Brain Study Reveals How Visual Cues Affect Drug Cravings
However, with the advent of brain imaging, scientists were able to look inside the brain, beyond behavior, to better understand how substances were affecting the brain itself. Now with functional magnetic resonance imaging (fMRI), researchers can watch the brain in action, which is opening new doors of understanding in the area of substance abuse and addiction.
Drug-Dependent Visual Cues and Reward
The fMRI technology was key in a recent study conducted at the School of Behavioral and Brain Sciences at the University of Texas in Dallas. The brain scans were used to learn how visual cues affect a drug user’s cravings.
Drug dependency is a tough habit to break because even seeing items associated with the substance can trigger a longing to use. This study watched inside the brain while marijuana users and people dependent on marijuana were exposed to marijuana paraphernalia to evaluate how the stimuli affected the mind.
Study the Brain of Marijuana Users
For their study, the University researchers recruited 71 subjects, all of whom were regular marijuana users. Just over one half of the study group qualified ad dependent users. All of the subjects agreed to undergo an fMRI brain scan. During the scan, individuals were handed either a pencil or a similar sized marijuana pipe. Subjects were able to see and to touch the items while being scanned.
Looking at the various fMRI scans, scientists found that the reward portion of the brain, known as the nucleus accumbens, lit up for every user when they came into contact with the marijuana pipe. All of the users responded positively to the visual cue of marijuana paraphernalia. At the same time, however, researchers were able to identify differences in connectivity with other parts of the brain between those who were regular marijuana users and those who were marijuana dependent.
Different Reward Drivers in Drug Dependency
Based on what they saw, the researchers concluded that the reward responses themselves are actually triggered by another system within the brain. But the reward region was not always stimulated in the same way. Certain triggers were in play for regular users and other triggers acted for dependent users.
For dependent users, the emotional areas of the brain (anterior cingulate gyrus; amygdala) were the active drivers for reward stimulation. However, with non-dependent regular users, there was increased activity and connectivity with regions associated with attention and memory (hippocampus; orbital frontal cortex). Thus, there are stronger emotional connections with reward for those dependent on marijuana while non-dependent users also experience visual activation of reward responsiveness, but it’s based more on memory.
Results Point to Drug Addictiveness
The study yielded other useful information. A chief claim made by those who favor nation-wide de-criminalizing marijuana use is that the drug is non-addictive. The claim has been in dispute for years, but the study reveals how the same brain activity patterns which have been observed in those addicted to cocaine and nicotine (substances whose addictive properties are not in dispute) are present among people who are dependent on marijuana. It’s hard to sell the idea that a drug is non-addictive when it behaves in the brain in ways that mirror the behavior of drugs known to be highly addictive.
Marijuana Favorability Based on Misperception
According to a National Survey on Drug Use and Health in 2012, marijuana is the most common illicit drug in the U.S. and close to one half of American adults report having at least tried the drug, according to the 2013 Pew Research survey. Many Americans are reporting a favorable attitude toward marijuana use while a significant number of young Americans view the drug as harmless.
Yet the National Institute on Drug Addiction reports that 9 percent of those who use marijuana daily wind up becoming dependent. The new University of Texas study, which appears in a July 2014 issue of the journal Drug and Alcohol Dependence, shows how these beliefs may be shortchanging the true addictiveness of this drug.