Impulsive responding increases during a laboratory model of a cocaine binge in individuals who use cocaine: A preliminary study.

BACKGROUND

Individuals with a binge pattern of cocaine use have been found to exhibit cognitive decrements relative to controls, but also experience increases in cognitive performance during binge cocaine administration in the laboratory.

OBJECTIVE

We examined cognitive performance during binge cocaine administration in the laboratory, but with varied amounts of cocaine, to better estimate its cognitive effects in the natural ecology.

METHODS

This study was approved by the Institutional Review Board of the New York State Psychiatric Institute, and all participants provided written informed consent to participate. Twelve individuals who used cocaine regularly (males=91.7%) and were physically/psychiatrically - healthy, completed a nightly counterbalanced cognitive battery during 2 phases of cocaine administration, separated by a period of cocaine abstinence (all phases maximum 5 days each). During cocaine phases, participants smoked cocaine up to 12 times per day (25 mg per occasion) as part of an experimenter-administered or self-administered protocol.

RESULTS

On average, participants exhibited decreased attentional response inhibition (F(2,48)=12.70, p<0.05) during Binge 1 (M=1072.5 mg cocaine), relative to Abstinence (0.0 mg cocaine) and Binge 2 (M=650.0 mg cocaine). The self-administration group exhibited decreased motor tracking (F=6.11(1,12.4), p<0.05) during Binge 2, relative to the other study phases, whereas the experimenter-administration group did not.

CONCLUSIONS

These data suggest that response inhibition, but not immediate memory or psychomotor speed, was impaired during periods of binge cocaine administration in experienced users. This finding has important implications for behaviors that require inhibitory control, such as driving, during cocaine intoxication.