The study, by Rinah Yamamoto and colleagues at McLean Hospital in Belmont, Massachusetts assessed the suspected link by contrasting reactions to varying perceived availability of the drug. The researchers suggest that more appropriate care could be given if the degree of dependency and abuse were assessed in a natural environment with a potential access to the drug, rather than in a clinical setting.
Yamamoto explains that craving, is an intense and often irrepressible urge to seek and consume the drug, which can result in relapses even after extended periods of abstinence. In searching for effective therapies, understanding how craving, cognition and motivation are entwined is essential.
The researchers administered intravenous cocaine (0.2 mg/kg) to individuals with cocaine dependence who were not seeking treatment. "Unblinded" participants knew for certain they would receive cocaine, while the "blinded" group knew there was a 33 percent chance of getting the drug. The researchers obtained subjective ratings of craving, high, rush and low from the volunteers along with their heart rate and blood pressure measurements. Measurements were collected prior to cocaine administration and every minute for 20 minutes thereafter.
The results showed that several hours prior to the infusion all volunteers had similar craving scores. However, those volunteers who knew they were to receive a cocaine infusion said they felt a greater craving immediately prior to the receipt of cocaine than the "blinded" volunteers who did not know whether the infusion was placebo or the genuine drug. The team also found that the unblinded subjects experienced a more rapid onset of high and rush cocaine responses along with significantly higher cocaine-induced heart rate elevations.
The findings suggest that the cocaine expectancy state modulates the user's subjective and objective responses to the drug. These data are consistent with the previous studies demonstrating that drug-induced elevated dopamine concentrations in the brain may prime drug users to associate the cues around the source of dopamine boost (e.g., cocaine) with the pleasure experienced once the drug is taken.
Charlotte Webber | alfa
Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung
Scientists reveal source of human heartbeat in 3-D
07.08.2017 | University of Manchester
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
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