For many people struggling to overcome drug addiction, relapse is a dangerous part of the road to recovery. It can be triggered by a passing memory of the drug's pleasurable effects -- sometimes even after years of sobriety.
But what if scientists could hack into the brain to stop relapse at the source, by erasing that powerful memory?
A team of neuroscientists from The Scripps Research Institute have tested a new drug called blebbistatin on mice addicted to methamphetamine. Preliminary findings indicate that it can selectively erase dangerous addiction-associated memories.
"When people come out [of a treatment program], unfortunately one of the really big relapse factors are these memories, and they can last for a person's entire life," Dr. Courtney Miller, one of the study's authors, told The Huffington Post. "So they always have the risk of relapse when they encounter those triggers."
The findings could have enormous implications for individuals struggling with meth addiction, which is one of the most difficult drug addictions to overcome. The relapse rate for meth is an estimated 93 percent. Only 16 to 20 percent of meth addicts ever make a full recovery.
The researchers envision using a one-time memory-erasing treatment in conjunction with traditional treatments such as in-person rehabilitation and abstinence.
"When the person is in-patient, they'd use this treatment once and it would target those drug-associated memories that could be triggers for them," Miller said. "Later on when they're back in the real world, the memories wouldn't serve as triggers because they'd be gone."
The new findings, published online in the journal Molecular Psychiatry, build on a 2013 discovery made by the same research team.
The science of memory formation is complex, but here's the short story: Memories are stored in neurons, or brain cells. Inside the brain cells is a structural protein called actin that the body uses to store memories. When any memory is formed, the actin engages in a process of detaching and reattaching itself to the neuron.
In very strong, visceral memories, like those associated with drug addiction, the actin does this more quickly, and remains dynamic for a longer period of time than it does with other memories. Researchers found that with these memories specifically they could prevent the actin from reattaching to the neuron -- blocking access to the memory.
"Usually, the proteins stabilize quickly, but with the meth memories, the proteins remain dynamic," Miller said. "We were able to use a drug that only targeted the dynamic proteins that hold those memories."
The drug, a chemical compound known as blebbistatin, selectively targets brain actin by blocking a molecular motor protein that supports actin activity.
A single injection of blebbistatin was found to block relapse in the addicted mice for a month or longer. Though the drug erased the memories of the methamphetamine, it did not seem to have an effect on other memories, or on the formation of new memories.
Although more research is needed to determine whether the experimental drug is safe for human use, the Scripps team is optimistic about its potential for preventing meth relapse.
A next step for the team is to investigate whether the same approach could be effective for other types of addiction.
"Unfortunately we don't know yet, but that's at the top of our list of things to start working our way through," Miller said.
CORRECTION: A previous version of this article misstated the name of the journal in which the article appeared, as the Journal of Molecular Psychiatry. The publication was in fact Molecular Psychiatry.