Impulsivity can predict drug use: New Study

Apr 8, 2024

According to the results of a new study by researchers from the University of Geneva (UNIGE), impulsivity can predict cocaine consumption using rats as a model of addiction. Importantly, the study also showed that regular cocaine use does not diminish the brain’s ability to produce dopamine, as previously thought, showing the complexity of mechanisms of vulnerability to addiction.

Specifically, the study examined the interplay between personality traits and brain chemistry and revealed that impulsive actions, rather than risky decision-making, can be a better predictor of increased cocaine use in rats, indicating that impulsivity significantly influences drug abuse vulnerability.

This research also showed that chronic cocaine consumption does not affect the brain’s capacity to produce the neurotransmitter dopamine. What’s more, the study results suggest that individual differences in drug abuse vulnerability may stem from variations in how dopamine release is controlled, rather than the capacity for dopamine production, as some previous studies had indicated.

To carry out the study, the researchers first trained the rats in a gambling task to measure impulsive actions and risky decision-making. Then they measured the level of dopamine synthesis using a non-invasive neuroimaging technique before and after cocaine intake in the two groups of rats. They found that impulsive action, but not risky decision-making, predicted a greater number of cocaine injections and faster cocaine use by the animals.

“Until now, the idea that regular cocaine consumption could reduce the ability to produce dopamine was accepted. Our results contradict this assumption as both populations of rats retained the same capacity to produce dopamine, despite chronic consumption,’’ said study author Dr. Nathalie Ginovart, Associate Professor in the Department of Psychiatry and the Department of Basic Neurosciences at the UNIGE Faculty of Medicine, in a press release.

The results of this new research show that dopamine synthesis is not likely to be the main driver of impulsivity or vulnerability to cocaine use. In addition, they do not support the previously held hypothesis that cocaine use may directly reduce the capacity to produce dopamine, suggesting that there are other uncovered mechanisms that could explain individual vulnerability to addiction and drug abuse.

 ‘‘This variation in vulnerability could be linked to differences in the relative reactivity of dopaminergic neurons, so that certain stimuli, including drugs, are more salient for more impulsive animals,’’ states the research article. The researcher’s new aim is to evaluate how mechanisms controlling dopamine neuron reactivity influence vulnerability to abuse drugs.