Does cocaine damage your brain? While the answer is almost certainly yes, a new study by Cousijn et al. (2021) suggests that you might want to take particular caution with it if you’re a woman. These researchers wanted to see how cocaine might differently impact the brains of women versus men—important because most studies in the past have largely ignored possible sex differences in favor of focusing on male cocaine-use alone. Cousijn et al. argued that, if sex differences between compulsive cocaine users could be identified, then this might open the door for new “sex-tailored” interventions for cocaine addiction.
New, effective interventions are important to be developed for cocaine addiction because scientists know that the shift from a person using cocaine recreationally to using cocaine compulsively brings with it a host of negative neurobiological changes in the prefrontal cortex. Additionally, researchers also believe that damage imposed by recreational cocaine use to the prefrontal cortex facilitates the shift to compulsive cocaine addiction. The prefrontal context is the part of your brain located just behind your forehead: it is crucially involved in planning, reasoning, personality, and cognitive and emotional regulation. When this area is damaged, people have lots of behavioural trouble, such as difficulties with inhibition and long-term planning—these difficulties may further undermine the recovery process for compulsive cocaine users. Cousijn et al. (2021) knew that if they could show the PFC response to be different for females compared to male cocaine users, then this may allow for the eventual establishment of more effective addiction recovery programs.
Their study therefore set out to explore possible differences in PFC functioning between male and female cocaine users. Cousijn et al. (2021) recruited 44 regular cocaine users and 54 non-cocaine users through local advertisements and social media; they made sure that the participants were similar to each other in a variety of ways, as to minimize differences between the groups not caused by cocaine. Then, to measure PFC functioning, Cousijn et al. (2021) strapped their participants into an fMRI machine and got them to perform cognitive tasks. The fMRI technology allowed the researchers to scan the brains of the participants and examine changes in the PFC; the cognitive tasks given to the participants were specifically chosen as to active the PFC by taxing the ‘working memory’ of the participants, or their ability to mentally juggle multiple bits of information simultaneously. So, what did the researchers discover from this design?
Importantly, the results of the study showed that the groups differed significantly in how their brains reacted to the cognitive tasks. The fMRI scans showed that the cocaine-using women displayed higher prefrontal activity compared with non-using females, whereas cocaine using men displayed lower prefrontal activity compared to their non-using counterparts. Cousijn et al. (2021) also found that non-using males had a higher activation of the PFC compared to the non-using females. Additionally, the severity of cocaine use differently impacted the brain functioning of the different sex groups: activation of specific areas of the PFC was negatively associated with cocaine use severity in female cocaine users, but not in males.
The authors suggest that these results show that PFC deficits are, in fact, present in the brains of female cocaine users dissimilarly to male users. They propose that the increased activation of the PFC in female cocaine users reflects the brain’s way of trying to compensate for damage, leading to working memory problems. Yet, these results are speculative. Future research is still needed to conclusively determine if, how, and why this damage takes different forms in males versus females; only then may the interactions between PFC functioning, cocaine use, and sex be truly unraveled. Crucially, however, is the fact that Cousijn et al. (2021) have opened the gate for this type of research to occur.
If future research supports these findings, then we may see sex-tailored treatments for cocaine users become standard in the future. But for now, recovery from cocaine addiction is business as usual.
References
Cousijn, J., Ridderinkhof, K. R., & Kaag, A. M. (2021). Sex?dependent prefrontal cortex activation in regular cocaine users: A working memory functional magnetic resonance imaging study. Addiction Biology, 26(5). https://doi.org/10.1111/adb.13003