Altering the Factual Content of Memories

Over the last decade, researchers have had some success identifying drugs to dampen the emotional intensity of traumatic memories. Ongoing studies are looking at whether these drugs, like propranolol (already approved by the FDA to treat high blood pressure), may help treat or prevent PTSD. In an article I wrote a few years ago, I discussed the legal and ethical issues not only of drugs that alter the emotional content of memories but also more hypothetical drugs that alter the factual content of memories.

Faster than one likely would have predicted, drugs that alter the factual content of memories are becoming less hypothetical, so to speak, at least in rats. Using a drug called ZIP that started making big headlines within the last couple of years, the memories of rats can be entirely erased. If, for example, rats are taught to avoid a certain food, researchers can inject ZIP into their brains to make them forget the aversion. Until recently at least, ZIP hasn't been used to erase a particular memory or class of memories. If you taught rats to avoid two kinds of food, you couldn't erase the aversion to just one of them. A new study in which ZIP was injected directly into a rat's spinal cord at least reinforces the possibility of more targeted interventions.

While we still have a very long way to go, we may someday identify methods of erasing particular memories in humans. Such drugs may help treat people suffering from posttraumatic stress. They may also help treat drug addiction (interestingly, one study used ZIP to make cocaine-addicated rodents forget the location where they were regularly given cocaine). These drugs may also help treat chronic pain, since chronic pain may result in part from certain associations between a person's current condition and prior states of acute pain.

I recently wrote a two-page comment in the journal Nature discussing some of the issues raised by memory-dampening drugs. While such drugs may someday require thoughtful regulation, I argue that research into memory-dampening drugs should proceed despite what I consider excessive handwringing by some bioethicists. The comment is now available here on SSRN.