Psychopharmacology
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Drug reinforcement may represent the primary behavioral-pharmacological mechanism underlying two types of problematic use of benzodiazepines--recreational abuse by polydrug abusers and inappropriate chronic use by patients. High dose polydrug abuse for the purpose of getting high is readily recognized as a significant social problem. Inappropriate chronic benzodiazepine use is more subtle but relatively common: for anxiolytics, 36% of past-year users (3% of the adult population in the US) report using these drugs for 4 consecutive months or longer. ⋯ The problem of inappropriate long-term use of benzodiazepines by people without histories of drug abuse has been partially modeled in human studies showing that benzodiazepines function as reinforcers in subjects with anxiety, insomnia, and histories of moderate alcohol consumption, and in preclinical studies showing stable, low-rate benzodiazepine self-injection with concurrent physical dependence under conditions of continuous availability. Both human and animal research suggests that the drug history and current behavioral context may be important in the establishment of benzodiazepines as reinforcers. Limited human and animal research provides little support for the common belief that physical dependence enhances benzodiazepine reinforcement.
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Clinical Trial
Effects of hot tea, coffee and water ingestion on physiological responses and mood: the role of caffeine, water and beverage type.
Psychopharmacological studies using caffeinated beverages or caffeine have rarely considered temporal effects on psychological and physiological function or the specific contribution of caffeine, hot water, or beverage type to the observed effects. The effect of 400 ml hot tea, coffee, and water consumption on systolic and diastolic blood pressure (SBP and DBP), heart rate, skin conductance (a measure of sympathetic nervous system activation), skin temperature, salivary cortisol, and mood were monitored in 16 healthy caffeine-withdrawn (14 h) subjects in a complete crossover design. Beverages were ingested with/without 100 mg caffeine and milk (tea/coffee only). ⋯ In keeping with this, the responses to tea and coffee ingestion were similar and largely accounted for by the effects of hot water and caffeine. However, tea potentiated the increase in skin temperature compared to coffee and water indicative of a greater vasodilatory response plausibly related to the presence of flavonoids in tea. We conclude that ingestion of hot caffeinated beverages stimulates physiological processes faster than hitherto described, primarily via the effects of hot water and caffeine, but with beverage type and milk playing important modulatory roles.