From Pest to Test Subject: What Fruit Flies Can Teach Us About Addiction

The latest episode of American Addiction Center’s award-winning show “Addiction Talk” takes a deep dive into the science of addiction and how a common household pest is helping researchers learn new information about this complex disease.

Enter the fruit fly.

Host Joy Sutton speaks with neuroscientist Kristin Scaplen, who works as an assistant professor at nearby Bryant University. Scalpen earned her Ph.D. in neuroscience from Brown University and undergraduate degrees in biology and psychology from the University of Connecticut.

Scaplen’s cutting-edge research is focused on neurons—the human brain has 87 billion of them, by the way—and how these neural circuits function and change with repeated exposure to alcohol.

Most of her recent findings have come via a seemingly insignificant insect—yes, the fruit fly.

Why the fruit fly?

Fruit flies share 60% of the same genes as humans and 75% of the genes that cause disease, which means they are a powerful organism for understanding how genes affect human health and behavior.

In the context of addiction, fruit flies have remarkably similar behavior patterns to people, especially in how they respond to alcohol. In fact, according to Scalpen, scientists have been using these tiny, winged creatures as model organisms to study addiction for the past 30 years.

When it comes to alcohol addiction research, there is much to glean from Scalpen’s work. Here are some key takeaways from the episode:

• The basic connections in a fruit fly’s brain are very similar to those in a human, especially when trying to determine what’s rewarding or not (e.g., alcohol).
• Fruit flies can become intoxicated from alcohol, just like people. At first, exposure to alcohol causes increased activity. This is followed by a lack of coordination, and, with continued exposure, eventually leads to sedation.
• Scalpen views addiction as a memory disorder. Evidence suggests that over time, the memory circuits in people with addiction become disrupted. This results in an enduring preference for their drug of choice, habitual behaviors, and cravings, which increase the risk of relapse.
• In fruit flies, Scalpen’s work has revealed that memory circuits associated with alcohol last for up to seven days, which is a long time in the life of a fruit fly. Once repeated exposure occurs, a fruit fly will continue to go back for more alcohol and even endure a 120-volt shock in the process.
• This points to a key distinction of Scalpen’s research: While many previous studies have examined organisms that are already physiologically dependent on a substance, hers focuses on how alcohol exposure shapes the brain to develop dependence.
• On a broader scale, the fruit fly phenomenon also underscores the idea that addiction is a chronic brain disorder—and not the result of moral failing or lack of willpower, as it is sometimes posited to be.
• Scientists can use the findings from these simpler organisms (fruit flies) to inform research on more complex organisms (humans).
• This is the ultimate goal—to discover a universal principle that could somehow be manipulated or reversed on a neuron level to help people with substance use disorders.
• “There are so many people touched by this disease,” Scalpen explains. “It’s such an important problem, with very few effective treatments.”
• And it’s this hope for an eventual cure that motivates her on a daily basis.

A cure for addiction? Now, that would be something worth buzzing about.

Watch the full episode of “Addiction Talk” here.