Addiction as a disease of the brain
President Donald Trump has called the opioid crisis a public health emergency. But when he made that declaration last October, he seemed to hearken back to an earlier solution: Just say no.
Trump called for “really tough, really big, really great advertising” to persuade Americans not to take opioids in the first place.
But there's a problem with that, says Matthew Hearing, who has studied the effect of opioids on the brain at Marquette University. It’s not a choice. Addiction is a brain disease.
Hearing, assistant professor of biomedical sciences, leads a research team examining how the brain’s neuroplasticity — its ability to shape-shift — contributes to addictive behavior. Opioids rewire the brain, he said, suppressing judgment centers and overtaking pathways that control decision making and behavior. “At some point, you don’t really have a choice, despite the adverse consequences that might result.”
“I think we’re getting away from the stigma that it’s their fault, that they should just quit. There are changes in the brain that make it impossible to quit without proper therapeutic approaches.”
It’s important work: Opioids killed more than 42,000 people in 2016, according to the Centers for Disease Control and Prevention. Hearing is particularly concerned about young people, whose brains aren't fully developed. “The last part of your brain to develop is your prefrontal cortex (which controls judgment). That means that is one of the parts of the brain most susceptible to abuse. They are at a very vulnerable state.”
Hearing’s research is focused on discovering what drives the initial use of drugs and what causes such a high propensity to relapse. “The more we can identify which brain circuits are responsible for which behavior, the more we can develop targeted treatments,” he said.
In lab experiments with rodents, his team uses laser therapy to study and manipulate animal neurons at the single-cell level. They have had some success in reducing addictive behavior using the technique. They’ve also observed the incredibly addictive power of the drugs.
In one experiment, rodents learned to self-administer remifentanil, a highly addictive opioid, but had to run a gantlet to reach a lever to do so. Most of the animals learned that running the gantlet wasn’t worth it. But 15% to 20% — percentages that mimic the portion of the human population most prone to addiction — ran it anyway.
With all the work being done on opioids, Hearing is confident researchers will make progress. “The power of science is amazing when given the opportunity to do it,” he said. But he cautions that “there’s never going to be a magic pill that people can take and then they are not addicts.” That’s because, “once an addict, always an addict,” he said. But research could lead to therapies to help people regulate their behavior more appropriately.
Hearing’s work is supported by a $1 million grant from the National Institute on Drug Abuse.