Acquired tolerance to some behavioral effects of caffeine in humans is widely assumed to occur but is poorly documented and appears, at most, to be of low magnitude. Withdrawal from regular consumption of caffeine has been reported to result in a variety of symptoms, including: irritability, sleepiness, dysphoria, delerium, nausea, vomiting, rhinorrhea, nervousness, restlessness, anxiety, muscle tension, muscle pains and flushed face. Some of these same symptoms have been reported following excess intake of caffeine. The prevalence of symptoms reported on withdrawal in different studies also covers a wide range from 11% or less to 100%. It is suggested that the evidence leads to the conclusion that non pharmacological factors related to knowledge and expectation are the prime determinants of symptoms and their reported prevalence on withdrawal of caffeine after regular consumption.

Behavior↗
PubMed2001

A randomized, double-blind, placebo-controlled study of ritanserin pharmacotherapy for cocaine dependence.

Eighty cocaine-dependent individuals enrolled in outpatient treatment took part in a randomized, double-blind, placebo-controlled trial of ritanserin, a 5-HT(2) antagonist, as an adjunct therapy. Participants attended an outpatient day hospital therapy program each day and received tablets containing placebo or 10 mg ritanserin for a 4-week period. Primary outcome measures included retention in treatment, urine drug tests, and self-reports of craving. Secondary outcome measures were depression scores on the Beck and Hamilton inventories, negative mood as measured by the Profile of Mood States, and life functioning as measured by the Addiction Severity Index. Although participants showed improvement over the 4 weeks, there were no group differences on any of the measures. These results fail to support the use of ritanserin as a complement to outpatient psychosocial therapy for cocaine dependence.

Adult↗
PubMed2001

The effect of gamma-vinyl-GABA on the consumption of concurrently available oral cocaine and ethanol in the rat.

It has frequently been reported that a high percentage of individuals, identified as either alcohol- or cocaine-dependent, concurrently abuse both drugs. The experiments reported here represent a continuing effort to develop an animal model to predict the effects of a potential pharmacotherapeutic agent on concurrently available oral ethanol and cocaine. These experiments utilized drinkometer circuitry to assess the effects of gamma-vinyl-GABA (GVG), a gamma-aminobutyric acid (GABA) transaminase inhibitor, on the consumption and temporal pattern of responses for orally self-administered ethanol and cocaine. The results of these experiments showed that GVG, at doses of 100, 200 and 300 mg/kg, reduced both ethanol and cocaine consumption in a dose-related manner. When compared to vehicle, GVG at all doses significantly reduced ethanol consumption while consumption of cocaine was significantly reduced only at 300 mg/kg. This is consistent with data showing that GVG reduces consumption of these drugs when administered alone and data showing that GVG is more potent in reducing ethanol-induced compared to cocaine-induced extracellular dopamine in the nucleus accumbens. Analysis of the temporal pattern of drinking across the session suggests that GVG's effects are due to a disruption of the reinforcing properties of ethanol and cocaine rather than a more general reduction in motor behavior. These data suggest that GVG has potential for clinical use in populations that abuse either alcohol or cocaine alone or in combination.

Alcohol Drinking↗
PubMed2001

Cocaine dependence: a disease of the brain's reward centers.

Cocaine addiction affects brain reward centers that have evolved to ensure survival. Cocaine euphoria is intensely pleasurable and results from mesolimbic dopamine (DA) neurotransmission. DA signal-receiving neurons in the nucleus accumbens synthesize endogenous opioids and project to numerous reward regions. Cocaine-induced neuroadaptations, including DA depletion, may underlie craving and hedonic dysregulation. Cue-induced craving is vigorously triggered by conditioned elements of the drug environment and associated with measurable limbic activation. Reduced frontal lobe metabolism in cocaine-addicted individuals could explain important clinical phenomena such as denial and the loss of control over limbic impulses. Cocaine addiction is rapidly progressive and associated with severe medical, psychiatric, and psychosocial consequences. Denial shields addicted individuals from their predicament and must be addressed in treatment. Lacking pharmacological options, clinicians must rely entirely on psychosocial approaches. Treatment principles, including engagement, motivational enhancement, abstinence strategies, and craving reduction are discussed in terms of biological rationales.

Brain↗
PubMed2001

Effect of acamprosate and naltrexone, alone or in combination, on ethanol consumption.

Both acamprosate and naltrexone have demonstrated clinical utility in reducing relapse to alcohol use in recovering alcoholics. The present experiments examined the effects of acamprosate and naltrexone, either alone or in combination, on basal ethanol consumption in a limited-access model with the use of outbred Wistar rats. Naltrexone, 0.1 mg/kg, significantly reduced ethanol consumption as previously reported. Acamprosate, 50 mg/kg, did not significantly reduce ethanol consumption when administered alone and provided no evidence of additive or synergistic effects when combined with naltrexone. Acamprosate, 200 mg/kg, produced a modest reduction in ethanol consumption when administered alone but no evidence of additive or synergistic effects when combined with naltrexone. From these findings, it is suggested that a combination approach of these drugs may not be any more effective than monotherapy.

Acamprosate↗
PubMed2001

Cocaine withdrawal symptoms and initial urine toxicology results predict treatment attrition in outpatient cocaine dependence treatment.

This study evaluated the ability of cocaine withdrawal symptoms, measured by the Cocaine Selective Severity Assessment (CSSA) and initial urine toxicology results, to predict treatment attrition among 128 cocaine dependent veterans participating in a 4-week day hospital treatment program. The CSSA was administered and a urine toxicology screen was obtained at intake and at the start of the day hospital (about 1 week later). The combination of a positive urine toxicology screen and a high CSSA score at intake predicted failure to complete treatment. Urine toxicology results at the start of the day hospital, but not at intake, predicted failure to complete treatment. Among participants without other psychiatric illness, high CSSA scores at intake predicted failure to complete treatment. The presence of cocaine withdrawal symptoms and a positive urine toxicology screen are clinically useful predictors of treatment attrition.

Adult↗
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↗
PubMed2001

Predicting treatment response to naltrexone: the influence of craving and family history.

Naltrexone has repeatedly been shown to reduce drinking in alcohol-dependent patients. Previous clinical research suggests that naltrexone may be more effective at reducing drinking among patients with high levels of alcohol craving at the beginning of treatment. In addition, laboratory studies suggest that naltrexone may be more efficacious among patients with a high familial loading of alcohol problems. We explored both of these possibilities in the context of the first 12-week phase of a double blind, placebo-controlled naltrexone trial. A total of 121 patients were randomized to receive 100 mg/day naltrexone and 62 patients were randomized to receive placebo. Both naltrexone and placebo were given in conjunction with a psychosocial intervention designed to be integrated with the use of pharmacotherapy. This intervention was administered by nurse practitioners. Overall, patients randomized to naltrexone reported drinking five or more drinks on fewer days than did placebo controls (p = .04). Interactions were observed between medication group assignment and both craving level prior to randomization (p = .02) and family loading of alcohol problems (p = .05). In both cases, the interaction was in the predicted direction. These data suggest that patients with high levels of alcohol craving or a strong family history of alcoholism are more likely to benefit from naltrexone treatment.

Adult↗
PubMed2000

Drug dependence, a chronic medical illness: implications for treatment, insurance, and outcomes evaluation.

The effects of drug dependence on social systems has helped shape the generally held view that drug dependence is primarily a social problem, not a health problem. In turn, medical approaches to prevention and treatment are lacking. We examined evidence that drug (including alcohol) dependence is a chronic medical illness. A literature review compared the diagnoses, heritability, etiology (genetic and environmental factors), pathophysiology, and response to treatments (adherence and relapse) of drug dependence vs type 2 diabetes mellitus, hypertension, and asthma. Genetic heritability, personal choice, and environmental factors are comparably involved in the etiology and course of all of these disorders. Drug dependence produces significant and lasting changes in brain chemistry and function. Effective medications are available for treating nicotine, alcohol, and opiate dependence but not stimulant or marijuana dependence. Medication adherence and relapse rates are similar across these illnesses. Drug dependence generally has been treated as if it were an acute illness. Review results suggest that long-term care strategies of medication management and continued monitoring produce lasting benefits. Drug dependence should be insured, treated, and evaluated like other chronic illnesses. JAMA. 2000;284:1689-1695.

Asthma↗
PubMed2000

Mood state and recent cocaine use are not associated with levels of cocaine cue reactivity.

Eighty-one cocaine-dependent outpatients were assessed for their reactions to cocaine-related cues in a laboratory setting. All subjects contributed a urine sample prior to the session. Compared with non-drug control cues, the cocaine stimuli produced increases in physiological arousal, self-reports of high, craving, and withdrawal, and self-reports of negative mood. Subjects who tested cocaine-positive on the day of testing differed only in skin resistance responding from those who tested cocaine-negative. Changes in cue-induced physiological and self-report measures were also not associated with between-subject variations in mood as measured by the Profile of Mood States (POMS) questionnaire administered prior to cue assessment. Thus, variations in baseline mood and recent cocaine use history do not introduce an additional source of variability in cue reactivity measurements. However, negative mood states at the start of a session were associated with higher levels of self-reported craving, high, and withdrawal both before and after cue exposure.

Adult↗
PubMed2000

Psychosocially enhanced treatment for cocaine-dependent mothers: evidence of efficacy.

Eighty-four cocaine-dependent mothers were randomly assigned either to a case management-oriented outpatient treatment program (CM), or to a psychosocially enhanced treatment program (PET). Both programs included onsite child care and both offered daily group therapy sessions. Subjects randomized to the PET condition were offered a variety of additional onsite services designed to meet their special psychosocial needs including parenting skills class, access to a psychiatrist, individual therapy sessions, and GED class. Patients in the CM program could gain access to these services only through referrals to community resources. Program retention was significantly better for patients in the PET condition. In addition, while the mean number of days of cocaine use decreased from baseline in both groups, the PET group had significantly fewer days of cocaine use at 12-month follow-up than the CM group. These results show that providing psychosocial enhancement services onsite can improve treatment outcome for cocaine-dependent mothers.

Adult↗
PubMed2000

Do caffeine-containing analgesics promote dependence? A review and evaluation.

OBJECTIVE: Debates about the suspected association between kidney disease and use of analgesics have led to concern about whether caffeine could stimulate an undesirable overuse of phenacetin-free combined analgesics. A committee was asked to critically review the pertinent literature and to suggest guides for clinical practice and for consideration of international regulatory authorities. PARTICIPANTS: A group of international scientists, jointly selected by the regulatory authorities of Germany, Switzerland, and Austria and the pharmaceutical industry. EVIDENCE: All invited experts evaluated relevant literature and reports and added further information and comments. CONCLUSIONS: Caffeine has a synergistic effectiveness with analgesics. Although caffeine has a dependence potential, the potential is low. Experimental data regarding dependence potential for caffeine alone may not correspond to the conditions in patients with pain. Withdrawal is not likely to cause stimulation or sustainment of analgesic intake. For drug-induced headache, no single or combined analgesic was consistently identified as causative, and no evidence exists for a special role of caffeine. Strong dependence behavior was observed only in patients using phenacetin-containing preparations, coformulated with antipyretics/analgesics and caffeine. This finding may have led to the impression that caffeine stimulates overuse of analgesics. SUMMARY: Although more experimental and long-term data would be desirable to show possible mechanisms of dependence and to offer unequivocal proof of safety, the committee concluded that the available evidence does not support the claim that analgesics coformulated with caffeine, in the absence of phenacetin, stimulate or sustain overuse.

Analgesics↗
PubMed2000

Gender and psychiatric comorbidity: impact on clinical presentation of alcohol dependence.

We examined differences in clinical presentation for outpatient alcohol treatment in: 1) males and females, considering comorbidity; and 2) three comorbid groups, considering gender. Drinking indices and emotional, physical, and sexual abuse reports were compared in 127 male and 69 female alcohol-dependent patients who have a current (36.2%) or lifetime (20.4%) psychiatric disorder or who never had a psychiatric disorder (43.4%). Females reported more emotional and physical abuse than males. Females reported drinking smaller volumes of alcohol but on more days than males. All with current comorbidity, irrespective of gender, reported more days of heavy drinking than other groups. When evaluating drinking status, gender and comorbidity should be considered.

Adult↗
PubMed2000

Prognostic significance of antisocial personality disorder in cocaine-dependent patients entering continuing care.

This study examined the relationship of antisocial personality disorder (APD) to response to continuing care treatments in a sample of cocaine-dependent patients. Patients (N = 127) were randomly assigned to 20-week standard group or individualized relapse prevention continuing care interventions after the completion of an initial treatment episode and followed up at 3, 6, and 12 months. APD and non-APD patients did not differ on retention in continuing care, substance use outcomes, social function outcomes, or experiences before or during cocaine relapse episodes. A diagnosis of APD was also not a predictor of differential response to the two continuing care interventions in the study. However, APD patients had worse medical and psychiatric problem severity than non-APD patients at entrance to continuing care and during follow-up. These results suggest that cocaine patients with APD who are in the continuing care phase of outpatient rehabilitation might benefit from additional medical and psychiatric treatment services.

Aftercare↗