Opioid abuse can change the brain

In the United States, the opioid crisis has hit the country for more than twenty years and has become a scourge on the social and health landscape. In fact, approximately 2.5 million Americans suffer from disorders related to the use of these medications and, in 2023, 81,000 overdose deaths involving opioids have been recorded. As a reminder, this is a family of substances of natural or synthetic origin obtained from opium, a substance extracted from the poppy. Known for their analgesic and sedative effects, certain treatments, such as morphine, codeine and fentanyl, are frequently used for pain management.

Some brain regions where opioid receptors are located are smaller

“Previous research has suggested brain alterations associated with opioid use disorder. However, this has been limited by small sample sizes, low numbers of participants, and single-modal analyses,” indicated researchers from the Yale School of Medicine (United States). In a study, they wanted to verify this suggestion by recruiting 105 people, aged on average 27 years old, in good health and 103 adults, aged on average 37 years old, dependent on opioids. Participants had brain scans, specifically structural and functional MRIs. Functional MRIs measure brain activity by detecting changes in blood flow, while structural MRIs take pictures of the shape of different regions of the brain.

Compared to healthy volunteers, patients with opioid use disorder had smaller volumes in the thalamus and right medial temporal lobe. In these regions, we find opioid receptors. According to the results, published in the journal Radiologylarger volumes were observed in the brainstem and cerebellum. “Increased functional connectivity was seen in the thalamus, right cerebellum and brainstem. Structure and function were positively correlated in the cerebellum and brainstem”we can read in the work.

Opioid addiction: gender differences in brain changes

The results also noted some differences between men and women in brain changes linked to opioid addiction. “An interaction between sex and group was found for medial prefrontal cortex volume, with patients having larger volumes than participants in the opioid-dependent group.” Based on these findings, the team now wants to analyze what they mean and how they can influence a person’s behavior. Future work will also need to determine whether these brain changes are permanent or whether they disappear after a person receives addiction treatment.