The past twenty years have seen dramatic changes in the way we view addiction. We’ve gone from a paradigm that assumed people who develop alcohol and substance use disorders do so because of a character flaw, a moral failing, or a lack of willpower. We now view addiction as a disease of the brain.
We’ve changed the way we talk about addiction, too: we avoid words like addict, abuser, drunk, or alcoholic. We now put people first, and describe addiction the same way we describe other chronic, relapsing disease. In the same way we say a person with hypertension or a person with cancer, we say a person with a substance use disorder or a person with an alcohol use disorder.
Along with this change in the way we view addiction, we’ve changed the way we study the root causes of addiction. Researchers now use cutting-edge brain visualization technologies and sophisticate analytic methods look inside the brain – at the actual neurons and the networks they create – to find out exactly what happens inside a brain exposed to alcohol or drugs.
This year, researchers found something new: a specific brain circuit that can predict compulsive drinking behavior.
The New Study
The caveat to this research is that it was performed on the rodent model in a controlled laboratory setting. What that means, briefly, is that direct human application for this new discovery is still a few years away, because the testing and approval process for new therapeutic techniques is heavily regulated and takes time. As well it should. With that said, it’s important to understand that this is the process virtually all new medical therapies go through. Decades of testing on the rodent model confirms that what happens in the brains of mice and rats gives us a very good idea of what might be happening in the human brain.
Now, let’s talk about that study.
Quoted in an article in Science Daily, study author Cody Siciliano of Vanderbilt University says,
“We initially sought to understand how the brain is altered by binge drinking to drive compulsive alcohol consumption. In the process, we stumbled across a surprising finding where we were able to predict which animals would become compulsive based on neural activity the first time they drank.”
Science often happens like this. Researchers begin looking for one thing, but their results send them in a different direction. Sometimes that direction is a dead-end. Sometimes it looks promising but throws a hypothesis out the window. And in some rare cases – like this one – it both confirms initial ideas and adds knowledge that both supports and expands the initial hypothesis.
The Details: Predicting Compulsive Alcohol Consumption
In this experiment – click here to read the abstract – researcher set out to identify the underlying neural mechanisms that regulate the transition from moderate to compulsive alcohol consumption in laboratory mice.
Here’s what they found:
- A specific brain circuit that plays a central role in the development of compulsive drinking. A brain circuit is a collection of neurons that fire together and lead to specific behavior.
- The circuit, which facilitates communication between two specific regions of the brain, was active in the brains of mice that consumed alcohol compulsively. The same circuit was not active in the brains of mice that consumed alcohol in low or even high quantities.
- In mice that later drank compulsively, the circuit was activated upon initial consumption.
- Using a technique called optogenetics – click here for an excellent explainer video on optogenetics from MIT – researchers were able to activate and deactivate the circuit, which resulted in either increased (with activation) or decreased (with deactivation) compulsive alcohol consumption.
This discovery is an important step in understanding how alcohol works in the brain. Previous research identified the presence of an alcohol craving circuit. Various additional studies have examined the effect of this circuit on behavior that leads to relapse.
What this study adds is something completely new.
Future Applications
This discovery could potentially lead to therapies that can improve the lives of millions of people.
In the words of study authors:
“Our results provide a mechanistic explanation for individual variance in vulnerability to compulsive alcohol drinking.”
Let’s circle back to the beginning of this article and connect the dots.
The new paradigm in addiction science is that addiction is a chronic, relapsing disease of the brain. Addiction has physiological, psychological, emotional, and behavioral components. This discovery bolsters the brain science aspect of this new paradigm. Think about the last bullet point above. Scientists modulated alcohol consumption in mice by activating and deactivating a specific set of neurons.
The implications of this discovery are significant.
First, it shows that there’s a distinct marker in the brain that can predict future compulsive drinking. It’s likely identical in humans. Second, it shows that turning that circuit on and off has direct and immediate effects on specific drinking behavior. Third, it shows that in the future, we may be able to develop techniques to activate and deactivate this circuit in humans. That is, if indeed we find a functionally identical circuit in the human brain – which is probable.
Techniques based on this discovery that are appropriate for humans may be years away. However, if and when they do come, they promise to be an effective tool – in addition to therapy, social support, and behavioral change – to help people move past their problem drinking and live a life free from the painful and often destructive cycles of addiction.