Cannabinoid addiction: behavioral models and neural correlates.
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The use of cannabis sativa preparations as recreational drugs can be traced back to the earliest civilizations. However, animal models of cannabinoid addiction allowing the exploration of neural correlates of cannabinoid abuse have been developed only recently. We review these models and the role of the CB1 cannabinoid receptor, the main target of natural cannabinoids, and its interaction with opioid and dopamine transmission in reward circuits. Extensive reviews on the molecular basis of cannabinoid action are available elsewhere (Piomelli et al., 2000; Schlicker and Kathmann, 2001). (+info)
Neuronal systems underlying behaviors related to nicotine addiction: neural circuits and molecular genetics.
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Nicotine addiction is a complex behavioral phenomenon comprising effects on several neural systems. Recent studies have expanded initial observations that the actions of nicotine on dopaminergic systems increase dopaminergic activity and release, leading to nicotine-induced reinforcement. Indeed, the actions of nicotine on many systems, including brainstem cholinergic, GABAergic, noradrenergic, and serotonergic nuclei, may help to mediate nicotine effects related to addiction. Furthermore, studies of mice lacking nicotinic acetylcholine receptor subunits or expressing supersensitive forms of these subunits have begun to tie together the molecular, neurochemical, and behavioral effects of nicotine. The use of multiple techniques by many laboratories provides optimism that the field is advancing toward elucidating the basic mechanisms of nicotine dependence. (+info)
Drug addiction. Part II. Neurobiology of addiction.
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The drug addiction may be regarded as the disease of the brain reward system. This system, closely related to the system of emotional arousal, is located predominantly in the limbic structures of the brain. Its existence was proved by demonstration of the "pleasure centers," that were discovered as location from which electrical self-stimulation is readily evoked. The main neurotransmitter involved in the reward is dopamine, but other monoamines and acetylcholine may also participate. The anatomical core of the reward system are dopaminergic neurons of the ventral tegmentum that project to the nucleus accumbens, amygdala, prefrontal cortex and other forebrain structures. Several of those structures may be specifically involved in the reward produced by different substances, when anticipating the reward. The recent discovery of CART peptides may importantly expand our knowledge about the neurochemistry of reward. Natural rewarding activities and artificial chemical rewarding stimuli act at the same locations, but while natural activities are controlled by feedback mechanisms that activate aversive centers, no such restrictions bind the responses to artificial stimuli. There are several groups of substances that activate the reward system and they may produce addiction, which in humans is a chronic, recurrent disease, characterized by absolute dominance of drug-seeking behavior. The craving induced by substances of addiction inhibits other behaviors. The adaptation of an organism to a chronic intake of drugs involves development of adaptive changes, sensitization or tolerance. It is thought that the gap between sensitization developing for the incentive value of the drug and tolerance to the reward induced by its consumption underlies the vicious circle of events leading to drug dependence. The vulnerability to addiction is dependent not only on the environment, but also on genetic factors. (+info)
Effects of bremazocine on self-administration of smoked cocaine base and orally delivered ethanol, phencyclidine, saccharin, and food in rhesus monkeys: a behavioral economic analysis.
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There is increasing evidence that kappa-opioid receptor agonists modulate cocaine-maintained behavior, and limited findings implicate the involvement of kappa-opioid receptors in ethanol-maintained behaviors. The purpose of the present study was to investigate the effects of bremazocine, a kappa-opioid agonist, on the self-administration of smoked cocaine base and oral ethanol in rhesus monkeys (Macaca mulatta). To determine the selectivity of bremazocine, the effects of bremazocine pretreatment on the oral self-administration of phencyclidine (PCP), saccharin, and food were also examined. Adult male rhesus monkeys were trained to self-administer oral ethanol, PCP, saccharin (n = 8), food (n = 6), or smoked cocaine base (n = 6) and water during daily sessions. Bremazocine (0.00032-, 0.001-, and 0.0025-mg/kg i.m.) injections were given 15 min before session. The 4 days of stable behavior before pretreatment served as baseline. Demand curves (consumption x fixed ratio; FR) were obtained for smoked cocaine base, ethanol, and PCP by varying the cost (FR) of drug deliveries and measuring consumption (deliveries). Bremazocine (0.001 mg/kg) was administered at each FR value in nonsystematic order. Results indicate that bremazocine dose dependently reduced cocaine, ethanol, PCP, and saccharin intake. Food intake was affected less by bremazocine than the other substances in five of the six monkeys. Generally, bremazocine treatment reduced the demand for cocaine, ethanol, and PCP as well as other measures of response strength. These results extend the findings that kappa-agonists reduce the self-administration of drug and nondrug reinforcers to smoked cocaine base and oral ethanol, PCP, and saccharin in rhesus monkeys. (+info)
Benefit-cost analysis of addiction treatment: methodological guidelines and empirical application using the DATCAP and ASI.
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OBJECTIVE: To provide detailed methodological guidelines for using the Drug Abuse Treatment Cost Analysis Program (DATCAP) and Addiction Severity Index (ASI) in a benefit-cost analysis of addiction treatment. DATA SOURCES/STUDY SETTING: A representative benefit-cost analysis of three outpatient programs was conducted to demonstrate the feasibility and value of the methodological guidelines. STUDY DESIGN: Procedures are outlined for using resource use and cost data collected with the DATCAP. Techniques are described for converting outcome measures from the ASI to economic (dollar) benefits of treatment. Finally, principles are advanced for conducting a benefit-cost analysis and a sensitivity analysis of the estimates. DATA COLLECTION/EXTRACTION METHODS: The DATCAP was administered at three outpatient drug-free programs in Philadelphia, PA, for 2 consecutive fiscal years (1996 and 1997). The ASI was administered to a sample of 178 treatment clients at treatment entry and at 7-months postadmission. PRINCIPAL FINDINGS: The DATCAP and ASI appear to have significant potential for contributing to an economic evaluation of addiction treatment. The benefit-cost analysis and subsequent sensitivity analysis all showed that total economic benefit was greater than total economic cost at the three outpatient programs, but this representative application is meant to stimulate future economic research rather than justifying treatment per se. CONCLUSIONS: This study used previously validated, research-proven instruments and methods to perform a practical benefit-cost analysis of real-world treatment programs. The study demonstrates one way to combine economic and clinical data and offers a methodological foundation for future economic evaluations of addiction treatment. (+info)
Why and how the tobacco industry sells cigarettes to young adults: evidence from industry documents.
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OBJECTIVES: To improve tobacco control campaigns, we analyzed tobacco industry strategies that encourage young adults (aged 18 to 24) to smoke. METHODS: Initial searches of tobacco industry documents with keywords (e.g., "young adult") were extended by using names, locations, and dates. RESULTS: Approximately 200 relevant documents were found. Transitions from experimentation to addiction, with adult levels of cigarette consumption, may take years. Tobacco marketing solidifies addiction among young adults. Cigarette advertisements encourage regular smoking and increased consumption by integrating smoking into activities and places where young adults' lives change (e.g., leaving home, college, jobs, the military, bars). CONCLUSIONS: Tobacco control efforts should include both adults and youths. Life changes are also opportunities to stop occasional smokers' progress to addiction. Clean air policies in workplaces, the military, bars, colleges, and homes can combat tobacco marketing. (+info)
Tobacco industry youth smoking prevention programs: protecting the industry and hurting tobacco control.
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OBJECTIVES: This report describes the history, true goals, and effects of tobacco industry-sponsored youth smoking prevention programs. METHODS: We analyzed previously-secret tobacco industry documents. RESULTS: The industry started these programs in the 1980s to forestall legislation that would restrict industry activities. Industry programs portray smoking as an adult choice and fail to discuss how tobacco advertising promotes smoking or the health dangers of smoking. The industry has used these programs to fight taxes, clean-indoor-air laws, and marketing restrictions worldwide. There is no evidence that these programs decrease smoking among youths. CONCLUSIONS: Tobacco industry youth programs do more harm than good for tobacco control. The tobacco industry should not be allowed to run or directly fund youth smoking prevention programs. (+info)
Burning Love: big tobacco takes aim at LGBT youths.
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Secret tobacco industry documents lay bare the industry's targeting, seduction, and recruitment of minority groups and children. They also unmask Big Tobacco's disdain for its targets. (+info)