A recent neuroimaging study involving young adults discovered that those with a stronger startle reaction to unpredictable threats, like electric shocks, were more prone to binge drinking a year later. These individuals also displayed increased reactivity in the bilateral anterior insula and the dorsal anterior cingulate cortex regions of the brain when subjected to such threats. The study was published in Neuropsychopharmacology.
Alcohol use disorder is a persistent medical condition marked by an inability to regulate alcohol consumption despite adverse consequences in personal, social, or occupational spheres. Those with this disorder intensely crave alcohol, develop increased alcohol tolerance, and experience withdrawal symptoms when not drinking. They often prioritize alcohol over other life commitments.
In many countries, adolescents begin consuming alcohol at a young age. In the U.S., the average age of first alcohol consumption is 16. By the age of 18, over 60% of young people have tried alcohol. Additionally, 21% of 18-year-olds admit to a binge-drinking event in the previous month. A binge-drinking episode is defined as consuming four or more standard whiskey shots (or a comparable alcoholic beverage) on a single occasion. Typically, those diagnosed with alcohol use disorder have had multiple episodes of binge drinking.
The lead researcher, Stephanie M. Gorka, and her team wanted to know whether it is possible to predict the risk that an individual will engage in binge drinking early, based on the behavior of the person’s brain and its reaction to certain situations. They were interested in exploring this on 17-19-year-olds, because that is the age when alcohol use starts to escalate.
Although prior studies have associated an enhanced brain startle response to unpredictable threats with heavy drinking, these studies’ design made it unclear if this heightened brain reactivity was a cause or a result of excessive alcohol consumption. In their research, Gorka and her colleagues measured participants’ brain reactions to experimental threats and monitored their alcohol consumption habits for the following year.
The study consisted of 95 participants aged between 17 and 19, who had consumed between one and 100 alcoholic drinks in their lifetime. Those associating with risk-prone peers and having easy access to alcohol were chosen because of their potential risk of developing alcohol use disorder. The research was conducted at Ohio State University. Participants underwent lab sessions and later reported on their alcohol consumption after a year.
At the study’s outset, participants were assessed for lifetime psychopathology using the Structured Clinical Interview for DSM-5 disorders and the threat task. For this task, electrodes capable of delivering electric shocks were placed on the participants’ left wrist. Trials were conducted to determine the shock intensity considered “highly annoying but not painful” by the participant.
The threat task had three conditions: a no-shock condition, a predictable shock condition with a countdown, and an unpredictable shock condition where participants couldn’t anticipate when they’d receive a shock. Concurrently, the system released loud sounds to measure the startle reflex. Electrodes placed over a muscle below the left eye recorded the eye blink startle response and its intensity. Following this, participants underwent functional magnetic resonance imaging during the same threat tasks, but this time with electrodes on their left foot.
Results indicated that those with higher startle reactivity to unpredictable threats were more likely to binge drink a year later. Essentially, for every unit increase in the startle reaction, the probability of binge drinking nearly doubled in the subsequent year.
Functional magnetic resonance imaging revealed that increased reactivity in the bilateral anterior insula and dorsal anterior cingulate cortex regions, when faced with uncertain threats, also correlated with a higher likelihood of binge drinking a year later.
“Consistent with our hypotheses, results revealed that behavioral and brain reactivity to U-threat [uncertain threat, unpredictable electric shocks in this case] predicts probability of binge drinking one-year later. Findings demonstrate that exaggerated reactivity to U-threat [uncertain threat] is not just an alcohol use disorder marker; it reflects a brain-based individual difference factor that connotes risk for problem drinking,” the study authors concluded.
The study sheds light on the neural underpinnings of alcohol use development. However, it also has limitations that need to be taken into account. Notably, study participants were primarily female and the follow-up period was limited to 12 months. A more gender-balanced sample and a longer follow-up period might have produced different results.
The study, “Behavioral and brain reactivity to uncertain stress prospectively predicts binge drinking in youth”, was authored by Stephanie M. Gorka, Milena Radoman, Jagan Jimmy, Kayla A. Kreutzer, Charles Manzler, and Stacey Culp.