Ethanol self-administration reduced the efficacy of a behavioral intervention to decrease cocaine choice in socially
Mia I Rough1, Emory A Lewis1, Cameron F Rough1
1Department of Translational Neuroscience, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1083, USA.
Drug and Alcohol Dependence
|November 19, 2025
Summary
Ethanol self-administration increased the reinforcing strength of cocaine, even when non-drug options were available. This suggests alcohol may reduce the effectiveness of treatments for cocaine use disorder (CUD).
Area of Science:
- Neuroscience
- Behavioral Pharmacology
- Addiction Research
Background:
- Cocaine use disorder (CUD) is often comorbid with alcohol use.
- This polysubstance use pattern is associated with worse treatment outcomes.
- The effect of alcohol on cocaine reinforcement, especially with alternative reinforcers, is not well understood.
Purpose of the Study:
- To investigate how ethanol self-administration affects cocaine reinforcement in the presence of an alternative non-drug reinforcer.
- To determine if ethanol alters the reinforcing potency or strength of cocaine.
Main Methods:
- Eight socially housed cynomolgus monkeys (male and female) underwent daily sessions.
- Initially, monkeys had access to ethanol (1.5g/kg) or a vehicle control for one hour.
- Following fluid access, a choice between cocaine (0.001-0.1mg/kg/injection) and food (1.0-g pellet) was presented.
Main Results:
- Cocaine choice increased dose-dependently.
- Ethanol self-administration did not change cocaine's potency.
- However, longer delays were required to decrease cocaine choice after ethanol exposure, indicating increased reinforcing strength.
Conclusions:
- Ethanol self-administration enhances the reinforcing effects of cocaine when non-drug alternatives are available.
- These findings suggest alcohol co-use may impede behavioral interventions for CUD.
- Preclinical modeling of polysubstance use is crucial for developing effective clinical treatments.
