Experimental and clinical psychopharmacology
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Exp Clin Psychopharmacol · Aug 2001
Clinical TrialVoucher-based reinforcement of opiate plus cocaine abstinence in treatment-resistant methadone patients: effects of reinforcer magnitude.
The study tested a voucher-based abstinence reinforcement procedure for reducing opiate and cocaine use in a population of treatment-resistant opiate- and cocaine-abusing methadone patients. Vouchers exchangeable for goods and services were contingent on abstinence from both opiates and cocaine. In two conditions, participants could earn up to $374 or $3,369 in vouchers for providing opiate- and cocaine-free urine samples. ⋯ The dose was increased in a second phase, and the voucher conditions were replicated. Analyses of both phases revealed trends toward greater abstinence under the high voucher condition and suggested that higher doses may enhance the efficacy of voucher reinforcement. The results show that reinforcement for abstinence from 2 drugs simultaneously can be effective even in a treatment-resistant population.
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Exp Clin Psychopharmacol · Feb 2000
Randomized Controlled Trial Clinical TrialA clinical laboratory model for direct assessment of medication-induced antihyperalgesia and subjective effects: initial validation study.
Analgesic medications are often tested in clinical laboratory studies by observing their ability to reduce the pain produced by noxious stimuli presented to healthy skin. These medications may then be used clinically to reduce disease-related hyperalgesia. ⋯ Results demonstrate that ultraviolet (UV) light induces hyperalgesia, commonly prescribed analgesic medications reduce UV-induced hyperalgesia, and this UV-induced hyperalgesia model can be used to assess the time course of a medication's antihyperalgesia effects. Coupled with participant-rated measures of drug liking and mood, this model may prove useful for predicting the clinical efficacy and side-effect profile of novel analgesic medications in cost-efficient and statistically powerful laboratory studies.
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Exp Clin Psychopharmacol · Aug 1999
Clinical TrialSubjective effects of caffeine among introverts and extraverts in the morning and evening.
In previous studies of psychomotor performance, the stimulant effects of caffeine differed by personality characteristics. For example, caffeine improved the task performance of extraverts but overaroused introverts and thus impaired their performance. The present study compared the effects of caffeine on subjective arousal among introverts and extraverts. ⋯ Caffeine effects on mood and task performance did not significantly interact with extraversion, except for nonsignificant trends for caffeine to increase happiness and vigor more among extraverts than introverts. No 3-way interactions of group, time, and dose were found on any scales or on the DSST. Results do not support the hypothesis that caffeine differentially affects extraverts and introverts, particularly at different times of the day.
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Exp Clin Psychopharmacol · Nov 1998
Naloxone blocks reinforcement but not motivation in an operant runway model of heroin-seeking behavior.
The present study examined the effects of opiate receptor antagonism on both the motivation to seek heroin and the reinforcing consequences of heroin administration. Subjects were trained to discriminate between olfactory cues predicting either the delivery of intravenous heroin reinforcement (S+) or saline (S-). ⋯ However, 24 hr later on the first posttreatment trial, subjects that had received heroin in the presence of naloxone (on the previous trial) now traversed the alley more slowly when presented with the S+. These data suggest that although the motivation to seek heroin was not disrupted by naloxone, the reinforcing consequences of heroin administration were.
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Exp Clin Psychopharmacol · Nov 1998
Comparative Study Clinical TrialAdults seeking treatment for marijuana dependence: a comparison with cocaine-dependent treatment seekers.
Sixty-two individuals seeking treatment for marijuana dependence completed a comprehensive assessment. Sociodemographics, substance use, psychosocial functioning, psychiatric symptoms, and medical status were compared with similar data collected from 70 treatment-seeking, cocaine-dependent individuals. ⋯ The marijuana group was more ambivalent and less confident about stopping their marijuana use than the cocaine group was about stopping their cocaine use. These findings indicate that treatment-seeking, marijuana-dependent individuals exhibit substantial problems and that further efforts to develop effective treatments for this population are warranted.