New ‘snail study’ reports successfully erasing selective memories that trigger anxiety and PTSD. But is this a good idea?
Almost everyone can think of a time they’d like to forget.
Perhaps it was when you acted out of character, were embarrassed in front of someone you respect, or failed at a task you value.
Or maybe it was a bad breakup of a relationship, as was the basic plot of the 2004 film “Eternal Sunshine of the Spotless Mind.”
While unpleasant to recall, we can often live with these types of memories without them interfering with our daily lives.
However, traumatic events, such as experiencing rape or war aren’t so easy to accept, and often trigger anxiety. In some cases, they cause post-traumatic stress disorder (PTSD).
Could erasing such memories help people cope?
Findings from a new study suggest so.
Researchers at Columbia University Medical Center (CUMC) and McGill University reported that it may be possible to create drugs that would delete memories that trigger anxiety and PTSD while keeping other important memories in place.
Researchers say that during emotional or traumatic events some memories can become encoded.
“There are associative memories, which are directly related to the event, and nonassociative memories that are created by incidental information that is present when the event occurs,” Samuel M. Schacher, PhD, professor of neuroscience at CUMC and co-author of the study paper, told Healthline.
For example, Schacher said if you are mugged while in a dark alley, and during the event you notice a mailbox in the alley, you might get nervous and anxious every time you mail something after the event.
In this scenario, being afraid of alleys is an associative memory while the mailbox is a nonassociative memory.
“Many nonassociative memories [like the mailbox] become not useful at all and prevent one from doing useful things, while associative memories are important in our lives because they teach us how we make predictions about things, and are a critical component of our learning from consequences. For example, one might avoid walking through dark alleys after being mugged in one,” explained Schacher.
Because of this, Schacher and his colleagues focused on removing nonassociative memories. However, during their research they discovered that both types of memories can be selectively reversed or mediated in part without affecting the other.
“In principle, this now allows one to address problematic memories that inhibit people from doing things in their lives that are really important. This could be a useful form of therapy for people with anxiety disorders,” said Schacher.
Edna B. Foa, PhD, professor of clinical psychology at the University of Pennsylvania, and director of the Center for the Treatment and Study of Anxiety, is not sold on this concept.
“It’s not by chance that negative or traumatic memories are fixed in our brains more than pleasant memories are,” Foa told Healthline. “If you suffer from anxiety or PTSD, traumatic memories don’t just go away, and there is an evolutionary reason for it. It’s not good to forget bad things that happen to you. Remembering them may protect you in the future.”
Schacher admitted that every manipulation of bodily function could have unintended consequences.
“One can use one’s imagination and conjure up every scenario that could go wrong. We can’t assume that a particular development is only beneficial. There may be downsides, so as we use science to improve our lives, governmental and societal regulation of the implementation and the correct use needs to be strengthened,” said Schacher.
He points to the opioid epidemic.
“These are drugs that were developed for pain relief or anesthesia during certain surgical and diagnostic tests that we routinely use now. They have done great things for us, but have also had downsides,” he said.
If the goal of erasing traumatic memories is to reduce pain, Foa said effective methods already exist.
This includes prolonged exposure, a form of cognitive behavioral therapy that focuses on facing trauma-related memories, feelings, and situations rather than avoiding them. Repeatedly talking about fears allows the person to gain control of them.
“The goal is to remember the traumatic memory but without undue pain. To think about it when you want to think about it and be able to put it away for long-term or when you don’t want to think about it,” said Foa.
She added that after participating in about 20 sessions of prolonged exposure (PE), most people are better able to cope with anxiety.
“PE is effective. I don’t think there is a base to all the enthusiasm about erasing negative traumatic memories, even if we could do it,” Foa noted.
And if there is a memory erasing drug someday, how would it differ from existing anti-anxiety meds?
Schacher said current drugs treat the final steps that lead to people being anxious.
“Most of these drugs address the final pathway that leads to anxiety, so they dampen actions of specific chemicals in our nervous system that are producing psychological consequences of anxiety: increased heart rate, sweating, frozen behavior, all the aspects of a fear response,” explained Schacher.
The possible drug reported in his research is focused on “the initial circuitry associated with the triggering,” Schacher said. “This might be a place where one can now address and make the dissociation between whatever triggers the anxiety and the anxiety effect.”
Still, Schacher believes some form of therapy would need to accompany a drug that erases memories.
“If a person is given a drug that’s short acting, it could disrupt the memory of, say, the mailbox and trauma. However, talk therapy combined with drugs is probably for most cases the best way to deal with anxiety. Drugs by themselves could work, but they are just drugs and acting in a vacuum, so to speak,” he said.
Foa believes we are farfromseeing a drug with these capabilities, while Schacher thinks it will exist during his lifetime.
However, for perspective, he points out that the study was performed on snails, which have 20 thousand neurons. Humans have 86 billion neurons.
“More studies are needed to apply this to humans,” Schacher said. “We’ve only tipped the iceberg by identifying interesting molecules that play roles in different types of memories, so in principle can be targeted, but we think there are at least dozens more. Once we have a catalog of groups of molecules that can be targeted then one can say Drug X already exists and may work for this purpose, or we can develop a new drug that can target this class of molecules.”
He is confident that the prevalence of anxiety will drive the availability of resources needed to develop this type of pharmacological therapy.
After that, will a pill for inserting memories be the focus?
While he won’t say “never,” Schacher believes it’s unlikely.
“It’s sort of been done in mice through a technique that basically gets the animal to respond in a way as if it performed a particular memory,” he said. “And artificially generated fear memories in people has happened too through unethical behavior. Think “The Manchurian Candidate.” But, I don’t see a drug for creating new memories happening anytime soon.”