Newly identified neuromarker reveals clues about drug and food cravings

Abstract: Researchers have identified neural biomarkers associated with food and drug craving. The findings could help pave the way for new treatments for addiction.

Source: Yale

Craving is known to be a key factor in drug addiction disorders and can increase the likelihood of future drug use or relapse. Yet its neural basis—or how the brain triggers craving—is not well understood.

In a new study, researchers from Yale, Dartmouth and the French National Center for Scientific Research (CNRS) have identified a stable brain pattern, or neuromarker, for drug and food craving. Their findings were published in The neuroscience of nature.

The discovery could be an important step toward understanding the brain basis of craving, addiction as a brain disorder, and how to better treat addiction in the future, researchers say. Importantly, this neuromarker can also be used to differentiate drug users from non-users, making it not only a neuromarker for craving, but also a potential neuromarker that could one day be used in the diagnosis of drug addiction disorders.

For many diseases, there are biological markers that doctors can use to diagnose and treat patients. To diagnose diabetes, for example, doctors test a blood marker called A1C.

“One of the advantages of having a stable biological indicator for a disease is that you can then give a test to any person and say they do or don’t have the disease,” said Hedy Kober, an associate professor of psychiatry at Yale School of Medicine. and the author of the study. “And we don’t have that for psychopathology, and especially not for addiction.”

To determine whether such a marker could be established for craving, Kober and her colleagues — Leonie Koban of CRNS and Tor Wager of Dartmouth College — used a machine learning algorithm. Their idea was that if many individuals with similar craving levels shared a pattern of brain activity, then a machine learning algorithm could detect that pattern and use it to predict craving levels based on brain images.

For the study, they used functional magnetic resonance imaging (fMRI) data—which offers insight into brain activity—and self-reported craving ratings from 99 people to train and test a machine learning algorithm.

fMRI data was collected while individuals—who identified themselves as drug users or non-users—viewed images of drugs and highly palatable food. Participants then rated how much they craved the objects they saw.

The algorithm identified a pattern of brain activity that could be used to predict the intensity of drug and food cravings from fMRI images alone, the researchers said.

The pattern they observed—which they called the “Neurobiological Signature of Craving (NCS)”—involved activity in several brain areas, some of which previous research has linked to substance use and craving.

However, NCS also provides a new level of detail, showing how neural activity within subregions of these brain areas can predict craving.

“It gives us a really precise understanding of how these regions interact and predict the subjective experience of craving,” Kober said.

NCS also found that the brain’s responses to both drugs and food were similar, suggesting that drug cravings arise from the same neural systems that generate food cravings. Importantly, the marker was able to differentiate drug users from non-users based on their brain responses to drug cues, but not to food cues.

“These findings are not specific to one substance because we included participants who used cocaine, alcohol, and cigarettes, all of which are predicted by the NCS,” Kober said. “So it’s really a biomarker for craving and addiction. There is something common in all of these substance abuse disorders that is trapped in the moment of craving.”

Wager also points out that emotional and motivational processes that may seem similar actually involve different brain pathways and can be measured in different ways.

“What we’re seeing here is probably not a general ‘reward’ signature,” he said, “but something more selective for food and drug craving.”

In addition, NCS also offers a new brain target for better understanding how context or emotional states can influence food and drug craving. “For example,” Koban said, “we can use the NCS in future studies to measure how stress or negative emotions increase the desire to use drugs or indulge in our favorite chocolate.”

Kober notes that while NCS is promising, it needs further validation and is not yet ready for clinical use. That’s probably in a few years. Now she—along with her team and collaborators—is working to gain a deeper understanding of this network of brain regions and see if NCS can predict how people with substance abuse disorders will respond to treatment.

This, she said, would make this neuromarker a powerful tool to inform treatment strategies.

“We hope,” Kober said, “that the brain, and specifically the NCS as a stable biological indicator, might allow us to not only identify who has substance abuse disorder and understand the variation in people’s outcomes, but also who will respond to certain treatments.”

About this addiction research news

Author: Press office
Source: Yale
Contact: Press Office – Yale
Picture: The image is in the public domain

Original research: Closed access.
“A neuromarker for drug and food craving distinguishes drug users from nonusersby Hedy Kober et al. The neuroscience of nature

---

Abstract

A neuromarker for drug and food craving distinguishes drug users from nonusers

Craving is a core feature of substance abuse disorders. It is a strong predictor of substance use and relapse and is associated with binge eating, gambling, and other maladaptive behaviors.

Craving is measured through self-report, which is limited by an introspective approach and sociocultural contexts. Neurobiological markers of craving are needed and lacking, and it remains unclear whether drug and food craving involve similar mechanisms.

Through three functional magnetic resonance studies (n= 99), we used machine learning to identify a cross-validated neuromarker that predicts the intensity of cue-induced drug and food craving (P< 0.0002).

This pattern, which we call the neurobiological signature of craving (NCS), includes the ventromedial prefrontal and cingulate cortices, ventral striatum, temporal/parietal association areas, mediodorsal thalamus, and cerebellum.

Importantly, NCS responses to drug versus food cues distinguished drug users from nonusers with 82% accuracy. NCS is also modulated by self-regulatory strategy. Transfer between separate neuromarkers for drug and food craving suggests common neurobiological mechanisms.

Future studies may assess the discriminant and convergent validity of the NCS and test whether it responds to clinical interventions and predicts long-term clinical outcomes.