Highs And Lows Of Cravings
The anticipation of a cocaine fix and the actual craving to abuse the drug are two closely related phenomena, according to new evidence published in the journal Substance Abuse Treatment, Prevention, and Policy.
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.
Substance Abuse Treatment, Prevention, and Policy 2007, 2:30doi:10.1186/1747-597X-2-30
Effects of perceived cocaine availability on subjective and objective responses to the drug
Rinah T Yamamoto, Katherine H Karlsgodt, David Rott, Scott E Lukas and Igor Elman
Rationale: Several lines of evidence suggest that cocaine expectancy and craving are two related phenomena. The present study assessed this potential link by contrasting reactions to varying degrees of the drug’s perceived availability.
Non-treatment seeking individuals with cocaine dependence were administered an intravenous bolus of cocaine (0.2 mg/kg) under 100% (‘unblinded’; N=33) and 33% (‘blinded’; N=12) probability conditions for the delivery of drug. Subjective ratings of craving, high, rush and low along with heart rate and blood pressure measurements were collected at baseline and every minute for 20 minutes following the infusions.
Compared to the ‘blinded’ subjects, their ‘unblinded’ counterparts had similar craving scores on a multidimensional assessment several hours before the infusion, but reported higher craving levels on a more proximal evaluation, immediately prior to the receipt of cocaine. Furthermore, the ‘unblinded’ subjects displayed a more rapid onset of high and rush cocaine responses along with significantly higher cocaine-induced heart rate elevations.
These results support the hypothesis that cocaine expectancy modulates subjective and objective responses to the drug. Provided the important public health policy implications of heavy cocaine use, health policy makers and clinicians alike may favor cocaine craving assessments performed in the settings with access to the drug rather than in more neutral environments as a more meaningful marker of disease staging and assignment to the proper level of care.