Getting Rid of Bad Memories

Sandra Parshall

If you could get a simple injection or pill that would erase your worst memories and leave everything else intact, would you do it?

Few things interest me more than the mystery of human memory, and I've dwelled on it a good bit in my writing. So I was fascinated by Jonah Lehrer’s article in Wired magazine about the latest efforts to find a cure for post-traumatic stress disorder.

War veterans aren’t the only people who are crippled by PTSD. Survivors of rape, child molestation, violent muggings, fires, and natural disasters will never lead normal lives again if they can’t find a way to stop the past from poisoning the present. Few effective treatments exist to help these people, and at least one widely used approach, called critical incident stress debriefing (CISD), may have done more harm than good.

CISD has been endorsed and used for years by the Department of Defense, FEMA, the Red Cross, the United Nations, and the Israeli Army. The basic premise is that forcing a victim or survivor to recall the trauma in deep detail as soon as possible after the experience will prevent the memory from festering into PTSD. This “treatment” has been used on thousands of people, including some affected by the September 11, 2001 terrorist attacks. Unfortunately, as Lehrer reports in his article, it rarely helps, and studies show it often increases emotional suffering by reinforcing the trauma. Now psychologists have begun recommending that CISD be discontinued.

The real answer to PTSD probably lies in the neurochemistry of our brains. Scitentists have established that memories, those snapshots of the past that we either cherish or fear, are nothing more than a collection of chemicals and neurons. They aren’t cemented in place, unchangeable, waiting for our consciousness to shine a light on them. Our brains have to reconstruct a memory each time it’s called up, a process called memory reconsolidation. Our present mood or circumstances can alter our memories and our reactions to them.

In most cases, as a person’s emotions settle down after a loss or a stressful event, the memories become less heartwrenching or frightening. They can also become less accurate, as our brains change details or do a wholesale rewrite. We’re not aware this is happening, so an eyewitness to a crime may give false testimony while sincerely believing that he or she is remembering things correctly. Two people with wildly different memories of the same event can have a heated argument over whose account is accurate, when it’s likely that neither is.

But back to PTSD. In the late 1990s, a young neuroscientist named Karim Nader began examining the chemistry of memory recall. If a memory must be reconstructed each time it is called up, would blocking the chemical rebuilding process during recall destroy the memory itself? His experiments with rats proved that it would, without affecting any other memories.

Nader’s discovery, like other breakthroughs in the history of science, was greeted with scorn by his colleagues. Nobody would listen. He was shunned at conferences and couldn’t get his findings published in journals. Infuriated by this cold reception, Nader pushed on, and by 2005 his work was being taken seriously. During the same period, neuroscientist Todd Sacktor of Columbia University discovered that a neuro protein called PKMzeta plays the key role in memory formation, and without it the brain loses its ability to reconstruct long-term memories. If the production of PKMzeta is blocked while a specific memory is recalled, the memory itself may vanish.

Although treatment of PTSD seems the logical use of this breakthrough, Sacktor believes the first to benefit will be people suffering from persistent, unexplained physical pain and drug addiction. In one case, the body’s memory of pain will be erased and the cycle broken. In the other, erasing the memory of pleasure associated with drugs may take away the desire for them.

How much farther will we go with it, though, when this treatment is available beyond the testing lab? We already edit and rewrite our memories, and all of us have probably suppressed a few bad memories. But what about the big, ugly one that won’t go away, the one that invades your dreams and makes you miserable each time it intrudes on the present? Would you pay to have that memory removed forever from your brain?