Effects of Cocaine and Alcohol, Alone and in Combination, on Human Learning and Performance

Abstract

The acute effects of cocaine hydrochloride (4 to 96 mg/70 kg) and alcohol (0 to 1.0 g/kg), administered alone and in combination, were assessed in two experiments with human volunteers responding under a multiple schedule of repeated acquisition and performance of response chains. Subjects were intermittent users of cocaine and regular drinkers who were not cocaine or alcohol dependent. Alcohol was mixed with orange juice and ingested in six drinks within 30 min; cocaine was administered intranasally 45 min after completion of drinking. In each component of the multiple schedule, subjects completed response sequences using three keys of a numeric keypad. In the acquisition component, a new sequence was learned each session. In the performance component, the response sequence always remained the same. Results were consistent in both experiments, despite variations in the order in which the drugs were tested alone and in combination. Alcohol administered alone increased overall percentage of errors and decreased rates of responding in the acquisition component, whereas responding in the performance component generally was unaffected. Cocaine administered alone decreased rates of responding but did not affect accuracy of responding in the acquisition component, and enhanced accuracy of responding without affecting rates of responding in the performance component. The combined doses of cocaine and alcohol attenuated the effects observed with alcohol and cocaine alone. These results suggest that, under the conditions investigated in this study, (a) alcohol produces greater behavioral disruption than cocaine or cocaine-alcohol combinations, (b) cocaine and alcohol each attenuate effects of the other, and (c) such attenuation is most pronounced for cocaine attenuating the disruptive effects of alcohol.

Effects of chronic binge-like ethanol consumption on cocaine self-administration in rhesus monkeys

“…Moreover, similar alterations in brain DA systems—particularly D2 receptors—have been observed in alcoholics and cocaine abusers (e.g., Cosgrove, 2010; Volkow et al, 1996,1999, 2002). When combined, cardiovascular effects of cocaine and EtOH can be enhanced, while effects on cognitive performance may be attenuated (Farre et al, 1993; Foltin and Fischman, 1988; Foltin et al, 1993; Higgins et al, 1992). Experiments in laboratory animals have also indicated that co-administration of cocaine and EtOH can produce more pronounced effects than either drug alone.…”

Health Profiles of Clients in Substance Abuse Treatment: A Comparison of Clients Dependent on Alcohol or Cocaine With Those Concurrently Dependent

“…These findings suggest the effects of both drugs combined may be additive (McCance, Price, Kosten, & Jatlow, 1995). Epidemiological studies on accidental injuries of concurrent users compared to those using either drug mainly alone have not been found in the literature; however, one experimental study shows that cocaine helps to attenuate the effects of alcohol (Higgins et al, 1992), suggesting that concurrent users may have fewer accidental injuries than those using mainly alcohol alone. Research by Salloum, Douaihy, Ndimbie, & Kirisci, (2004) found that simultaneous users have higher rates of sexually transmitted infections than users of cocaine or alcohol alone.…”

Interactive effects of ethanol and nicotine on learning in C57BL/6J mice depend on both dose and duration of treatment

“…Many studies have demonstrated that impairments in learning and memory are associated with high doses of ethanol; this is seen for tasks that include passive avoidance, delay matching-toposition, free recall, radial maze, and both delay and trace fear conditioning (Bammer and Chesher 1982;Gibson 1985;Gould 2003a;Higgins et al 1992;Weitemier and Ryabinin 2003). Research has also demonstrated that acute nicotine enhances learning in many of the same tasks (Davis et al 2005b;Gould and Lommock 2003;Hahn et al 2002;Rezvani and Levin 2003).…”